Effect of post-weld heat treatment on the fatigue strength of HFMI-treated mild steel joints

Effect of high frequency mechanical impact treatment on fatigue strength of welded 1300 MPa yield strength steel

“…8 and Table 7). This seems to be in contradiction with previous studies where an increase in the toe radius after HFMI treatment has been reported [14,35]. This seemingly contradictory observation can most probably be related to the fact that the weld toe radii in as-welded condition (Table 7) were already large as compared to the weld toe radii reported in previous studies [14,36].…”

“…Maximum compressive residual stresses of 20% and 62% of the steel yield strength in the transverse and longitudinal directions, were obtained very close to the weld toe. The longitudinal residual stress is within the range reported in several studies on welded steels with yield strengths below 1000 MPa [14,35,36,39,41,43]. However, the transverse residual stress seems to be relatively low.…”

“…According to the Volvo standard system [37], which considers weld quality measures such as weld toe radius, the welded joints in this study are grouped into class VC (high quality welds) with a weld toe radius larger than 1 mm. This should be kept in mind when comparing to earlier reported results of HFMI treatments which was done on welds with as-welded toe radii in the ranges of 0.4-1 mm [14] and 0.3-1 mm [35]. Another reason why the radii did not increase markedly due to the treatment can be related to the radii of the indenter tips.…”

“…The radii of the indenters used were 1.5 mm and 3 mm for the lower (L1 and L2) and upper (U1 and U2) weld toes, respectively. Leitner et al [35] measured a weld toe radius of 2 mm after HFMI treatment which was equal to the radius of the indentation tip used. The radius of the indenter tip can therefore be considered to be a limiting factor when aiming for a larger toe radii in the treated region.…”

Impact of Angular Distortion on the Fatigue Performance of High-Strength Steel T-Joints in as-Welded and High Frequency Mechanical Impact-Treated Condition

“…The scientific aim of this work is to contribute to the effect of angular specimen distortion on the fatigue strength of welded transversal joints. Previous research work [24,25] already emphasized that further investigations on this topic are needed. The current analysis includes tumescent tensile fatigue tests involving specimens with varying welding distortion.…”