Comparative Analysis of Metal Inert Gas Welding, Braze Welding and Friction Stir Welding for AA5083 Aluminium Alloy

摘要

A comparative study was made for the weldability of 4-mm-thick 5083 aluminum-alloy sheets using friction-stir welding (FSW), metal inert gas (MIG) welding and braze welding. FSW joint characteristics were obtained using the high-speed steel tool having conical pin with rotation speedof 1000 rpm and transverse feed rate of 28 mm/min with the tool tilt angle held constant at 2°. MIG welding was carried out using Al5183 filler metal and UNIMIG-400 MIG welding machine with Ar as shielding gas. Braze welding was carried out using the acetylene flame with the AA4047 fillerwire and Alu powder as a flux. Samples obtained in all the three cases were subjected to microstructural analysis, Vickers micro-hardness measurements and tensile-testing. Results indicated that of all the samples, FSW samples showed maximum tensile strength, approaching that of base metal.This could be attributed to wrought microstructure observed in the weld zone of FSW samples. Similarly, lower tensile strength of MIG and braze welded sample could be attributed to coarse grain microstructure and porosity observed in the respective samples. Variation of micro-hardness acrossthe weld zone and base metal also gave insight into the relation between tensile strength properties and microstructural properties of these samples.