40MnBH轧制钢棒裂纹分析

Analysis on Cracks in Rolled Bar of 40MnBH Steel

通过夹杂物检验、蓝脆断口检验以及电子探针能谱分析对40MnBH钢表面出现轴向裂纹的成因进行了分析。结果表明:裂纹是由连铸坯卷渣造成的。由于连铸拉速过高,导致钢水在结晶器内形成紊流,使得吸附了大量Al_2O_3和SiO_2等脱氧产物的保护渣被卷入钢水中,形成了连铸坯卷渣。

Axial cracking were found on the surface of some 40MnBH steel bars. Inclusion testing, blue brittleness testing and EPMA analysis were applied to analyse the cause of the cracks. The results showed that the cracks were caused by the protective slag entrapment of continuous casting. The high continuous casting speed led to the turbulent flow of the hot melt in the mould, resulting in the entrapment of the protective slag that has absorbed lots of deoxidation products, such as Al2O3 and SiO2.