A recommendation for the application and fatigue assessment of the HFMI post-treatment was published by the IIW in 2016. Recently, the therein recommended HFMI design curves in case of constant amplitude loading (CAL) were validated involving test data with different base material yield strengths, increased plate thicknesses, and elevated load ratios. Continuative to this previous work, this paper focuses on the fatigue assessment of HFMI-treated steel joints under variable amplitude loading (VAL). Four test data sets including randomly distributed VAL and a sufficient amount of tested specimens to ensure a statistically verified assessment are investigated. It is shown that an application of the recommended equivalent stress range approach and a further comparison of the test results to the design curves under CAL lead to a conservative fatigue assessment if the recommended value of the specified damage sum of D = 0.5 is used. Furthermore, an increased value of D = 1.0 still maintains a conservative design as presented in the study. Based on this work involving the analysed data sets, it can be concluded that the recommended procedure is well applicable and a conservative fatigue design is facilitated.

中文翻译：

---

变幅载荷下HFMI处理的钢接头疲劳强度评估的验证

IIW于2016年发布了HFMI后处理的应用和疲劳评估建议。最近，其中推荐的HFMI设计曲线在恒定振幅载荷（CAL）的情况下得到了验证，其中涉及具有不同基础材料屈服强度的测试数据，增加板的厚度和提高载荷比。在此之前工作的基础上，本文重点研究了在可变振幅载荷（VAL）下对HFMI处理的钢制接头的疲劳评估。研究了四个测试数据集，包括随机分布的VAL和足够数量的测试样本，以确保进行统计验证的评估。使用D  = 0.5。此外，D  = 1.0的增加值仍然保持研究中提出的保守设计。基于涉及分析数据集的这项工作，可以得出结论，建议的程序非常适用，并且有助于进行保守的疲劳设计。