DZ22合金空心叶片内腔表面裂纹成因

Analysis and Solutions of Inner Surface Cracks in Hollow Blades of DZ22 Superalloy

对DZ22合金空心叶片内腔表面裂纹进行宏观观察,比较叶片铸件在脱芯前与脱芯后内腔表面显微组织的差异,采用X射线衍射仪测量叶片铸件榫头附近残余应力,结合实际生产工艺分析叶片内腔表面沿晶裂纹的形成原因并提出相应的解决措施。结果表明:叶片铸件表面残余应力与脱芯过程中的强碱腐蚀环境共同作用,是造成DZ22合金空心叶片内腔沿晶裂纹的主要原因;适当降低浇铸温度并使用强度较低的型芯可以有效避免叶片内腔裂纹的形成。

The inner surface cracks in hollow blades of DZ22 superalloy were analyzed by macroscopic observation. In addition,the microstructures near the casting inner surface were observed before and after ceramic cores removing. Residual stress near the blades tenon was measured by using X-ray diffraction method. Finally,the reasons for the cracks were analyzed based on the production process of the hollow blades. The results show that the main reason for the inner surface cracks is the coeffect of the residual stress and the alkaline corrosion during ceramic cores removing process. The inner surface cracks in hollow blades can be avoided by lowering casting temperature and using low-strength ceramic cores.