GH3230合金焊接板材长期热暴露后组织和性能研究

Study on Microstructure and Properties of GH3230 Welded Plates after Long-Term Heat Exposure Treatment

摘要:

研究了GH3230合金焊接板材在经过不同温度(700-1000 ℃),不同时间(1000-2000 h)的长期热暴露处理后显微组织和力学性能的变化。结果表明：热暴露处理后熔化区铸态组织的枝晶成分偏析程度显著降低,并且随着热暴露温度的升高,降低效果更明显,逐渐形成晶粒组织。室温抗拉强度和屈服强度降低,延伸率上升,主要是由于热影响区小颗粒状(CrW)₂₃C₆碳化物回溶和W₆C碳化物粗化导致的。高温持久性能随热暴露温度升高,持久断裂时间明显降低,而持久塑性有所升高,晶粒尺寸变化和碳化物粗化是焊接板材断在母材处的原因。GH3230合金焊接板材焊接接头组织未发现TCP脆性相等有害相,该合金适宜作长期使用的燃烧室和叶片。

Abstract:

_{:The changes of microstructure and mechanical properties of GH3230 alloy plate after long-term heat exposure treatment at different temperatures (700-1000 ℃) and different times (1000-2000 h) were studied. The results show that the degree of dendrite segregation of as cast microstructure in the melting zone is significantly reduced after heat exposure treatment, andwith the increase of heat exposure temperature, the reduction effect is more obvious, and the grain structure is gradually formed. The tensile strength and yield strength at room temperature decreased and the elongation increased, which wasmainlycaused by the solubilizing of small granular (CrW)23C6 carbides in the heat affected zone and the coarsening of W6C carbides. With the increase of heat exposure temperature, the protractedrupturetimesignificantly decreases, whilethe endurance plasticity increases. The change of grain size and carbide coarsening are the reasons for fracture of welded plates at the base metal. No harmful phase such as TCP brittleness was found in the welded joint of GH3230 alloy welded plate. The alloy is suitable for long-term use as combustion chamber and blade.}