Study of Fatigue Properties of AISI4130 Steel Joined by Upset Welding in Heat Treated Condition
Resistance upset welding (UW) is a widely used for joining metals parts. In this research, the fatigue properties of AISI4130 steel joined by upset welding in annealed and quenched-tempered heat treated condition are investigated. Microstructure of weld and base metals was studied using optical microscopy. Tensile, impact and fatigue tests were performed and the final fracture surface was studied by scanning electron microscopy (SEM). The fatigue resistance is better for tempered martensite base metal than for the ferrite-pearlite and upset welded specimens. Results shows during the welding, proeutectoid ferrite phase forms at the interface which reduce the fatigue strength of welded specimens. Fractography of fatigue and tension welded samples indicated that in all samples fracture occurred in the middle of weld interface. Study of fracture surface of fatigue samples shows that the final fracture mode for welded samples is cleavage.