论文部分内容阅读
针对目前国内某钢厂生产S355J2钢时产生大量表面横裂纹的现状,利用扫描电镜、EDS能谱仪对铸坯表面横裂纹进行分析,利用Gleeble-1500热模拟试验机对铸坯热塑性进行分析研究,利用透射电镜对试样中析出物的形貌和尺寸进行研究并对析出物进行热力学计算。试验研究结果表明,裂纹处发生硫偏析使晶界处生成硫化物粒子,增加了γ→α转变时的脆性,从而导致横裂纹敏感性增加;试样的低温脆性区为750~910℃,横裂纹敏感区间为745~903℃,低温脆性区间与横裂纹敏感区间基本一致;钢的热塑性随着析出物粒子尺寸的减小而降低,随着奥氏体晶界处铁素体薄膜厚度的增加而降低。
In view of the present situation of large amount of surface transverse cracks produced by a steel mill in China, the transverse cracks on slab surface were analyzed by SEM and EDS, and the thermoplasticity of slab was analyzed by Gleeble-1500 thermal simulation machine , The morphology and size of the precipitates in the sample were studied by transmission electron microscopy and the thermodynamics of the precipitates were calculated. Experimental results show that sulfur segregation occurs at the crack site to generate sulfide particles at the grain boundaries and increase the brittleness at the γ → α transition, resulting in increased transverse crack susceptibility. The low-temperature brittle region of the sample is 750-910 ° C., The crack sensitivity range is from 745 to 903 ℃, and the low temperature brittleness range is basically consistent with the transverse crack sensitivity range. The thermoplasticity of steel decreases with the decrease of precipitated particle size. With the increase of the ferrite film thickness at austenite grain boundaries, Lower.