JPH0459901A - Manufacture of conjugated roll - Google Patents

Abstract

PURPOSE:To provide manufacturing method of a conjugated roll, which is available to large load at the time of rolling, by fitting metal capsule to outer peripheral part of a solid roll core material, packing metal powder into annular space, degassing, sealing, executing HIP treatment, sintering and metallurgically joining to the core material. CONSTITUTION:The capsule 1 is a cylindrical metal vessel constituted with a barrel 1a, bottom cover 1b and upper cover 1c, and the capsule bottom cover 1b is weld-joined at lower end of the barrel 1a. At center part of this capsule 1, the solid roll core material 2 is set. The metal powder 4 is packed into annular space 3 arranged to outer periphery of intermediate part of this solid roll core material 2. Successively, the upper cover 1c is weld-joined to the barrel 1a and inner part of the capsule 1 is degassed and the air is discharged from a degassing hole 6 arranged at the upper cover 1c and the degassing hole 6 is sealed. This metal powder packed capsule 1 is charged into an HIP treating furnace and the metal powder 4 is sintered under high temp. and high pressure gas atmosphere, and also metallurgically joined to the solid roll core material 2. Successively, after forged-forming 2-1 both end parts 2a, 2b except the metal powder packing part 3 at center of the capsule 1 by heating to the prescribed temp. in a heating furnace, the capsule 1 is removed. Heat treatment is applied to the obtd. roll material 7 and this is formed into a roll-shape.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a composite roll using shaping sintering by hot isostatic pressing (HIP) based on a powder metallurgy method.

[Conventional technology]

As recent trends in rolling include stricter geometric and dimensional accuracy for rolled materials and increased demands for high surface cleanliness, the operating conditions for rolling rolls are becoming increasingly severe. This applies a large force to the roll, and conventional casting rolls, in which the outer layer is made of wear-resistant cast iron and the inner layer is made of cast iron, cannot withstand use due to the lack of strength and toughness of the inner layer and the lack of wear resistance of the outer layer. It's no longer possible.

On the other hand, if the outer layer material is made of wear-resistant cast iron and the inner layer material is cast steel (the melting point of the outer layer material (the melting point of the inner layer material)) in the casting method, shrinkage cavities are formed at the boundary between the outer layer and the inner layer during solidification, which is inconvenient.

From the above background, we use rope as the core material that becomes the roll shaft material.
As a method for manufacturing a composite roll in which the outer layer material is formed as a powder sintered layer, there is, for example, Japanese Patent Application Laid-Open No. 47-2851.

As shown in Fig. 3, this manufacturing method involves encasing the entire roll 2 in a metal capsule l, filling the outer periphery of the core material that forms the outer layer of the roll with a predetermined metal powder 3, and then heating the entire roll under high temperature and high pressure. It is subjected to HIP processing. However, this manufacturing method is limited by the HIP processing equipment, and cannot manufacture rolls with a length that exceeds the HIP processing equipment.

To solve the above-mentioned problems, JP-A-56
There is -69304. As shown in FIG. 4, in this manufacturing method, a capsule 1 is attached so as to form an annular space on the outer periphery of a solid roll core material 2, and after filling the annular space with metal powder 3 and sealing it. , HIP treatment is performed to sinter the powder 3, and then the capsule 1 is removed and roll supports 8 are metallurgically or mechanically joined to both ends of the solid roll core material 2 to form a roll. It manufactures.

[Problem to be solved by the invention]

However, in this manufacturing method, the boundaries of the connecting portions are joined metallurgically or mechanically, resulting in poor reliability. Therefore, severe impact force or bending stress generated at this joint near the roll axis, particularly the roll support, during rolling may cause the joint to break.

An object of the present invention is to provide a method for manufacturing a composite roll, which is a long roll that exceeds the length of HIP processing equipment and is effective against large loads during rolling.

[Means to solve the problem]

In order to achieve this object, the present invention includes attaching a metal capsule to the outer periphery of a solid roll core material so as to form an annular space serving as a metal powder filling layer, and filling the annular space with metal powder. The powder is sintered and metallurgically joined to the core material by degassing and sealing and HIPing in a high-temperature, high-pressure gas atmosphere, followed by forging both ends of the solid roll core material into a predetermined shape. After stretching, the metal capsule is removed to obtain a roll material, and then the roll material is processed and formed into a predetermined roll shape.

[Function and Examples]

Embodiments of the method of the present invention will be explained with reference to the accompanying drawings.

FIG. 1 shows an embodiment for manufacturing the roll material of the present invention, in which a capsule 1 is a cylindrical metal container consisting of a body 1as, a bottom lid 1b, and an upper lid 1c.The lower end of the body 1a has a capsule bottom lid. 1b are welded together, and a solid roll core material 2 whose both ends 2a and 2b approximate the inner diameter of the metal capsule 1 is arranged at the center of this capsule, and a solid roll core material 2 is placed at the center of the capsule, and a solid roll core material 2 is arranged at the center of the capsule. A predetermined metal powder 4 is introduced into the annular space 3 provided through the gap 5 between the inner surface of the upper end of the capsule 1 and the upper end of the solid roll core material 2.
Fill it.

The lengths of both end portions 2a and 2b of the solid roll core material 2 are designed to have a sufficient volume to later become a roll shaft portion.

Next, the upper lid IC is welded to the body 1a, and the inside of the capsule 1 is degassed through the deaeration hole 6 provided in the upper lid 1C, and the deaeration hole 6 is sealed.

HIP the metal powder-filled capsule 1 that has completed the above preparations.
The metal powder 4 is charged into a processing furnace, sintered in a high temperature and high pressure gas atmosphere, and metallurgically joined to the solid roll core material 2.

After shaping and sintering, the pressure is reduced and cooled, and then heated to a predetermined temperature in a heating furnace to form the metal powder filling layer 3 of the core of the capsule 1.
After the both ends 2a and 2b are forged and stretched, the capsule 1 is removed and a roll material 7 as shown in FIG. 2 is obtained.

After heat-treating the roll material 7 obtained as described above, it is formed into a predetermined roll shape by machining.

Example 1 A mild steel capsule with an inner diameter of 330 mm and a depth of 1315 mm has a lower diameter of 330 mm, a length of 300 mm, an upper diameter of 325 mm, a length of 320 mm, and a middle diameter of 215 mm.
SCM440 with m% length of 655 mm and total length of 1300 mm
A solid roll core material was installed.

Next, from the gap between the capsule and the upper part of the solid roll core material, C: 2.2%, Cr: 4.5%, MO, V: 6% each in weight ratio.
, W: 5% balance of Fe high speed steel powder was filled up to the upper end of the solid roll core material in the capsule. Next, a mild steel top lid was welded onto the top of the solid roll core material and the powder, gas was removed from the inside of the capsule through the degassing hole attached to the top lid, and the capsule was sealed. 1800kg/cff using argon gas as pressure medium
99.9% of theoretical density after HIP treatment under 1 pressure.
It was sintered to the above extent and was metallurgically joined to the solid roll core material.

By forging this, the solid roll core material diameter is 330[[
1I11 capsule lower part and solid roll core diameter 325m
After forging and forming the upper part of the capsule of m to a diameter of 220 to 190 m+n, the capsule was removed to obtain a roll material in which this portion corresponded to the roll shaft material.

The roll material was then quenched, tempered, and then machined to produce a wire rod rolling roll with a body diameter of 292 mm, a body length of 610 mm, and a total length of 1670 mm that was highly reliable and had excellent wear resistance and roughness resistance. .

Example 2 An example in which the length of the roll support part is restricted depending on the size of the HIP processing furnace will be shown below.

Inside the tube of a mild steel capsule with an inner diameter of 384 mm and a depth of 2395 m, the lower diameter is 3I34 mm and the length is 410 mm.
The upper diameter is 380mm, the length is 200m, the middle diameter is 260mm, the length is 1750mm, and the total length is 2400mm.
A solid roll core material of SC1,1440 was installed.

Next, from the gap between the capsule and the upper part of the solid roll material, the weight ratio of C: 2.1%, Cr: 14%, N+: 1%
.

A powder having a composition of 1.5% Mo, 5% TiN, and the balance Fe was filled up to the upper end of the solid roll core material in the capsule. Next, a mild steel top cover is welded onto the top end of the solid roll core material and the powder, and the inside of the capsule is degassed through the degassing hole attached to the top cover, sealed, and then heated to 1170°C, at the same time as a pressurized medium. 1 using argon gas
800kg/cm! The material was subjected to HIP treatment under a pressure of 100% to sinter it to 99.8% of its theoretical density, and was metallurgically bonded to a solid roll core material.

This was then forged to form the lower part of the capsule with a solid roll core diameter of 384 mm and the upper part of the capsule with a core diameter of 380 flllll to 240 mm, and then the capsule was removed to obtain a roll material in which this part corresponds to the roll shaft material. . Next, the outer diameter of the roll material is cut, quenched, and tempered, and SCM440 extension shaft members are joined by welding to the outside of the roll bearings at both ends of the roll material, and machining is performed. Highly reliable, with excellent abrasion resistance and roughness resistance, body diameter: 330 mm, body length: 1440 mm, total length: 355 mm
A work roll for hot rolling with 0 holes was manufactured.

[Effects of the Invention] As explained above, the method for manufacturing rolls by HIP processing according to the present invention can be used to manufacture composite rolls that are longer than the length of the HIP processing equipment, using conventional machines that combine the core material and shaft extension material of the HIP processing body. This has the great effect of providing rolls with excellent abrasion resistance and surface roughness resistance that are highly reliable even under severe roll loads compared to mechanical or metallurgical joints.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing an embodiment for manufacturing a composite roll of the present invention, Fig. 2 is a cross-sectional view of a roll material obtained by removing the capsule after forging both ends of the capsule, and Fig. 3 is a cross-sectional view of the roll material obtained by removing the capsule after forging both ends of the capsule. FIG. 4 is a sectional view showing a method for manufacturing a composite roll using a conventional method. FIG. 4 is a sectional view showing a method for manufacturing a composite roll using another conventional method. 1...Metal Turnip Cenobe 1a...Torso, 1b...
・Bottom cover, IC...Top cover, 2...Solid roll core material, 2a, 2b...Both ends, 3...Annular space, 4...Metal powder, 5...Gap,
6... Deaeration hole, 7... Roll material,
8... Roll support section. 1b Figure Figure Date

Claims (1)

[Claims] In a method for manufacturing a composite roll having a sintered layer of metal powder 4 on the outer peripheral surface of a solid roll core material 2, metal powder 4 is added to the outer peripheral portion of the solid roll core material 2 in consideration of the shape of a predetermined material.
A metal capsule 1 is attached so as to form an annular space 3 that becomes a packed layer, and the annular space 3 is filled with metal powder 4, sealed after degassing, and subjected to hot isostatic pressing in a high temperature and high pressure gas atmosphere. By doing this, the metal powder 4 is sintered and metallurgically joined to the solid roll core material 2, and then both ends 2a and 2b of the solid roll core material 2 are forged into a predetermined shape, and then the metal capsule 1 is formed. A method for manufacturing a composite roll, which comprises removing the roll material 7 to obtain a roll material 7, and then processing the roll material 7 to form it into a predetermined roll shape.