Fatigue Strength of HFMI-treated High-strength Steel Joints under Constant and Variable Amplitude Block Loading

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

“…The fatigue results suggest a quite high FAT of 306 MPa, for welds in as-welded condition, which is about 36% higher than the IIW FAT 225. This agrees well with findings by Leitner et al [19], where only a minor enhancement of fatigue strength after HFMI treatment was found. They mentioned the high quality of welds as the reason for the low increase in fatigue strength.…”

“…Several papers have demonstrated the effectiveness of HFMI to improve the fatigue strength of welds [7][8][9][10][11][12][13][14][15][16]. It is believed that the improvement is achieved via modification of the weld toe geometry, induced compressive residual stresses and increased surface hardness in the treated region [15,[17][18][19][20][21].…”

Numerical fatigue life analysis of a high frequency mechanical impact treated industrial component based on damage mechanics models

“…Figure 4. A significant increase in fatigue life could be determined [2][3][4][5][6][7][8][9][10][11][12][13][14]. For a better comparison the inverse slope m and the FAT value at 2Á10 6 cycles for a failure probability of 50 % according to the equation…”

“…The advantages of removing the potential threats of unwanted (tensile) residual stresses and exploiting the beneficial (compressive) residual stresses by mechanical treatments are already known in welding communities. In this context, high frequency hammer peening as post weld treatment is a statistically proven method to increase the fatigue life of welded joints [2][3][4][5][6][7][8][9][10][11][12][13]. During this process, a hardened cylindrical metal pin with a spherical tip impacts the weld toe surface with high frequency and induces local plastic deformation.…”

Life Extension Technique for Welded Structure Using Hfmi/Pit: A Review on Past and Current Researches With Applications

“…11 indicate the stress distribution and plastic deformation at the weld toe using the developed simulation loop. Leitner et al [15] examined the effect of variable amplitude loading on the fatigue strength of HFMI/PIT-treated T-joints. Their primary aim was to assess the local fatigue strength of welded and HFMI post-treated high-strength steel joints of steels S690 and S960, and compared with common construction steel S355.…”