摘要:
利用光学显微镜及X-射线衍射等测试手段对中厚板坯Q235B钢种保护渣渣膜的矿物组成、结晶率、厚度、分层结构进行了系统分析研究。结果表明,中厚板坯Q235B钢种保护渣渣膜矿物组成为镁黄长石、枪晶石、硅灰石和玻璃相。出现纵裂的事故渣膜的结晶相主要为黄长石、枪晶石,结晶率为50%~55%,呈玻璃层-结晶层-玻璃层三层结构;出现粘结漏钢现象的事故渣膜几乎全为结晶层,主要为枪晶石和硅灰石;正常渣膜结晶相以黄长石为主,结晶率为90%以上。为减少中碳钢铸坯表面纵裂及防止铸坯粘结漏钢的发生,建议提高保护渣渣膜中的结晶率,降低硅灰石的含量。
Abstract:
The mineral compositions,crystallization rates,thicknesses,layered structures of slag film of casting powder for continuous casting of Q235B steel plates were analyzed by optical microscope and Xray diffractometer.The result shows that the mineral compositions of slag film consist of akermanite,cuspidine,wollastonite and glass phase.When longitudinal cracks are found on strand surface during casting,the crystalline phases of the slag film are mainly melilite and cuspidine with a crystallization rate of 50%~55%,and the film exists in a glassy layer-crystallizing layer-glassy layer structure.When sticking-type breakouts are found on strand,the slag film is dominated by crystallizing layer consisting of cuspidine and wollastonite.The crystalline phases of slag film under normal circumstances consists of melilite with crystallization rate of 90%.In order to avoid longitudinal cracks on medium carbon steel's strand surface and sticking-type breakout of strand,it it suggested that the crystallization rate be improved and the content of wollastonite be reduced.
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