GH907合金铸锭均匀化热处理

Homogenization heat treatment of GH907 ingot

为了系统研究GH907合金铸锭枝晶间Laves相的固溶规律和铸锭中铌元素的扩散规律,以指导生产实践。以抚顺特钢生产的GH907合金φ508 mm铸锭为研究对象,利用光学显微镜、扫描电镜等手段,系统研究了GH907合金铸锭不同温度和时间下的均匀化情况。结果表明,GH907合金铸锭枝晶间Laves相的最佳扩散温度为1 160℃,扩散10h以上Laves相可以完全消除;同时计算得知,GH907合金铸锭中铌元素在1 160℃下的表观扩散系数为D=0.488 55×10^（-14） m^2/s;理论计算表明,在1 160℃下处理56h后,GH907合金中铌元素的残余偏析指数δi可以达到0.02。

In order to guide the production practice of alloy GH907,the solid solution law of the interdendritic Laves phase and the diffusion law of Nb element in the GH907 ingot is systematically studied.The homogenization diffusion of alloy GH907φ508 mm cast ingot at different temperature and time,which was produced by Fushun Special Steel Co.,Ltd.,was discussed using the optical microscope and the scanning electron microscope.Studies showed that the best diffusion temperature of Laves phases in GH907 cast ingots was 1 160 ℃,and the Laves phase can be completely eliminated when the diffusion time was more than 10 h.The calculated apparent diffusion coefficients of Nb in GH907 cast ingots was D=0.488 55×10^（-14） m^2/s at 1 160℃.The theoretical calculation showed that the residual segregation index of Nb in GH907 cast ingots could reach 0.02 when the heat treatment was at 1 160 ℃ for 56 h.