Analysis of white spot defects in large forging of ultra-high strength steel
NING Jing 1， TIAN Zhao-fu 2， XIE Jin-peng 3， SU Jie 1
1. Institute for Special Steels， Central Iron and Steel Research Institute， Beijing 100081， China； 2. NORINCO Group Air Ammunition Research Institute， Harbin 150030， China； 3. Failure Analysis Center， Central Iron and Steel Research Institute， Beijing 100081， China
Abstract：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 large-size blind hole forging of a 1 700 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.
宁 静， 田兆富， 谢金鹏， 苏 杰. 超高强度钢大型锻件白点缺陷分析[J]. 物理测试, 2020, 38(6): 53-.
NING Jing, TIAN Zhao-fu， XIE Jin-peng， SU Jie. Analysis of white spot defects in large forging of ultra-high strength steel. PHYSICS EXAMINATION AND TESTING, 2020, 38(6): 53-.
2020, Vol. 38 
