Forming Cause of Fluorescence Showed Defects on the surface of Titanium Alloy Investment Casting

Author of the article:LI Weidong1 , ZHOU Haohao2 , LIU Yinqi1 , YANG Xuedong1 , SHI Fengling2

Author's Workplace：1. Luoyang Shuangrui Precision Casting Titanium Co., Ltd., Luoyang 471000, China; 2. AECC Shen Yang Li Ming Aero-engine Corporation Ltd., Shenyang 110043, China

Key Words：titanium alloy; investment casting; fluorescence; vacuum heat treatment

Abstract：The defects of fluorescent display on the surface of titanium alloy investment precision castings seriously restrict product quality and production cycle. This article introduces the type, time and reason of the surface fluorescent display defects in the production process of investment casting titanium alloy castings and the post-treatment process. The types of fluorescent display defects on the surface of titanium alloy investment precision castings are mainly surface cracks and surface pits; the time of defects is mainly three time nodes after casting, repair welding and vacuum heat treatment; the main reasons for the fluorescent display defects are Casting stress, the reaction between molten metal and the shell, the stress caused by repair welding, and the stress caused by surface deformation caused by the release of residual stress in vacuum heat treatment