750MPa级高强汽车大梁钢冲压开裂原因及机制

Stamping Cracking Mechanism of High Strength Beam Steel of 750MPa Level

700MPa以上级高强汽车大梁钢的冲压开裂现象一直是困扰该类钢种使用的主要问题。控制夹杂物、中心偏析及剪切面修磨等手段可以降低冲压开裂的概率。侧重从热轧工艺角度寻找导致带钢冲压开裂的原因及机制。通过分析对比正常带钢及冲压开裂带钢的组织、力学性能、加热及粗轧温度制度、精轧卷取温度制度、轧制速度的不同,同时考虑热装制度的影响,详细分析了热轧工艺各参数在750MPa级高强大梁钢冲压开裂缺陷中可能起到的作用,为该类钢种的生产提供了有益的经验。结果表明,保证精轧区轧制速度是降低冲压开裂发生率的重要热轧生产手段。

The stamping cracking defect is the main problem for the utility of high strength beam steel with the strength exceeding 700 MPa. Controlling the inclusions and center segregation and grinding the shear plane can re- duce the probability of stamping cracking. The paper was mainly focused on hot rolling process to investigate the cause and mechanism leading to stamping cracking. The mierostructure, mechanical properties, heating and rough rolling temperature system, finishing rolling and coiling temperature system, finishing rolling speed, as well as the influence of hot charging system, were all comparatively analyzed, considering the difference between the normal strip and stamping cracking strip of 750 MPa level beam steel. And some beneficial experiences were provided for production of this kind of steel. The results show that ensuring fine rolling speed is the important way to low the probability of stamping cracking defect.