Abstract: Microstructure changes of NCF3015 valve alloy at different solution temperatures were analyzed by means of metallographic microscope and scanning electron microscope, and the mechanical properties of the NCF3015 alloy at different solution and aging temperatures were studied by means of universal tensile testing machine. The results show that the grain size grows rapidly when the solution temperature exceeds 1010 ℃. The solution treated alloy matrix is mainly composed of austenite with equiaxed crystal structure, and a small amount of carbon nitride precipitates on the matrix. After aging, diffusively distributed spherical γ′ strengthened phase is precipitated from the alloy matrix. The size of strengthened phase is smaller with the increase of solution temperature. The high temperature tensile properties of the alloy show that the alloy has relatively good mechanical properties when used below 750 ℃.

Key words: NCF3015 alloy, heat treatment process, microstructure, properties