汽车悬架用弹簧钢55SiCr制备技术的研究进展

悬架弹簧钢是汽车悬架系统的重要部件,研发高性能汽车悬架弹簧钢制备技术对于推动特殊钢材料的国产化有着重要的意义。从洁净度控制、组织性能调控和表面脱碳控制3个方面介绍近年来汽车悬架弹簧钢55SiCr制备技术的最新进展。在洁净度控制上,对弹簧钢中夹杂物的控制方向、脱氧工艺、精炼渣和耐火材料等相关研究进行介绍。在组织性能调控中,重点介绍作者所在研究所在悬架弹簧钢55SiCr热处理工艺改进与优化上的探索,比较了淬火-回火、等温淬火和淬火-配分工艺对悬架弹簧钢55SiCr力学性能的影响。表面脱碳控制的相关研究表明,在进行热处理或热加工的过程中,应尽量避免在低于弹簧钢奥氏体/铁素体转变温度(约800 ℃)附近停留,虽然较高的温度有利于避免全脱碳,但是出于晶粒粗化、能耗和氧化等方面的考虑,热处理温度不宜高于1 100 ℃。

Research progress for fabrication technology of automobile spring steel 55SiCr

Suspension spring steel is an important component of automobile suspension system. It is of great significance to develop the fabrication technology of excellent performance automobile suspension spring steel for promoting the localization of special steel materials. The advance for fabrication technology of 55SiCr suspension spring steel in recent years is introduced from three aspects of cleanliness control, microstructure and properties control, and surface decarburization control. In cleanliness control, the control direction of inclusions in spring steels, deoxidation processes, refining slags and refractory materials are introduced. In the control of microstructure and properties, the exploration of heat treatment process design and optimization of suspension spring steel 55SiCr carried out by the institute to which the author belongs is emphatically introduced, and effects of quenching-tempering, austempering and quenching-partitioning processes on mechanical properties of the suspension spring steel 55SiCr are compared. The research on surface decarburization control shows that during heat treatment or hot working, it is necessary to avoid staying near the austenite/ferrite transition temperature (about 800 ℃). Although higher temperature is beneficial to avoid complete decarburization, it should not be higher than 1 100 ℃ concerning grain coarsening, energy consumption and oxidation.