10B21冷镦钢冷镦开裂原因分析

Analysis of cold cracking causes of cold heading steel 10B21

Φ22 mm规格10B21冷镦钢在生产标准件过程中出现了冷镦开裂现象,通过金相检验与SEM扫描对冷镦开裂原因进行了分析,得出其冷镦开裂的主要原因是盘条存在局部增碳行为,增碳区域珠光体含量较基体明显偏高,冷镦钢的塑性、韧性下降,其在冷镦变形过程中受力,沿薄弱处撕裂。针对此种情况,对连铸过程铸坯增碳行为进行了分析研究,通过采取结晶器电磁搅拌及液面自动控制技术,恒拉速浇注,防止浇铸时卷渣可消除铸坯表面增碳。

The Φ22 mm size 10 B21 cold crucible steel had cold cracking during the production of standard parts.The reasons for cracking of cold headings were analyzed by metallographic examination and SEM scanning. The main reason for the cracking of cold heading was the local carbon addition behavior of wire rods.The pearlite content in the carbon increase area was significantly higher than that in the matrix. The plasticity and toughness of the Φ22 mm size 10 B21 cold crucible steel decreased,and it was torn along the weak areas during the cold crucible deformation.In view of this situation,the carbon-removal behavior of slabs in the continuous casting process was analyzed and studied.By adopting the electromagnetic stirring of the crystallizer and the automatic liquid level control technology,the casting is poured at a constant speed so as to prevent the slag from being removed during the casting to eliminate carbonation on the surface of the casting blank.