JPS61284527A - Manufacture of composite roll - Google Patents

Abstract

PURPOSE:To manufacture a roll having superior resistance to wear, denting and cracking by applying proper compressive residual stress to the surface of a composite forged steel roll consisting of an outer layer of a high-C high- alloy steel and a core of an ordinary steel or a low- or medium-alloy steel. CONSTITUTION:A roll is composed of an outer layer of a high-C high-alloy steel and a core of an ordinary steel or a low- or medium-alloy steel. The outer layer is rapidly heated to the austenitizing temp. only by the required thickness by induction heating, and it is immediately cooled by spraying water to carry out hardening. Thus, >=50kg/mm<2> compressive residual stress is applied to the surface of the roll and a composite work roll having superior resistance to wear, denting and cracking and suitable for the cold rolling of a metallic material is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention relates to rolling rolls, and particularly to heat treatment of forged steel composite rolls suitable for cold rolling of metal materials.

[Background of the invention]

Conventionally, for hardening of high carbon high alloy steels such as cold die steel and high speed steel, oil cooling is generally used as specified in JIS G4403 and G 4404, and the maximum hardness is about H2O2, and surface residual stress is However, work rolls used for cold rolling of metal materials have a hardness of H,95 or higher and a compression rate of 50 kg/mm.
A surface residual stress of more than m" is necessary from the viewpoint of dent resistance and crack resistance, and these points have not been taken into consideration.

[Purpose of the invention]

An object of the present invention is to provide a dispersed composite roll having excellent wear resistance, dent resistance, and crack resistance in cold rolling of metal materials.

[Summary of the invention]

The present invention provides a composite forged steel roll having an outer layer made of cold die steel, high-speed steel, etc., in which only the necessary thickness of the outer layer is added to the appropriate austenite temperature) m'-.-to! f
it, **”141” 50 compressed on one surface by 13
It imparts a residual stress of more than "kg/rare" and increases wear resistance, dent resistance, and crack resistance, and the temperature of the core material is kept below the austenite temperature to impart sufficient toughness.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the structure of a roll 1 of this embodiment. The outer diameter is 17
0++no, the core diameter is 140mm, and the length is 100mm. The chemical composition of the core material is CQ, 43%, Si0.22%,
It is a low alloy steel with Mn0.63%, Cr1.18%, Mo0.17%, and the outer layer has C0.87% and Si0.23%.
.

Mn0.37%, Cr4.42%, Mo8.06%,
Vl, 92% high speed steel was overlaid by electroslag welding and then spread.

The heat treatment was performed by increasing the temperature to an austenitizing temperature of 1170° C. in 9 minutes by induction heating at 1000 Hz, holding it for 4 minutes, and then cooling by water injection. The surface hardness after quenching was H2O2, and the residual stress was 60 kg/mm" in compression. Figure 2 shows a roll with the same structure immersed in a 1170°C salt bath for 15 minutes, then immersed in a 400°C salt bath. This figure shows a comparison of transfer fatigue properties with a roll that has been quenched to have a surface hardness of H, 91, and a residual stress compression of 5 kg/mad.

According to this example, by imparting high compressive residual stress to one surface, there is an effect of improving wear resistance and crack resistance.

〔Effect of the invention〕

According to the present invention, a cold die steel with inherently excellent wear resistance,
Composite rolls with an outer layer of high-carbon, high-alloy steel such as high-speed steel, hardness of H, 95 or more, compression of 50 kg/ff1m
``Because it is possible to apply more residual stress.

It is possible to manufacture a work roll suitable for cold rolling of metal materials that has excellent wear resistance, dent resistance, and crack resistance.

[Brief explanation of drawings]

FIG. 1 is a structural diagram of a roll according to an embodiment of the present invention, and FIG.
The figure is a diagram showing the relationship between the number of transfers and wear loss. 1...roll,
・' 1 \1, 1

Claims (1)

[Claims] 1. Outer layer of high carbon, high alloy steel and ordinary steel or low
A method for manufacturing a composite roll, characterized in that a residual stress of 50 kg/mm^2 or more is applied to the surface of a roll made of a core material of medium alloy steel by compression.