吝江,张永辉,王晓春,等.SP2215和HR3C异种钢焊接接头长期服役后的微观组织和力学性能[J].精密成形工程,2025,17(6):215-224.
LIN Jiang,ZHANG Yonghui,WANG Xiaochun,et al.Microstructure and Mechanical Properties of SP2215 and HR3C Dissimilar Steel Welded Joints after Service[J].Journal of Netshape Forming Engineering,2025,17(6):215-224. |
| SP2215和HR3C异种钢焊接接头长期服役后的微观组织和力学性能 |
| Microstructure and Mechanical Properties of SP2215 and HR3C Dissimilar Steel Welded Joints after Service |
| 投稿时间：2024-11-22 |
| DOI：10.3969/j.issn.1674-6457.2025.06.023 |
| 中文关键词: 超超临界机组 奥氏体耐热钢 焊接接头 微观组织 力学性能 |
| 英文关键词: ultra-supercritical unit austenitic heat-resistant steel welded joint microstructure mechanical property |
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| 摘要点击次数: 29 |
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| 中文摘要: |
| 目的 对比国内外超超临界机组锅炉用奥氏体耐热钢及异种钢焊接接头的服役状况差异及可靠性。方法 通过室温拉伸测试、冲击测试以及光学显微镜和扫描电子显微镜，对620 ℃下服役4 000 h的再热器蒸汽管的母材HR3C、SP2215以及这2种钢焊接接头的显微组织和力学性能进行精确表征和测试。结果 服役后，母材SP2215、HR3C以及焊接接头均具有较高的强度，但塑性和韧性较低。与焊接接头相比，母材的强度、塑性和韧性均更高，且SP2215的强度性能优于HR3C的。对微观组织进行观察后发现，母材和接头的断口形貌都呈现出明显的冰糖状，是典型的沿晶断裂模式。结论 母材SP2215由奥氏体基体组成，晶界处富Cr碳化物M23C6已形成链状结构，HR3C也由奥氏体基体组成，晶界处发生Cr元素聚集，焊缝金属也为典型的奥氏体组织，晶界处有M23C6和G相析出。母材SP2215和HR3C的晶粒内部均有富Nb相析出，焊缝处的晶粒内部则有富Nb相和γʹ相析出。晶界的析出相对母材及接头的塑性和韧性都产生了不利影响，而晶粒内部的析出相使母材及接头在服役后仍保持着较高的强度性能。 |
| 英文摘要: |
| The work aims to compare the service condition differences and reliability of austenitic heat-resistant steel and dissimilar steel welded joints for boilers of ultra-supercritical units in China and abroad. Through room temperature tensile testing, impact testing, as well as optical microscopy and scanning electron microscopy, the microstructure and mechanical properties of the base metals HR3C and SP2215 of the reheater steam pipe and the welded joints of these two steels after 4 000 h of service at 620 ℃ were accurately characterized and tested. After service, the base metals SP2215, HR3C, and the welded joints all had high strength but low plasticity and toughness. Moreover, the strength, plasticity, and toughness of the base metals were higher than those of the welded joints, and the strength performance of SP2215 was better than that of HR3C. After observing the microstructure, it was found that the fracture morphologies of the base metals and the joints both showed an obvious rock candy shape, which was a typical intergranular fracture mode. The base metal SP2215 is composed of an austenite matrix. A chain-like structure of Cr-rich carbide M23C6 has been formed at the grain boundary. HR3C is also composed of an austenite matrix. Cr element accumulates at the grain boundary. The weld metal is also a typical austenitic structure. M23C6 and G phases precipitate at the grain boundary. There are Nb-rich phases precipitated inside the grains of the base metals SP2215 and HR3C. There are Nb-rich phases and γʹ phases precipitated inside the grains at the weld. The precipitated phases at the grain boundary have an adverse effect on the plasticity and toughness of the base metal and the joint, while the precipitated phases inside the grains enable the base metal and the joint to maintain high strength performance after service. |
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