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针对微合金亚包晶钢凝固过程中产生大量裂纹缺陷的现状,采用光学显微镜、扫描电镜及能谱分析仪对铸坯表面裂纹进行分析,并对析出物进行热力学计算,利用Gleeble-1500对铸坯热塑性进行分析研究。结果表明:裂纹处存在(Fe,Mn,Si,Al)(S,O)等夹杂物,加剧应力对基体的影响;裂纹处存在Ti-Al-(C,N)夹杂物,增加了γ→α转变的脆性,横裂纹敏感性增加。高温脆性区易产生纵裂,断面收缩率(Z)最小值为37.59%,纵裂纹敏感区间为1 454~1 478℃。900~750℃为低温脆性区,易产生横裂纹,Z最小值为45.24%,横裂纹敏感区间900~750℃。896℃时,铁素体开始析出,使得晶界上进一步集中,导致裂纹发生。
Aiming at the present situation of a large number of crack defects during the solidification of microalloy subaluminate steel, the surface cracks of the slab were analyzed by optical microscope, scanning electron microscope and energy spectrum analyzer. The thermodynamics of the precipitate was calculated. Billet thermoplastic analysis. The results show that inclusions such as (Fe, Mn, Si, Al) (S, O) exist in the crack and aggravate the influence of stress on the matrix. There are Ti-Al- (C, α transition brittle, transverse crack sensitivity increased. Longitudinal cracks are easy to occur in the high temperature brittle zone. The minimum value of the area shrinkage (Z) is 37.59% and the longitudinal crack sensitivity is 1 454-1 478 ℃. 900 ~ 750 ℃ for low temperature brittle zone, easy to produce transverse cracks, Z minimum 45.24%, horizontal crack sensitivity range 900 ~ 750 ℃. At 896 ° C, ferrite begins to precipitate, causing further concentration on the grain boundaries, resulting in cracks.