非调质钢38MnVS轧制裂纹机制分析

Analysis of rolled cracks on 38MnVS non-quenched and tempered steel

针对非调质钢38MnVS轧制过程中出现的裂纹,采用金相显微镜、扫描电子显微镜、小样电解技术对裂纹区域进行二维、三维分析。结果表明,裂纹两侧存在明显脱碳层,在裂纹周边及延伸区域存在大量沿线分布的硅锰酸盐夹杂物。由于大量长条和不规则状硅锰酸盐夹杂物的存在,在连铸过程铸坯表面产生了微细的纵向裂纹。在铸坯热送过程,微细裂纹进一步扩展,形成贯穿裂纹,从而导致整个轧材报废。根据裂纹产生的机制,优化连铸过程保护渣,取消对铸坯的热装热送,能有效控制裂纹产生,使成材率明显提升。

Aiming at the rolling cracks of 38 MnVS non-quenched and tempered steel,the two-dimensional and the three-dimensional morphology of cracks were analyzed by metallographic microscope,scanning electron microscope,energy spectrum.The results showed that there were obvious decarburization layers on both sides of the crack,and a large number of silicomanganese inclusions distributed along the crack periphery and extension area.Small longitudinal cracks were emerged on the surface during the continuous casting,because of the presence of endogenous inclusions,long and irregular silicic manganate inclusions.In the heat transfer and rolling process,these cracks further expansion,forming perforated cracks and leading to the scrap of the whole rolled.According to the mechanism of crack generation,optimizing the slag during the continuous casting process,and canceling the hot transferring and hot charging during the rolling process can effectively control the crack generation and significantly improve the finished product rate.