Influence of Manufacturing Conditions on Fatigue Life of Welded Joints

This paper presents a study on the influence of manufacturing conditions on the fatigue life of welded joints of high strength steels P355NL-1 and P355NL-2. Welding conditions were varied by adjusting the welding parameters and component-welding positions for a range of railway bogie welded joints. Prepared joints were then assessed for cracks and porosity defects. It was observed that an increase in welding speed resulted in an increase in crack and pore sizes. The same applied to increase in welding angle. Identified crack sizes ranged from 0.2 to 2.6 mm. Impact of such defects on fatigue life was assessed by evaluating the residual fatigue life of the component using the Paris law for stress amplitude of 150 MPa. The fatigue life of the bogie was estimated to be 6.23 × 105 instead of the required 1 × 106 cycles. It was concluded that manufacturing conditions have a significant effect on fatigue life of high strength steel welded joints. Travel speed and welding angle are critical.