16mm厚的700L钢热轧卷板低温冲击性能不合格的原因分析

Cause Analysis of Unqualified Low Temperature Impact Properties of 16mm Thick 700L Steel Hot Rolled Coil

16 mm厚的700L汽车大梁钢热轧卷板-20℃低温冲击性能不合格。采用光学显微镜、扫描电镜及能谱仪对其进行了检测,分析了不合格的原因。结果表明:钢板1/2厚度处晶粒粗大是导致-20℃低温冲击性能不合格的主要原因。通过优化热轧工艺温度控制范围,提高中间坯厚度等措施,钢板厚度方向上晶粒更均匀,热轧卷板-20℃低温冲击性能的稳定性得到提高。

The-20℃ low temperature impact performance of 16 mm thick hot rolled coil plate of 700L automobile beam steel was not qualified. It was detected by optical microscope, scanning electron microscope and energy spectrometer. The reasons of nonconformity were analyzed. The results show that the coarse grains at the 1/2 thickness of the steel plate are the main cause of the unqualified low-temperature impact property at-20 ℃. By optimizing the temperature control range of the hot rolling process and increasing the thickness of the intermediate billet, the grains of the steel plate in the thickness direction are more uniform, and the stability of-20 ℃ low temperature impact performance is improved.