高压涡轮导向叶片裂纹原因分析与控制

Analysis and Controlling of Cracks in High Pressure Turbine Guide Blades

针对定向凝固过程中高压涡轮导向叶片存在沿柱状晶晶界开裂的现象,分析了高温合金柱状晶凝固收缩机理及材料成分对热裂倾向的影响,并对陶瓷型芯高温形变、陶瓷型芯对金属收缩的阻碍等进行了分析。结果发现,定向凝固柱状晶晶界裂纹与晶界结构、合金收缩受阻、陶瓷型芯的形变与漂移有一定的关系。通过采取调整叶型壁厚、陶瓷型芯定位、调整材料成分等措施来抑制定向凝固叶片沿晶界开裂的倾向。

Aiming at the crack along columnar grain boundary of high pressure turbine guide blade,solidification shrinkage mechanism of columnar crystal grain boundary in the high-temperature alloy,the component affecting hot crack tendency in casting alloy was analyzed.Meanwhile,the deformation of ceramic core at high temperature and the hindering from ceramic core to metal were expounded.The results show that the cracks at columnar crystal boundary in directional solidification process is obviously related with the structure of grain boundary,the contract inhibition of alloy,the deformation and drift of ceramic core.Through adjusting thickness of the leaf type,locating the ceramic core and adjusting components of the materials,crack along columnar grain boundary was improved greatly.