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对API X65管线钢进行模拟高压干法水下焊接,对不同环境压力条件下(0.1,0.3,0.5,0.7 MPa)焊接接头的显微组织及硬度进行测试,分析环境压力对焊接接头组织和性能的影响。结果表明:X65管线钢的组织由铁素体、珠光体和上贝氏体组成。不同环境压力下焊缝的显微组织均为铁素体、珠光体和少量的碳化物;热影响区的组织均为针状铁素体和少量的珠光体。热影响区熔合线附近的硬度较高,远离融合线处硬度降低,并逐渐接近母材金属的硬度。环境压力对焊接接头的显微组织及硬度的影响不大。
The pressure of X65 pipeline steel was simulated under high pressure dry-process underwater welding. The microstructure and hardness of welded joints under different environmental pressures (0.1,0.3,0.5,0.7 MPa) were tested. The effects of environmental pressure on the microstructure and properties of welded joints Impact. The results show that the microstructure of X65 pipeline steel consists of ferrite, pearlite and upper bainite. Under different environmental pressures, the microstructure of the weld is ferrite, pearlite and a small amount of carbides. The microstructure of the HAZ is acicular ferrite and a small amount of pearlite. The HAZ has a higher hardness near the weld line and a lower hardness away from the weld line and gradually approaches the hardness of the parent metal. Environmental pressure has little effect on the microstructure and hardness of welded joints.