作　　者： ; ; ; ;

机构地区： 辽宁石油化工大学机械工程学院

出　　处： 《材料热处理学报》 2015年第5期117-122,共6页

摘　　要： 针对厚度超过90 mm Q345特厚钢板超声波探伤合格率较低的现象,采用高倍金相检验、扫描电镜、能谱分析和力学分析等方法对90 mm Q345超声波探伤检测不合格与合格钢板进行了对比研究。结果表明:引起特厚板超声波探伤不合格的原因是钢板厚度中心区域珠光体带中存在微裂纹。微裂纹产生的原因一方面是铸坯中心碳、锰元素偏析引起的组织应力及钢板轧后快速冷却引起的热应力,另一方面是钢板心部Mn S和氧化物等夹杂物的聚集致使与钢基体界面结合较弱,促进了微裂纹的萌生与扩展。通过改善铸坯质量、合理选择宽厚板铸坯坯型和合理安排轧制规程,有效提高了Q345宽厚板的超声波探伤检测合格率。 In view of the phenomenon of low qualified percent of Q345 ultra-heavy steel plate with thickness more than 90 mm by ultrasonic inspection,comparative study on the Q345 plates with 90 mm thickness which were qualified and unqualified in ultrasonic inspection detection was carried out by SEM,metallographic examination,EDS and mechanical analysis. The results show that the flaws in the steel plate are caused by micro-cracks in the pearlite band at the center area of the plate along thickness direction. The reason for the crack one hand is the structural stress which because of carbon and manganese element centerline segregation of slab,and thermal stress which due to rapid cooling after rolling. The other hand is weak binding force between matrix interface of the steel and inclusion which owe to the aggregation of Mn S and oxide inclusion,and promote the initiation and growth of micro cracks. By improving the casting slab quality,selecting appropriate casting slab model and arranging reasonable rolling regulation,good ultrasonic inspection qualified rate of the Q345 heavy steel plate can be obtained.

关 键 词： 特厚板 探伤 微裂纹 偏析 夹杂物

领　　域： [金属学及工艺] [金属学及工艺]