某模铸轴承钢皮下夹杂缺陷的分析与控制

Analysis and Control of Subsurface Inclusions of the Mould-Casting Bearing Steel

某模铸轴承钢在水浸式自动超声波检测时出现连续横波报警。采用化学成分分析、低倍组织及非金属夹杂物检验、扫描电镜及能谱分析的方法,分析了缺陷的性质和产生的原因。结果表明:该模铸轴承钢超声波检测的缺陷为皮下夹杂;该皮下夹杂的成分以铝、硅、钙的氧化物为主,并含有少量的钠、钾等元素的氧化物,是由浇铸过程中保护渣卷入钢液中所致。对保护渣采用吊渣及烘烤等措施,可有效避免该类缺陷的产生。

Continuous transverse wave alarm occurred to the mould-casting bearing steel during the automatic immersion-ultrasonic detection.Chemical composition analysis, macrostructure and non-metallic inclusion examination,scanning electron microscope and energy spectrum analysis were used to analyze the mechanism and causes of the defects.The results show that：the defects of the mould-casting bearing steel detected by ultrasonic were subsurface inclusions;the subsurface inclusions included the oxide of aluminum,silicon,calcium,and a small amount of the oxide of sodium,potassium and other elements;the cause of subsurface inclusions was that the protective slag was brought into the liquid steel in the casting process.The generation of such defects could be effectively avoided by measures such as slinging slag and baking slag.