A manufacturing method of graphite-containing high-speed steel centrifugal composite steel core roll

Abstract

The invention discloses a manufacturing method of a graphite-contained high-speed steel centrifugal composite steel core roller, and belongs to the field of mechanical casting. Chemical elements of B and N are introduced in a traditional high-speed steel component, MC type and / or M2C type dotted and / or blocky high-hard alloy carbides, nitrides and borides with the total area percentage of 20% to 35% are dispersed and distributed in a work layer base body structure; through carbide, nitride and boride modification, graphite is subject to two-step treatment of modification and inoculation, graphite is precipitated in an original structure, and therefore the high-speed steel roller has the advantages of the specific high-temperature wear resisting of traditional high-speed steel and meanwhile the problem that an original traditional high-speed steel roller is large in friction coefficient is solved; wear-resisting performance of the high-speed steel is fully developed, the lubricating effect between the roller and a workpiece in the rolling process is achieved, and happening of the steel bonding phenomenon is avoided; due to the heat conduction performance and the lubricating characteristic of graphite, the defects that the high-speed steel roller is sensitive to hot impact and hot-cracking susceptibility, steel bonding is prone to happening, and surface roughing is prone to happening can be overcome, and particularly when a finished product rack is used, the surface bright degree of a rolled material is obviously improved.

Description

technical field [0001] The invention relates to a manufacturing method of a graphite-containing high-speed steel centrifugal composite steel core roll, which belongs to the field of mechanical casting. Background technique [0002] The alloy content of the outer layer (working layer) of the existing traditional high-speed steel roll is usually C 1.5-2.5, Si 0.2-0.8, Mn0.4-0.8, P≤0.05, S≤0.02, Cr 4-6, Ni 0.6 -1.5, Mo 3-5, W 0-3, the metallographic structure of the outer layer does not contain graphite, and these alloy elements mainly exist in the form of carbides in the roll structure, and the proportion of carbides is usually 10-20 %between. The proportion of granular alloy carbides is relatively low, and the proportion of matrix area is relatively large. Therefore, during the use of the roll, especially when it is used for the finish rolling product stand, the rolling temperature is low, and the rolling speed is high, the roll base is exposed to the rolling material passi...

AI Technical Summary

Problems solved by technology

Therefore, during the use of the roll, especially when it is used for the finish rolling product stand, the rolling temperature is low, and the rolling speed is high, the roll base is exposed to the rolling material passing through at low temperature and high speed and the entrainment on the surface of the rolling material. Under the friction of oxide scales, the matrix is ​​preferentially worn and the fulcrum of high-hard carbide is exposed on the surface of the roll, which is specifically manifested in the increase of the surface friction coefficient of the roll (pass type), the decrease of brightness (the phenomenon of roughening), and in severe cases There is steel sticking on the pass surface, which affects the surface quality of rolled products

As a result, the unique anti-wear performance of high-speed steel and the ability to maintain roll shape cannot be effectively exerted, resulting in early roll change

[0003] In addition, when the existing traditional high-speed steel rolls are used in the process of preparing the finished round bar frame with large specifications and high surface quality requirements, due to the deep pass, the inner groove bottom and the groove side of the roll pass The linear velocity difference in different radial directions leads to the relative solid slip (rheology) of the rolled material at the same section, and the huge solid slip produces a file force on the surface of the roll pass, resulting in slippage between the bottom and the side wall of the roll pass. The wrinkle texture is shifted, and the wear of the bottom of the groove is intensified, which affects the precision and surface quality of the rolled material, and cannot fully exert the wear-resistant characteristics of high-speed steel, resulting in early roll change

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