430不锈钢用连铸保护渣渣圈形成长大机理分析和控制措施

Analysis on Formation and Growth Mechanism of 430 Stainless Steel Mold Powder Slag-Bonding Rim and Control Measures

针对430不锈钢(0.03~0.04C,16~17Cr)生产过程中渣圈粗大的问题,利用电感耦合等离子体发射光谱仪、半球点熔点仪、粘度仪等设备对比分析了保护渣与渣圈的化学成分与理化性能,通过电子探针观测渣圈的微观结构,探究渣圈形成长大的机理。研究发现:除渣圈C含量0.53%和原渣C含量2.87%外渣圈成分与原渣无明显变化,但粘度与熔点均有所降低,渣圈约70%的区域由烧结相构成,其余30%为结晶相,主要由枪晶石与黄长石构成。烧结相的大量粘结是渣圈形成长大的主要原因。提高保护渣中预熔料比例至70%~80%及炭黑含量≥2%,并在生产中进一步稳定保护渣熔化过程,可有效抑制渣圈长大。

In response to the problem of coarse slag-bonding rim in 430 stainless steel production process,the chemical composition and physicochemical properties of the mold powder and slag-bonding rim are compared and analyzed using ICPOES,hemispherical point melting point meter,viscometer and other equipment,and the microstructure of the slag-bonding rim is observed through the electronic probe to explore the mechanism of slag rim formation and growth.It is found that except C content of slag-bonding rim being 0.53%and C content original mold powder being 2.87%,the composition of the slag-bonding rim and the original mold powder is not much different,but viscosity and melting point are reduced,about 70%of the area of the slag rim consists of the sintered phase,the remaining 30%is the crystalline phase,mainly composed of cuspidine and melilite.The sintered phase of a large number of bonding become a main reason for the formation and growth of the slag rim.Increasing the proportion of pre-melt material to 70%~80%and the content of carbon black in the mold flux≥2%,and further stabilizing the melting process of the mold powder in production,can effectively inhibit the growth of the slag rim.