ZHU Xue-song
,
ZHU Guo-hui
,
MAO Wei-min
钢铁研究学报(英文版)
Average grain size and grain size distribution in as hot-rolled SPHC, SPHD, and SPHE sheets manufactured by compact strip production (CSP) processing and traditional continuous casting and rolling (CCR) processing respectively were investigated by quantitative metallographic method. The results show that the average grain size and distribution width of grain size in sheets manufactured by CSP processing was obviously larger than that by CCR processing. It was analyzed that multi-phase transformation and high reduction ratio in CCR processing resulted in refining grain size, which would be dominant reason for controlling grain size. In plain carbon steels such as SPHC, SPHD and SPHE, the effect of fine precipitation in CSP on behavior of deformation and recrystallization of austenite during rolling, and consequent refinement of grain size seem not to be as important as the effect of re-heating and roughing in CCR processing. Homogenizing in re-heating and refining grain size in roughing in CCR processing would refine final grain size and also make grain size homogenized. Very coarse grain size would result in mixed grain size, large distribution width of grain size due to interaction of static and dynamic recrystallization in CSP processing.
关键词:
CSP
,
CCR
,
hot-rolled plate
,
grain size
张超，，宋畅，韩斌，谭佳梅，郭茜，吴润
钢铁研究学报
在武钢CSP生产线上，通过控轧控冷工艺生产低成本低碳CMn钢薄板。结果表明，生产出的薄板屈服强度大于313MPa，抗拉强度高于400MPa，伸长率超过37%，屈强比低于083，冷弯性能良好，满足塑性要求，但常出现表面裂纹。从热力学角度分析出尺寸大于83nm的硬脆粒子会引起裂纹，而钢中析出物尺寸约为30nm，不足以引起裂纹。金相和扫描电镜观察到裂纹周围有混晶现象，计算表明混晶造成的应力集中约为120MPa，大于F3轧制时钢带的强度，容易导致裂纹的产生。经提高开轧温度、降低终轧温度及卷取温度后，表面裂纹发生率从367%降低到了134%。
关键词:
CSP
,
surface crack
,
thermodynamics
,
mixedgrain
