Friction welding technique and joint properties of thin-walled pipe friction-welded joint between type 6063 aluminum alloy and AISI 304 austenitic stainless steel

Abstract

The joint characteristics of thin-walled pipe friction-welded joint between AA6063 aluminum alloy (A6063) and AISI 304 stainless steel (SUS304) were investigated. The pipe had a thickness of 1.5 mm, and the joint was made with a friction speed of 27.5 rps and a friction pressure of 30 MPa. The joint, which was made by a continuous drive friction welding machine, had heavy deformation on the A6063 side during braking. To prevent deformation until rotation stop with braking, the joint was made by a technique in which the relative speed between both specimens instantly decreased to 0 when the setting friction time was finished, and consequently, the joining could be successfully achieved. The joint with a friction pressure of 30 MPa and a friction time of 0.4 s did not have the intermetallic compound (IMC) layer (interlayer) at the weld interface, although that with a friction time of 1.6 s had it. However, the joint with a forge pressure of 150 MPa had the A6063 side buckling. Moreover, the joint efficiency of the joint with flash was higher than that of the joint without flash because the inner flash of A6063 was stuck to the inner surface of the SUS304 side. Therefore, the joint should be made with the opportune friction time without the IMC interlayer and with the opportune forge pressure without buckling, and the accurate joint efficiency should be evaluated without flash.