Q355B宽带钢表面开裂原因

Reason for surface cracking of Q355B broadband steel

某Q355B钢边部表面发生开裂现象。采用宏观观察、化学成分分析、金相检验、扫描电镜及能谱分析等方法分析了裂纹产生的原因。结果表明:钢板表面裂纹产生于连铸工艺环节,裂纹附近存在砷、铜等有害元素富集现象;砷、铜等有害元素形成了低熔点的富集相,使钢板的塑性变差,破坏了钢基体连续性,在拉应力的作用下,钢板表面发生开裂现象。

Cracking occurred on the edge surface of a Q355B steel.The cause of crack formation was analyzed using methods such as macroscopic observation,chemical composition analysis,metallographic examination,scanning electron microscopy and energy spectrum analysis.The results show that surface cracks on the steel plate occurred during the continuous casting process,and there was an accumulation of harmful elements such as arsenic and copper near the cracks.Harmful elements such as arsenic and copper formed low melting point enriched phases,which deteriorated the plasticity of the steel plate and disrupted the continuity of the steel matrix.Under the action of tensile stress,the surface of the steel plate cracked.