Full-process TMCP (thermal mechanical control processing) rolled 55SiCr spring steel and production method thereof

Abstract

The invention provides full-process TMCP (thermal mechanical control processing) rolled 55SiCr spring steel and a production method thereof. The full-process TMCP rolled 55SiCr spring steel comprises0.52-0.58% of C, 1.20-1.60% of Si, 0.50-0.80% of Mn, 0.60-0.80% of Cr, less than or equal to 0.10% of Ni, less than or equal to 0.10% of Cu, less than or equal to 0.0020% of Ti, less than or equal to0.015% of P, less than or equal to 0.010% of S, less than or equal to 0.010% of Alt, less than or equal to 10PPm of O, less than or equal to 1.0PPm of H and the balance Fe and inevitable impurities. Compared with the prior art, the full-process TMCP rolled 55SiCr spring steel and the production method have advantages that the surface of a finished product is free of a fully decarburized layer, thetotal decarburized layer depth is smaller than 0.10mm, a metallographic structure is formed by pearlite and a small quantity of ferrite, a surface ultrafine grain layer is avoided, grades of nonmetallic inclusions A, B, C, D and Ds are lower than or equal to 1.0, plasticity and toughness are better than those of common springs, and durability and safety in use are improved.

Description

technical field [0001] The invention belongs to the technical field of spring steel and its production technology, and in particular relates to a full-process TMCP thermomechanically rolled 55SiCr spring steel and a production method thereof. Background technique [0002] Springs are the most commonly used parts in the machinery industry and in daily life. In recent years, with the rapid development of the modern automobile industry and lightweight requirements, spring steel is moving towards high stress and high reliability. The spring market has shifted from price competition to technical quality competition, and the requirements for fatigue strength and anti-ballistic performance of springs are becoming more and more High, which puts forward very strict requirements on the stability of the spring steel production process, so the quality of the spring wire must be continuously improved. [0003] Although my country's spring steel can reach the international advanced level...

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Problems solved by technology

[0003] Although my country's spring steel can reach the international advanced level at present, the localization rate of spring steel wire rods for suspension springs is about 90%; but the quality stability is poor, and there is still a certain gap with the international advanced level. The main reasons are as follows: from steelmaking In terms of equipment level, it is basically the same at home and abroad, but domestic steel mills have not fully mastered the production process of inclusion denaturation, and the control level of finished product inclusions is unstable; due to the level of heating furnace equipment, research and development management, etc., it is difficult for domestic spring steel Completely avoid, sometimes very serious; In addition, problems such as surface quality, composition segregation and tissue segregation of spring steel wire rods have not been completely resolved

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