JPS6233007A - Composite ring roll for angle rolling - Google Patents

Abstract

PURPOSE:To reduce a price of a composite ring roll for angle rolling and to extend roll life by embedding an annular ring of an excellent wear resistance material and of an angle-shaped section into a base body with the periphery of the ring being cropped out and joining the ring with the body diffusely. CONSTITUTION:Composite ring rolls 1a and 1b are made up of ring bodies 2a, 2b for rolling and ring base bodies 3a, 3b, respectively. The ring bodies 2a and 2b are formed by sintering high alloy powders having an excellent wear resistance; the periphery of the ring bodies 2a and 2b contacts with a rolling stock and rolls and forms the stock into an angle. The ring base bodies 3a and 3b are of a low carbon low alloy steel having ferrite base and embedding grooves 4a and 4b are formed on the periphery of respective annular rings and irregularity is formed on the embedding plane. The embedding grooves 4a and 4b are press filled with powders of high wear resistance material into an angle shape and the powders are sintered and joined with the grooves 4a and 4b diffusely. Therefore, joining strength is increased so that the ring rolls 1a and 1b are fixed to a shaft by shrinkage fitting, welding, or bolting.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a composite ring roll for rolling that is assembled on a shaft and used in an assembly roll for rolling angle steel.

(Prior art) In angle rolling rolls, especially rolls for finishing rolling mills, wear resistance is required for the part that comes into contact with the rolled material (rolling layer), so the outer layer, which is the rolling layer, and the tough A composite roll is used in which a shaft core portion made of a material is welded and integrated, and a diamond-shaped caliber for angle forming is provided on the outer layer. This type of composite roll is mainly integrated into a composite roll at the casting stage using a centrifugal casting method.

On the other hand, in the finishing row of wire rod rolling, carbide ring rolls are almost always used these days. For example, in block mills, as shown in Figure 7, for example, WC (!: W
A ring roll 11 made of C-based carbide material is used. In addition to being used alone, the ring roll 11 is often fixed to a shaft by mechanical means and used as an assembled roll.

(Problems to be Solved by the Invention) When a carbide ring roll is shaft-fitted and used as an assembly roll, the entire ring roll is made of carbide material, which is not economical, and the assembly structure is complicated as shown in Fig. 6. It is necessary to do so. That is, when assembling and fixing the ring roll 11'' to the shaft, it is necessary to firmly fix it to the shaft using the fixing ring 12, spacer ring 13, etc. Also, the thermal expansion coefficient of the steel thread shaft and the carbide ring material It is necessary to alleviate the large difference in
Power and et al. result in such a complex structure. As a result, such assembled rolls are very costly.

Further, when a carbide ring roll is used for angle adjustment rolling, there is a big problem in terms of cost. In other words, with a carbide ring for wire rod rolling that has a relatively shallow caliber, the ring thickness will not be very large, but for steady rolling, especially angle rolling, a large diamond-shaped caliber is required to form the angular shape. Therefore, if a ring roll having such a caliber is made of carbide material, it will be very expensive and there will be problems in terms of strength.

In addition, conventional methods have been used to impart wear resistance to only the part of the caliber in contact with the rolled material, such as applying wear-resistant material to the surface of a part of the caliber of a cast steel roll by welding or thermal spraying, and surface treatment such as surface hardening. There is a method of hardening the steel, but the build-up part peels off due to rolling pressure, and it is difficult to thicken the hardened layer, resulting in a short life. Furthermore, since it is necessary to select a material with good weldability as the roll material, there has been a problem in the use of materials with excellent wear resistance such as high carbon materials and high alloy materials.

The present invention has been made in view of such problems, and an object of the present invention is to provide a composite ring roll for angle rolling that is low in cost, easy to fit around the shaft, and has a long rolling life.

(Means for Solving the Problems) A feature of the present invention for achieving the above object is that a rolling ring having an angled cross section is formed by sintering a powder of a high alloy material with excellent wear resistance. The ring base is made of a strong material and is engaged with the ring body at the buried surface, and is heat-resistant. It is made by diffusion bonding using hydrostatic pressure.

(Example) Next, the composite ring roll for angle rolling of the present invention will be described in detail with reference to the drawings.

Figures 1+1) and (2) are cross-sectional views showing the structure of the composite ring roll of the present invention, and Figure 1 (1) is a female composite ring roll la having recesses for forming the outer surface of the angle. The figure (2) shows a male composite ring roll 1b having a convex portion for forming the inner surface of the angle. As shown in FIG. 2, these composite ring rolls work together as a pair to roll and form angle steel.

The composite ring rolls la, lb are composed of rolling ring bodies 2a, 2b having an angled cross section and ring base bodies 3a, 3b embedded in the ring bodies 2a, 2b with their outer circumferential surfaces exposed. The ring bodies 2a, 2b and the ring base bodies 3a, 3b engage with the unevenness on their buried surfaces and are subjected to hot isostatic pressing (
Hereinafter referred to as HIP. ) is used for diffusion bonding.

The rolling rings 2a and 2b are portions whose outer circumferential surfaces are in contact with the rolled material and roll-formed into an angle shape, and the WC
Carbide material made of heat-resistant high hardness materials such as WC powder, etc.
It is made of a material made of a wear-resistant material with a residual content of % or less, or a high-alloy steel material that is wear-resistant and has high hardness at high temperatures. Preferred types of the high alloy steel material are illustrated in Table 1 below.

Table 1 The tough materials forming the ring bases 3a and 3b are as follows:
In general, the material can be appropriately selected from materials such as mechanical structural carbon steel and structural alloy steel, which have excellent toughness.

Next, a method for manufacturing such a composite ring roll will be described.

First, a ring base 3 in which the rolling rings 2a and 2b are embedded.
Prepare a and 3b. The ring base bodies 3a, 3b are
Figure +11. (As shown in 21, embedding grooves 4a and 4b are formed on the outer circumferential surface of a cylindrical material ring made of a strong material.In the female ring base 3a, the embedding grooves 4a are formed in the material ring. It is recessed in a V-shaped cross section along the outer peripheral surface of the ring, while in the male ring base 3b, the embedded a4b is recessed in an inverted V-shape with a raised mountain-shaped bottom. Further, each surface (embedding groove) of the embedding grooves 4a and 4b is provided with an unevenness having a depth of about 11 by machining.

Next, powder of a highly wear-resistant material, which has been processed into powder by water atomization or the like, is placed into the grooves 4a and 4b of the ring bases 3a and 3b in an angled shape to form the rolling rings 2a and 2b. The powder is pressed and filled, a cheating process is performed to prevent the powder from spilling, and after being degassed in a vacuum, it is subjected to a HIP process, and the powder is sintered to form a rolling ring part and the two are diffusion bonded. The composite ring material thus obtained is subjected to caliber processing to obtain the desired composite ring roll. At this time, the wall thickness of the rolling rings 2a, 2b after the finishing process is set to be equal to the thickness necessary for reshaping and have some margin.

When the rolling ring is made of high-alloy steel, the composite ring material is subjected to quenching and tempering heat treatment before or after forming the caliber in order to impart wear resistance to the rolling ring.

As explained above, the rolling rings 2a, 2b and the ring base bodies 3a, 3b are diffusion bonded by HIP processing, and the composite ring material is sometimes subjected to quenching and tempering heat treatment. The use of low carbon, low alloy steel comprising a ferrite base for the ring base is extremely advantageous in various respects. In other words, the material made of such a ferrite base has a small coefficient of thermal expansion, so it is less deformed even by temperature changes during HIP processing oil thermal cooling, and cracks and peeling at the diffusion bonding surface are less likely to occur, and the heat treatment of the composite ring material In this case, even if the entire material is hardened, the hardening effect does not reach the ring base, and the toughness does not deteriorate. If the ring base body has a hardening effect, it is undesirable because breakage is likely to occur when the composite ring roll is shaft-fitted to form an assembled roll.

It is also possible to subject only the outer layer of the composite ring material including the rolling ring to the quenching heat treatment, but this is more complicated and less productive than heat treating the whole.

The composite ring rolls 1a, 1b for angle rolling of the present invention have rolling ring bodies 2a, 2b having an angled cross section embedded in ring base bodies 3a, 3b, and interlock with each other due to the unevenness provided in the embedding grooves. Furthermore, since the two are diffusion bonded, the bonding area between the two can be increased, and the strength of the bonded part can be extremely increased. Even in such cases, it is possible to effectively prevent the crushed pieces from scattering due to rotation.

In addition, although the rolling rings 2a and 2b in contact with the rolled material are made of WC-based cemented carbide or high-alloy steel that has extremely high wear resistance, the ring bases 3a and 3b are made of strong steel or other materials. Because it is made of steel, it has good workability and weldability, and when fixing composite ring rolls LA and LB to shafts made of steel or cast iron, it is possible to use shrink fitting, welding, or tight fitting by providing a keyway. It becomes possible to fix it to the shaft using an easy method that has been used in the past. Furthermore, since the rolling rings 2a, 2b and the ring bases 3a, 3b are diffusion bonded, there is no possibility that the high alloy components of the rolling rings will mix into the ring base and deteriorate the toughness of the ring base. do not have.

This becomes a serious problem when both are integrally cast. Further, a rolling ring body 2a formed of a high alloy material,
2b has an angled cross-section, and it is advantageous in terms of cost because it uses expensive material only in the part that comes into contact with the rolled material, that is, the part along the caliber, and it is also advantageous in terms of cost. It is economical to simply fill the powder with a highly wear-resistant material and sinter it.

When the composite ring rolls 1a and 1b described above are used in a block mill or the like, they are used as they are without being assembled on a shaft, but as shown in FIGS. 4 and 5, they can be assembled on a shaft and used as an assembly roll. There are many cases where

That is, as shown in FIG. 4, two composite ring rolls 1'a are shrink-fitted onto a shaft 6 having an annular protrusion 5 integrally formed on the outer periphery of the center part, with the annular protrusion 5 in between, and A fixing ring 7 made of a strong material such as steel is fixed to the shaft 6 by shrink fitting, welding, screwing, etc. to obtain an assembled roll to which the composite ring roll 1a is fixed.

In the example described above, two composite ring rolls 1°a each having two calibers were fixed to the shaft, but the number of composite ring rolls fixed by shaft fitting or welding may vary. Of course, the number is not limited to one, as shown in FIG. 5, or two or more may be provided depending on the rolled product and roll shape. Having a large number of calibers has the advantage of lower assembly, processing, etc. costs.

In addition, although FIG. 4 and FIG. 5 show the case where the female type composite ring roll 1°a is shaft-fitted, the male-type composite ring roll is also shaft-fitted in the same way, and the two form a pair and are angled. Naturally, it is used for rolling steel.

Next, specific examples will be listed and explained.

Composite ring roll for small angle rolling (330φX10
0 l Tsuru) production example.

+11 On the outer circumferential surface of a material ring with an inner diameter of 180 mm, an outer diameter of 350 mm, and a width of 100 mm, in Fig. 3 (as shown in 11 and +21,
A single embedding groove was formed. The dimensions (l■) of the embedding groove are A-80SB=40, C=80, and D=30 in the same figure. The material of the ring base is C: 0.25%, Si:
0.15%, Mn: 0.40% (each M amount%) low C
It is steel.

(2) Fill and press SKH10 material powder (100 mesh or less) with the ingredients listed in Table 2 below into the embedding groove, and after cheating and degassing, 200 kg/c+J, 118
HIP treatment was performed at 0° C. to simultaneously sinter the powder and diffusion bond the two.

Note to Table 2: Unit weight % The remainder is essentially Fe (3) Then, the can material is removed at room temperature, and HIP is carried out.
After machining a portion of the caliber with regular dimensions in its original state, it was heated in vacuum to 1180°C, oil-cooled and quenched, and then tempered at 530°C to obtain a composite ring roll. The hardness of the rolling ring of the roll is Hs95-96, and the other parts are Hs
It was 39-40.

(4) The inner diameters of the two pairs of female/male composite ring rolls obtained in this way are processed with a grinder, and as shown in Fig. 4, they are fixed to the shaft by shrink fitting, and the upper and lower assembly rolls for angle rolling are assembled. I got it.

(Effects of the Invention) As explained above, the composite ring roll for angle rolling according to the present invention has a rolling ring made of a material with excellent wear resistance only in the part that contacts the rolled material, and is made of a material with excellent toughness. Since it is embedded in a ring base made of steel material, etc., it is low cost and has an excellent lifespan as an angle steel rolling roll.

In addition, since the rolling ring body and the ring base body are diffusion bonded by HIP processing, it is possible to prevent as much as possible the mixing of high alloy components from the ring body made of high alloy material into the ring base body, and to improve the toughness of the ring base body. will not deteriorate.

Furthermore, the rolling ring body has an angled cross section and is embedded in the ring base body, and engages with each other in a meshing manner by the unevenness provided on the buried surface, and furthermore, the two are diffusion bonded. The joint area between the two can be increased, the strength of the joint can be extremely increased, and even if the rolling ring breaks, it will not scatter, resulting in excellent safety.

Furthermore, if the composite ring roll of the present invention whose ring base is made of a strong material can be used as an assembly roll, it can be assembled onto a shaft at low cost using a simple shrink fit method, welding, screws, bolts, etc. Moreover, the shaft can be reused.

[Brief explanation of the drawing]

Figures 1 +1) and +2) are partial sectional views of the composite ring roll for angle rolling according to the present invention, Figure 2 is a partial front view showing the setting state of the composite ring roll for angle rolling during rolling, and Figure 3 +11. ．． (2+ is a partial sectional view of the ring base, FIGS. 4 and 5 are partial sectional views of an assembled roll to which the composite ring roll for angle rolling of the present invention is applied, and FIG. 6 is a sectional view of a conventional assembled roll, Figure 7 shows a cross-sectional view of a conventional ring roll. la, lb, l'a - composite ring roll, 2a, 2b
- Ring body for rolling, 3a, 3b...Ring base, 4a, 4
b... Embedded groove.

Claims (1)

[Claims] 1. A rolling ring body with an angled cross-section formed by sintering from powder of a high-alloy material with excellent wear resistance, and a ring embedded with the outer peripheral surface of the ring body exposed. and a base body, the base body is made of a strong material, and is engaged with the ring body at an embedded surface in an uneven manner, and is diffusion bonded by hot isostatic pressing. Composite ring roll. 2. The composite ring roll according to claim 1, wherein the ring base is made of low carbon, low alloy steel comprising a ferrite base.