JPS58387A - Production of composite roll - Google Patents

Abstract

PURPOSE:To weld faying surfaces by diffusion and to improve the binding strength between an arbor and a sleeve by sealing and heating under pressure the circumferential edge parts of the faying surfaces to be left after shrinkage fitting of the sleeve and arbor consisting of prescribed carbon steel. CONSTITUTION:After an arbor 2 made of low carbon steel and a sleeve 1 made of high carbon steel are formed respectively separately to prescribed shapes, grooves 3 are provided in the circumferential edge parts on the inside circumferential surface of the sleeve and the circumferential edge parts in the body part of the arbor. This sleeve 1 is heated to the extent of not producing oxide scale and both are shrinkage fitted. The grooves 3 are welded to seal tightly the faying surfaces of the sleeve 1 and the arbor 2, after which these are heated under pressure. The diffusion bonding progresses thoroughly without formation of oxide scale on the faying surfaces and the binding strength is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a composite roll, and particularly to a method suitable for manufacturing a composite roll for rolling.

Rolls for rolling require both abrasion resistance and strength, so the sleeve in contact with the material to be rolled is made of a material with high abrasion resistance, and the gaa bar is made of a material with high strength, making it a composite roll. is sometimes used.

Conventionally, such composite rolls have been manufactured by shrink fitting, that is, heating and expanding the sleeve, coaxially inserting the arbor into the sleeve, cooling and shrinking the sleeve, and fixing the sleeve and the arbor by the shrinkage force. Ta.

However, rolls manufactured by this method have low joint strength because the joint surfaces of the arbor and sleeve are not diffusion bonded, and slippage may occur between the arbor and the sleeve during rolling.

As a means to solve this problem, attempts have been made to shrink-fit the arbor and sleeve and then apply heat and pressure to diffusion bond them together. The problem is that very few connections are made.

An object of the present invention is to solve the problems of the prior art and to provide a method for manufacturing a composite roll in which an arbor and a sleeve are diffusion-bonded and the bonding strength is high.

In the present invention, after a sleeve and an arbor made of metals having different compositions are fixed by cold fitting, the peripheral edge of the joining surface between the sleeve and the arbor is welded to seal the joining surface, and then heated and pressurized. The above object is achieved by a method for manufacturing a composite roll, which is characterized in that the bonding surfaces are diffusion bonded.

The present invention will be explained below based on the accompanying drawings.

In FIG. 1, 1 is a sleeve made of high carbon @, and 2 is an arbor made of low carbon steel. In the diagram, 3 is the bevel, 4 is the overlay, and 5
is the welded meat.

Such a composite roll is manufactured as follows.

That is, after the aper and the sleeve are separately melted, forged, and heat treated, and then rough-finished into a predetermined shape, grooves are provided at the periphery of the inner circumferential surface of the sleeve and the circumferential edge of the outer circumferential surface of the aper body. . Next, the arbor and sleeve are each preheated to a temperature that will not cause welding cracks, and after the groove is welded with mild steel and built up, annealing is performed to remove strain. Next, the oxide scale on the surface is removed, the arbor and sleeve are finished, and the inner diameter of the sleeve is made slightly larger than the outer diameter of the arbor.The arbor is then heated and the arbor and sleeve are shrink-fitted and fixed. The heating temperature of this Arno;- is preferably a temperature that does not cause oxide scale.

Next, the groove is welded to seal the joining surface of the sleeve and arbor, and then heated and pressurized to diffusion bond the sleeve and arbor. After this, it is annealed as necessary to improve machinability.

Furthermore, heat treatment is applied depending on the material to increase the strength of the aper and the hardness of the sleeve.

When manufactured in this way, the joint surfaces are sealed when the aper and sleeve are heated and pressurized for diffusion bonding, so oxide scale does not form on the joint surfaces even when heated in the atmosphere, and diffusion The bonding will proceed sufficiently. Therefore, a composite roll with extremely high bonding strength between the arbor and the sleeve can be obtained.

Also, it is difficult to directly weld low carbon steel and high carbon steel using one welding steel, but as mentioned above, grooves are provided in the arbor and sleeve in advance, and mild steel is separately welded. By building up the material and then welding it, sufficient welding strength can be obtained and the joint surface can be sufficiently sealed.

After fixing the aper and the sleeve, the conventional method of heating and pressurizing can be adopted, but especially the second
As shown in the figure, the cross-sectional shape of the pressure surface is circular.
It is preferable to perform tap forging using a separate anvil 6 while rotating the rolls, since pressure is uniformly applied to the joint surfaces and uniform joint strength can be obtained. As a heating means during this forging, a normal heating furnace such as a heavy oil furnace or an electric furnace can be used.
The atmosphere can also be an oxidizing atmosphere such as air. This heating temperature depends on the steel type and is not constant, but
Usually it is about 900 to 1300 tZ'.

Examples of annealing to improve machinability after forging include spheroidizing annealing.

Examples will be described below.

The sleeve is made using 5KD-11 (C1, 5%), which is a high carbon steel, and separately from 80M, which is a low carbon steel.
-3 (C0, 3%) was used to produce Arno (-). A bevel was provided on the inner circumferential edge of the sleeve and the outer circumferential edge of Arno (- body), and each was built up with mild steel. The rear sleeve was heated to 200C and both were shrink-fitted and fixed.Next, it was heated to 1100tl and forged by 30% using the tap forging device shown in Fig. 2, and the joint surfaces were diffusion bonded. After being held for a time, the roll was slowly cooled and annealed to form a spheroid.Then, this roll was quenched at 850C and then tempered at 630C.Heat treatment was performed to give it the strength of SCM-3, which is an arbor material.Next, the sleeve was heated in a high-frequency induction furnace. The material was heated and quenched, and then heat treated to give the hardness of the tempered sleeve.The quenching temperature was 1050°C.
C. The tempering temperature is 500tll'.

FIG. 3 shows a micrograph (400x magnification) of the metallographic structure of the boundary layer between the arbor and sleeve joined in this manner. From FIG. 3, it can be seen that the arbor and sleeve are diffusion bonded.

Further, in the composite roll manufactured in this manner, no slippage of the sleeve occurred during rolling operation.

Moreover, the hardness of the roll surface was such that it could be used as a rolling roll.

As described above, according to the method of the present invention, it is possible to obtain a composite roll in which a high-strength aperture and a highly hard sleeve are firmly pressure-bonded by diffusion bonding. Since it can be carried out with

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a composite roll, FIG. 2 is a cross-sectional explanatory view of an anvil used for forging, and FIG. 3 is a microscopic photograph of the metal structure of the boundary layer between the aperture and the sleeve.

Claims (1)

[Claims] 1. After the sleeve and the arbor, which are made of metals with different compositions, are shrink-fitted and fixed, the peripheral edge of the joint surface between the sleeve and the arbor is welded to seal the joint surface, and A method for manufacturing a composite roll, characterized in that the bonding surfaces are diffusion bonded by heating and pressurizing. 2. A method for manufacturing a composite roll according to claim 1, characterized in that the welding is performed after a groove is provided at the peripheral edge of the joint surface of the sleeve and the arbor. 3.% Permissible The method for manufacturing a composite roll according to claim 2, characterized in that the sleeve is made of high carbon steel and the arbor is made of low carbon steel. 4. A method for manufacturing a composite roll according to claim 3, characterized in that the grooves of the sleeve and arbor are overlaid with mild steel and then welded.