Effect of friction welding condition on joining phenomena and joint strength of friction welded joint between brass and low carbon steel

This paper describes the effect of friction welding condition on joining phenomena and joint strength of friction welded joints between copper–zinc alloy (brass) and low carbon steel (LCS). When the joint was made at a friction pressure of 30 MPa with a friction speed of 27·5 s⁻¹, brass transferred to the half radius region of the weld interface on the LCS side. Then, transferred brass extended towards the almost whole weld interface with increasing friction time. The joint efficiency increased with increasing friction time, and then the joint obtained 100% and the brass base metal fracture when the joint was made with a friction time of 4·2 s or longer. However, the fact that all joints had some cracks at the periphery portion of the weld interface was due to a deficiency of transferred brass at the periphery portion on the weld interface of the LCS side. On the other hand, brass transferred to the peripheral region of the weld interface on the LCS side, and then transferred towards the entire weld interface when the joint was made at a friction pressure of 90 MPa with a friction speed of 27·5 s⁻¹. The joint efficiency increased with increasing friction time, and it reached 100% at a friction time of 1·5 s or longer. In addition, all joints fractured from the brass base metal with no cracking at the weld interface. To obtain 100% joint efficiency and the brass base metal fracture with no cracking at the weld interface, the joint should be made with opportune high friction pressure and friction time at which the entire weld interface had the transferred brass.