300M钢制件磨削延迟开裂失效分析  

Failure analysis for grinding delayed cracking of 300M steel components

作　　者：岳海燕 贾敏 曾志强 孙新明 程胜 Yue Haiyan;Jia Min;Zeng Zhiqiang;Sun Xinming;Cheng Sheng(Shanghai Aircraft Manufacturing Co.,Ltd.,Shanghai 200436,China)

机构地区：[1]上海飞机制造有限公司,上海200436

出　　处：《金属热处理》2024年第11期315-319,共5页Heat Treatment of Metals

基　　金：工信部商用飞机质量和可靠性保证体系研究项目(3-0106300-029)。

摘　　要：300M钢制件制备完成后静置一段时间发现制件一表面存在大量微裂纹。从外观、材料化学成分、显微组织和裂纹特征、硬度方面对该批制件的开裂原因和开裂机制进行了分析。结果表明,制件裂纹为磨削裂纹,起源于磨削面的近表层,主要呈沿晶和准解理开裂特征。开裂原因是制件镀铬后,在磨削过程中表层材料发生塑性流动并在急冷条件下产生了残余拉应力,表层和近表层组织发生烧伤产生组织拉应力且近表层材料硬度降低,在后续制件静置过程中,由于镀铬引入的氢原子向近表层扩散,并在位错和晶界处聚集,在残余拉应力和组织拉应力作用下,氢原子诱导磨削裂纹在近表层发生延迟开裂。A large number of micro-cracks were found after the finishing of 300M steel components.The cracking reasons and mechanisms of this batch of components were analyzed from the aspects of appearance,material chemical composition,microstructure and crack characteristics and hardness.The results show that these are grinding micro-cracks,which initiate in the near-surface layer,mainly exhibiting intergranular and quasi cleavage cracking characteristics.The reason for the cracking is that after chrome plating,the surface material undergoes plastic flow during the grinding process and residual tensile stress is generated under rapid cooling conditions.The surface and near-surface material are burned and the phase transition stress is formed.Meanwhile,the hardness of burned material decreases.After a long time,hydrogen atoms from chrome plating diffuse to near-surface and gather at the dislocations and grain boundaries,that induces the grinding crack to have delayed forming in near-surface under the action of residual tensile stress and microstructure tensile stress.

关 键 词：300M钢 表面微裂纹 磨削 镀铬 延迟失效 

分 类 号：TG506[金属学及工艺—金属切削加工及机床]