Rolling process capable of eliminating 20MnCr5 steel as-rolled mixed crystal structure

Abstract

The invention provides a rolling process capable of eliminating the 20MnCr5 steel as-rolled mixed crystal structure. The rolling process comprises the following steps: 1, selecting a billet of 20MnCr5 steel; 2, heating the steel billet; 3, performing rough rolling on the steel billet; 4, performing intermediate rolling on the steel billet; 5, performing finish rolling on the steel billet; and 6, cooling the steel to obtain a 20MnCr5 steel finished product finally. According to the method, after the temperature at which the 20MnCr5 steel starts dynamic recrystallization is accurately checked, the appropriate rolling starting temperature is determined, and rolling is started in the temperature interval higher than 1050 DEG C, so that distortion energy in the steel is accumulated, the recrystallization tendency is increased, and finally the effects of refining grains and eliminating mixed crystals are achieved. The uniformity, the grain size, the hardness and the mechanical property of the obtained 20MnCr5 steel as-rolled structure are greatly improved, and the production efficiency cannot be reduced due to process changes.

Description

technical field [0001] The invention belongs to the technical field of iron and steel; in particular, it relates to a rolling process for eliminating the mixed grain structure of 20MnCr5 steel as rolled. Background technique [0002] Gears are extremely important transmission components in automobiles, and their quality directly affects the safety, power, and gearbox noise of the automobile. Since the gearbox gears are subjected to bending stress, impact, and alternating loads, etc., they are required to have high precision. High, low noise, and good strength and toughness, wear resistance, fatigue resistance, contact resistance and other properties to withstand reciprocating impact and stress, the quality of the gear mainly depends on its own material and heat treatment process. The 20MnCr5 gear steel imported from Germany has the characteristics of high cleanliness, good surface hardness and wear resistance, fatigue resistance, hardenability, and small quenching deformatio...

AI Technical Summary

Problems solved by technology

The existing technology does not adopt the controlled rolling process in the production process. Due to the steel type characteristics and the improper setting of the rolling temperature, the 20MnCr5 steel has a mixed crystal structure, and the rolled grain size and hardness are inconsistent.

In order to meet the requirements of users, the preparation of 20MnCr5 steel in the existing technology must add normalizing in the later stage. The normalizing process is used to solve the problem of inconsistency between mixed crystal structure and hardness.

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