P92钢脉冲电弧焊与GTAW-SMAW焊接接头微观组织及力学性能对比分析

Comparative analysis on microstructure and mechanical properties of P92 steel welded joints by pulsed arc welding and GTAW-SMAW welding process

  • 摘要:
    目的 旨在研究脉冲电弧焊对P92钢焊接接头微观组织和力学性能的影响,及其改善P92钢焊接接头力学性能的可靠性。
    方法 采用脉冲电弧焊和氩弧焊(Gas tungsten arc welding, GTAW)−焊条电弧焊(Shielded metal arc welding, SMAW)制备相应的P92钢焊接接头试样,对焊接接头的微观组织、显微硬度、室温与高温拉伸性能、高温持久性能进行测试及分析。
    结果 结果表明,脉冲电弧焊的焊接接头焊缝及热影响区微观组织较GTAW-SMAW工艺的焊接接头更细小,形成的热影响区更窄,微观组织中无明显的过热粗晶区,但从显微硬度分布可以分析出紧邻熔合线区域仍存在过热硬化区;脉冲电弧焊接接头与GTAW-SMAW焊接接头的室温拉伸性能相近,高温拉伸性能略优于GTAW-SMAW接头;在650 ℃,100 MPa条件下,脉冲电弧焊接接头蠕变断裂寿命与GTAW-SMAW焊接接头相当,原因在于2种工艺接头热影响区中软化区的宽度相近,而软化区的微观组织和力学性能决定了整个接头的蠕变断裂寿命。
    结论 通过对比2种焊接方法的P92钢焊接接头微观组织及力学性能,证明了脉冲电弧焊可作为P92钢焊接的备选方法。

     

    Abstract: Objective The influence of pulsed arc welding on microstructure and mechanical properties of P92 steel welded joint was investigated, and explored the reliability of pulsed arc welding improved mechanical properties of P92 steel welded joint. Methods The welded joint samples of P92 steel were produced by pulsed arc welding process and GTAW-SMAW process. The microstructures, microhardness, room temperature and high temperature tensile properties and creep rupture property of the welded joints were tested and analyzed. Results The results showed that the microstructure of weld and HAZ of pulsed arc welding joint was finer than that of GTAW-SMAW welded joint. The area of HAZ in pulsed arc welding joint was narrower than that in GTAW-SMAW welded joint. No obvious overheated coarse-grained HAZ was observed in the pulsed arc welding joint, but the micro-hardness results showed that the area near the fusion line exhibited an overheated hardening zone. The tensile properties of pulsed arc welding joint at room temperature were similar to those of the GTAW-SMAW welded joint, while the tensile properties at high temperature were slightly better than those of GTAW-SMAW welded joint. The creep rupture life of the pulsed arc welding joint at 650 ℃ and 100 MPa was similar to that of the GTAW-SMAW joint, which can be attributed to the similar width of the softening zone of the heat affected zone in two kinds of welded joints, because the microstructure and mechanical properties of the softening zone determined the creep rupture life of the whole welded joints. Conclusion By comparing the microstructure and mechanical properties of P92 steel welded joint with two welding methods, it proved that pulsed arc welding could be used as an alternative method for P92 steel welding.

     

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