JPS5950151A - Hot rolling roll made of superhigh alloy steel - Google Patents

Abstract

PURPOSE:To produce a hot rolling roll having excellent abrasion resistance, heat resistance and toughness, by reducing and alloying a mixture of metallic oxides consisting essentially of Fe and carbon then adding a specific amt. of V thereto, forming the mixture to a roll shape and hardening and tempering the roll after sintering. CONSTITUTION:Carbon powder for forming a reducing agent consisting of carbide is added and mixed to and with a mixture consisting essentially of oxide powder of Fe and consisting of oxides such as Cr, Mo, W, Co, Mn or the like. The mixture is heated to 1,000+ or -100 deg.C in gaseous H2 flow to reduce the above- mentioned metallic oxides to metal and to alloy the same by inducing solid phase diffusion among the formed metals, whereby intermediate powder is produced. V is added to such powder so as to be contained at >=6% and if necessary hard powders of TiC, TiN, TiCN, etc. are added at 1-25%, then the mixture is formed into a roll shape. After the roll is sintered, the roll is hardened and tempered, whereby the hot rolling roll having the martensitic base dispersed therein with the hard metallic carbides, nitrides and carbonitrides is produced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hot rolling roll made of ultra-high alloy steel.

Since hot rolling rolls are subject to severe usage conditions and are prone to damage, many proposals have been made to improve this, and many improvements have been made in terms of material and housing. . For example, in the case of hot rolling rolls for wire rod processing, hot rolling rolls made of various materials are combined, such as cast steel for the rough rolling stand and intermediate stand, and carbide for the finishing stand. Due to other circumstances, the scope of use of cemented carbide materials has expanded and even cast steel hot rolling rolls are being replaced by cemented carbide ones. This cemented carbide material has various excellent properties. In particular, in terms of wear resistance, it is unrivaled by other metal materials, and there is a tendency for it to be used frequently in hot rolling rolls in the future, but it is inferior in toughness. On the other hand, high-speed steel is known as a material with excellent toughness, but steel has low wear resistance and is considered unsuitable for hot rolling rolls.

This invention was developed focusing on the material of such hot rolling rolls. The purpose is not to provide rolling mill rolls. Specifically, the hot rolling roll made of ultra-high alloy steel according to the present invention is made by adding 8 pieces of carbon powder to a metal acid arsenide powder, blending it into an alloy composition, and mixing and pulverizing it to obtain a raw material powder.

This raw material powder is heated in a hydrogen stream, and the oxide is co-reduced and alloyed with hydrogen and carbon to form an intermediate powder, and this intermediate powder is made to contain a large amount of V in advance, or a large amount of ■ is added to this intermediate powder. Let's have a mouthful.

This powder is then used to form a roll-shaped product [-9, which is made by heat-treating the alloy matrix after sintering to make it martensite [first invention], and then adding carbon powder to the metal oxide powder. A large amount of V is added to the intermediate powder in advance by heating the raw powder in a hydrogen stream and co-reducing and alloying the oxide with hydrogen and carbon to form an intermediate powder. A large amount of V is added to this intermediate powder, and then a carbide, nitride, or carbonitride powder is mixed and adjusted with this powder, and a roll-shaped product is formed using this powder. After sintering, the alloy matrix is made into martensite by heat treatment.

The details will be explained below, but first, the raw material powder targeted by the present invention is obtained by adding carbon powder to metal oxide powder, blending it into an alloy composition, and mixing and pulverizing the mixture.

As metal acid monoarsenide powder, ]ρe, cr, MO,
W, Co.

Oxide powders corresponding to Mn and V are employed. F'
e is used as a group, Or, Mo, W, Co
, Mn, is selected at least one kind, ■ is contained in a considerably large amount (for example, about 15 Ti), and C
Each component element is contained in an amount necessary and sufficient to form a carbonized product. The highest value for V-containing alloy steel is 5.2 g of J-Ko S 5KH10 type, but in this invention, it is even higher than this value and has a so-called ultra-high V value, which is higher than the normal high V value, in the intermediate powder or final product described later. It contains so much ■ that it can be said that (2) is one of the elements with the strongest ability to form carbides, and also functions as an independent component, so V fjl can theoretically be between 0 and any value, but based on various experiments conducted by the inventors, It has been found that the preferred content range for V@ after sintering is approximately 6.0-58 weight coefficient. When it exceeds 60%, the effect of ultra-high ■ becomes noticeable, and grinding is easy up to 58 mm, so it is necessary to finish the roll-shaped product to obtain a final product with the desired dimensions. It would be sufficient to set it to about %.

When preparing the raw material powder, 1j11 carbon powder is added to the metal acid 1 arsenide powder, and an amount of carbon sufficient to reduce the metal oxide as CCJ is added as powder.

When mixing and pulverizing, it is desirable to pulverize to an average particle size of 10 μm or less.

The raw material powder prepared in this way was mixed and ground.

In this invention, the oxide is co-reduced (simultaneous reduction) with hydrogen and carbon by heating in a hydrogen stream, and the alloy is heated to form an intermediate powder. Specifically, with sufficient hydrogen supply, the material is heated and maintained at a temperature of 1000±100'C, and the raw material powder (acid-arsenic powder) is co-reduced with hydrogen and carbon, and alloyed by solid-phase diffusion.9 An intermediate powder as an alloy powder is obtained. -f-shi lever-like 9. The alloy powder (intermediate powder) does not cause strong secondary growth (agglomeration) and is easy to crush afterwards. This intermediate powder may contain a large amount of ■ in advance, or this intermediate powder may be
Add.

Up to this point, the first invention and the second invention have the same content,
The following will be explained separately because they are different.

In the first invention, the thus obtained powder containing a large amount of V is molded into a roll-shaped product, and after sintering, heat treatment is performed to convert the alloy wood into martensitic 1-9 super alloy steel. This is a hot rolling roll manufactured by the company. When forming roll-shaped products, 1. Now, add a binder to the powder containing a large amount of ■ and mold it as is (-, but it is preferable to crush it once with the original particle sizer in order to lightly crush the secondary growth powder.

Then, it may be compacted and sintered in a vacuum of 0.1 mmHy or less to prevent post-oxidation and fluctuations in carbon content. The thus obtained rolled sintered body has fine carbides (particle size of approximately 01 to 2 μm) uniformly dispersed in the austenite base. however.

Particularly when considering the toughness, for example, if the material is subjected to isostatic pressure treatment in an inert gas at high temperature and high strength, the density can be increased to 100 mm, and an improvement in toughness can be expected. Next, the substrate is turned into martensite by heat treatment. As mentioned above, the sintered body of the roll-shaped product is an austenite base, and by quenching, this austenite matrix is turned into martensite, and by tempering, residual austenite disappears and martensite is stabilized. (() It is expected that mechanical properties, that is, toughness and wear resistance, will be improved.The specific conditions of the heat treatment can be based on the alloy composition and are based on those normally adopted. As a result, a sintered ultra-high-vi high-alloy steel with a composition in which fine carbides are uniformly dispersed in a martensitic iron alloy matrix is produced.
Get a hot rolling roll.

In the second invention, before forming a roll-shaped product using powder containing a large amount of V, powder of any one of carbide, nitride, or carbonitride is mixed and adjusted. Attachment 8
1 as a powder (rj, VC.

VN, VON, TiN, T1CN, ZrN, ZrCN,
07N, H (ON, NbN.

NbCN, TaN, TaCN, etc. are suitable, and one or more types can be used. In particular, T I C, T I
Addition of N, TiCN, etc. improves wear resistance and heat resistance.

The content should be at least 10-250% by weight. It is then molded, sintered, and heat treated to form fine carbon particles in the martensitic iron alloy matrix.

A hot rolling roll made of a so-called sintered ultra-high V and nitride-containing high alloy steel with a composition in which nitrides are uniformly dispersed is obtained. The contents of the present invention, molding, sintering, and heat treatment are substantially the same as those of the first invention, and therefore redundant explanations will be omitted.

The hot rolling roll made of ultra-high alloy steel according to the present invention has been described above (as described above, it contains ultra-high V as described above in the first invention), and further contains a large amount of nitrides in addition to a large amount of V (second invention). invention), it combines the wear resistance and toughness required of high-speed steel, which is not required of cemented carbide, and exhibits excellent properties in wear resistance, heat resistance, and toughness, so it can withstand harsh conditions. Under (11) the product life can be extended without damage even if the product is damaged, and its public and economic benefits are significant.Continued from page 1 ■Applicant Kanto Denka Kogyo Co., Ltd. Tokyo 1-2-1 Marunouchi, Chiyoda-ku ■Applicant Furukawa Electric Co., Ltd. 2-6-1 Marunouchi, Chiyoda-ku, Tokyo

Claims (4)

[Claims] (1) Carbon powder is added to metal oxide powder, blended into an alloy composition, and mixed and ground to obtain a raw material powder. This raw powder is heated in a hydrogen stream, and the oxide is co-reduced and alloyed with hydrogen and carbon to form an intermediate powder. Either a large amount of V is pre-contained in this intermediate powder, or a large amount of ■ is added to this intermediate powder. 9. A hot rolling roll made of ultra-high alloy steel, which is then formed into a roll-shaped product using this powder, and is heat-treated after sintering to make the alloy matrix martensite. (2) The amount of (v) contained in the intermediate/intermediate powder in advance or added to the intermediate powder after sintering is at least at least. 60/weight or higher. A hot rolling roll made of ultra-high alloy steel according to claim 1. (3) Carbon powder is added to the metal acid monomer powder to form an alloy composition, and the mixed powder is used as a raw material powder. Heating this raw material powder in a hydrogen stream 1. Oxides are co-reduced and alloyed with hydrogen and carbon to form an intermediate powder, and this intermediate powder contains a large amount of (2) in advance, or a large amount of (2) is added to this intermediate powder, and then carbides, nitrides, or Mix and adjust any powder of carbonitride. This powder is used to form a roll-shaped product in steps 1 to 1. A hot rolling roll made of ultra-high alloy steel whose alloy matrix is made into martensite by heat treatment after sintering. (4) The powder to be mixed and adjusted with the intermediate powder is T j O, Ti
N. The hot rolling roll made of ultra-high alloy steel according to claim 6, which is a powder of any one of T i CN.