热处理工艺对GH909板材TIG焊缝析出相的影响

Effects on precipitates of GH909 plate TIG weld under different heat treatments

为改善GH909板材的焊接工艺及使用性能,采用扫描电镜和EDX分析研究了GH909板材在TIG焊后不同热处理工艺焊缝析出相的变化规律,对提高GH909板材TIG焊接接头质量具有重要的应用价值.研究结果表明:焊缝形成的相有针片状ε/ε″相、γ/Laves低熔点共晶相,且都在γ晶间分布;焊缝中心低熔点共晶相所占比例均比离焊缝中心不远的焊缝边部小,经过固溶处理的焊缝低熔点共晶相所占比例加大;ε/ε″相大部分溶解,且Nb、Ti偏析较严重,焊缝结晶裂纹敏感性高,影响合金的综合性能.

To improve the welding process and the performances of GH909,a study on precipitates of GH909 plate TIG weld under different heat treatments had been carried out by SEM and EDX.The study had found ε/ε＂ platelets,γ/Laves low-melting eutectic phases distribute in the weld of austenite intergranular.The ratios of low-melting eutectic phases in weld center were smaller than weld edge which was near the weld center.After solution treatment,the proportions of low-melting eutectic phases were increased,most of ε/ε＂ were dissolved,and the segregation of Nb and Si were more serious.This could lead to higher weld solidification cracking sensitivity and affect the comprehensive properties of GH909.