【摘要】 采用金相显微镜、扫描电镜、X射线衍射仪以及拉伸和弯曲试验研究了高温服役4.2万小时超超临界机组用HR3C钢焊接接头的微观组织和力学性能。结果表明,高温长时服役后HR3C钢焊缝金属中形成了大量条状和颗粒状M23C6析出相,焊接热影响区奥氏体晶粒长大,在晶界附近形成了板状M23C6相。拉伸和弯曲试验结果表明HR3C钢焊接接头高温服役后表现出明显的时效脆化倾向。更多还原

【Abstract】 Microstructure and mechanical properties of HR3C steel weld joint serviced at high temperature for 42 000 h were investigated by optical microscopy, scanning electron microscopy, X-ray diffractometer, and tensile and bending test. Results show that after high temperature service for long term,large amount of bar-like and granular M23C6 carbide precipitates in the weld metal of HR3C steel.Coarsened austenite grain was observed in the heat affected zone with some blocky M23C6 carbides along grain boundary. The results of tensile and bending test show that aging embrittlement occurs in the HR3C steel weld joint after high temperature service for long-term.更多还原