60Si2MnA盘条断裂原因分析

Φ12.5mm的60Si2MnA盘条拉拔过程中产生抽芯断裂,钢丝绕簧过程中产生劈裂断裂。对盘条进行力学性能检测,对2种断口进行非金属夹杂物、金相组织、酸浸检测和扫描电镜分析,结果表明:连铸坯中存在较多的疏松、微孔与偏析,在轧制过程中由于压缩比太小,致使盘条中残留有疏松与偏析,最终造成60Si2MnA弹簧钢盘条在拉拔及绕簧过程中断裂。减轻疏松与中心偏析的措施:在结晶器内和最后凝固区进行电磁搅拌,对最后凝固区附近的铸坯轻压下。

Fracture cause analysis of 60Si2MnA wire rod

φ12.5 mm 60Si2MnA wire rod produced core-pulling fracture in drawing process. The steel wire produced splitting fracture in spring making process. The mechanical properties were tested on wire rod. The two fractures were analyzed in such aspect as non-metallic inclusions, metallographic structure, pickling macrostructure test and SEM. Results show that there are some looseness, shrinkage void and segregation in continuous casting billet, adding compression ratio too small, which leads looseness and segregation existing in wire rod, causes 60Si2MnA spring steel wire rod fracture in the drawing and spring making process. The measures to relieve looseness and central segregation： electromagnetic stirring in mold and the last solidification, and soft reduction near the casting billet in the last solidification.