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通过高周疲劳试验,测定了大厚壁NiCrMoV钢深窄间隙埋弧焊焊接接头的S-N特征曲线。疲劳试验发现,疲劳试样断裂位置多发生在焊缝处,并对疲劳断口进行了SEM分析。发现疲劳裂纹源出现在材料内部,焊缝的裂纹源多萌生于焊接缺陷处,非金属夹杂是造成母材疲劳裂纹形核的原因。试验得出了该焊接接头的条件疲劳强度(N=5×107)为405 MPa,从而为结构设计工作人员提供了技术依据;严格控制焊接缺陷可改善整个接头的疲劳性能。
Through the high-cycle fatigue test, the S-N characteristic curve of submerged arc welded joints of deep thick narrow NiCrMoV steel was measured. Fatigue test found that the fracture location of fatigue specimens occurred in the weld, and the fatigue fracture SEM analysis. It is found that the sources of fatigue cracks appear in the material, and the source of the crack in the weld is mainly generated in the weld defects. The non-metallic inclusions are the cause of the fatigue crack nucleation in the base metal. The test results show that the fatigue strength (N = 5 × 107) of the welded joint is 405 MPa, which provides the technical basis for the structural design staff. Strict control of welding defects can improve the fatigue performance of the joint.