Experience with high-frequency mechanical impact method for weldments of sheets of different thicknesses

Abstract

The interim results of two projects of the Technology Agency of the Czech Republic are presented, the subject of which is the verification of the potential of the industrial use of the high-frequency mechanical impact (HFMI) method for increasing the load-bearing capacity and fatigue of the material. The fatigue life of welds of steel sheets of various thicknesses and in a wide range of strengths of welded steels for the construction of rolling stock and steel bridges are experimentally verified. The authors have already presented partial results, Kepka jr. et al. (2022). The new results are based on a larger number of test samples. First findings on the application of the HFMI method to thin (4 mm) and very thick (90 mm) sheet welds are included. The results are compared with the general recommendation of the International Institute of Welding (2016). Partial attention was also paid to the endurance of compressive stresses introduced into the weld area by the application of HFMI. The fatigue tests were completed by measuring residual stresses by X-ray diffraction on selected test specimens with the application of HFMI before and after the completion of 10 million loading cycles.