Abstract: Nb and Si diffusing rule at 1 190℃ in GH2907 (0.02C,38,20Ni,13.92Co,4. 92Nb,l. 60Ti,0.32Si) alloy ϕ508 mm 3 t ingot is studied by using optical microscope, scanning electron microscope etc. Studies have shown that the dendrite spacing of the GH2907 alloy ϕ508 mm ingot is approximately 110μm, the apparent diffusion coefficients of Nb and Si at 1190℃ are respectively D = (0.704 ±0.041) X 10^-14m²/s and D = (1. 870 ±0.511) x 10^-14m²/s. Theoretical calculation shows that,when Nb diffuses 44.8 ~50.3 h or Si diffuses 14.0~24.5 h at 1 190℃,the residual segregation index δ_i will reach 0.02 respectively.

摘要： 利用光学显微镜、扫描电镜等研究了 GH2907（0.02C，38.20Ni，13.92Co，4.92Nb，1.60Ti，0.32Si）合金Φ508 mm 3 t钢锭Nb和Si在1190℃的扩散规律。研究表明，GH2907合金Φ508 mm钢锭的枝晶间距大约110μm，Nb和Si在1190℃的表观扩散系数分别为D=（0.704±0.041）× 10^-14 m²/s，和D=（1.870±0.511）×10^-14m²/s。理论计算表明，1190 ℃Nb扩散44.8～50.3 h，Si扩散14.0～24.5 h可使其残余偏析指数δ_i达到0.02。

关键词: GH2907合金, 1190℃扩散, 表观扩散系数, 偏析