In order to enhance the fatigue strength of the pressure equalizing hole on labyrinth seal disc for a compressor

three kinds of coldworking techniques with different processes have been designed

i. e .:one-sided multiple extrusion process

cylindrical extrusion process and T shape extrusion process.High cycle fatigue tests of sheet metal specimen made of two kinds of materials with hole were conducted under room temperature and high temperature in three different processes.Test results indicate that sheet metal with coldworking hole produced in T shape extrusion process can efficiently enhance the fatigue strength.