Method for refining, metamorphosing and casting cold roll steel by casting instead of forging

Abstract

The invention discloses a method for refining, metamorphosing and casting cold roll steel by casting instead of forging. A work roll sleeve or a work layer of the cold roll steel comprises the following chemical components in percentage by weight: 0.6 to 1.2 percent of C, 0.2 to 1.5 percent of Si, 0.3 to 1.5 percent of Mn, 1.6 to 6.0 percent of Cr, less than or equal to 3.5 percent of W and Mo, less than or equal to 1.5 percent of Ni and Cu, less than or equal to 1.5 percent of V, less than or equal to 0.15 percent of Re, less than or equal to 0.10 percent of Ba and Mg, less than or equal to 0.05 percent of K and Na, less than or equal to 0.015 percent of S, less than or equal to 0.002 percent of O and the balance of ferrum, and trace impurities which are difficult to measure; and a work layer of a supporting roll comprises the following chemical components in percentage by weight: 0.4 to 1.0 percent of C, 0.3 to 2.0 percent of Si, 0.6 to 2.5 percent of Mn, 1.0 to 4.5 percent of Cr, less than or equal to 1.5 percent of W and Mo, less than or equal to 1.5 percent of Ni and Cu, less than or equal to 1.0 percent of V, less than or equal to 0.15 percent of Re, less than or equal to 0.10 percent of Ba and Mg, less than or equal to 0.05 percent of K and Na, less than or equal to 0.02 percent of S and less than or equal to 0.003 percent of O. Liquid steel is refined repeatedly and metamorphosed complexly in and out of a furnace to improve the purity of the steel and refine metallographic structures and carbide particles; gas protection and liquid steel filtration are performed in the process of steel taping and casting; and the metallurgical fusion of a metal type blank for making the roll sleeve and a roll core is performed during casting by a CPC method to prepare a composite cold roll, so the method has remarkable energy saving and consumption reduction benefits.

Description

technical field [0001] The invention relates to the refining, modification and casting method of cold rolled roll steel by casting instead of forging. Background technique [0002] The main working object of the cold rolling roll is the cold metal strip. The medium plate is rolled into a thin plate. The metal plate is hardened during rolling, and the harder it is rolled, the greater the rolling force, it is easy to cause broken rolls, collapse and peeling off. or fatigue cracks, so the steel quality requirements for cold rolls are very high. The existing cold roll steels need to be melted and cast in electric furnaces, electroslag remelted into ingots and repeated multi-dimensional upsetting and forging, which consumes a lot of energy, low production efficiency and high cost. The processing volume is large, the material utilization rate is only about 60%, and the price is expensive. For many years, the grade 9Cr2Mo(V) used in cold rolling steel has low fatigue strength, low ...

AI Technical Summary

Problems solved by technology

[0002] The main working object of the cold rolling roll is the cold metal strip. The medium plate is rolled into a thin plate. The metal plate is hardened during rolling, and the harder it is rolled, the greater the rolling force, it is easy to cause broken rolls, collapse and peeling off. or fatigue cracks, so the steel quality requirements for cold rolls are very high. The existing cold roll steels need to be melted and cast in electric furnaces, electroslag remelted into ingots and repeated multi-dimensional upsetting and forging, which consumes a lot of energy, low production efficiency and high cost. The processing volume is large, the material utilization rate is only about 60%, and the price is expensive. For many years, the grade 9Cr2Mo(V) used in cold rolling steel has low fatigue strength, low plastic toughness, poor tempering resistance, and shallow hardening depth. Defects: For different uses of work rolls and back-up rolls with different requirements, the chemical composition of steel has different requirements. Back-up rolls require strong hardenability, good toughness, wear resistance does not have to be too high, and work rolls require hardness High fatigue strength, good wear resistance, followed by hardenability requirements

Generally, the size and weight of roll steel ingots are too large, and the solidification is slow, which affects the composition segregation of the steel. The crystals are coarse, and there are segregation and porosity. Although forged, there are still banded segregation and network carbides. There are very few improvements on it, such as 9Cr2Mo(V) adding rare earth can improve the performance and life of cold rolling rolls, but this improvement has not been used in production, and the multiple technological measures adopted by the applicant in aspects such as refining and metamorphism, pouring, etc. have no effect on 9Cr2Mo (V) No or unavailable for forging blanks

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