JPS59159973A - Sliding member - Google Patents

Abstract

PURPOSE:To provide a sliding member having good sliding lubricity and excellent mechanical strength and toughness by having the compsn. consisting of specifically composed C, Si, Mn, Cr, Mo, V and Fe, etc. CONSTITUTION:A sliding member is formed of the compsn. contg. 0.6-1.2wt% C, <=3% Si, <=3% Mn, 6-10% Cr, 0.1-1.5% Mo, and 0.01-1% V, and, if necessary, contg. >=1 kind of 0.0005-0.01% B and 0.0005-0.3% REM to improve hardenability, >=1 kind among <=0.2% S, <=0.4% Pb, <=0.3% Se, <=0.5% Bi, <=0.3% Te and 0.0002-0.01% Ca to improve machinability, >=1 kind among <=1.2% Ni, <=2% Cu, <=2% W, <=2% Co and <=2% Nb to improve wear resistance and consisting of the balance Fe and unavoidably included impurities, by which the sliding member having good sliding lubricity and excellent mechanical strength and toughness and suitable for a segment of a steel pipe expander, etc. is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a highly tough sliding member (material and parts) that has good strength and toughness and also has excellent sliding lubricity.

Traditionally, devices that use sliding materials include pumps and compressors that reciprocate a piston within a cylinder, lathes that reciprocate a tool post on a bed, and grinders that reciprocate a table on a base. machine tools, and tube expanders that fit multiple segments around the outer periphery of a tapered cone and move each segment forward and backward in the radial direction.

Among these tube expanders, there are, for example, those having structures shown in FIGS. 1 and 2. In the figure, l is a steel pipe,
2 is a pull rod, 3 is a tapered cone with a regular polygonal cross section fitted on the outer periphery of the pull rod 2, and 4 is a nut that is screwed into the male threaded portion 2a at the end of the pull rod 2 and holds the cone 3 via a ring 5. be. An inverted T-shaped groove 3a is formed on each surface of the cone 3, as shown in FIG. and connect the segments 6 to the pull opening and the end 2 on each side of the cone 3 with a regular polygonal cross section.
It is configured to be able to slide in the same direction as the axial direction of the. Also,
Reference numeral 7 denotes an annular flange that abuts the end of each segment 6, and 8 a boom that supports the annular flange 7 and accommodates the pull rod 2.

In a tube expander having such a configuration, a pressurizing cylinder (not shown) is operated to move the pull rod 2 to the left in FIG. Operate the cylinder and pull rod 2
When cone 3 is moved to the right in Figure 1, cone 3 also moves to the first position at the same time.
Although each segment 6 moves in the right direction in the figure, since movement in the above direction is prevented by the annular flange 7, each segment 6 moves in the radial direction and pushes and expands the steel pipe 1 from the inside. Shape correction, 9 dimension adjustment,
The residual stress is uniformly diffused, etc. After that, when the pressure cylinder is actuated ξ and the pull rod 2 is moved to the left in FIG. 1, each segment 6 moves in the centripetal direction.
It becomes possible to take out the steel pipe l.

In this case, the surface on the outer periphery of each segment 6 where the steel pipe 1 is actually expanded is referred to as the effective expansion surface, and its longitudinal dimension is referred to as the effective expansion length. Generally, the feed pitch P per feed of the steel pipe 1 is shorter than the effective pipe expansion length L1.

In such a tube expander, forward and backward operations are repeatedly performed by a pressurizing cylinder (not shown), and the outer sliding surface 3b of the tapered cone 3 having a regular polygonal cross section and the inner sliding surface of each segment 6 are 6b, frictional sliding is frequently repeated.

By the way, in this type of conventional tube expanding machine, the cone 3 is made of alloy cast iron, and the segment 6 is made of special cast steel, and the sliding lubricity between the two can be said to be quite good. Since this segment 6 is cast, its mechanical strength is low, especially when it is made of thick-walled steel pipe (e.g.
When expanding pipes (t/D≧4%, x-65 grade), there was a problem in that the segments 6 often cracked or were damaged, resulting in a shutdown of the operation.

Therefore, measures to prevent cracking or damage of such segments are mainly considered from the viewpoint of the shape of the segment and from the viewpoint of the material. It has been desired that the sliding member of the present invention not only have good sliding properties but also excellent mechanical strength and toughness.

This invention was made in order to solve the above-mentioned conventional problems, and the object is to obtain a sliding member that has high strength, high toughness, and excellent sliding characteristics, especially in terms of material. It is.

By the way, the performance required of the above-mentioned sliding members such as segments is that they have good sliding properties with mating materials such as cones, and at the same time, they must have high strength and high toughness to prevent breakage. However, these properties are generally contradictory, and in the past, if a cast product was made with priority given to sliding lubricity, the mechanical strength would decrease, and The reality is that when changing from a cast product to a forged product, for example, the sliding lubricity deteriorates.

Therefore, the inventors of the present invention have conducted various experimental studies and found that 1.5%C-12%Cr-1.2% is used as a member other than cast steel.
Mo-0,3%V-Fe system and 0.5%C-5%Cr
-We conducted experiments by selecting alloy tool steels such as Fe-based alloys, but
Although these materials have superior mechanical strength compared to cast steel products, they have the problem of inferior sliding lubricity, and as a result of experimental research, it was found that they have good mechanical strength and toughness. We have now developed a sliding member with excellent sliding lubricity.

That is, the sliding member according to the present invention has a C:
0.6 to 1.2%, Sf: 3% or less, Mn+3% or less,
Cr: 6-10%, MO=0.1-1.5%, V: 0.
01 to i%, and if necessary, in order to further improve wear resistance, Ni: 1.2% or less, Cu: 2% or less, W: 2% or less, Co: 2% or less, Nb: One or more of 2% or less, B: 0.0005~0.01%, HEM (rare earth element): 0.0O05~0.3% to improve hardenability. One or more of these, S: 0.2% or less, Pb: 0, to improve machinability during finishing after machining or forging.
．． 4% or less, Se: 0.3% or less, Bi: 0.5% or less, Te: 0.3% or less, Ca: 0.0002 to 0.01
%, and the remainder substantially consists of Fe.

From the perspective of improving the mechanical strength and toughness of sliding members, the present inventors have conducted various studies based on conventional tool steel, focusing on the amount of giant carbides and sliding lubricity, and have determined the optimal composition range. I found out. That is, F e -C-Cr-
High temperature tempering hardness of 1% MO type rust is approximately 515'
When we investigated the effects of C and Cr contents on the number of primary carbides (hereinafter referred to as macrocarbides) on lO loci in microstructures of C) and microstructures, we obtained the results shown in Figure 3, and found that the C content was 0. By setting the Cr content to 6 to 1.2% and 6 to 10%, mechanical strength and toughness can be made good, and at the same time, sliding properties can be improved by the presence of appropriate giant carbides. I understand. The reason for limiting the range of each component of the sliding member of the present invention based on such knowledge will be explained below.

C: 0.6-1.2% C is an element necessary for forming carbides that contribute to improving wear resistance, and is used to improve hardenability, increase the hardness of martensite, and obtain excellent strength. Although it is a necessary element, 0
．． If it is less than 6%, the hardenability decreases, making it difficult to obtain the necessary hardness after quenching and tempering, and the ability to form carbides decreases, resulting in insufficient strength and wear resistance.
%, large amounts of giant carbides are produced as shown in FIG. 3, which deteriorates the sliding properties and also deteriorates the toughness, so the range is set to 0.6 to 1.2%.

Si: 3% or less Si is an element that acts as a deoxidizing agent and contributes to increasing the tempering resistance of martensite, but if it is too large, the toughness deteriorates, so it is set to 3% or less.

Mn: 3% or less Mn acts as a deoxidizing and desulfurizing agent, improving the cleanliness of steel and contributing to good hardenability, but too much will impair workability and cause residual It is set to 3% or less in order to generate austenite and reduce hardness after quenching and tempering.

Cr: 6-12% Cr dissolves into the matrix during hardening to improve hardenability, forms Cr carbide to improve wear resistance, and at the same time improves oxidation resistance, but if it is less than 6%, If the amount of giant carbide produced is small and exceeds 12%, as shown in FIG. 3, there will be too much giant carbide, deteriorating sliding properties and toughness, so it is set in the range of 6 to 12%.

Mo: 0.1 to 1.5% MO dissolves in the matrix during quenching, forms carbides, improves wear resistance as a sliding material, and is effective in increasing quenching and tempering resistance. It is an element that
For this purpose, it is necessary to contain 0.1% or more, but 1
．． If it exceeds 5%, the toughness will deteriorate, so if it exceeds 0.1 to 1.
The range shall be 5%.

V: 0.01-1% ■ is an element that prevents the coarsening of austenite crystal grains in the matrix, forms fine carbides, and contributes to improving wear resistance and hardening resistance. It is necessary to contain 0.01% or more, but (2) must be contained in an amount of 1% or less because too much C fixes effective carbon, and if it is too large, it will actually cause a decrease in hardness.

Ni: 1.2% or less, Cu: 2% or less, W: 2% or less,
One or two of Co: 2% or less, Nb: 2% or less
Ni, Cu, W, Co, and Nb all contribute to strengthening the matrix and form carbides to improve wear resistance, but when added in large amounts, they reduce hot workability and toughness, so the above It is appropriate to limit the range of each component.

B: 0.0005 to 0.01%, REM (rare earth element): one or two of O,0O05 to 0.3%
Species B and REM are both elements that contribute to improving hardenability, and are effective in improving toughness and preventing cracking and breakage. However, if added in large amounts, they impair workability, so It is appropriate to limit the scope.

S: 0.2% or less, Pb: 0.4% or less, Se: 0.3
% or less, Bi: 0.5% or less, Te: 0°3% or less, C
a: One or more of 0.0002 to 0.01% of S, Pb, Se, Bi, Te, and Ca are all effective elements for improving machinability, and are effective for machining and machining. It improves the workability during finishing processing after plastic working (#9 forming processing, etc.), but if it is too large, it reduces hot workability and toughness, so it is recommended to limit the content of each component to the above range. Appropriate.

On the other hand, mating materials for the sliding member according to the present invention include ingot materials, forged materials, cast materials, sintered materials, sintered forged materials, etc. of metallic or non-metallic materials. For example, in the case of cast iron, has a basic composition of C: 2.5 to 2.8% by weight.
, Si: 1.6-1.8%, Mn+1.0-1.2%,
Desirably, the remainder consists essentially of Fe,
Cr, Mo, 'Ni, Cu, V, Co as necessary.

Those containing B are also desirable. It also shows good properties against ceramics, cerements, etc.

Hereinafter, a rough explanation will be given based on examples.

First, steel with the chemical composition shown in Table 1 (invention material: No. 1
~9, Comparative materials: No. 10~14) were melted and then quenched and tempered under the conditions shown in Table 2, and the tempered hardness, impact value, bending test transverse value, and rotary bending fatigue test were performed. (107 times) When the strength and friction coefficient were examined, the results were also shown in Table 2.

Next, using alloyed cast iron having the chemical composition shown in Table 3 as a mating material, the contact surface pressure between each test material was 5 to 30 kgf/
mm2. Friction speed: 30-100mm/sec
, lubricating oil: When a sliding test was conducted under the conditions of mineral oil type and oil type, the results of the friction coefficient and seizure surface pressure were shown in Table 2.

Furthermore, when a tube expansion test was conducted using an actual machine under the conditions shown in Table 4, the results shown in Table 2 regarding the attractive force and seizure status were obtained.

/ Table 3 Table 4 As is clear from the results shown in the above tables, the invention material No.
, 1, and 2 all have excellent strength, toughness, and sliding lubricity, and Ni, Co,
With No. 3.6°79 to which Nb and Cu were added, better strength and toughness could be obtained.

Furthermore, B, No. with REM added, 4.7°8.9
The hardenability was improved, and improvements in strength and toughness were observed in actual machines, and good wear resistance was obtained. Also, S
, No. 5.6, and No. 8.9 to which Pb, Ca, and Te were added had good machinability when preparing test pieces.

On the other hand, No. 10 with high C1 high Cr and high CO
, and No. and ll with high C9 and high Or, had poor toughness, high friction coefficient, and low seizure surface pressure. Moreover, No. 12 with low C2 and low Or had low strength, a large wear coefficient, and a low seizure surface pressure.

Furthermore, No. 13, which does not contain Mo, and No. 14, which does not contain (2), have a higher strength than the steel of the present invention.

Toughness was low. In addition, cast iron No. 15 had a friction coefficient and a seizure pressure at the same level as the present invention material. In other words, the material of the present invention was confirmed to exhibit ground motion lubricity equivalent to that of cast iron, and was able to solve the problems of cast iron, such as low strength and low toughness.

As explained above, the sliding member according to the present invention is
It has good sliding lubricity as well as excellent mechanical strength and toughness, and can be used not only when the mating material is cast iron, but also ferrous or non-ferrous metal materials, and even sintered bodies of non-metal materials9. It has excellent sliding properties with surface-treated objects, etc.
In addition to being suitable as a material for segments that make sliding contact with a tapered cone to expand the tube material from the inner side, it also has the remarkable effect of being suitable as a sliding material or sliding component for various uses.

[Brief explanation of drawings]

Figures 1 (a) and (b) are a cross-sectional explanatory view and a longitudinal cross-sectional view showing an example of the structure of a tube expander, respectively, and Figure 2 is an enlarged view showing the fitting part of the cone and segment of the tube expander in Figure 1. FIG. 3 is a graph showing the influence of C and Cr contents on the high temperature tempering hardness and the number of giant carbides of Fe-C-Cr-1% MO steel. Patent applicant Nippon Steel Corporation Patent applicant Daido Steel Co., Ltd. Representative patent attorney Yutaka Oshio

Claims (1)

[Claims] (1) In weight%, C: 0.6 to 1.2%, Si: 3% or less, Mn: 3% or less, Cr: 6 to 10%, Mo: 0.1
~1.5%, V: 0.01~1%, and the balance is Fe and unavoidably mixed impurities. A sliding member with good sliding lubricity and excellent mechanical strength and toughness. . (2) A sliding member having good sliding lubricity and excellent mechanical strength and toughness according to claim (1), wherein the sliding member is a segment of a steel pipe expanding machine. (3) In weight%, C: 0.6 to 1.2%, Si: 3% or less, Mn: 3% or less, Cr: 6 to 10%, Mo: 0
．． 1-1, 5%, V: 0.01-1%, and B: 0
．． 0005-0.01%, REM: 0.0005-0
．． A sliding member having good sliding lubricity and excellent mechanical strength and toughness, characterized in that it is made of one or two of the following: (4) A sliding member having good sliding lubricity and excellent mechanical strength and toughness according to claim (3), wherein the sliding member is a segment of a steel pipe expanding machine. (5) In weight%, C: 0.6 to 1.2%, Si: 3% or less, Mn: 3% or less, 0126 to 10%, Mo: 0.1
~1.5%, V: 0.01~1%, and S: 0°2%
Below, Pb: 0.4% or less. Se: 0.3% or less, Bi: 0.5% or less, Te20.
3% or less, Ca: 1 of 0.0002-0.01%
1. A sliding member having good sliding lubricity and excellent mechanical strength and toughness, characterized by comprising one or more species, the remainder being Fe and impurities inevitably mixed in. (6) A sliding part having good sliding lubricity and excellent mechanical strength and toughness according to claim (5), wherein the sliding member is a segment of a steel pipe expanding machine. ,C:
0.6 to 1.2%, Si: 3% or less, Mn: 3% or less,
Cr: 6-10%, Mo: 0.1-1.5%, V: 0.
01 to 1%, and one or more of the following: Ni: 1.2% or less, Cu: 2% or less, W: 2% or less, Co: 2% or less, Nb: 2% or less, the balance being Fe. and unavoidably mixed impurities, the sliding member having good sliding lubricity and excellent mechanical strength and toughness. (8) A sliding member having good sliding lubricity and excellent mechanical strength and toughness according to claim (7), wherein the sliding member is a segment of a steel pipe expanding machine. (9) In weight%, C: 0.6-1°2%, Si: 3% or less, Mn: 3% or less, Cr: 6-10%, Mo+0.1
~1.5%, V: 0.01-1%, and B: 0.0O
05 to 0.01%, REM: one or two or more of 0.0005 to 0.3%, further S: 0.2% or less,
Pb: 0.4% or less, Se: 0.3% or less, Bi: 0
．． 5% or less, Te: 0.3% or less, Ca: 0.0002
~0.01% of one or more types, the balance being Fe
A sliding member characterized by having good sliding lubricity and excellent mechanical strength and toughness, characterized by comprising impurities that are unavoidably included. (10) A sliding member having good sliding lubricity and excellent mechanical strength and toughness according to claim (9), wherein the sliding member is a segment of a steel pipe expanding machine. (11) In weight%, C: 0.6-1.2%, Si: 3%
Below, Mn: 3% or less, Cr: 6 to 1O%, Mo: O,
1-1.5%, V: 0.01-i%, and B: O,0
O05~0.01%, REM:0.0005~0.3%
One or more of the following, Ni: 1.2% or less, Cu: 2% or less, W: 2% or less, Co: 2% or less,
Nb: 2% or less of one or more types, the balance being F
1. A sliding member which has good sliding lubricity and excellent mechanical strength and toughness, characterized by comprising e.g. and unavoidably mixed impurities. (12) A sliding member having good sliding lubricity and excellent mechanical strength and toughness according to claim (11), wherein the sliding member is a segment of a steel pipe expanding machine. (13) In weight%, C: 0.6-1.2%, Si: 3%
Below, Mn: 3% or less, Cr: 6-10%, Mo: 0.
1 to 1.5%, V: 0.01 to 1%, and S: 0.
2% or less, Pb: 0.4% or less. Se: 0.3% or less, Bi: 0.5% or less, Te: 0.
3% or less, Ca: one or more of 0.0002 to 0.01%, rough Ni: 1.2% or less, Cu
: 2% or less, W: 2% or less. One or two of Co: 2% or less, Nb: 2% or less
1. A sliding member having good sliding lubricity and excellent mechanical strength and toughness, characterized in that the remaining portion is Fe and unavoidably mixed impurities. (14) A sliding member having good sliding lubricity and excellent mechanical strength and toughness according to claim (13), wherein the sliding member is a segment of a steel pipe expanding machine. (15) In weight%, C: 0.6-1.2%, Si: 3%
Below, Mn: 3% or less, Cr: 6-10%, Mo: 0.
1-1.5%, V: 0.01-1%, and B: 0
．． 0005-0.01%, REM: 0.0005-0.
One or more of 3%, and S: 0.2%
Below, Pb: 0.4% or less, Se: 0.3% or less, Bi
: 0.5% or less, Te: 0.3% or less, Ca: 0.00
One or more of 02 to 0.01%, Ni: 1.2% or less, Cu: 2% or less, W: 2% or less,
One or two of Co: 2% or less, Nb: 2% or less
1. A sliding member having good sliding lubricity and excellent mechanical strength and toughness, characterized in that the remaining portion is Fe and unavoidably mixed impurities. (16) A sliding member having good sliding lubricity and excellent mechanical strength and toughness according to claim (15), wherein the sliding member is a segment of a steel pipe expanding machine.