A kind of production method of tool steel capable of direct cold rolling

Abstract

The invention provides a production method of tool steel capable of being directly cold rolled. The production method of the tool steel capable of being directly cold rolled comprises the following steps: heating a casting blank, and descaling with high pressure water; carrying out rough rolling; descaling with the high pressure water before precision rolling is carried out; carrying out precision rolling; carrying out laminar cooling; coiling; tempering; and straightening and then carrying out cold rolling. The production method of the tool steel capable of being directly cold rolled has the advantages that plasticity and toughness are good, a spheroidizing annealing operation does not need to be carried out while usability of tool steel is guaranteed, cold rolling can be directly carried out after hot rolling is finished, and a production cycle is shortened for at least 7 hours; a metallographic structure of the produced tool steel is annealed and changed into a tempered sorbite with uniform carbide, so that the spheroidizing annealing operation before cold rolling can be eliminated; and resource consumption and pollution to the environment can be reduced.

Description

technical field [0001] The invention relates to a production method of tool steel, in particular to a production method of tool steel capable of direct cold rolling. Background technique [0002] Tool steel has good properties such as strength, toughness, hardness, wear resistance and tempering stability, and is mainly used to manufacture various cutting tools, forming tools and measuring tools. When making knives and measuring tools, the thinnest steel strip used is required to reach 0.01mm, while the thinnest hot-rolled steel strip can only reach 2mm, which needs to be realized by cold rolling. [0003] At present, the carbon content in tool steel is generally greater than 0.7%, and the structure after hot rolling is generally pearlite or pearlite + massive cementite. Although it has high strength and hardness, it has poor plasticity and toughness. In order to solve the poor plasticity and toughness, and reduce the rolling load during the cold rolling process of hot-rolle...

AI Technical Summary

Problems solved by technology

Although the problem has been solved, the spheroidizing annealing process takes a long time, that is, the processing time is generally not less than 10 hours, and there is also a problem that when the hot-rolled coil is annealed in the bell annealing furnace, due to the uneven temperature distribution of the steel coil, Often results in non-homogeneous final tissue

[0004] After searching, a method for manufacturing high-quality high-strength cold heading steel without spheroidizing annealing (public number: CN102676929A) sets the current controlled rolling and controlled cooling process, controls the heating temperature of the billet to 900-1120°C, and the final rolling temperature to 720-850°C ℃, spinning temperature 800-860℃, cooled at 3-8℃ / s to 650-800℃ and then put into the hood, the cooling rate in the hood is 0.2-0.7℃ / s, the obtained structure is fine lamellar Pearlite, the control method of spheroidizing annealing in this document is to refine the structure size, but the plasticity and toughness of the flaky carbides in the obtained pearlite are worse than that of granular carbides; an online spheroidizing rolling process for medium carbon steel ( CN100999775A) The controlled rolling and controlled cooling low-temperature rolling process is adopted in the finishing rolling process, the rolling temperature is controlled at 680-850°C, the deformation of the cross-section is the cumulative area reduction rate of 50%-80%, and the cooling rate is controlled after low-temperature rolling , the rolled piece is cooled to 660-720°C at a cooling rate of 3°C / sec to 15°C / sec, and then undergoes an isothermal process, and then the rolled piece is naturally cooled to room temperature to obtain a granular pearlite structure. The rolling load in the rolling stage is large, which is not conducive to the shape control, and because the rolling temperature is too low, it may cause the mixed crystal phenomenon of deformed grains and undeformed grains

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