18CrNiMo7-6合金结构钢真空电子束焊接头组织及性能研究

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Abstract： Welding procedure test of 18CrNiMo7-6 with end-lock structure was caried out by vacuum electron beam welding.The microstructure and mechanical properties of vacuum electron beam welding joint of 18CrNiMo7-6 were analyzed by microscopic examination， microhardnes，tensile test， Charpy impact test and fatigue test. The results show that，the molten metal is cooled rapidly during welding，weld region is mainly composed of lat martensite，and HAZ is composed of martensite and ferrite.Hardness value of weld zone and HAZ is higher than thatofbasematerial，thetensilestrengthofjointreaches 950MPa ，andtheweldingcoefficientreachesO.91.The impact performance of weld and HAZ is higher than that of base material. The fatigue limit is 354MPa ，the fracture morphology shows obvious fatigue partition characteristics.

Keywords： vacuum electron beam welding; structural alloy steel; microstructure; mechanical property; fatigue performance

1序言

18CrNiMo7-6是一种具有高强度和高韧性的渗碳型合金结构钢，具有淬透性能优良、热处理变形量小等优点，表面进行渗碳和淬火处理后可获得较高的表面硬度和耐磨性，综合力学性能良好。（剩余5059字）