304不锈钢连铸过程中结晶器渣圈形成机制

Formation mechanism of slag rim in 304 stainless steel continuous casting mold

在连铸过程中,结晶器易结渣圈是造成铸坯产生缺陷的主要原因之一。对304不锈钢板坯连铸过程中结晶器保护渣原渣、距开浇60 min时的液渣和渣圈的化学组成、理化性能、结晶矿相以及渣圈形貌结构进行对比分析。结果表明,连铸过程中TiO_2和Cr_2O_3从钢液进入液渣生成高熔点氧化物,使液渣和渣圈的完全熔化温度和黏度显著增大,碱度、转折温度降低。液渣与渣圈的物相以枪晶石和钙铝黄长石为主。高熔点相钙铝黄长石的大量析出以及TiO_2和Cr_2O_3进入液渣使液渣黏度增大是渣圈形成并长大的重要原因。

Formation and growth of slag rim in continuous casting mold is one of the important causes to worse slab quality. In this article,the chemical ingredient,physical-chemical properties,crystallized mineralogical phases,composition and structure of slag rim,original mold flux and mold flux for 304 stainless steel after 60 min from casting start were studied. The results show that TiO_2 and Cr_2O_3 in molten steel moved into the mold flux and generated some oxides with high melting point during continuous casting process,during which the completely melting temperature and viscosity of mold liquid flux and slag rim increased obviously,while the basicity and break temperature decreased. The mold liquid flux and slag rim were mainly composed of cuspidine and gehlenite. The precipitation of high-melting-point phase gehlenite and the increasing of mold flux viscosity caused by TiO_2 and Cr_2O_3 are the main causes to form the slag rim in mold.