Q390B板材屈服强度偏低的原因分析

CAUSE ANALYSIS OF LOW YIELD STRENGTH OF Q390B PLATE

针对河钢唐钢中厚板公司生产的Q390B屈服强度偏低的情况,利用能谱分析仪、全相显微镜,分别对试样的化学成分、断口形貌、显微组织及夹杂物进行了分析,并与合格试样进行对比,确定Q390B中厚板屈服强度低的主要原因为钢组织中含有大量的混晶,且硫化物夹杂较多。通过采取增加RH真空精炼工序,连铸中间包加设挡渣坝、挡渣堰,轧钢过程采用粗轧高温大压下及降低终轧温度等措施,保证了钢板内部组织均匀细小无异常,综合力学性能得到有效提高。

In view of the low yield strength of Q390B produced by Tangsteel Medium and Heavy Plate Company of HBIS Group, the chemical composition, fracture morphology, microstructure and inclusions of the samples were analyzed by energy spectrum analyzer and full-phase microscope. Compared with the qualified samples, the main reason for the low yield strength is that there are a lot of mixed crystals in the steel structure and more sulfide inclusions. By measures of increasing RH vacuum refining process, adding slag dam and slag barrier in tundish, adopting high temperature large reduction in rough rolling, and decreasing the final rolling temperature, the uniform and fine internal structure of steel plate is ensured, and the comprehensive mechanical properties are effectively improved.