调质型容器板探伤不合格原因分析与改进措施

Cause Analysis and Improvement Measures of Hardened and Tempered Vessel Plate Non-conformity at Detection Test

某调质型高强度容器板在生产过程中出现大批量探伤不合格,对探伤不合格区域进行取样,通过采用金相检验、扫描电镜等手段进行检测,对探伤不合格钢板的组织进行了观察和分析,发现夹杂物、中心裂纹等缺陷是造成探伤不合的主要原因。分析认为,钢坯原始裂纹导致钢板中存在轧后裂纹,钢水精炼过程中的钙铝酸盐夹杂物上浮不充分,造成钢板中存在大尺寸夹杂物。提出了提高钢水纯净度及钢坯内部质量等改进措施。改进后钢板探伤合格率提高了12%,效果较好。

The hardened and tempered high strength vessel plate was found non-conformity in big batch at detection test during production. Samples were taken in non-qualified section in order to observe and analyze the microstructure of non-qualified plate by metallographic inspection and scanning electronic microscope. The defects of inclusion and central crack were found to be the main causes. Analysis showed that billet crack resulted in plate after-rolling crack and insufficient floating of calcium aluminate during refining, big inclusion in the plate. Improvement measures of increasing steel cleanliness and billet internal quality were proposed. The qualification rate was increased by 12% after improvement. Good effect was achieved.