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为了研究高强钢在工程机械焊接结构中的疲劳特性,对HQ70、1E0170和WH60钢焊接接头的疲劳裂纹扩展特性进行了较系统的研究。研究中应用了一种柔度法疲劳裂纹自动测量系统进行裂纹长度测量。用三点弯曲试样对这些焊接结构的疲劳特性进行研究。用三参数方程和Paris公式回归得出这些钢种焊缝的裂纹扩展规律及门槛值，对研究结果进行讨论。HQ70钢焊接件的疲劳特性较其它两种钢都好。焊接质量对疲劳裂纹扩展特性影响很大。由于焊接接头的裂纹扩展速率波动较大，测量门槛值时应特别小心。
In order to study the fatigue properties of high strength steel in welded structures of construction machinery, the fatigue crack propagation characteristics of welded joints of HQ70, 1E0170 and WH60 steel were systematically studied. In the study, a softness fatigue crack automatic measurement system was used to measure the crack length. The fatigue characteristics of these welded structures were investigated using three-point bending specimens. Using the three-parameter equation and the Paris formula regression, the crack propagation rules and thresholds of the welds of these steels were obtained, and the results were discussed. HQ70 steel welding fatigue properties than the other two are good. The welding quality has a great influence on the fatigue crack propagation characteristics. Due to large fluctuations in the rate of crack propagation in welded joints, extreme care should be taken when measuring thresholds.