超高强度钢大型锻件白点缺陷分析

Analysis of white spot defects in large forging of ultra-high strength steel

针对1700 MPa级新型超高强度钢大规格盲孔锻件局部出现的探伤缺陷问题,采用横截面酸浸试验、热处理后力学性能试验、断口及裂纹面观察等手段进行综合分析,鉴定缺陷为氢致裂纹(白点),并详细分析了其可能产生的工艺环节,对此提出了提高渣料烘烤温度和时间、延长扩氢退火时间、加强心部锻透性等改进措施。

Cross section pickling,mechanical property tests after heat treatment,fracture and crack surface observation and other test methods were employed to comprehensively analyze the local ultrasonic flaw detection defects of a largesize blind hole forging of a 1700 MPa new ultra-high strength steel.The defects were identified as hydrogen-induced cracking(white spots).The possible generation process was analyzed in detail.The corresponding improvement measures,such as enhancing slag baking temperature and time,increasing hydrogen diffusion annealing time,improving forging ratio and the forging penetration efficiency of the core part,were proposed.