An investigation into the friction stir welding of aluminium pipe with stainless steel plate

Abstract

In this project the feasibility of friction stir welding (FSW) of Aluminium alloy pipe with Stainless Steel plate is investigated. Aluminium alloy and Stainless Steel are widely used in aerospace, automotive, marine, defense, construction etc. due to their high strength, low weight, high machinability, good conductivity of heat and electricity etc. Friction stir welding is preferred for joining these materials as it is a solid state forge welding process and problems related with welding of Aluminium alloys and stainless steel can be subdued through this process. This welding process is a solid state welding procedure that uses a non-consumable rotating tool that is permitted to rub against the work piece hence generating frictional heat. When the weld constraints such as tool or work piece rotation speed, welding time, axial load are optimum the friction between the work piece and the tool generates enough heat to create a plastic deformation layer at the weld interface. The process doesn’t involve any melting process and whole process occurs in solid state through plastic deformation and mass flow among the work pieces. The experimental investigation of FSW is done by varying the friction stir welding parameters such as work piece rotation speed, welding time, feed (axial load).The work piece is rotated at the speeds 860 rpm, 1400 rpm and 2000 rpm. The experiment is done in a general purpose center lathe machine. To hold the work piece a fixture is designed. A tool(C-45 carbon steel) is also designed. The experiment is done using Aluminium alloy pipe of different diameters such as Aluminium pipes with diameters 18.5 mm, 25 mm and 32 mm. The experiment is conducted and the results are assessed.