Papers by Keyword: Hammer Peening

Abstract: The influence of hammer peening on the fatigue resistance of high strength welded joints of the high strength structural steel S690 has been investigated. The effect of three different parameters has been studied: geometrical effect (shape of weld tooth, roughness), microstructural effect (grain microstructure, strain-hardened depth) or residual stress effect evaluated by X-ray diffraction.

Abstract: Mechanical post treatments for welded structures have been applied in various industrial fields and, in most cases, have been found to cause substantial increase in their fatigue strength. These methods, generally, consist of the modification of weld toe geometry and the introduction of compressive residual stresses. In hammer peening, the weld profile is modified due to removal or reduction of minute crack-like flaws; compressive residual stresses are also induced by repeated hammering of the weld toe region with blunt-nosed chisel. In this study, a hammer peening procedure, using commercial pneumatic chipping hammer, was developed; a quantitative measure of fatigue strength improvement was performed. The fatigue life of hammer-peened specimen was prolonged by approximately 10 times in
S=240MPa, and was doubled for the as-welded specimen.