Influence of Local Properties on Fatigue Crack Growth of Laser Butt Welds in Thin Plates of High-Strength Low-Alloy Steel

Abstract

In this work, local properties such as hardness and fatigue crack grow rate in the heat-affected zone of four laser-welded butt joints in thin high-strength low-alloy steel were examined, so as to explain and predict fatigue lives at high stress levels through the fracture mechanics approach. The different welded series presented a similar fatigue crack growth rate in the heat-affected and fusion zones, but lower than base metal due to the higher hardness of the bainitic­­–martensitic microstructure verified in the welded series. The results showed that at high stress levels in the as-welded condition, the fatigue initiation stage can be neglected and assume some types of cracks, with an initial crack of 0.07 mm and appropriate fatigue crack growth rates, estimates of fatigue life close to the experimental results were obtained.

Physical Simulation of Mold Steels Repaired by Laser Beam Fusion Deposition

“…In both materials, the PM2 series showed the worst mechanical behavior. The fatigue life is strongly influenced by the quantity, size, and location of metallurgic defects [20]. However, the reparation process was applied with success, and can be applied as palliative reparation using the laser beam fusion deposition parameters used in the PM3 test series.…”