摘要
对Q345R厚板探伤不合部位取样进行金相、扫描电镜分析,钢板组织存在贝氏体、马氏体、中心微裂纹和MnS夹杂;Z向拉伸断口表明,试样中心部位脆性解理面积大;试样正火后探伤缺陷宽度明显减小。分析认为,铸坯偏析和钢板冷却速度过快是导致钢板异常组织造成探伤不合的主要原因。减轻铸坯偏析和钢板轧后堆垛缓冷是提高Q345R厚板探伤合格率的有效措施。
The authors sampled Q345R heavy plate in site by ultrasonic inspection and carried out metallography and SEM researches.The results showed that bainite,martensite,micro cracks in center and MnS inclusion existed in the microstructure.Z direction tensile fracture indicated that brittle cleavage fracture in the sample center.After the sample normalizing,ultrasonic inspection defect width was reduced obviously.Therefore,slab segregation and fast cooling speed of the plate are the main causations resulted in abnormal microstructure of the plate and disqualification inspection.Lightening slab segregation and stacking for slow cooling after rolling are effective measures to increase nondestructive inspection qualification rate of Q345R heavy steel plate.
出处
《山东冶金》
CAS
2011年第2期43-44,48,共3页
Shandong Metallurgy
关键词
Q345R厚板
探伤不合
异常组织
微裂纹
偏析
Q345R heavy plate
flaw detection
abnormal organization
microcrack
segregation
