A kind of manufacturing method of graphite-containing high-speed steel roll

Abstract

The invention discloses a manufacturing method of a graphite-containing high-speed steel roll and belongs to the technical field of mechanical casting. B and N chemical elements are introduced into a conventional high-speed steel component, and MC type and / or M2C type dotted and / or blocky high-hardness alloy carbide, nitride and boride with the total percentage of the area being 20%-35% are / is distributed in a matrix structure of a work layer; graphite is separated out of original tissue through two steps including modification of carbide, nitride and boride and metamorphic inoculation of graphite, so that the high-speed steel roll not only reserves the advantage of peculiar high-temperature wear resistance of conventional high-speed steel, but also solves the problem that an original conventional high-speed steel roll has a large friction coefficient, the wear-resisting property of the high-speed steel is sufficiently played, the lubricating function between the roll in rolling and a workpiece is realized, and the steel bonding phenomenon is prevented; by means of the heat conductivity and lubrication characteristics of graphite, the defects that high-speed steel rolls are sensitive to heat shock and heat cracking and are prone to steel bonding and surface texturing can be overcome, and particularly, when the graphite-containing high-speed steel roll is used in a finished rack, the brightness degree of the surface of the roll material is remarkably improved.

Description

technical field [0001] The invention relates to a method for manufacturing a graphite-containing high-speed steel roll, belonging to the technical 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 passing through at low temperat...

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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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