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采用焊接热模拟、电子显微分析、力学性能测试等技术手段,研究了国产9Ni钢在多种焊接热输入条件下焊接热影响粗晶区的低温韧性,讨论了多次焊接热循环对9Ni钢焊接热影响区组织性能的影响规律,以及不同焊接热过程中的组织特征和脆化倾向。研究结果表明,9Ni钢并不适合采用单道焊,在多道焊接过程中,后续焊道的热作用可以良好地改善其低温韧性,粗大晶粒组织的重结晶是提高低温韧性的主要因素。
The low temperature toughness of the welded heat-affected coarse-grained region of domestic 9Ni steel under various welding heat input conditions was studied by means of welding thermal simulation, electron microscopic analysis and mechanical property testing. The effects of multiple welding heat cycles on the mechanical properties of 9Ni steel The influence law of microstructure and properties of HAZ and the microstructure and embrittlement tendency in different welding heat processes. The results show that 9Ni steel is not suitable for single pass welding. In the multi-pass welding process, the thermal effect of subsequent weld bead can improve its low temperature toughness. The recrystallization of coarse grain is the main factor to improve the low temperature toughness.