Experimental analysis on friction hydro pillar processing of cylindrical coupling of 2024 aluminum alloy

The cylindrical coupling of 2024 Aluminum alloy was welded by friction hydro pillar processing(FHPP) in the first domestic friction stitch welding machine.The diameter of the consumed metal stud is 14 mm, the depth and diameter of the pre-drilled hole are 25 mm and 16 mm respectively.The effects of rotational speed and shielding gas on the FHPP quality were mainly studied, and the microstructure and its properties of the sample were analyzed by means of some measuring apparatus such as optical microscope and microhardness tester etc.The results indicate that the low rotation can form the insufficient bonding, even result in the cease of the weld head motor during the welding.The quality of welded joint is better when the rotational speed is 5 000 r/min and the feeding rate is 0.5 mm/s.The shielding gas can improve the quality of FHPP with thinner fusion line, and the upper part of the metal stud is bonded to the base metal very well.