汽车轻量化下热轧淬火配分钢的组织性能研究

Study on Microstructure and Properties of Hot-Rolled Q&P Steel for Automobile Lightweighting

摘要: 基于汽车轻量化原则，以低碳C-Si-Mn系钢为原料，采用热轧 + 超快冷 + 淬火配分一体化工艺制备QP980钢，替代传统离线热处理工艺并探究其组织和性能。结果表明：试验钢形成板条马氏体与薄膜状残余奥氏体复合组织，残余奥氏体体积分数9.1%，碳在奥氏体区富集实现室温稳定。该钢强塑积达18.95 GPa·%，满足CR550/980QP牌号要求，冷加工性能优异。该钢替代传统软钢可实现车身结构件显著减重，适配冷冲压成形工艺。

Abstract: Based on the principle of vehicle lightweight, QP980 steel with a low-carbon C-Si-Mn was prepared by an integrated process of hot-rolling, ultra fast cooling and quenching and partitioning, replacing the conventional offline heat treatment route, and then the microstructure and mechanical properties of the tested steel was studied. The results show that the tested steel develops a composite microstructure consisting of elongated martensite and film-like residual austenite, the volume fraction of austenite is 9.1%, and carbon is enriched in the austenite regions, resulting in its stability at room temperature. The strength plasticity product of the tested steel is 18.95 GPa·%, which meets the requirements of the CR550/980QP grade and exhibits excellent cold workability. The steel serves as a substitute for conventional mild steel, offers significant weight reduction in automotive body structures and is suitable for cold stamping forming processes.