热处理工艺对气阀合金NCF3015组织和性能的影响

Effect of heat treatment process on microstructure and properties of valve alloy NCF3015

通过金相显微镜和扫描电镜分析了NCF3015气阀合金不同固溶温度下的组织变化规律,使用万能拉伸试验机研究了NCF3015合金在不同固溶时效温度下的力学性能变化规律。结果表明,固溶温度超过1010℃,晶粒快速长大。固溶态合金基体主要为奥氏体等轴晶组织,基体上析出少量的碳氮化物。时效处理后,合金基体析出球形的γ′强化相,固溶温度越高,强化相尺寸越小。合金高温拉伸性能显示,合金在低于750℃下使用,力学性能较好。

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 ℃.