Study on heat treatment of satellite 6 precisely casted cobalt base superalloy

摘要

A new metal phase calculation software programe, JMatPro, was used to calculate the equilibrium phase diagram of Stellite 6 alloy.Based on the phase diagram, the paper investigated further the effect of heat treatment on microstructure and properties.The results show that the solution heat treatment of 1280 °C for 4 hours and water cooling has some effect on dissolution of primary carbide M7C3 ,however, the primary carbide M7C3 become rounded.The aging heat treatment of 930 °C for 12 hours and air cooling has also almost no effect on shape of primary carbide M7 C3 , but fine dispersed carbides M23 C6 was observed through metallographic structure and hardness of sample increased significantly and well-distributed.Solution at 1200 °C for 4 hours and water cooling has no effect on shape and size of prime carbide M7 C3 , however, the hardness of sample increased.The observation of etched microstructure through SEM show that cast sample microstructure distribute fine lamellar structure continuously, and after heat treatment the structure necked and nodulized, transformed to granulated structure and lead to improving the properties of sample.