JP2021055134A - Member, titanium tube forming roll, titanium tube forming apparatus and method for manufacturing titanium tube - Google Patents

Abstract

To provide a titanium tube forming roll excellent in adhesion resistance, wear resistance, peel resistance and roll surface friction coefficient.SOLUTION: A member comprises: a base material having a steel composition including, by mass%, C:1.00-2.30%, Si: 0.10-0.60%, Mn: 0.20-0.80%, P:0.030% or less, S:0.030% or less, Cr: 4.80-13.00% and the remainder consisting of iron and inevitable impurities; and a first plating layer formed on at least the rolled surface of the base material and including Ni. The first plating layer obtained by including h-BN particles of 0.5-3 mass% in a Ni-P-B plating layer including P:3.0-7.0 mass%, B:0.5-3.0 mass% and the remainder consisting of Ni and impurities has a Vickers hardness of 700-1100.SELECTED DRAWING: None

Description

The present invention relates to a member, a titanium tube forming roll, a titanium tube forming apparatus, and a method for manufacturing a titanium tube.

Usually, when manufacturing steel pipes and other metal pipes, a molding process using a molding roll is performed after welding for the purpose of ensuring high-precision outer diameter and roundness and straightening the bending of the pipe.

If the forming roll is heavily worn, accurate forming cannot be performed, and high-precision roundness cannot be ensured in the steel pipe to be formed. Therefore, the molded roll is required to have excellent wear resistance that can maintain the state of the roll surface for a long period of time.

Further, in recent years, in order to improve the productivity of steel pipes, it is often molded under harsh conditions in which the carrying speed in the molding process is increased. When operating under such conditions, due to the difference in peripheral speed between the surface of the steel pipe and the surface of the forming roll, adhesion (seizure) is likely to occur in that portion, and seizure marks may occur. When adhesion occurs between the forming roll and the steel pipe in this way, defects remain on the surface of the steel pipe, so that the forming roll must be replaced before wear or adhesion occurs.

Therefore, a roll for forming a steel pipe is required to have both wear resistance and adhesion resistance that can reduce seizure defects, and a long-life roll that can reduce the frequency of roll replacement.

Conventionally, various techniques have been studied to meet the demands for wear resistance and adhesion resistance for such molding rolls.

For example, a method of forming a ceramic film on the roll surface to secure hardness (Patent Document 1), and improving the hardness by forming one kind of surface hardened layer selected from a sulfurized nitride layer, a nitrided layer and TiC on the roll surface. (Patent Document 2), in a roll provided with a hard film on the surface, the carbides dispersed on the surface layer of the roll are miniaturized to ensure the adhesion between the roll and the hard film, and the hard film is prevented from peeling to withstand the resistance. A method for ensuring wear resistance and adhesion resistance (Patent Document 3) and the like are being studied.

In general, tool steel such as die steel is often used as the material for forming rolls, but in order to improve wear resistance and adhesion resistance, measures to use cemented carbide instead of tool steel are also available. Has been taken.

Here, titanium has been developed as a constituent material for various chemical reaction towers, containers, pipes, etc. because it has remarkably excellent corrosion resistance in various environments as compared with other metal materials. In recent years, titanium pipes are often used as heat transfer tubes for steam turbine condensers of thermal power plants and nuclear power plants and desalination equipment for evaporation method seawater.

As described above, various studies have been made on the wear resistance and adhesion resistance of the forming roll when forming the steel pipe. However, little has been said about the molding roll properties for forming titanium tubes. Further, even if the above-mentioned conventional technique is adopted for the forming roll at the time of forming the titanium tube, the wear resistance and the adhesion resistance may be insufficient.
Further, in recent years, a copper alloy is often used as a material for a titanium tube forming roll because the surface texture of the roll can be maintained well. However, since the hardness of the copper alloy is insufficient, sufficient wear resistance cannot be ensured. There was a case.

Generally, when forming a titanium tube, roundness and residual stress are controlled by forming with a plurality of multi-stage forming rolls arranged in the conveying direction.
A plurality of forming rolls are roughly classified into a driven roll and a non-driven roll. The drive roll consists of a pair of rolls that are vertically opposed to each other, and the upper and lower rolls are driven by applying a driving rotational force to pull the titanium tube in the transport direction. One of the non-driving rolls is arranged to face each other on the left and right. It consists of a pair of rolled rolls, and no driving rotational force is applied.

Here, the present inventors have investigated in more detail the characteristics required for the driven roll and the non-driven roll. As a result, it was found that the drive roll has a larger difference in peripheral speed than the non-drive roll, so that the roll surface is peeled off especially at the flange portion, and the titanium tube, which is the object to be molded, is easily scratched. Further, it was found that even when a hard film is applied for the purpose of hardening the roll surface, the hard film of the driving roll is more easily peeled off than the non-driving roll, and the roll life is shortened.
In other words, since the driving roll is used in a harsher environment than the non-driving roll, it has not only wear resistance and adhesion resistance, but also peeling resistance and excellent slip resistance of the roll surface, that is, low friction resistance. Was found to be required. Further, from the viewpoint of increasing the productivity of the titanium tube, it is desired that the low wear resistance of the roll surface is maintained for a long period of time.

Japanese Unexamined Patent Publication No. 8-174014 Japanese Unexamined Patent Publication No. 1-201443 International Publication No. 2000/51756

The present invention has been made in view of the above problems, and is excellent in abrasion resistance, adhesion resistance, peeling resistance, and friction coefficient of the roll surface in a roll used for forming and forming a titanium tube. It is an object of the present invention to provide an inexpensive titanium tube forming roll, a titanium tube forming apparatus capable of extending the life of the roll, and a method for manufacturing a titanium tube. Another object of the present invention is to provide an inexpensive member having excellent wear resistance, adhesion resistance, peeling resistance, and surface friction coefficient.

As a result of studying a titanium pipe forming roll which is inexpensive, has excellent wear resistance, adhesion resistance, peeling resistance and friction coefficient of the roll surface, and has a long roll life, the present inventors usually use it as a material for the forming roll. The alloy tool steel used is used as a base material, and by forming a first plating layer mainly composed of Ni, containing B and P, and further containing h-BN particles on the base material, wear resistance and abrasion resistance are formed. It was found that it is possible to provide a roll having a long life, which can achieve both wear resistance, peel resistance and low friction on the roll surface, and can reduce the frequency of roll replacement. Similarly, it has been found that it is possible to provide a member that is inexpensive and has excellent wear resistance, adhesion resistance, peel resistance, and surface friction coefficient.
The gist of the present invention is as follows.

(1) By mass%
C: 1.00 to 2.30%,
Si: 0.10 to 0.60%,
Mn: 0.25 to 0.80%,
P: 0.030% or less,
S: 0.030% or less,
Cr: 4.80 to 13.00%,
Mo: 0 to 1.20%,
V: 0-1.00%,
W: Contains 0 to 0.80%,
With a base material having a chemical composition in which the balance is iron and impurities,
A first plating layer containing Ni formed on the surface of the base material is provided.
The first plating layer contains P: 3.0 to 7.0% by mass and B: 0.5 to 3.0% by mass, and the balance is a Ni-P-B plating layer composed of Ni and impurities. A member containing 0.5 to 3% by mass of h-BN particles and having a Vickers hardness in the range of 700 to 1100.
(2) By mass%
C: 1.00 to 2.30%,
Si: 0.10 to 0.60%,
Mn: 0.25 to 0.80%,
P: 0.030% or less,
S: 0.030% or less,
Cr: 4.80 to 13.00%,
Mo: 0 to 1.20%,
V: 0-1.00%,
W: Contains 0 to 0.80%,
With a base material having a chemical composition in which the balance is iron and impurities,
A first plating layer containing Ni formed on at least the rolled surface of the base material is provided.
The first plating layer contains P: 3.0 to 7.0% by mass and B: 0.5 to 3.0% by mass, and the balance is a Ni-P-B plating layer composed of Ni and impurities. A titanium tube forming roll containing 0.5 to 3% by mass of h-BN particles and having a Vickers hardness in the range of 700 to 1100.
(3) The titanium tube forming roll according to (2), wherein the Vickers hardness of the first plating layer is in the range of more than 800 to 1100.
(4) The titanium tube forming roll according to (2), wherein the Vickers hardness of the first plating layer is in the range of 700 to 800.
(5) A second plating layer containing Ni is provided between the first plating layer and the base material.
The second plating layer is a Ni-B plating layer containing B: 0.3 to 3.0% by mass, the balance being Ni and impurities, and a Vickers hardness of 700 to 820 (2) to (2) to ( The titanium tube forming roll according to any one of 4).
(6) A second plating layer containing Ni is provided between the first plating layer and the base material.
The second plating layer is a Ni-B plating layer containing B: 0.3 to 3.0% by mass, the balance being Ni and impurities, and a Vickers hardness of 900 to 1100 (2) to ( The titanium tube forming roll according to any one of 4).
(7) A second plating layer containing Ni is provided between the first plating layer and the base material.
The second plating layer is a Ni-P plating layer containing P: 3.0 to 10.0% by mass, the balance being Ni and impurities, and a Vickers hardness of 700 to 1100 (2) to ( The titanium tube forming roll according to any one of 4).
(8) A second plating layer containing Ni is provided between the first plating layer and the base material.
The second plating layer contains P: 3.0 to 10.0% by mass and B: 0.5 to 3.0% by mass, the balance is composed of Ni and impurities, and the Vickers hardness is 900 to 1100. The titanium tube forming roll according to any one of (2) to (4), which is a Ni-BP plating layer.
(9) A second plating layer containing Ni is provided between the first plating layer and the base material.
The second plating layer contains P: 3.0 to 10.0% by mass and B: 0.5 to 3.0% by mass, the balance is composed of Ni and impurities, and the Vickers hardness is 700 to 800. The titanium tube forming roll according to any one of (2) to (4), which is a Ni-BP plating layer.
(10) Any one of (2) to (9) in which an electric Ni plating layer having a thickness of 0.1 to 1 μm is formed between the base material and the first plating layer or the second plating layer. The titanium tube forming roll according to the section.
(11) The titanium tube forming roll according to any one of (2) to (10), wherein the thickness of the first plating layer is in the range of 1 to 10 μm.
(12) The titanium tube forming roll according to any one of (2) to (11), wherein the thickness of the second plating layer is in the range of 1 to 2 μm.
(13) The titanium tube forming roll according to any one of (2) to (12), wherein the Vickers hardness of the base material is 550 to 650.
(14) The titanium tube forming roll according to any one of (2) to (13), wherein a nitride layer is formed on the rolled surface of the base material.
(15) The titanium tube forming roll according to (14), wherein the nitrided layer has a thickness of 0.5 μm to 50.0 μm.
(16) The titanium tube forming roll according to (14) or (15), wherein the average nitrogen concentration of the nitrided layer is 0.10 to 1.0% by mass.
(17) The titanium tube forming roll according to any one of (14) to (16), which has a concentration gradient in which the nitrogen concentration distribution in the nitrided layer decreases from the surface layer of the nitrided layer in the depth direction.
(18) The base material is based on mass%.
Mo: 0.70 to 1.20%,
V: 0.15-1.00%,
W: The titanium tube forming roll according to any one of (2) to (17), which contains one or more selected from 0.60 to 0.80%.
(19) A hole-shaped roll in which a semicircular roll recess is provided over the entire circumference of the roll body.
The titanium tube forming roll according to any one of (2) to (18), wherein the rolled surface is the surface of the roll recess.
(20) The roll main body includes a roll central portion and a pair of rotating flange portions arranged on both sides of the roll central portion so as to be rotatable with respect to the roll central portion.
The titanium tube forming roll according to (19), wherein the roll recess is divided by the roll central portion and the rotating flange portion.
(21) The roll central portion is fixed to a rotating shaft that drives the roll body, and the rotating flange portion is rotatable with respect to the rotating shaft and the roll central portion (20). ). The titanium tube forming roll.
(22) The roll central portion is provided with a base portion and a protruding portion protruding from the roll width direction central portion of the base portion in the roll outer peripheral direction.
The rotating flange portions are located on the base portion and are arranged on both sides of the protruding portion in the roll width direction.
The titanium tube forming roll according to (20) or (21), wherein a first bearing portion is provided between the base portion of the roll central portion and the rotating flange portion.
(23) The facing surfaces of the roll center portion facing each other between the base portion and the rotating flange portion are the raceway surfaces of the rolling elements of the first bearing portion, and the facing surfaces are the facing surfaces. The titanium tube forming roll according to (22), comprising the first plating layer, or any of the first plating layer and the second plating layer.
(24) A second fixed flange portion arranged on both sides of the pair of the rotating flange portions in the roll width direction and fixed to the center portion of the roll, and a second arranged between the fixed flange portion and the rotating flange portion. The titanium tube forming roll according to any one of (20) to (23), comprising two bearing portions.
(25) The facing surfaces facing each other between the fixed flange portion and the rotating flange portion are the raceway surfaces of the rolling elements of the second bearing portion, and the facing surfaces are the first plating. The titanium tube forming roll according to (24), comprising a layer or the first plating layer and the second plating layer.
(26) The titanium tube forming roll according to (24) or (25), wherein the fixed flange portion is provided with a draw screw portion for attracting and fixing the rotating flange portion.
(27) Two titanium tube forming rolls according to any one of (19) to (26) are provided.
The two titanium tube forming rolls are arranged so that their respective roll recesses face each other, and the respective roll recesses are arranged so as to be in contact with each other on the same circumference of the outer peripheral surface of the titanium tube to be molded. Titanium tube molding equipment.
(28) A roll body made of the base material is provided.
The roll body is provided with a roll recess having an arcuate cross-sectional view provided over the entire circumference thereof and both sides of the roll recess in the width direction, and the roll body is rotated toward the outside in the roll width direction of the roll body. It has an inclined part that inclines toward the shaft side,
The surface of the roll recess is the rolled surface, and the surface of the roll recess is provided with either the first plating layer or the first plating layer and the second plating layer.
Further, any one of (2) to (18), wherein the surface of the inclined portion is also provided with the first plating layer, or any of the first plating layer and the second plating layer. Titanium tube forming roll according to.
(29) The four titanium tube forming rolls according to (28) are provided.
Of the four titanium tube forming rolls, the roll recesses of the two titanium tube forming rolls are arranged so as to face each other, and the roll recesses of the other two titanium tube forming rolls face each other. The roll recesses of the four titanium tube forming rolls are arranged so as to be in contact with each other on the same circumference of the outer peripheral surface of the titanium tube to be formed, and the titanium tube forming rolls adjacent to each other are further arranged. A titanium tube forming device in which inclined parts face each other.
(30) A titanium tube forming apparatus provided with the titanium tube forming roll according to any one of (2) to (26) or (28), wherein the titanium tube forming is performed on a part of the titanium tube forming roll. A titanium tube forming device having a lubricating nozzle that supplies a lubricant inside.
(31) The titanium pipe molding apparatus according to (30), wherein the position of the lubrication nozzle can be changed according to the molding size of the titanium pipe.
(32) The titanium tube forming apparatus according to (30) or (31), wherein the position of the lubricating nozzle can be changed according to the diameter of the titanium tube forming roll.
(33) The titanium tube molding apparatus according to any one of (30) to (32), wherein the position and orientation of the lubrication nozzle can be arbitrarily adjusted.
(34) The titanium tube forming apparatus according to any one of (30) to (33), wherein the lubricating nozzle is a tube having an inner diameter of 0.5 to 3.0 mm.
(35) In any one of (30) to (32), a soluble oil-based lubricant is used as the lubricant, and the lubricant is supplied by dropping a small amount at 1.0 to 20.0 ml / hr or less. The titanium tube forming apparatus according to the above.
(36) A method for producing a titanium tube, which is formed by using the titanium tube forming roll according to any one of (2) to (26) or (28).
(37) A method for producing a titanium tube, which is formed by using the titanium tube forming apparatus according to any one of (27) or (29) to (35).

According to the present invention, in a roll used for molding and forming a titanium tube, an inexpensive titanium tube forming roll having excellent wear resistance, adhesion resistance, peeling resistance, and friction coefficient of the roll surface, In addition, it is possible to provide a titanium tube forming apparatus and a method for manufacturing a titanium tube, which can extend the life of the roll. Further, according to the present invention, it is possible to provide an inexpensive member having excellent wear resistance, adhesion resistance, peeling resistance, and surface friction coefficient.

FIG. 1 is a schematic side view showing a method for manufacturing a titanium tube using a titanium tube forming roll, which is the first example of the embodiment of the present invention. FIG. 2 is a front schematic view showing a titanium tube forming roll according to an embodiment of the present invention. FIG. 3 is a schematic front sectional view showing a titanium tube forming roll which is a second example of the embodiment of the present invention. FIG. 4 is a front cross-sectional exploded schematic view showing a titanium tube forming roll which is a second example of the embodiment of the present invention. FIG. 5 is a schematic front sectional view showing another example of the titanium tube forming roll of the present embodiment. FIG. 6 is a schematic front sectional view showing still another example of the titanium tube forming roll of the present embodiment. FIG. 7 is a schematic front sectional view showing a titanium tube forming roll which is a third example of the embodiment of the present invention. FIG. 8 is a front schematic view for explaining a lubrication method and an apparatus using a titanium tube forming apparatus. FIG. 9 is a front schematic view for explaining an arrangement example of the lubrication nozzle shown in FIG. 10 is a schematic top view and a schematic side view for explaining the width direction adjusting mechanism and the vertical direction adjusting mechanism of the lubrication nozzle shown in FIG. FIG. 11 is a diagram showing a structure of a roller pump (lubrication supply device) for dropping a small amount of lubricant using a lubrication nozzle. FIG. 12 is a front schematic view showing another example of the titanium tube forming apparatus of this embodiment. FIG. 13 is a schematic side view showing another example of the titanium tube forming apparatus of the present embodiment. FIG. 14 is a front schematic view showing a main part of another example of the titanium tube molding apparatus of this embodiment. 15 is a schematic view showing a titanium tube forming roll provided in the titanium tube forming apparatus shown in FIGS. 12 to 13, where FIG. 15A is a partial cross-sectional front view and FIG. 15B is a side view.

Hereinafter, a member, a titanium tube forming roll, a titanium tube forming apparatus, and a method for manufacturing a titanium tube according to an embodiment of the present invention will be described.

The members of the present embodiment are, in mass%, C: 1.00 to 2.30%, Si: 0.10 to 0.60%, Mn: 0.25 to 0.80%, P: 0.030%. Hereinafter, S: 0.030% or less, Cr: 4.80 to 13.00%, Mo: 0 to 1.20%, V: 0 to 1.00%, W: 0 to 0.80% are contained. A base material having a chemical composition in which the balance is iron and impurities, and a first plating layer containing Ni formed on the surface of the base material are provided, and the first plating layer has P: 3.0 to 7. 0.5 to 3% by mass of h-BN particles are contained in the Ni-P-B plating layer containing 0% by mass and B: 0.5 to 3.0% by mass and the balance being Ni and impurities. The Vickers hardness is in the range of 700 to 1100. A second plating layer may be provided between the base material and the first plating layer.

Since the first plating layer is formed on the surface of the base material, the member of the present embodiment can provide a member that is inexpensive and has excellent wear resistance, adhesion resistance, peeling resistance, and surface friction coefficient. ..

The coating structure of the first plating layer, the second plating layer, etc. in the present invention can be used in various members, for example, a titanium pipe forming roll, a titanium or stainless steel fuel pipe processing tool, a titanium or stainless steel pipe. Bending tools (for example, rotary pull bending rollers, inner surface tools and cores), dies and shaft push dies for titanium hydrofoam processing, press dies for deep rolling of titanium materials (sinks, cameras, mobile phones) , For housings such as cameras, for automobile wheels), dies for forming fuel tanks for automobiles and two-wheeled vehicles, guide rolls for rolling, rollers for transportation, titanium pipes, pipes with fins, and tools for fin processing, Forming rolls for welded pipes, open channel forming rolls for forming sashes, metal roofs, etc., press dies for titanium tile forming, reducing roller tools for pipe end face processing (for diameter reduction, taper processing, flare) It can be applied to pipe expansion tools for fixing face plates for heat exchange tubes, rollers for repeatedly bending titanium shape straighteners (for rolling shape straightening), cold forging tools and dies.

Hereinafter, a titanium tube forming roll will be described as an example of the member. In addition, since this embodiment is described in detail in order to better understand the gist of the titanium tube forming roll of the present invention, the present invention is not limited unless otherwise specified.

[First example of a titanium tube forming roll, a titanium tube forming apparatus, and a method for manufacturing a titanium tube]
FIG. 1 shows a side schematic view of a titanium tube forming roll, a titanium tube forming apparatus, and a method for manufacturing a titanium tube using a titanium tube forming roll, which is the first example of the present embodiment. Further, FIG. 2 shows a schematic front view of the titanium tube forming roll. As shown in FIGS. 1 and 2, the titanium tube forming roll 1 of the present embodiment is a so-called hole-shaped roll, and is a roll body (base material) 2 made of a steel material and a rotating shaft 3 inserted through the roll body 2. And are provided. The roll surface 2a of the roll body 2 is provided with a roll recess 4 formed in an arc shape in a cross-sectional view, more specifically in a semicircular shape, over the entire circumference of the roll body 2. Further, a first plating layer is provided on the surface of the roll recess 4. Further, a second plating layer may be formed between the surface of the roll recess 4 and the first plating layer.

As shown in FIG. 1, when the titanium tube 10 which is a hollow cylindrical tube is formed into a perfect circle, for example, the rotation axes 3 of the pair of titanium tube forming rolls 1 are arranged horizontally and each rotation. Arrange the axes 3 so that they are parallel to each other. In this way, the titanium tube forming apparatus is configured. The titanium tube forming apparatus of FIG. 1 is composed of two titanium tube forming rolls 1, and each titanium tube forming roll 1 is arranged so that the roll recesses 4 face each other, and each roll recess 4 is titanium to be formed. It is arranged so as to be in contact with the same circumference of the outer peripheral surface of the pipe 10. Then, the titanium tube 10 before molding is passed between the pair of titanium tube forming rolls 1 arranged one above the other. Between the pair of titanium tube forming rolls 1, a hole portion having a perfect circular shape when viewed from the front side is provided by the roll recess 4 of each titanium tube forming roll 1, and this hole portion is provided with a titanium tube. When the 10 passes, the titanium tube 10 is formed into a perfect circle. The arrangement of the titanium tube forming roll 1 is not limited to the vertical direction, and may be horizontal or diagonal. Further, as shown in FIG. 1, the rotating shafts 3 of the pair of titanium tube forming rolls 1 are arranged horizontally, and the rotating axes 3 are arranged so as to be parallel to each other. The part is composed.

The rotating shaft 3 of the titanium tube forming roll 1 may be a driving shaft driven by a driving means or a non-driving shaft. Even if the titanium tube forming roll 1 of the present embodiment is connected to the drive shaft, it is provided with the first plating layer, so that it has abrasion resistance, adhesion resistance, peeling resistance, and a friction coefficient of the roll surface. Will be excellent.

The base material of the roll body 2 of the titanium tube forming roll 1 according to the present embodiment is C: 1.00 to 2.30%, Si: 0.10 to 0.60%, Mn: 0.20 in mass%. From a steel material containing ~ 0.80%, P: 0.030% or less, S: 0.030% or less, Cr: 4.80 to 13.00%, and having a steel composition in which the balance is composed of iron and impurities. Become.
A first plating layer is provided on the surface of at least the roll recess 4 of the titanium tube forming roll 1 made of this base material.
The first plating layer contains P: 3.0 to 7.0% by mass and B: 0.5 to 3.0% by mass, and the balance is 0 in the Ni-P-B plating layer composed of Ni and impurities. It contains 5 to 3% by mass of h-BN particles. The Vickers hardness of the first plating layer is in the range of 700 to 1100.
The Vickers hardness of the first plating layer may be in the range of more than 800 to 1100.
The Vickers hardness of the first plating layer may be in the range of 700 to 800.
A second plating layer containing Ni may be provided between the first plating layer and the base material.
The second plating layer may be a Ni-B plating layer containing B: 0.3 to 3.0% by mass, the balance being Ni and impurities, and a Vickers hardness of 700 to 820.
Further, the second plating layer may be a Ni−B plating layer containing B: 0.3 to 3.0% by mass, the balance being Ni and impurities, and a Vickers hardness of 900 to 1100.
Further, the second plating layer may be a Ni-P plating layer containing P: 3.0 to 10.0% by mass, the balance being Ni and impurities, and a Vickers hardness of 700 to 1100.
The second plating layer contains P: 3.0 to 10.0% by mass and B: 0.5 to 3.0% by mass, the balance is composed of Ni and impurities, and the Vickers hardness is 900 to 1100. The Ni-BP plating layer may be used.
The second plating layer contains P: 3.0 to 10.0% by mass and B: 0.5 to 3.0% by mass, the balance is composed of Ni and impurities, and the Vickers hardness is 700 to 800. The Ni-BP plating layer may be used.
An electric Ni plating layer having a thickness of 0.1 to 1 μm may be formed between the base material and the first plating layer.
The thickness of the first plating layer may be in the range of 1 to 10 μm. The thickness of the second plating layer may be in the range of 1 to 2 μm.
The Vickers hardness of the base material may be 550 to 650.
A nitride layer may be formed on the rolled surface of the base material. The thickness of the nitrided layer may be 0.5 μm to 50.0 μm. The average nitrogen concentration of the nitrided layer may be 0.10 to 1.0% by mass. The nitrogen concentration distribution in the nitrided layer may have a concentration gradient that decreases in the depth direction from the surface layer of the nitrided layer.
The titanium tube forming roll in this embodiment will be described in detail below.

In the following description, a film composed of the first plating layer or a film formed by laminating the first plating layer and the second plating layer may be referred to as a surface treatment film.

[Structure of base material]
First, regarding the base material composition of the titanium tube forming roll 1 of the present embodiment, the reasons for limiting each element will be described in detail.
In the following description, unless otherwise specified, "%" represents mass%. In addition, the balance of the basic components and selected elements shown below consists of iron and unavoidable impurities.

(C: carbon) 1.00 to 2.30%
C is an element necessary for forming carbides and ensuring hardness. Further, since it forms a hard carbide by combining with Cr, Mo, V and the like, it is important as an element that enhances quenching and tempering hardness and constitutes wear resistance. Therefore, in this embodiment, C is contained in an amount of 1.00% or more. From the viewpoint of ensuring hardness, it is preferable to contain 1.40% or more.
On the other hand, when the C content exceeds 2.30%, the toughness is significantly deteriorated. Therefore, in the present embodiment, the C content is limited to 2.30% or less. From the viewpoint of ensuring toughness, the upper limit of the C content is preferably 2.20%, more preferably 2.00% or less.

(Si: Silicon) 0.10 to 0.60%
Si is contained as an antacid. Further, Si is contained because it has an effect of increasing softening resistance during high-temperature tempering. From these viewpoints, Si is contained in an amount of 0.10% or more. On the other hand, if the Si content exceeds 0.60%, the hot workability and toughness may be lowered, and non-metal inclusions may be increased. Therefore, the Si content is set to 0.60% or less. From the viewpoint of ensuring toughness, the upper limit of the Si content is preferably 0.50%.

(Mn: manganese) 0.25 to 0.80%
Mn is an element having a deoxidizing effect like Si, and is an element that improves hardenability and at the same time increases retained austenite. From this point of view, Mn is contained in an amount of 0.20% or more. From the viewpoint of ensuring hardness, it is preferable to contain 0.30 or more. In consideration of the balance with toughness, the upper limit of the amount of Mn is set to 0.80% in this embodiment. Preferably, it is 0.60% or less.

(P: Phosphorus) 0.030% or less (S: Sulfur) 0.030% or less Both P and S are impurity elements that are preferably not present in steel. Therefore, the content of both P and S is limited to 0.030% or less. Preferably, it is limited to 0.020% or less.

(Cr: Chromium) 4.80 to 13.00%
Cr is a demanding element that improves wear resistance by binding to C and forming carbides. The amount of Cr is 4.80% or more, preferably 8.00% or more, and more preferably 11.00% or more.
On the other hand, if Cr is excessively contained, the toughness may deteriorate due to the formation of coarse carbides, so the upper limit of the amount of Cr is set to 13.000% or less. It is preferably 12.50% or less.

In the present embodiment, the component composition may further contain one or more of Mo: 0 to 1.20% and V: 0 to 1.00%.

(Mo: molybdenum) 0 to 1.20%
Mo has the effect of improving temper softening resistance and imparting wear resistance by forming carbides. From these viewpoints, Mo is preferably contained in an amount of 0.70% or more, more preferably 0.80% or more.
On the other hand, if Mo is excessively contained, the toughness may be deteriorated. From this, it is preferable that Mo is contained in an amount of 1.20% or less, and more preferably 1.10% or less.

(V: vanadium) 0-1.00%
V is effective for improving the hardenability of the base material, suppressing tempering and softening, and further refining the carbide. Therefore, V is preferably contained in an amount of 0.15% or more, more preferably 0.20% or more.
On the other hand, if V is excessively contained, cold workability may be impaired. Therefore, V is preferably contained in an amount of 1.00% or less, more preferably 0.50% or less.

Further, in the present embodiment, W: 0 to 0.80% may be further contained in the above component composition.

(W: Tungsten) 0 to 0.80%
Like V, W is effective in improving the hardenability of the base material, suppressing tempering and softening, and further miniaturizing carbides. Therefore, it is preferable that W is contained in an amount of 0.6% or more. On the other hand, if W is excessively contained, cold workability may be impaired. Therefore, it is preferable that W is contained in an amount of 0.80% or less.

In the present embodiment, the balance other than the above-mentioned elements is substantially composed of Fe, and impurities and other elements that do not impair the action and effect of the present invention can be contained in a trace amount.

In the titanium tube forming roll 1 of the present embodiment, a material having the above-mentioned component composition is used as the material of the base material, but among them, from the viewpoint of ensuring a good balance between wear resistance and adhesion resistance at a lower cost. Therefore, it is preferable to use SKD1, SKD2, SKD10, SKD11 or SKD12 (all within the above component composition range) specified in JIS G 4404, and among these, it is more preferable to use SKD11.

The hardness of the base material having the above-mentioned component composition is about 550 to 650 in Vickers hardness. That is, when the titanium tube 10 is formed with the base material as it is without forming a film or the like on the base material, the hardness of the base material itself can be secured, so that the wear resistance is relatively good. However, with regard to adhesion resistance, the material of the titanium tube is seized on the base material, and a large number of flaws occur in the titanium tube forming roll 1.

Therefore, the present inventors have focused on a plating layer containing Ni as a material having excellent adhesion resistance to titanium pipes and excellent wear resistance. It has been found that when a plating layer containing Ni is selected as the material of the pore-shaped roll when the titanium tube is cold-worked, Ni exhibits adhesion resistance to titanium. Furthermore, it has been found that it is effective and important to include h-BN particles in the plating layer in order to impart lubricity to the plating layer containing Ni. By increasing the lubricity to titanium, it becomes possible to further improve the adhesion resistance. Furthermore, it has been found that the adhesion of the first plating layer can be improved by forming another plating layer between the first plating layer containing h-BN particles and the base material. Therefore, in the present embodiment, as the titanium tube forming roll, a roll in which the first plating layer is laminated on the base material is used. A layer formed by laminating a second plating layer and a first plating layer may be used. Hereinafter, the first plating layer and the second plating layer will be described.

The first plating layer is a plating layer mainly containing Ni, and h-BN particles are contained inside the plating layer. The first plating layer is preferably a plating formed by an electroless method, and in particular, a Ni-P-B plating layer containing P and B is preferable. The Ni-P-B plating layer formed by the electroless plating method can obtain a plating layer having stable quality even when h-BN particles are contained in the plating bath. Therefore, the first plating layer preferably contains h-BN particles in the Ni-P-B plating layer.

The composition of the Ni-P-B plating layer constituting the first plating layer contains P: 3.0 to 7.0% by mass and B: 0.5 to 3.0% by mass, and the balance is Ni and impurities. Consists of. The smaller the amount of P or B, the better the Vickers hardness of the first plating layer, but if the amount of P or B is too small, the density of the plating decreases. Therefore, the amount of P should be 3.0% by mass or more. B is 0.5% or more. If the amount of P or B becomes excessive, the Vickers hardness decreases. Therefore, the amount of P is 7.0% by mass or less, and the amount of B is 3.0% or less. A more preferable range of the amount of P is 4.0 to 7.0% by mass. A more preferable range of the amount of B is 0.5 to 2.0% by mass.

By containing hexagonal h-BN particles in the first plating layer, the lubricity of the first plating layer with respect to the titanium tube can be improved, and the adhesion of the titanium tube when using the titanium tube forming roll can be prevented. .. The content of h-BN particles is in the range of 0.5 to 3.0% by mass in terms of mass ratio with respect to the first plating layer. By setting the h-BN particles to 0.5% by mass or more, the lubricity of the first plating layer can be sufficiently enhanced, and adhesion of the titanium tube when using the titanium tube forming roll can be prevented. Further, by setting the h-BN particles to 3.0% by mass or less, it is possible to prevent a decrease in Vickers hardness of the first plating layer. A more preferable range of the content of h-BN particles is a range of 0.7 to 2.5% by mass ratio in the first plating layer.

The average particle size of the h-BN particles is preferably in the range of 0.1 to 0.3 μm. By setting the average particle size of the h-BN particles to 0.1 μm or more, it is possible to prevent agglomeration of the h-BN particles and improve the density of the first plating layer. Further, the density of the first plating layer can be improved by setting the average particle size of the h-BN particles to 0.3 μm or less.

In addition to hexagonal h-BN, BN (boron nitride) also includes cubic c-BN, but when c-BN particles are contained in the Ni-P-B plating layer, , The lubricity of the plating layer with respect to the titanium tube cannot be sufficiently obtained. Therefore, in the present embodiment, hexagonal h-BN particles are contained in the first plating layer.

The Vickers hardness of the first plating layer is in the range of 700 to 1100. Since the first plating layer contains h-BN particles, the Vickers hardness is relatively low, but due to the effect of improving the lubricity by the h-BN particles, even if the Vickers hardness is low, the wear resistance and resistance to the titanium tube are relatively low. Adhesion can be sufficiently enhanced. When the Vickers hardness of the first plating layer is 700 or more, the wear resistance and the adhesion resistance can be sufficiently improved. Further, since the Vickers hardness of the first plating layer is affected by the content of h-BN particles, it is necessary to reduce the content of h-BN particles in order to increase the Vickers hardness of the first plating layer. Yes, in this case the lubricity is reduced. Therefore, it is preferable that the Vickers hardness of the first plating layer is increased as much as possible while ensuring lubricity. Therefore, the upper limit of the Vickers hardness of the first plating layer is 1100 or less.

Further, the Vickers hardness of the first plating layer can be further adjusted depending on whether or not heat treatment is performed after the formation of the first plating layer. That is, the Vickers hardness of the first plating layer can be in the range of 700 to 800 when the heat treatment is not performed after the formation of the first plating layer, while the Vickers hardness of the first plating layer exceeds 800 when the heat treatment is performed. It can be adjusted in the range of ~ 1100. It can also be adjusted in the range of 820 to 1070 depending on the heat treatment conditions. However, when processing a titanium tube, it is preferable that the Vickers hardness is slightly low. That is, the range of 700 to 800, preferably the range of 700 to 780 is preferable.

The thickness of the first plating layer is preferably in the range of 1 to 10 μm. By setting the first plating layer to 1 μm or more, the wear resistance to the titanium tube can be sufficiently improved. Further, by setting the first plating layer to 10 μm or less, cracks do not occur in the first plating layer even when a load is applied when using the titanium tube roll. From these facts, the thickness of the first plating layer is preferably 1 μm to 10 μm, more preferably 2 μm to 8 μm, and further preferably 3 to 7 μm.

The first plating layer is preferably formed by an electroless plating method. At that time, it is preferable to disperse the h-BN particles in the plating bath. The dispersion concentration of the h-BN particles in the plating bath may be adjusted so that the h-BN particles are contained in the range of 0.5 to 3.0% by mass with respect to the Ni-P-B plating layer. The first plating layer formed by the electroless plating method may or may not be heat-treated. Examples of the heat treatment conditions include conditions at 300 to 500 ° C. for 0.5 to 3 hours. By setting the heat treatment temperature to 300 ° C., the Vickers hardness of the first plating layer can be sufficiently increased. Further, even if the heat treatment temperature exceeds 500 ° C., the hardness cannot be expected to be improved and the base material may soften. Therefore, the upper limit is set to 500 ° C. or less.

Further, although the titanium tube roll has a relatively complicated shape, the first plating layer can be formed to have a uniform thickness by adopting the electroless plating method.

The first plating layer is a plating layer that comes into contact with the titanium tube when the roll is used. Titanium is said to be a metal that easily adheres to other metals, but by including h-BN particles in the first plating layer, the adhesion of titanium can be significantly suppressed. Therefore, in the present embodiment, a plating layer mainly composed of Ni is adopted as a hard layer for preventing wear of the base material of the titanium tube forming roll.

As described above, in the titanium tube forming roll of the present embodiment, the first plating layer is laminated on the base material, and the first plating layer and the second plating layer may be laminated. That is, a second plating layer may be provided between the base material and the first plating layer. Hereinafter, the second plating layer will be described.

The second plating layer is a plating layer containing Ni. The second plating layer is preferably plating formed by an electroless method. In particular, the second plating layer is a Ni-P plating layer containing P, a Ni-B plating layer containing B, or a Ni-BP plating containing P and B among the Ni plating formed by the electroless method. Layers are preferred.

The Ni-P plating layer is preferably a heat-treated plating layer. Since the reducing agent contained in the plating bath of the Ni-P plating layer is relatively stable, a plating layer having stable quality can be obtained. Further, the Ni-P plating layer after the heat treatment has the same or slightly higher Vickers hardness than the Ni-B plating layer, and thus has excellent wear resistance. Therefore, the type of the second plating layer may be selected according to the required performance.

The Ni-B plating layer and the Ni-BP plating layer may be a heat-treated plating layer or a non-heat-treated plating layer.

When the second plating layer is a Ni-P plating layer, the composition preferably contains 3.0 to 10.0% by mass of P, and the balance is Ni and impurities. The smaller the amount of P, the better the Vickers hardness of the second plating layer, but if the amount of P is too small, the density of the plating decreases, so the amount of P is preferably 3.0% by mass or more. Since the Vickers hardness decreases when the amount of P becomes excessive, the amount of P is preferably 10.0% by mass or less. A more preferable range of the amount of P is 4.0 to 7.0% by mass.

When the second plating layer is a Ni-B plating layer, the composition preferably contains 0.3 to 3.0% by mass of B, and the balance is Ni and impurities. The smaller the amount of B, the better the Vickers hardness of the second plating layer, but if the amount of B is too small, the density of the plating decreases, so the amount of B is preferably 0.3% by mass or more. Since the Vickers hardness decreases when the amount of B becomes excessive, the amount of B is preferably 3.0% by mass or less. A more preferable range of the amount of B is 0.5 to 2.0% by mass.

When the second plating layer is a Ni-BP plating layer, the composition contains 3.0 to 10.0% by mass of P, 0.3 to 3.0% by mass of B, and the balance is Ni and It preferably consists of impurities. The smaller the amount of B or P, the better the Vickers hardness of the second plating layer, but if the amount of B or P is too small, the density of the plating decreases, so the amount of P is 3.0% by mass or more and B. The amount is preferably 0.3% by mass or more. If the amount of B or P becomes excessive, the Vickers hardness decreases. Therefore, the amount of P is preferably 10.0% by mass or less, and the amount of B is preferably 3.0% by mass or less. A more preferable range of the amount of P is 4.0 to 7.0% by mass, and a more preferable range of the amount of B is 0.5 to 2.0% by mass.

When the second plating layer is a Ni-P plating layer, the Vickers hardness is preferably in the range of 700 to 1100.

When the second plating layer is a Ni-B plating layer and the second plating layer is not heat-treated, the Vickers hardness is preferably in the range of 700 to 820. Further, the second plating layer is a Ni-B plating layer, and the Vickers hardness when the second plating layer is heat-treated is preferably in the range of 900 to 1100.

When the second plating layer is a Ni-BP plating layer and the second plating layer is not heat-treated, the Vickers hardness is preferably in the range of 700 to 800. Further, the second plating layer is a Ni-BP plating layer, and the Vickers hardness when the second plating layer is heat-treated is preferably in the range of 900 to 1100.

The second plating layer has a higher Vickers hardness than the base material, and cracks are less likely to occur when a rolling load is applied. Further, even when the first plating layer is worn, the wear resistance can be ensured by having the second plating layer. If the Vickers hardness of the second plating layer is 700 or more, the wear resistance can be improved. On the other hand, if the Vickers hardness is too high, cracks may occur. Therefore, the upper limit of the Ni-P plating layer is set to 1100 or less, the upper limit of the Ni-B plating layer is set to 820 or less or 1100 or less, and Ni-B is set. The upper limit of the -P plating layer is 820 or less or 1100 or less. For example, if you want to secure the Vickers hardness in the range of 700 to 800 or 700 to 820, select the Ni-P plating layer, the Ni-B plating layer without heat treatment, or the Ni-BP plating layer without heat treatment. If it is desired to secure a Vickers hardness in the range of 900 to 1100, it is preferable to select a Ni-B plating layer with heat treatment or a Ni-BP plating layer with heat treatment.

The thickness of the second plating layer is preferably in the range of 1 to 2 μm. By setting the thickness of the second plating layer to 1 μm or more, the smoothness of the surface of the plating layer can be improved, and the wear resistance and adhesion resistance can be sufficiently improved. Further, by setting the thickness of the second plating layer to 2 μm or less, cracks do not occur in the second plating layer even when a load is applied when the roll is used. For these reasons, the thickness of the second plating layer is preferably 1 μm to 2 μm. A more preferable range of the thickness of the second plating layer is 1.2 to 1.8 μm.

The second plating layer is preferably formed by an electroless plating method. Since the Vickers hardness of the plating layer formed by the electroless plating method remains relatively low, heat treatment may be performed after the formation of the second plating layer in order to increase the Vickers hardness. Examples of the heat treatment conditions include a heat treatment temperature of 300 to 500 ° C. and a heat treatment time of 0.5 to 3 hours. By setting the heat treatment temperature to 300 ° C. or higher, the Vickers hardness of the second plating layer can be sufficiently increased. Further, by setting the heat treatment temperature to 500 ° C. or lower, softening of the base material due to tempering can be prevented. By setting the heat treatment time in the range of 0.5 to 3 hours, the Vickers hardness of the second plating layer can be sufficiently improved.

Further, even when the surface roughness of the base material is relatively large, the surface of the base material is smoothed and the surface of the second plating layer is smoothed by forming the second plating layer by the electroless plating method. it can. Therefore, when re-plating the first plating layer and the second plating layer when regenerating the titanium tube roll whose service life has expired, it may be possible to omit the adjustment of the surface roughness of the base material, and the titanium tube forming roll may be used. Productivity can be increased. Further, although the titanium tube roll has a relatively complicated shape, the second plating layer can be formed to have a uniform thickness by adopting the electroless plating method.

The second plating layer is a base layer of the first plating layer, and is formed to ensure the adhesion of the first plating layer. Since the first plating layer contains h-BN particles, the adhesion to the substrate is slightly low. On the other hand, since the second plating layer does not contain h-BN particles, the adhesion to the substrate is relatively high. Further, since the second plating layer is a plating layer mainly composed of Ni like the second plating layer, the adhesion to the second plating layer is relatively high. Therefore, by forming the second plating layer on the base material and forming the first plating layer on the second plating layer, the adhesion of the first plating layer to the base material can be further enhanced.

Next, the electric Ni plating layer will be described. In the present embodiment, an electric Ni plating layer may be formed between the base material and the first plating layer or the second plating layer. When the first plating layer is formed on the base material, only the electric Ni plating layer may be provided between the base material and the first plating layer. When the second plating layer and the first plating layer are formed on the base material, an electric Ni plating layer may be provided between the base material and the second plating layer. This electro-Ni plating layer is called strike plating, and can remove the passivation film on the surface of the base material when the electro-Ni plating layer is formed. As a result, the adhesion of the first plating layer or the second plating layer can be improved as compared with the case where the first plating layer or the second plating layer is directly formed on the base material. The thickness of the electro-Ni plating layer is preferably in the range of 0.1 to 1 μm.

Further, a nitride layer may be provided on the surface of the base material by subjecting the surface layer of the base material to plasma nitriding treatment. By forming the nitrided layer on the surface layer of the base material in this way, the adhesion between the first plating layer or the second plating layer and the base material can be improved, and in particular, the peeling of the first plating layer is reduced. It is possible to improve the adhesion resistance.

The Vickers hardness of the nitrided layer is 800 to 1200. By setting the Vickers hardness in the range of 800 or more and 1200 or less, the adhesion between the first plating layer or the second plating layer and the base material can be enhanced.

The thickness of the nitrided layer is not particularly limited, but in the present embodiment, it is preferably 0.5 μm to 50.0 μm.
In order to improve the adhesion between the first plating layer or the second plating layer and the base material, it is preferable to secure a thickness of the nitrided layer of 0.5 μm or more. More preferably, it is 1.0 μm or more. On the other hand, if the thickness of the nitrided layer is made too thick, the time required for the plasma nitriding process becomes long, the productivity is lowered, and the manufacturing cost is also high. Further, if the thickness of the nitrided layer is excessively increased, the surface roughness of the base material becomes large, and it becomes necessary to polish the surface of the base material before forming the first plating layer or the second plating layer. From these viewpoints, the thickness of the nitrided layer is preferably 50.0 μm or less.

The average nitrogen concentration in the nitrided layer is preferably 0.10 to 1.0% by mass.
If the nitrogen concentration in the nitrided layer is too low, the increase in hardness is small, and sufficient wear resistance may not be obtained. The average nitrogen concentration in the nitrided layer is preferably 0.10% by mass or more. More preferably, it is 0.20% or more.

On the other hand, if the nitrogen concentration in the nitrided layer is too high, the surface of the nitrided layer may become brittle and crack may occur. For this reason, the average nitrogen concentration in the nitrided layer is preferably 1.0% by mass or less. More preferably, it is 0.40% or less.

Further, it is preferable that the nitrogen concentration distribution in the nitrided layer has a concentration gradient that decreases from the surface layer of the nitrided layer toward the depth direction.
It is not preferable that a remarkably large change in hardness occurs inside the base material from the viewpoint of adhesion and strength between the first plating layer or the second plating layer and the base material. Therefore, it is preferable that the hardness gradient inside the base material, as a specific example, along the depth direction inside the roll is gentle. For that purpose, it is preferable to adjust the concentration distribution of nitrogen in the nitrided layer so as to have a concentration gradient that decreases from the surface layer of the nitrided layer toward the substrate side.

In order to adjust the nitrogen concentration distribution so that the gradient decreases from the surface layer of the nitrided layer toward the depth direction, the plasma nitriding treatment on the surface layer of the base material forming the nitrided layer is divided into a plurality of times. , The nitrogen concentration distribution in the nitrided layer may be adjusted by performing each treatment under different conditions.

The "nitriding layer" can be discriminated (determining the boundary between the base material and the "nitriding layer") by a glow discharge emission analyzer (GDS). Specifically, first, in the surface layer of the base material nitrided by the plasma nitriding treatment, the analysis region is set to 1 mm in diameter, and normal glow discharge emission analysis is performed. Continuing the analysis in the depth direction, the region up to the point where the amount of nitrogen in the analysis region exceeds the average nitrogen concentration of the base material (base material) is defined as the "nitriding layer". That is, the glow discharge emission analysis is performed in the depth direction, and the point where the amount of nitrogen drops to the average nitrogen concentration of the base material is determined as the boundary between the base material and the "nitriding layer".

The average nitrogen concentration in the nitrided layer can also be measured using GDS. In this embodiment, the analysis region has a diameter of 1 mm, analysis is performed in the depth direction using GDS, and the QDP (Quantitative Depth Profile) method specified in JIS K 0150 is applied to each depth of 50 nm. Measure the nitrogen concentration. This makes it possible to obtain the nitrogen concentration distribution in the nitrided layer. Further, the average nitrogen concentration of the entire nitrided layer can be obtained by calculating the average of each nitrogen concentration at each depth of 50 nm.

Before forming the nitrided layer, it is desirable to mirror-polish the surface of the roll (base material). It is also desirable to perform shot blasting. As a result, the surface properties of the roll can be improved, the adhesion between the first plating layer and the base material can be improved, and excellent adhesion resistance can be obtained.

Hereinafter, a method for manufacturing a titanium tube forming roll will be described.

The titanium tube forming roll is manufactured by sequentially forming a second plating layer and then a first plating layer on a base material by an electroless plating method, or by forming a first plating layer, but the first plating layer or Before forming the second plating layer on the surface of the base material, various treatments described below may be appropriately selected for the base material.

Of the base material, the surface on which the first plating layer or the second plating layer is formed is preferably polished in advance to improve the smoothness.

Further, before the formation of the plating layer, the base material may be subjected to subzero treatment to transform the retained austenite contained in the structure of the base material into martensite. The sub-zero treatment may be performed by cooling to about −75 ° C. to −130 ° C. at the time of quenching. Thereby, the Vickers hardness of the base material can be further increased, and for example, the Vickers hardness can be in the range of 600 to 700. Further, by reducing the amount of retained austenite, the shape stability of the first plating layer or the second plating layer during heat treatment can be improved.

Further, the base material may be subjected to radical nitriding treatment to form a nitride layer on the surface of the base material.
By carrying out the radical nitriding treatment, the Vickers hardness of the surface of the base material can be made 1000 HV or more.

Further, an electric Ni plating layer may be formed on the surface of the base material before forming the first plating layer or the second plating layer.
By forming the electric Ni plating layer, the passivation film on the surface of the base material can be removed, and the adhesion of the first plating layer or the second plating layer to the base material can be further enhanced.

Hereinafter, a method for forming the plating layer will be described. The titanium tube forming roll of the present embodiment can be formed by either a step of forming a first plating layer on a base material or a step of sequentially forming a second plating layer and a first plating layer on a base material. .. The method of forming the first plating layer and the second plating layer in each step is as follows.

(Method of forming the second plating layer)
The second plating layer is formed by an electroless plating method. As the plating bath, any one of the following three plating baths is preferable. That is, a plating bath containing 3.0 to 10.0% by mass of P and capable of forming a Ni-P plating layer in which the balance is composed of Ni and impurities, or 0.3 to 3.0% by mass of B is contained. A plating bath capable of forming a Ni-B plating layer in which the balance is composed of Ni and impurities, or contains P of 3.0 to 10.0% by mass and B of 0.3 to 3.0% by mass. A plating bath capable of forming a Ni-BP plating layer in which the balance is composed of Ni and impurities.

The second plating layer formed by the electroless plating method may be heat-treated in order to increase the Vickers hardness. Examples of the heat treatment conditions include conditions at 300 to 500 ° C. for 0.5 to 3 hours. When forming a Ni-P plating layer as the second plating layer, it is desirable to perform heat treatment. When a Ni-B plating layer or a Ni-BP plating layer is formed as the second plating layer, heat treatment may or may not be performed.

(Method of forming the first plating layer)
The first plating layer is formed by an electroless plating method. When the second plating layer is formed, it is preferable to form the first plating layer on the second plating layer. When the second plating layer is not formed, it is preferable to form the first plating layer on the base material.

When forming the first plating layer, h-BN particles are dispersed in the plating bath. The dispersion concentration of the h-BN particles in the plating bath may be adjusted so that the h-BN particles are contained in the range of 0.5 to 3.0% by mass in terms of the mass ratio with respect to the first plating layer. The plating bath contains P: 3.0 to 7.0% by mass and B: 0.5 to 3.0% by mass, and is capable of forming a Ni-P-B plating layer in which the balance is composed of Ni and impurities. Take a bath.

The first plating layer formed by the electroless plating method may be heat-treated in order to increase the Vickers hardness. Examples of the heat treatment conditions include conditions at 300 to 350 ° C. for 0.5 to 3 hours.

Further, in the present embodiment, the Vickers hardness of the first plating layer and the second plating layer may be increased at the same time by performing the heat treatment at once after forming the first plating layer and the second plating layer. As the heat treatment conditions in that case, for example, the conditions at 300 to 350 ° C. for 0.5 to 3 hours can be exemplified.

A titanium tube roll can be manufactured by the above steps.

The titanium tube forming roll 1 according to the present embodiment has been described above. However, when the titanium tube 10 is manufactured, water or an emulsion or a soluble oil-based lubricant usually used for forming a titanium tube may be used as a lubricant. , It is preferable because the friction between the titanium tube 10 and the titanium tube forming roll 1 is further reduced. From the viewpoint of lubrication performance and ease of removing the lubricant adhering to the product, a soluble oil-based lubricant, which is a water-soluble cutting fluid, is most suitable.

[Second example of a titanium tube forming roll and a method for manufacturing a titanium tube]
Next, a second example of the titanium tube forming roll and the method for manufacturing the titanium tube according to the embodiment of the present invention will be described with reference to FIGS. 3 to 4. In the following description, a film composed of the first plating layer or a film formed by laminating the first plating layer and the second plating layer are both referred to as surface treatment films.

3 and 4 show a titanium tube forming roll 11 which is a second example of the present embodiment. The titanium tube forming roll 11 shown in FIGS. 3 and 4 is a so-called hole-shaped roll, and includes a roll body 12 made of a steel material and a rotating shaft 3 inserted through the roll body 12. The roll surface 12a of the roll body 12 is provided with a roll recess 14 formed in a semicircular cross-sectional view over the entire circumference of the roll body 12. Further, a surface treatment film is laminated on the surface of the roll recess 14 which is a rolled surface. A nitride layer or an electro-Ni plating layer may be provided between the base material and the surface treatment film. Similar to the case of FIG. 1, two titanium tube forming rolls 11 shown in FIGS. 3 and 4 are prepared, and the roll recesses 14 are arranged so as to face each other, and each roll recess 14 is a titanium tube to be molded. A titanium tube forming device is configured by arranging them so as to be in contact with each other on the same circumference of the outer peripheral surface.

The roll body 12 includes a roll central portion 21, a pair of rotating flange portions 22 arranged on both sides of the roll central portion 21 and rotatable with respect to the roll central portion 21, and a pair of fixed flange portions 23. Is provided. The roll recess 14 is divided by a roll central portion 21 and a rotating flange portion 22. Further, a first bearing portion 24 is provided between the roll central portion 21 and the rotating flange portion 22, and a second bearing portion 25 is provided between the fixed flange portion 23 and the rotating flange portion 22. There is. Further, the roll central portion 21 and the fixing flange portion 23 are mutually fixed by fixing bolts 26.

The roll central portion 21 is fixed to a rotating shaft 3 that drives the roll main body 12. On the other hand, the rotating flange portion 22 is rotatable with respect to the rotating shaft 3 and the roll center portion 21. The fixing flange portion 23 is fixed to the roll center portion 21 by a fixing bolt 26. That is, the fixed flange portion 23 is integrally fixed to the rotating shaft 3 together with the roll central portion 21.
As the rotation shaft 3 rotates, the roll central portion 21 and the fixed flange portion 23 rotate. On the other hand, since the rotating flange portion 22 is made rotatable with respect to the roll central portion 21 and the fixed flange portion 23 by the first and second bearing portions 24 and 25, the roll central portion 21 and the fixed flange portion 23 Does not work with. Hereinafter, each part will be described in detail.

The roll central portion 21 includes a cylindrical base portion 21a through which the rotation shaft 3 is inserted, and a protruding portion 21b protruding from the center of the base portion 21a in the roll width direction. The base portion 21a is provided with an insertion hole 21c for inserting the rotating shaft 3. The upper surface 21d of the protruding portion 21b is formed in a circular groove shape that is recessed on the rotation shaft 3 side and is continuous over the entire circumference of the roll body 12, and the upper surface 21d constitutes a part of the roll recess 14. There is. The roll central portion 21 is composed of a base material having the steel component described in the first example. Further, the surface treatment film described in the first example is laminated on the upper surface 21d of the roll central portion 21. Further, a nitride layer or an electric Ni plating layer may be provided between the base material and the surface treatment film.

The rotating flange portion 22 is a substantially ring-shaped member, and is fitted on the outer peripheral side of the base portion 21a of the roll central portion 21 and on both sides of the protruding portion 21b in the roll width direction. In this way, the rotating flange portions 22 are arranged on both sides of the protruding portions 21b in the roll width direction on the base portion 21a. A first bearing 24 is arranged between the base portion 21a of the roll central portion 21 and the rotary flange portion 22. Further, a gap of about 0.1 mm is provided between _{the side wall surface 21b 1} of the protruding portion 21b of the roll central portion 21 and the rotating flange portion 22. Due to this gap and the first bearing portion 24, the rotary flange portion 22 is rotatable with respect to the roll central portion 21 without sliding. Further, the outer peripheral inclined surface 22a of the rotary flange portion 22 is formed into a concave arc surface when viewed in cross section, and is an arc surface continuous with the upper surface 21d of the roll central portion 21. As a result, the roll recess 14 is formed by the outer peripheral inclined surface 22a of the rotating flange portion 22 and the upper surface 21d of the roll central portion 21.

Further, as can be seen from a cross-sectional view of the rotating flange portion 22, the tip portion 22d including the outer peripheral inclined surface 22a of the rotating flange portion 22 is bent so as to cover the tip of the protruding portion 21b.
As a result, when the rotating flange portion 22 receives the load from the titanium tube 10, it is possible to sufficiently receive the load.

The rotating flange portion 22 is composed of a base material having the steel component described in the first example. Further, the surface treatment film described in the first example is laminated on the outer peripheral inclined surface 22a of the rotating flange portion 22. Further, a nitride layer or an electric Ni plating layer may be provided between the base material and the surface treatment film. Further, a surface treatment film may be laminated on the entire surface of the rotary flange portion 22. Further, there may be a nitride layer or an electro-Ni plating layer between the base material and the surface treatment film.

Next, the first bearing portion 24 is composed of a plurality of rolling elements 24a made of needle-shaped rollers and a raceway surface that abuts on the plurality of rolling elements 24a. _{The raceway surfaces are the outer peripheral surface 21a 1} of the base portion 21a of the roll central portion 21, and the inner peripheral surface 22b of the rotating flange portion 22, which are surfaces adjacent to the rolling element 24a. In other words, the base portion 21a of the roll central portion 21 and the rotary flange portion 22 form the inner peripheral race and the outer peripheral race of the first bearing portion 24, respectively. In the present embodiment, the surface treatment film described in the first example is laminated on _{the outer peripheral surface 21a 1 and the inner peripheral surface 22b.} Further, a nitride layer or an electric Ni plating layer may be provided between the base material and the surface treatment film.

Next, the fixed flange portion 23 is a substantially disk-shaped member, and is a member provided with an insertion hole 23a through which the rotating shaft 3 can be inserted in the center. The fixed flange portions 23 are arranged on both sides of the roll body 12 in the roll width direction. The portion of the fixing flange portion 23 near the rotation axis is fixed to the base portion 21a of the roll central portion 21 by the fixing bolt 26. Further, the portions of the fixed flange portion 23 near the outer circumference are located on both sides of the rotary flange portion 22 in the roll width direction and face the rotary flange portion 22. A second bearing portion 25 is arranged between the fixed flange portion 23 and the rotating flange portion 22.

The fixed flange portion 23 is composed of a base material having the steel component described in the first example. Further, among the fixed flange portions 23, the surface treatment film described in the first example may be laminated on the facing surface 23b facing the rotating flange portion 22. Further, there may be a nitride layer or an electro-Ni plating layer between the base material and the surface treatment film.

The second bearing portion 25 is composed of a plurality of rolling elements 25a made of needle-shaped rollers and a starting surface for holding the plurality of rolling elements 25a. The raceway surfaces are the facing surface 23b of the fixed flange portion 23 and the side surface 22c of the rotating flange portion 22, which are surfaces adjacent to the rolling element 25a. In other words, the facing surface 23b of the fixed flange portion 23 and the side surface 22c of the rotating flange portion 22 are races of the second bearing portion 25, respectively. In the present embodiment, the surface treatment film is laminated on the base material on the facing surface 23b and the side surface 22c as in the first example. Further, a nitride layer or an electric Ni plating layer may be provided between the base material and the surface treatment film.

As shown in FIG. 4, in the titanium tube forming roll 1 of this example, by removing the fixing bolt 26, the roll main body 12 is changed to the roll center portion 21, the rotating flange portion 22, the fixing flange portion 23, and the first. It can be disassembled into a bearing portion 24 and a second bearing portion 25.

With the above configuration, when the titanium tube 10 is formed, the roll central portion 21 and the fixed flange portion 23 are rotated by the rotational drive of the rotating shaft 3. When the titanium tube 10 is inserted between the pair of titanium tube forming rolls 1 in this state, the upper surface 21d of the roll central portion 21 comes into contact with the titanium tube 10 and transmits the rotational torque of the rotating shaft 3 to the titanium tube 10. On the other hand, the titanium tube 10 also comes into contact with the outer peripheral inclined surface 22a of the rotating flange portion 22, but the rotating flange portion 22 is rotated by the titanium tube 10 in accordance with the movement of the titanium tube 10. At this time, since the peripheral speed of the outer peripheral inclined surface 22a is smaller than the peripheral speed of the upper surface 21d of the roll central portion, the rotational speed of the rotating flange portion 22 is smaller than the rotational speed of the roll central portion 21. The rotating flange portion 22 is made rotatable with respect to the roll central portion 21 and the fixed flange portion 23 by the first and second bearing portions 24 and 25, respectively, and the rotating flange portion 22 and the roll are formed. Since there is a gap of about 0.1 mm between the central portion 21 and the protruding portion 21b, the rotating flange portion 22 rotates at a rotation speed smaller than the rotation speed of the roll central portion 21. As a result, the slip ratio of the roll with respect to the titanium tube 10 is reduced as a whole, and the occurrence of flaws in the titanium tube 10 is suppressed.

Further, when the titanium tube 10 is inserted between the pair of titanium tube forming rolls 1 and the titanium tube 10 enters the roll recess 14, the rotary flange portion 22 is slightly pushed outward in the roll width direction and the fixed flange portion 23 is formed. On the other hand, a gap of about 0.1 mm is secured between the rotating flange portion 22 and the protruding portion 21b of the roll central portion 21. As a result, the rotating flange portion 22 rotates smoothly without the rotating flange portion 22 and the protruding portion 21b rubbing against each other.

As described above, according to the titanium tube forming roll 11 of the second example of the present embodiment, the roll main body 12 is arranged on both sides of the roll central portion 21 and the roll central portion 21 and is located on the roll central portion 21. On the other hand, it is composed of a pair of rotating flange portions 22 that are rotatable, and since the roll recess 14 is divided by the roll central portion 21 and the rotating flange portion 22, the rotating flange portion 22 and the titanium pipe are formed. The titanium tube 10 is less likely to slip with each other, which makes it difficult for the titanium tube 10 to be scratched and the surface treatment film formed on the rotating flange portion 22 to be less likely to peel off. As described above, according to the titanium tube forming roll 1 of this example, wear resistance, adhesion resistance, and peeling resistance are improved, and the friction coefficient of the roll surface can be reduced.

Further, while the roll central portion 21 is fixed to the rotating shaft 3 that drives the roll main body 12, the rotating flange portion 22 is rotatable with respect to the rotating shaft 3 and the roll central portion 21, so that the rotation can be performed. When the shaft 3 serves as a drive shaft, the roll central portion 21 becomes a drive roll, the rotary flange portion 22 becomes a non-drive roll, and the slip ratio in the rotary flange portion 22 which becomes a non-drive roll becomes small, so that the titanium tube is used. It is possible to prevent the occurrence of flaws in No. 10 and to suppress the peeling of the surface treatment film formed on the rotating flange portion 22. As a result, the durability of the titanium tube forming roll 1 can be improved, and the frequency of maintenance can be reduced.

Further, the roll central portion 21 is provided with a base portion 21a and a protruding portion 21b, and the rotating flange portion 22 is located on the base portion 21a and is arranged on both sides of the protruding portion 21b in the roll width direction. By providing the first bearing portion 24 between the and, the rotating flange portion 22 can be smoothly rotated with respect to the roll central portion 21.

Further, when the titanium tube 10 enters the roll recess 14, the rotary flange portion 22 is slightly pushed outward in the roll width direction, and a gap of about 0.1 mm is secured between the rotary flange portion 22 and the protruding portion 21b. As a result, the rotating flange portion 22 can be smoothly rotated without the rotating flange portion 22 and the protruding portion 21b rubbing against each other.

Further, the facing surfaces facing each other between the base portion 21a of the roll central portion 21 and the rotating flange portion 22 are the raceway surfaces of the rolling elements 24a of the first bearing portion 24, and the first plating layer is formed on these facing surfaces. Since the second plating layer is provided, the life of the first bearing portion 24 can be extended. Further, since the first bearing portion 24 itself can be made smaller, the roll main body 12 can be made smaller to make the equipment more compact.

Further, the roll main body 12 is provided with a fixed flange portion 23 and a second bearing portion 25, and the fixed flange portion 23 prevents the rotating flange portion 22 from falling off from the roll central portion 21 while preventing the second bearing portion 22 from falling off. The bearing portion 25 can smoothly rotate the rotating flange portion 22.

Further, the facing surfaces facing each other between the fixed flange portion 23 and the rotating flange portion 22 are the raceway surfaces of the rolling element 25a of the second bearing portion 25, and the first plating layer and the second plating layer and the second facing surfaces are facing each other. Since the plating layer is provided, the life of the second bearing portion 25 can be extended. Further, since the second bearing portion 25 itself can be made smaller, the roll main body 12 can be made smaller to make the equipment more compact.

Further, as shown in FIG. 4, in the titanium tube forming roll 1 of this example, by removing the fixing bolt 26, the roll main body 12 can be changed to the roll center portion 21, the rotating flange portion 22, the fixing flange portion 23, and the second. Since it can be disassembled into the first bearing portion 24 and the second bearing portion 25, maintenance work can be easily performed. For example, if only the rotating flange portion 22 is worn and the surface treatment film is peeled off, it can be used immediately by replacing it with a spare rotating flange portion 22, and the titanium tube molding process is continued. be able to. Further, the removed rotating flange portion 22 can be made reusable only by forming a surface treatment film on a portion requiring repair.

Further, the first plating layer, the second plating layer, the nitrided layer, and the electric Ni plating layer according to the present embodiment are formed not only on the surface of the roll recess 14 but also on any portion of the titanium tube forming roll 1. The life can be extended. For example, as described above, by forming a surface treatment film on the raceway surfaces of the rolling elements 24a and 25a of the first and second bearing portions 24 and 25, the wear resistance and fatigue resistance are originally excellent. Even where the material for bearings should be applied, by forming a surface treatment film on the material of the roll body 14, the rolling elements 24a and 25a can be made into raceway surfaces. Further, by forming a surface treatment film on the surface of the roll central portion 21 where the protruding portion 21b and the rotating flange portion 22 face each other, wear between the protruding portion 21b and the rotating flange portion 22 can be prevented.

Furthermore, it is preferable to use water or an emulsion or soluble oil-based lubricant usually used for forming titanium tubes as a lubricant because the friction between the titanium tube 10 and the titanium tube forming roll 11 is further reduced. Further, by using an emulsion or a soluble oil-based lubricant as a lubricant, a pair of rotations arranged on both sides of the roll central portion 21 and the roll central portion 21 so as to be rotatable with respect to the roll central portion 21. Friction with the flange portion 22 is also further reduced, which is preferable. When a lubricant is used, a soluble oil-based lubricant, which is a water-soluble cutting oil, is most suitable from the viewpoint of lubrication performance and ease of removing the lubricant adhering to the product.

Although the titanium tube forming roll 11 of the second example has been described above, in this example, the modified example shown in FIG. 5 or FIG. 6 may be adopted.
In the modified example shown in FIG. 5, when the roll main body 12 is viewed in cross section, the boundary surface between the rotating flange portion 22 and the protruding portion 21b extends straight toward the outer peripheral direction of the roll main body 12. According to the example of FIG. 5, the shapes of the rotating flange portion 22 and the protruding portion 21b can be made into a relatively simple shape as compared with the case of FIG. 3, rattling is less likely to occur, and the titanium tube 10 is molded. The accuracy can be improved. In the example of FIG. 5, it can be applied when the load received from the titanium tube 10 is relatively small.

Further, in the modified example shown in FIG. 6, when the roll body 12 is viewed in cross section, the tip portion 22d of the rotating flange portion 22 is bent substantially laterally. Also in the example of FIG. 6, the shapes of the rotating flange portion 22 and the protruding portion 21b can be made into a relatively simple shape as compared with the case of FIG. 3, rattling is less likely to occur, and the molding accuracy of the titanium tube 10 is reduced. Can be enhanced. The example of FIG. 6 can also be applied when the load received from the titanium tube 10 is relatively small.

[Third example of a titanium tube forming roll and a method for manufacturing a titanium tube]
Next, a third example of the titanium tube forming roll and the method for manufacturing the titanium tube according to the embodiment of the present invention will be described with reference to FIG. 7. The difference between the titanium tube forming roll 31 shown in FIG. 7 and the titanium tube forming roll 11 of the second example shown in FIGS. 3 to 4 is that the mechanism for fixing the rotating flange portion 22 to the fixed flange portion 23 is provided. It is a provided point, and there is no difference in other points. In the following description, a mechanism for fixing the rotating flange portion 22 to the fixed flange portion 23 will be described. In FIG. 7, the description of the first bearing portion and the second bearing portion is omitted.

FIG. 7 shows a titanium tube forming roll 31, which is a third example of the present embodiment. The titanium tube forming roll 31 is provided with a pull screw portion 32 that attracts and fixes the rotating flange portion 22 to the fixed flange portion 23. The draw screw portion 32 is provided at three locations, for example, the fixed flange portion 23. The draw screw portion 32 is composed of a detachable bolt 32a and a screw hole 32b into which the detachable bolt 32a is inserted. The screw holes 32b are provided in the fixed flange portion 23 and the rotating flange portion 22, respectively.

When molding the titanium tube 10, the attachment / detachment bolt 32a is removed to make the rotating flange portion 22 rotatable with respect to the fixed flange portion 23 and the roll center portion 21.

On the other hand, when repairing the roll recess 14 of the titanium tube forming roll 31, the attachment / detachment bolt 32a is inserted into the screw hole 32b and screwed. As a result, the rotating flange portion 22 is attracted to the fixed flange portion 23 side and comes into close contact with the fixed flange portion 23, while 0.1 mm between the rotating flange portion 22 and the protruding portion 21b of the roll center portion 21. There will be a gap of the degree. This state is substantially the same as the state in which the rotating flange portion 32 is pushed toward the fixed flange portion 23 while the titanium tube 10 is being molded. Then, the roll recess 14 is repaired in a state where the rotating flange portion 22 and the fixed flange portion 23 are in close contact with each other. Specifically, when the roll recess 14 is partially worn and the roundness is lowered, the inner surface of the roll recess 14 is polished so as to restore the roundness. That is, the rotating flange portion 22 is pulled toward the fixed flange portion 23 side to bring the titanium tube 10 into the same state as in the case of molding, and the repair is performed.

As described above, the titanium pipe forming roll 31 of this example is provided with a draw screw portion 32 for fixing the rotating flange portion 22 and the fixed flange portion 23 in close contact with each other, and repairs the roll recess 14. At the same time, the rotating flange portion 22 can be in the same state as in the case of molding the titanium tube 10, so that the roundness of the roll recess after repair can be improved.

[Titanium tube manufacturing method and equipment]
The titanium tube forming apparatus according to the present embodiment includes any of the titanium tube forming rolls 1, 11 and 31 shown in FIGS. 1, 3 or 7, and for a part of the titanium tube forming rolls 1, 11 and 31. , Equipped with a lubrication nozzle that supplies lubricant during titanium tube molding. The use of a lubricant and the use of the lubrication nozzle shown here are desirable, but if necessary, whether or not to use the lubricant and whether or not to use the lubrication nozzle may be appropriately selected. Further, when a lubricant is used, other methods such as dipping the lubricant in a cloth and applying the lubricant, or spraying the lubricant with a spray may be used.

In general, when actually forming a titanium pipe, a water-soluble lubricant is often used in the routine process after welding the titanium pipe to prevent and cool the pipe.
Therefore, in order to further improve the life of the titanium tube forming roll according to the present embodiment and prevent roll marks and flaws on the roll surface, the titanium tube forming apparatus according to the present embodiment is used with respect to the titanium tube forming roll. It is preferable to provide a lubricating nozzle for supplying the lubricant.
Hereinafter, an example of a titanium tube forming apparatus provided with a lubrication nozzle will be described with reference to the drawings, but the drawings shown below are for explaining the configuration of the titanium tube forming apparatus, and each of the illustrated parts is shown. The size, thickness, dimensions, etc. may differ from the actual dimensional relations of the heating furnace.
Although various methods can be applied to the welding of titanium pipes, TIG welding is preferable.

8A and 8B are views showing a titanium pipe forming apparatus according to the present embodiment, FIG. 8A is a front schematic view, FIG. 8B is a side view showing a configuration in the vicinity of the lubrication nozzle 101, and FIG. 8C. ) Is a cross-sectional view showing a configuration in the vicinity of the lubrication nozzle 101. 9A and 9B are views for explaining an arrangement example of the lubrication nozzle 101, where FIG. 9A is a front schematic view and FIG. 9B is a side schematic view. 10A and 10B are views for explaining in detail the width direction adjusting mechanism and the vertical direction adjusting mechanism of the lubrication nozzle 101. FIG. 10A is a schematic top view of a titanium tube forming apparatus, and FIG. 10B is a schematic side view. It is a figure.

The titanium tube 10 is conveyed while being molded by titanium tube forming rolls 1, 11 and 31 arranged so as to face each other in the vertical direction. Similar to the case of FIG. 1, in the titanium tube forming apparatus according to the present embodiment, two titanium tube forming rolls 1, 11 and 31 are prepared, and the roll recesses are arranged so as to face each other, and each roll recess is formed. Is arranged so as to be in contact with the same circumference of the outer peripheral surface of the titanium tube 10 to be molded.
At this time, in the vicinity of the roll flange portion (the roll parallel portion at the end of the hole type) where the forming rolls 1, 11, 31 and the titanium tube 10 are in contact, wear and scratches due to friction are more likely to occur than in other portions. .. Therefore, when molding the titanium tube 10, it is necessary to drop the lubricant in the vicinity of the roll flange portion.

However, the position of the roll flange portion changes each time the diameters of the titanium tube forming rolls 1, 11 and 31 are changed. Therefore, the position of the lubrication nozzle 101 for dropping the lubricant must be adjusted each time. Therefore, in the present embodiment, when arranging the lubrication nozzle 101 for dropping the lubricant, it is preferable to provide an expansion / contraction mechanism that can adjust the dropping position of the lubricant in the width direction and the vertical direction.

A mechanism for expanding / contracting the lubrication nozzle 101 according to the present embodiment in the width direction will be described.
As shown in FIG. 8, a pipe-shaped horizontal movement guide 103 provided with a width movement groove (long groove) 118 is arranged in front of the forming rolls 1, 11, and 31, and on the horizontal movement guide 103, the horizontal movement guide 103 is arranged. A lubrication nozzle fixing base 102 and a lubrication nozzle 101 mounted on the lubrication nozzle fixing base 102 are provided via a width moving guide 119 fitted in the width moving groove 118. The width movement guide part 115 connected to the slidable lubrication nozzle angle adjustment jig 109 has a width adjustment screw (the left and right from the center are forward and reverse screws, respectively, and when the adjustment screw is rotated, the left and right sides are screwed. It has a mechanism that expands and contracts in the width direction by 114 (see FIG. 10) (the right guide portion 115 moves symmetrically in the opposite direction).

Further, as a mechanism for expanding and contracting the lubrication nozzle 101 in the vertical direction, there are a cast pedestal 107 fixed to the molding stand support 117 and a center position adjusting jig 106 provided so as to be slidable in the vertical direction with respect to the cast pedestal 107. And the vertical movement screw 116 inserted into the center position adjustment jig 106 adjusts the vertical position of the lubrication nozzle 101. Since the center position adjustment jig 106 is also connected to the horizontal movement guide 103, when the center position adjustment jig 106 moves up and down on the mold pedestal 107, the horizontal movement guide 103, that is, the lubrication nozzle 101 also moves up and down in the same manner. It will move in the direction.
The vertical movement screw 116 is connected to the vertical position adjustment handle 104, and by turning the vertical position adjustment handle 104, the vertical movement of the center position adjustment jig 106 can be controlled, and lubrication according to the roll flange portion can be controlled. The nozzle 101 can be adjusted in the vertical direction.

Further, the angle adjustment for the alignment of the lubrication nozzle 101 in consideration of the contact with the titanium tube 10 due to the fluctuation of the diameters of the titanium tube forming rolls 1, 21 and 31 is performed by the lubrication nozzle sandwiching jig (lubrication nozzle front-rear adjustment jig) 113. And the lubrication nozzle angle adjustment jig 109 can be adjusted by rotating the lubrication nozzle angle fixing screw 112.
The mechanism by which the lubrication nozzle 101 moves back and forth is a device having a lubrication nozzle sandwiching jig (lubrication nozzle front-rear adjustment jig) 113, and can be adjusted by the lubrication nozzle angle fixing screw 112.
With these mechanisms, the lubricant can be dropped in the vicinity of the roll flange portion where the titanium tube forming rolls 1, 21, 31 and the titanium tube 10 are in contact with each other.

Here, as the lubricant, a soluble oil-based lubricant, which is a water-soluble cutting oil, is most suitable from the viewpoint of lubrication performance and ease of removing the lubricant adhering to the product.

It is necessary to adjust the arrangement position of the lubrication nozzle 101 appropriately according to the titanium pipe size (roll flange width) so as to correspond to the roll flange portion. Further, depending on the condition of roll lubrication, it is necessary to drop the titanium tube forming rolls 1, 21, and 31 onto the upper roll from above the roll.
FIG. 9 is a front schematic view for explaining an arrangement example of the lubrication nozzle 101. As described above, the titanium pipe forming device is provided with front / rear / up / down and left / right adjustment mechanisms for the lubrication nozzle 101. Therefore, the position of the lubrication nozzle 101 can be appropriately changed to a desired position according to the size of the flange widths of the titanium tube forming rolls 1, 21, and 31.

The width direction adjusting mechanism and the vertical direction adjusting mechanism of the lubrication nozzle 101 will be described in detail with reference to FIG.
In addition, in order to make it easier to explain each direction adjusting mechanism of the lubrication nozzle 101, some members are omitted in FIG.
Two width adjusting screws 114 (left and right screws) that reverse forward and reverse are arranged in a substantially central portion of the pipe-shaped horizontal movement guide 103. The width adjusting screw 114 is connected to the left / right position adjusting handle 105 laid in the horizontal moving guide 103, and the horizontal moving guide 103 can be moved in the horizontal direction by turning the left / right position adjusting handle 105. As a result, the expansion and contraction of the lubrication nozzle 101 in the width direction can be adjusted according to the roll flange portion.
Further, the center positions of the titanium tube forming rolls 1, 21, and 31 can be aligned by moving the width adjusting screw 114 to the center and adjusting the center position adjusting jig 106 provided on the cast pedestal 107. it can.

Further, as shown in the side view of FIG. 10, the dropping position of the lubricant can be freely changed by adjusting the front-back adjustment of the lubrication nozzle 101 and the expansion / contraction movement position. It is possible to adjust the dropping position of the lubricant on the contact portion with 31.

The pedestal 107 is fixed to the molding stand support 117 via the stand support mounting jig 108, but when the stand support mounting jig 108 is fixed to the molding stand support 117, it can be easily mounted by the stand fixing screw 120. It is a cantilever format that can be used.

FIG. 11 is a diagram showing a structure of a roller pump (lubrication supply device) for dropping a small amount of lubricant using the lubrication nozzle 101 of FIG.
As the lubricant, in order to attach a small amount of a concentrated lubricant equivalent to the undiluted solution to the roll, the tube 132 called a tube pump is conveyed while being crushed by a roller 130 that revolves around the central shaft 131.
As a lubrication method, a tube 132 having an inner diameter of 3 mm or less is used, and a small amount of water is dropped using a non-contamination tube (roller) pump having a dropping speed of 20 ml / hr or less.

Here, as the lubricating nozzle 101, it is appropriate to use a tube having an inner diameter of 0.5 mm or more and 3 mm or less in order to supply an appropriate amount of the lubricant.

Further, it is suitable to supply the lubricant by dropping a small amount of the lubricant at a dropping rate of 1 ml / hr or more and 20 ml / hr or less.
If the supply rate of the lubricant is less than 1 ml / hr, the function as a lubricant cannot be fully exhibited, while if the supply rate exceeds 20 ml / hr, the function as a lubricant is saturated, rather, titanium tube molding. The rolls 1, 21 and 31 will slip, which will hinder the molding of the titanium tube and increase the amount of lubricant to be removed from the final product, resulting in an increase in manufacturing cost.

[Fourth Example of Titanium Tube Molding Roll and Titanium Tube Manufacturing Method]
Next, a fourth example of the titanium tube forming roll and the method for manufacturing the titanium tube will be described with reference to the drawings.
12 and 13 show a schematic view of a titanium tube forming roll, a titanium tube forming apparatus, and a method for manufacturing a titanium tube using a titanium tube forming roll, which is a fourth example of the present embodiment. FIG. 12 is a front view of a titanium tube forming apparatus provided with a titanium tube forming roll, and FIG. 13 is a side view. Further, FIG. 14 shows a front view of a main part of the titanium tube forming apparatus. Further, FIG. 15 shows a titanium tube forming roll provided in the titanium tube forming apparatus. FIG. 15A is a partial cross-sectional view of the titanium tube forming roll, and FIG. 15B is a side view of the titanium tube forming roll.

As shown in FIGS. 12 to 15, the titanium tube forming roll 41 of the present embodiment is a so-called hole-shaped roll, and includes a roll main body 42 made of a steel material and a rotating shaft 43 inserted through the roll main body 42. ing. The roll body 42 is provided with a roll surface 42a over the entire circumference thereof, and the roll surface 42a is provided with a roll recess 44 and an inclined portion 45. The roll recess 44 and the inclined portion 45 are provided on the entire circumference of the roll body 42. The steel material constituting the roll body 42 is preferably the steel described in the first example.

The roll recess 44 provided on the roll surface 42a is a rolled surface when forming the titanium tube 10, and has a shape recessed toward the rotation shaft 43 side, as shown in FIG. 15 (a). The shape of the roll body 42 in cross section is arcuate. The roll recess 44 is formed in the central portion of the roll body 42 in the width direction. The direction parallel to the rotation axis 43 of the roll body 42 is referred to as the width direction of the roll body 42. As shown in FIGS. 15 (a) and 15 (b), the roll recess 44 is a surface on which the titanium tube 10 to be molded comes into contact. The surface treatment film described in the first example is laminated on the surface of the roll recess 44. A nitride layer or an electric Ni plating layer may be provided between the roll recess 44 and the surface treatment film.

The inclined portions 45 are provided on both sides of the roll surface 42a in the width direction of the roll recesses 44. The inclined portion 45 is an inclined surface inclined toward the rotation shaft 43 side of the roll main body 42 toward the outside in the width direction of the roll main body 42. The inclination angle of the inclined portion 45 is, for example, an angle of 45 ° with respect to the axial direction of the rotating shaft 43. The inclined portion 45 is a surface that may come into contact with the inclined portion 45 of another adjacent titanium tube forming roll 41, as will be described later. Therefore, the surface treatment film described in the first example is also laminated on the surface of the inclined portion 45. A nitride layer or an electric Ni plating layer may be provided between the inclined portion 45 and the surface treatment film.

A convex curved surface portion 46 is provided at the boundary between the roll recess 44 and the inclined portion 45. The convex curved surface portion 46 is provided over the entire circumference of the roll main body 42. The surface treatment film described in the first example is also laminated on the convex curved surface portion 46. Further, there may be a nitride layer or an electric Ni plating layer.

The titanium tube forming apparatus 51 shown in FIGS. 12 and 13 is connected to the four titanium tube forming rolls 41 described above, a bearing portion 52 that rotatably supports each titanium tube forming roll 41, and a bearing portion 52. The first adjusting device 53 for adjusting the position of the titanium tube forming roll 41, the plate-shaped base portion 54 for fixing the four first adjusting devices 53, and the plate-shaped base portion 54 are supported by standing vertically. It is composed of a support housing 55 and a second adjusting device 56 that raises and lowers the position of the base portion 54 on the support housing 55. The titanium tube 10 to be molded is a titanium tube from the front side of the support housing 55 (left side of the support housing 55 in FIG. 13) toward the back side of the support housing 55 (right side of the support housing 55 in FIG. 13). When passing through the molding apparatus 51, it is molded so that the cross-sectional shape becomes a perfect circle by the titanium tube forming rolls 41 arranged on four sides.

The support housing 55 is installed, for example, on the ground surface of a titanium tube manufacturing factory. The support housing 55 is provided with a first flange portion 55a and a second flange portion 55b protruding from the surface thereof. The first flange portion 55a is located below the support housing 55, and the second flange portion 55b is located above the support housing 55. A base portion 54 is arranged between the first flange portion 55a and the second flange portion 55b. The support housing 55 is provided with a passage hole 55c through which the titanium tube 10 passes.

The base portion 54 is formed into a substantially octagonal shape when viewed from the front. The base portion 54 is provided with a first adjusting device 53, a bearing portion 52, and a titanium tube forming roll 41. A through hole 54a for passing the titanium tube is provided in the substantially center of the base portion 54. The through hole 54a communicates with the passage hole 55c of the titanium tube 10 provided in the support housing 55. Hereinafter, the region through which the titanium tube 10 passes is referred to as a passage region of the titanium tube 10. The titanium tube forming roll 41 is arranged so as to surround the titanium tube 10 from four sides. More specifically, of the four titanium tube forming rolls 41, the roll recesses 44 of the two titanium tube forming rolls 41 are arranged so as to face each other in the passing region of the titanium tube 10, and two other titaniums. The roll recesses 44 of the tube forming roll 41 are arranged so as to face each other in the passing region of the titanium tube 10. The pair of titanium tube forming rolls 41 in which the roll recesses 44 face each other are arranged so that their rotation axes 43 are parallel to each other. On the other hand, the titanium tube forming rolls 41 whose roll recesses 44 do not face each other, that is, the adjacent titanium tube forming rolls 41 are arranged so that the axial directions of the respective rotation axes 43 are orthogonal to each other.

Further, the roll recesses 44 of the four titanium tube forming rolls 41 are arranged so as to be in contact with each other on the same circumference of the outer peripheral surface of the titanium tube 10 to be formed. One titanium tube forming roll 41 is arranged so as to be in contact with 1/4 of the circumference of the outer peripheral surface of the titanium tube 10. That is, the length L of the roll recess 44 of the titanium tube forming roll 41 along the roll width direction is substantially equal to the length of 1/4 of the circumference of the outer peripheral surface of the titanium tube 10. As a result, the four titanium tube forming rolls 41 can simultaneously form the entire circumference of the outer peripheral surface of the titanium tube 10 to be formed.

Further, in the vicinity of the passage region of the titanium tube 10, the inclined portions 45 of the titanium tube forming rolls 41 adjacent to each other face each other. In FIGS. 12 and 14, the inclined portions 45 are shown in contact with each other, but the inclined portions 45 are positioned so as to have a predetermined clearance. In the titanium tube forming apparatus 51 of the present embodiment, a surface treatment film is formed on the surface of the inclined portion 45, and even when the inclined portions 45 come into contact with each other due to these coatings, the lubricity of the inclined portions 45 is maintained. Therefore, there is no risk of seizure between the inclined portions 45. Therefore, in the present embodiment, the clearance between the inclined portions 45 can be significantly reduced.

The titanium tube forming roll 41 is rotatably supported by the bearing portion 52. The bearing portion 52 is not directly attached to the base portion 54, but is attached to the base portion 54 via the first adjusting device 53. The first adjusting device 53 includes a position adjusting flange portion 53a attached to the base portion 54, a female screw hole 53b provided in the position adjusting flange portion 53a, an adjusting bolt 53c inserted into the female screw hole 53b, and a bearing. It is composed of a female screw hole 52a provided in the portion 52. The position adjusting flange portion 53a is formed by bending, for example, a metal plate, and is welded to the surface of the base portion 54. A male screw portion is formed in the adjusting bolt 53c, and is inserted into the female screw hole 53b of the position adjusting flange portion 53a and the female screw hole 52a provided in the bearing portion 52. By rotating the adjusting bolt 53c, the distance between the position adjusting flange portion 53a and the bearing portion 52 can be adjusted, whereby the relative position of the titanium tube forming roll 41 can be adjusted. .. More specifically, the clearance between the inclined portions 45 can be adjusted by the first adjusting device 53. Further, the positions of the roll recesses 44 of the four titanium tube forming rolls 41 can also be adjusted by the first adjusting device 53, and the center position of the radius of curvature of the roll recesses 44 coincides with the central axis of the titanium tube 10 to be molded. It is good to adjust as follows.

Next, the second adjusting device 56 will be described. A through hole 55c is provided in the second flange portion 55b of the support base 55, and a female screw portion is provided on the inner surface of the through hole 55c. Further, another position adjusting flange portion 54b is provided on the upper end side of the surface of the base portion 54. A through hole 54c is also provided in the position adjusting flange portion 54b, and a female screw portion is provided on the inner surface thereof. A bolt 56a having a male screw portion is inserted into the through hole 55c of the second flange portion 55b of the support base 55 and the through hole 54c of the position adjusting flange portion 54b from the vertical direction. As described above, the second adjusting device 56 is composed of the second flange portion 55b having the through hole 55c, the position adjusting flange portion 54b having the through hole 54c, and the bolt 56a. By rotating the bolt 56a inserted in the vertical direction, the distance between the second flange portion 55b and the position adjusting flange portion 54b can be adjusted, whereby the position of the base portion 54 in the support housing 55 can be adjusted. It can be moved up and down. This makes it possible to adjust the relative position of the titanium tube forming apparatus 51 with respect to other forming rolls in the front stage or the rear stage.

Next, a method of forming the titanium tube 10 by the titanium tube forming roll 41 and the titanium tube forming apparatus 55 shown in FIGS. 12 to 15 will be described.
When molding the titanium tube 10, the titanium tube 10 is inserted into the holes formed by the roll recesses 44 of the four titanium tube forming rolls 41. As a result, the outer peripheral surface of the titanium tube 10 comes into contact with the titanium tube forming roll 41 at the same position in the circumferential direction, and is formed into a perfect circular shape.

Here, the difference between this example and the third example will be described. In the third example, when the roll central portion 21 and the rotary flange portion 22 form the titanium tube 10, the roll central portion 21 and the rotary flange portion 21 and the rotary flange portion 22 are formed. Since the rotation axis of 22 is the same, the roll central portion 21 and the rotary flange portion 22 rotate in the same direction. In the roll central portion 21, the surface in contact with the titanium tube 10 is oriented in a direction close to parallel to the rotation axis, whereas in the rotation flange portion 22, the surface in contact with the titanium tube 10 is oriented in a direction close to perpendicular to the rotation axis. .. Therefore, in the rotary flange portion 22, the contact with the titanium tube 10 becomes complicated, and the possibility of causing a flaw in the titanium tube 10 is slightly higher than that in the roll central portion 21. Further, since the amount of load applied to the titanium tube 10 differs between the roll central portion 21 and the rotary flange portion 22, the load applied to the titanium tube 10 may vary. On the other hand, in this example, the roll surface corresponding to the rotating flange portion 22 in the third example is carried by another adjacent titanium tube forming roll 41, and the rotation axes of the adjacent titanium tube forming rolls 41 are parallel to each other. Therefore, as in the third example, the occurrence of flaws in the titanium tube 10 and the non-uniformity of the load on the titanium tube 10 due to the rotation of the roll center portion 21 and the rotating flange portion 22 coaxially are eliminated, and more. The titanium tube 10 can be formed in an ideal state.

Further, in this example, since the clearance between the inclined portions 45 of the adjacent titanium tube forming rolls 41 can be set smaller than before, the roundness of the titanium tube 10 can be further increased.

According to the titanium tube forming roll according to the present invention as described above, since the surface treatment film is formed on the base material, the wear resistance and the adhesion resistance can be improved. In particular, by incorporating h-BN particles in the first plating layer, the lubricity to the titanium tube can be enhanced, and the adhesion of titanium during titanium tube molding can be prevented. Further, by forming the second plating layer between the first plating layer and the base material, the adhesion of the first plating layer can be enhanced and the peeling of the first plating layer can be suppressed.

Further, when molding the titanium tube, the friction coefficient of the molding roll, particularly the driving roll, can be reduced by molding while dropping a small amount of the lubricant on a part of the molding roll. By preventing the roll flange from sticking due to the large difference in peripheral speed (large slip) due to this effect, it is possible to suppress the occurrence of flaws in the roll flange and roll marks that occur in the drive roll. ..

That is, according to the titanium tube forming roll, the titanium tube forming apparatus, and the titanium tube manufacturing method according to the present invention, the life of the forming roll can be remarkably improved, the frequency of exchanging the forming roll can be reduced, and the manufacturing cost can be significantly reduced. .. In addition, by reducing the frequency of molding roll replacement by improving the molding roll life, it is possible to prevent a decrease in yield due to roll adjustment (position adjustment, etc.) during roll replacement, and to improve yield (higher accuracy) by improving molding dimensional accuracy. Can be achieved.

Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to the conditions used in the following examples.

(Examples 1 and 2)
Tool steel SKD11 (steel containing C, Si, Mn, Cr, Mo, V, P, S, residual iron and impurities within the scope of the present invention) specified in JIS G 4404 is used as the base material for the forming roll. Then, quenching and tempering treatments were performed. Next, a Ni electroplating layer having a thickness of 0.2 μm was formed by an electroplating method.

Next, a first plating layer composed of a Ni-BP plating layer containing P and B was formed on the Ni electroplating layer. The first plating layer was formed by an electroless plating method. As the plating bath for the Ni-BP plating layer, one containing nickel sulfate, sodium hypochlorite, dimethylamine borane, a pH buffer, a stabilizer and a complexing agent was used. Further, h-BN particles having an average particle size of 0.3 μm were added to the plating bath. As a result, h-BN particles were contained in the first plating layer. After the formation of the first plating layer, the heat treatment of Example 1 was carried out under the conditions of a heat treatment temperature of 300 ° C. and a heat treatment time of 1 hour. Example 2 did not undergo heat treatment.

In this way, the molding rolls of Examples 1 and 2 as shown in Table 1 were produced.

(Examples 3 to 6)
Tool steel SKD11 (steel containing C, Si, Mn, Cr, Mo, V, P, S, residual iron and impurities within the scope of the present invention) specified in JIS G 4404 is used as the base material for the forming roll. Then, quenching and tempering treatments were performed. Next, a Ni electroplating layer having a thickness of 0.2 μm was formed by an electroplating method.

Next, a second plating layer composed of a Ni-BP plating layer containing P and B was formed on the Ni electroplating layer. The second plating layer was formed by an electroless plating method. As the plating bath for the Ni-BP plating layer, one containing nickel sulfate, sodium hypochlorite, dimethylamine borane, a pH buffer, a stabilizer and a complexing agent was used.

Next, a first plating layer composed of a Ni-BP plating layer containing P and B was formed on the second plating layer. The first plating layer was formed by an electroless plating method. The plating bath for the Ni-BP plating layer was the same as in Examples 1 and 2. After the formation of the first plating layer, heat treatment was performed on Examples 3 and 5 under the conditions of a heat treatment temperature of 300 ° C. and a heat treatment time of 1 hour. Examples 4 and 6 were not heat-treated.

In this way, the molding rolls of Examples 3 to 6 as shown in Table 1 were produced.

(Examples 7 and 8)
Tool steel SKD11 (steel containing C, Si, Mn, Cr, Mo, V, P, S, residual iron and impurities within the scope of the present invention) specified in JIS G 4404 is used as the base material for the forming roll. Then, quenching and tempering treatments were performed. Next, a Ni electroplating layer having a thickness of 0.2 μm was formed by an electroplating method.

Next, a second plating layer composed of a Ni−B plating layer containing B was formed on the Ni electroplating layer. The second plating layer was formed by an electroless plating method. As the plating bath for the Ni-B plating layer, one containing nickel sulfate, dimethylamine boron, a pH buffer, a stabilizer and a complexing agent was used.

Next, a first plating layer composed of a Ni-BP plating layer containing P and B was formed on the second plating layer. The first plating layer was formed by an electroless plating method. The plating bath for the Ni-BP plating layer was the same as in Examples 1 and 2. After the formation of the first plating layer, the heat treatment of Example 7 was carried out under the conditions of a heat treatment temperature of 300 ° C. and a heat treatment time of 1 hour. Example 8 was not heat treated.

In this way, the molding rolls of Examples 7 and 8 as shown in Table 1 were produced.

(Examples 9 and 10)
Tool steel SKD11 (steel containing C, Si, Mn, Cr, Mo, V, P, S, residual iron and impurities within the scope of the present invention) specified in JIS G 4404 is used as the base material for the forming roll. Then, quenching and tempering treatments were performed.

Next, after forming a nitride layer on the surface by plasma nitriding treatment, a Ni electroplating layer having a thickness of 0.2 μm was formed by an electroplating method.

Next, a second plating layer composed of a Ni-P plating layer containing P was formed on the Ni electroplating layer. The second plating layer was formed by an electroless plating method. As the plating bath for the Ni-P plating layer, one containing nickel sulfate, sodium hypophosphite, a pH buffer, a stabilizer and a complexing agent was used.

Next, a first plating layer composed of a Ni-BP plating layer containing P and B was formed on the second plating layer. The first plating layer was formed by an electroless plating method. The plating bath for the Ni-BP plating layer was the same as in Examples 1 and 2. After the formation of the first plating layer, the heat treatment of Example 9 was carried out under the conditions of a heat treatment temperature of 300 ° C. and a heat treatment time of 1 hour. In Example 10, after the formation of the second plating layer, heat treatment was performed under the conditions of a heat treatment temperature of 300 ° C. and a heat treatment time of 1 hour. No heat treatment was performed after the formation of the first plating layer.

In this way, the molding rolls of Examples 9 and 10 as shown in Table 1 were produced.

(Comparative Examples 1 and 2)
Tool steel SKD11 (steel containing C, Si, Mn, Cr, Mo, V, P, S, residual iron and impurities within the scope of the present invention) specified in JIS G 4404 is used as the base material for the forming roll. Then, quenching and tempering treatments were performed. Next, after forming a nitride layer on the surface by plasma nitriding treatment, a Ni electroplating layer having a thickness of 0.2 μm was formed by an electroplating method.

Next, a first plating layer composed of a Ni−B plating layer containing B was formed on the Ni electroplating layer. The first plating layer was formed by an electroless plating method. As the plating bath for the Ni-B plating layer, one containing nickel sulfate, dimethylamine boron, a pH buffer, a stabilizer and a complexing agent was used. Further, no h-BN particles were added to the plating bath. After the formation of the first plating layer, the heat treatment of Comparative Example 1 was performed under the conditions of a heat treatment temperature of 300 ° C. and a heat treatment time of 1 hour. Comparative Example 2 was not heat-treated.

In this way, the molding rolls of Comparative Examples 1 and 2 as shown in Table 1 were produced.

(Comparative Examples 3 and 4)
Molding rolls of Comparative Examples 3 and 4 were produced in the same manner as in Comparative Examples 1 and 2 except that a first plating layer composed of a Ni-BP plating layer containing P and B was formed as the first plating layer. did. Comparative Example 4 was heat-treated under the conditions of a heat treatment temperature of 300 ° C. and a heat treatment time of 1 hour. Comparative Example 3 was not heat-treated.

In this way, the molding rolls of Comparative Examples 3 and 4 as shown in Table 1 were produced.

(Comparative Example 5)
Tool steel SKD11 (steel containing C, Si, Mn, Cr, Mo, V, P, S, residual iron and impurities within the scope of the present invention) specified in JIS G 4404 is used as the base material for the forming roll. Then, quenching and tempering treatments were performed. Next, after forming a nitride layer on the surface by plasma nitriding treatment, a Ni electroplating layer having a thickness of 0.2 μm was formed by an electroplating method.

Next, a first plating layer composed of a Ni-BP plating layer containing P and B was formed on the Ni electroplating layer. The first plating layer was formed by an electroless plating method. As the plating bath for the Ni-BP plating layer, one containing nickel sulfate, sodium hypochlorite, dimethylamine borane, a pH buffer, a stabilizer and a complexing agent was used. Further, c-BN particles were added to the plating bath. The c-BN particles were made to contain 1% by mass in the first plating layer. No heat treatment was performed on the first plating layer.

In this way, the molding roll of Comparative Example 5 as shown in Table 1 was produced.

The molding rolls of Examples 1 to 10 and Comparative Examples 1 to 5 have the shapes shown in FIG. 2, and have a hole type R: 12.6 mm, a roll bottom diameter Dr: 100 mm, a roll outer diameter Do: 124 mm, and a roll. Width W: 60.0 mm.

<Evaluation>
The mechanical properties of each of the molding rolls of Examples 1 to 10 and Comparative Examples 1 to 5 were evaluated. The evaluation conditions were as follows: using a JIS Class 3 titanium metal tube having a diameter of 25.0 mm and a thickness of 0.5 mm, the tube forming speed by TIG welding was set to 6 / min, and after welding, molding was performed using the molding apparatus shown in FIG. .. At this time, a soluble oil-based lubricant was used as the lubricant, and molding was performed while dropping a small amount of this lubricant at 10 ml / hr.

As a result, in Examples 1 to 10, peeling of the surface-treated film of the roll did not occur and titanium adhesion did not occur even after the molding time had passed for 24 hours. Therefore, no roll defect occurred. Therefore, the durability was good.
On the other hand, when the JIS Class 3 titanium tube was molded using the rolls of Comparative Examples 1 to 5, roll defects were generated before 30 minutes had passed, and the base material of the molding roll was exposed. As described above, the molding rolls of Comparative Examples 1 to 5 had insufficient durability.

1, 21, 31 ... Titanium tube forming roll, 3 ... Rotating shaft, 10 ... Titanium tube, 12 ... Roll body (base material), 4, 14 ... Roll recess, 21 ... Roll center, 21a ₁ ... Outer surface (opposing) Surface), 21a ... Base, 21b ... Projection, 22 ... Rotating flange, 22b ... Inner peripheral surface (opposing surface), 22c ... Outer surface (opposing surface), 23 ... Fixed flange, 23b ... Facing surface, 24 ... 1st bearing part, 24a ... Rolling body, 25 ... 2nd bearing part, 25a ... Rolling body, 32 ... Pull thread part, 101 ... Lubrication nozzle, 102 ... Lubrication nozzle fixing base, 103 ... Horizontal movement guide, 104 ... Up and down Position adjustment handle, 105 ... Left and right position adjustment handle, 106 ... Center position adjustment jig, 107 ... Available type pedestal, 108 ... Stand support mounting jig, 109 ... Lubrication nozzle angle adjustment jig, 112 ... Lubrication nozzle angle fixing screw, 113 ... Lubrication Nozzle front / rear adjustment jig, 114 ... Width adjustment screw (normal / screw used), 115 ... Width movement guide part, 116 ... Vertical movement screw 117 ... Molding stand support, 118 ... Width movement groove, 119 ... Width movement guide, 120 ... Stand fixing screw, 130 ... Roller, 131 ... Central axis, 132 ... Silicon tube.

Claims (37)

By mass%
C: 1.00 to 2.30%,
Si: 0.10 to 0.60%,
Mn: 0.25 to 0.80%,
P: 0.030% or less,
S: 0.030% or less,
Cr: 4.80 to 13.00%,
Mo: 0 to 1.20%,
V: 0-1.00%,
W: Contains 0 to 0.80%,
With a base material having a chemical composition in which the balance is iron and impurities,
A first plating layer containing Ni formed on the surface of the base material is provided.
The first plating layer contains P: 3.0 to 7.0% by mass and B: 0.5 to 3.0% by mass, and the balance is a Ni-P-B plating layer composed of Ni and impurities. A member containing 0.5 to 3% by mass of h-BN particles and having a Vickers hardness in the range of 700 to 1100. By mass%
C: 1.00 to 2.30%,
Si: 0.10 to 0.60%,
Mn: 0.25 to 0.80%,
P: 0.030% or less,
S: 0.030% or less,
Cr: 4.80 to 13.00%,
Mo: 0 to 1.20%,
V: 0-1.00%,
W: Contains 0 to 0.80%,
With a base material having a chemical composition in which the balance is iron and impurities,
A first plating layer containing Ni formed on at least the rolled surface of the base material is provided.
The first plating layer contains P: 3.0 to 7.0% by mass and B: 0.5 to 3.0% by mass, and the balance is a Ni-P-B plating layer composed of Ni and impurities. A titanium tube forming roll containing 0.5 to 3% by mass of h-BN particles and having a Vickers hardness in the range of 700 to 1100. The titanium tube forming roll according to claim 2, wherein the Vickers hardness of the first plating layer is in the range of more than 800 to 1100. The titanium tube forming roll according to claim 2, wherein the Vickers hardness of the first plating layer is in the range of 700 to 800. A second plating layer containing Ni is provided between the first plating layer and the base material.
The second plating layer is a Ni-B plating layer containing B: 0.3 to 3.0% by mass, the balance being Ni and impurities, and a Vickers hardness of 700 to 820. Item 2. The titanium tube forming roll according to any one of Item 4. A second plating layer containing Ni is provided between the first plating layer and the base material.
The second plating layer is a Ni-B plating layer containing B: 0.3 to 3.0% by mass, the balance being Ni and impurities, and a Vickers hardness of 900 to 1100. Item 2. The titanium tube forming roll according to any one of Item 4. A second plating layer containing Ni is provided between the first plating layer and the base material.
Claims 2 to 2, wherein the second plating layer is a Ni-P plating layer containing P: 3.0 to 10.0% by mass, the balance being Ni and impurities, and a Vickers hardness of 700 to 1100. Item 2. The titanium tube forming roll according to any one of Item 4. A second plating layer containing Ni is provided between the first plating layer and the base material.
The second plating layer contains P: 3.0 to 10.0% by mass and B: 0.5 to 3.0% by mass, the balance is composed of Ni and impurities, and the Vickers hardness is 900 to 1100. The titanium tube forming roll according to any one of claims 2 to 4, which is a Ni-BP plating layer. A second plating layer containing Ni is provided between the first plating layer and the base material.
The second plating layer contains P: 3.0 to 10.0% by mass and B: 0.5 to 3.0% by mass, the balance is composed of Ni and impurities, and the Vickers hardness is 700 to 800. The titanium tube forming roll according to any one of claims 2 to 4, which is a Ni-BP plating layer. The invention according to any one of claims 2 to 9, wherein an electric Ni plating layer having a thickness of 0.1 to 1 μm is formed between the base material and the first plating layer or the second plating layer. Titanium tube forming roll. The titanium tube forming roll according to any one of claims 2 to 10, wherein the thickness of the first plating layer is in the range of 1 to 10 μm. The titanium tube forming roll according to any one of claims 2 to 11, wherein the thickness of the second plating layer is in the range of 1 to 2 μm. The titanium tube forming roll according to any one of claims 2 to 12, wherein the Vickers hardness of the base material is 550 to 650. The titanium tube forming roll according to any one of claims 2 to 13, wherein a nitride layer is formed on the rolled surface of the base material. The titanium tube forming roll according to claim 14, wherein the nitrided layer has a thickness of 0.5 μm to 50.0 μm. The titanium tube forming roll according to claim 14 or 15, wherein the average nitrogen concentration of the nitrided layer is 0.10 to 1.0% by mass. The titanium tube forming roll according to any one of claims 14 to 16, which has a concentration gradient in which the concentration distribution of nitrogen in the nitrided layer decreases from the surface layer of the nitrided layer in the depth direction. The base material is by mass%
Mo: 0.70 to 1.20%,
V: 0.15-1.00%,
W: The titanium tube forming roll according to any one of claims 2 to 17, which contains at least one selected from 0.60 to 0.80%. It is a hole-shaped roll in which a semicircular roll recess is provided over the entire circumference of the roll body.
The titanium tube forming roll according to any one of claims 2 to 18, wherein the rolled surface is the surface of the roll recess. The roll body includes a roll central portion and a pair of rotating flange portions arranged on both sides of the roll central portion so as to be rotatable with respect to the roll central portion.
The titanium tube forming roll according to claim 19, wherein the roll recess is divided by the roll central portion and the rotating flange portion. The 20th aspect of the present invention, wherein the roll central portion is fixed to a rotating shaft that drives the roll body, and the rotating flange portion is rotatable with respect to the rotating shaft and the roll central portion. Titanium tube forming roll. The roll central portion is provided with a base portion and a protruding portion protruding from the roll width direction central portion of the base portion toward the outer peripheral direction of the roll.
The rotating flange portions are located on the base portion and are arranged on both sides of the protruding portion in the roll width direction.
The titanium tube forming roll according to claim 20 or 21, wherein a first bearing portion is provided between the base portion of the roll central portion and the rotating flange portion. The facing surfaces facing each other between the base portion and the rotating flange portion at the center of the roll are the raceway surfaces of the rolling elements of the first bearing portion, and the facing surfaces are the first plating. The titanium tube forming roll according to claim 22, further comprising a layer or any of the first plating layer and the second plating layer. A fixed flange portion arranged on both sides of the pair of rotating flange portions in the roll width direction and fixed to the roll center portion, and a second bearing portion arranged between the fixed flange portion and the rotating flange portion. The titanium tube forming roll according to any one of claims 20 to 23. The facing surfaces facing each other between the fixed flange portion and the rotating flange portion are the raceway surfaces of the rolling elements of the second bearing portion, and the facing surfaces are the first plating layer or the first plating layer. The titanium tube forming roll according to claim 24, comprising the first plating layer and the second plating layer. The titanium tube forming roll according to claim 24 or 25, wherein the fixed flange portion is provided with a draw screw portion for attracting and fixing the rotating flange portion. The two titanium tube forming rolls according to any one of claims 19 to 26 are provided.
The two titanium tube forming rolls are arranged so that their respective roll recesses face each other, and the respective roll recesses are arranged so as to be in contact with each other on the same circumference of the outer peripheral surface of the titanium tube to be molded. Titanium tube molding equipment. A roll body made of the base material is provided.
The roll body is provided with a roll recess having an arcuate cross-sectional view provided over the entire circumference thereof and both sides of the roll recess in the width direction, and the roll body is rotated toward the outside in the roll width direction of the roll body. It has an inclined part that inclines toward the shaft side,
The surface of the roll recess is the rolled surface, and the surface of the roll recess is provided with either the first plating layer or the first plating layer and the second plating layer.
Further, any one of claims 2 to 18, wherein the surface of the inclined portion is also provided with the first plating layer, or any of the first plating layer and the second plating layer. The titanium tube forming roll described in. The four titanium tube forming rolls according to claim 28 are provided.
Of the four titanium tube forming rolls, the roll recesses of the two titanium tube forming rolls are arranged so as to face each other, and the roll recesses of the other two titanium tube forming rolls face each other. The roll recesses of the four titanium tube forming rolls are arranged so as to be in contact with each other on the same circumference of the outer peripheral surface of the titanium tube to be formed, and the titanium tube forming rolls adjacent to each other are further arranged. A titanium tube forming device in which inclined parts face each other. A titanium tube forming apparatus provided with the titanium tube forming roll according to any one of claims 2 to 26 or 28, wherein a part of the titanium tube forming roll is lubricated during titanium tube forming. A titanium tube forming apparatus having a lubricating nozzle for supplying an agent. The titanium pipe molding apparatus according to claim 30, wherein the position of the lubrication nozzle can be changed according to the molding size of the titanium pipe. The titanium tube forming apparatus according to claim 30, wherein the position of the lubricating nozzle can be changed according to the diameter of the titanium tube forming roll. The titanium tube molding apparatus according to any one of claims 30 to 32, wherein the position and orientation of the lubrication nozzle can be arbitrarily adjusted. The titanium tube molding apparatus according to any one of claims 30 to 33, wherein the lubricating nozzle is a tube having an inner diameter of 0.5 to 3.0 mm. The titanium according to any one of claims 30 to 32, wherein a soluble oil-based lubricant is used as the lubricant, and the lubricant is supplied by dropping a small amount at 1.0 to 20.0 ml / hr or less. Tube forming equipment. A method for producing a titanium tube, which is formed by using the titanium tube forming roll according to any one of claims 2 to 26 or 28. A method for producing a titanium tube, which is formed by using the titanium tube forming apparatus according to any one of claims 27 or 29 to 35.

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