Effect of grinding on the fatigue strength of mild and high strength steel fillet weld joints

Abstract

The study focuses on the increase in fatigue strength welded components considering grinding as post treatment. This is examined based on cruciform joints and transverse non-load-carrying attachment as most relevant and critical applications in regard to rail vehicle structures with focus on track laying machines. Firstly, the study starts with the determination of a new welding parameter for a cruciform joint of a S960 high strength steel. This parameter is verified by t8/5-time analysis and hardening measurements on the weld seam. Secondly, the received parameter set is compared to the current literature about cruciform joints. Furthermore, fatigue lifetime curves are compared in an as-welded and ground condition. Finally, the fatigue curves determined are summarised, which shows that the FAT-class also increases with the increasing yield strength in case of ground specimens.

Keywords

• High strength steel
• Post-weld treatment
• Cruciform joints
• Transverse non-load-carrying attachment
• Fatigue strength improvement
• Weld toe grinding