Abstract
M.Ing. (Mechanical Engineering)
Stainless steel is a member of iron based alloys with a good corrosion resistance property. Due to this good quality, stainless steel plates are increasingly used for building constructions materials food processing and kitchen equipment. Austenitic stainless steels are one of the best choices, as they combine noble corrosion performance and mechanical properties. Due to low carbon percentage in austenitic stainless steel, intergranular corrosion can be controlled.
The use of stainless steels is imperative. In fact, the numerous applications of type 304 austenitic stainless steel make it omnipresent in our daily life. This research work is aimed to establish optimized process parameters that will result in defect-free weld joint.
In this research work, studies were conducted on the material characterization of type 304 austenitic stainless steel hybrid weld produced by Tungsten inert gas (TIG) and Metal inert gas (MIG) welding Processes. The processes were carried out in three phases. In the first phase of welding, two similar 304 stainless steel plates were welded by MIG welding using welding current of 130A and 170A, , the second phase was produced by TIG welding using the currents of 130/150A, while third phase welding was an hybrid TIG-MIG welding produced at currents of 130/150 and 170/190A respectively. The effects of welding current and welding process on the mechanical properties of the welded joints were investigated for all the three types of butt weld joint. Optical microscopic analysis were done on the heat affected zone and weld zone to assessed the effect of the welding parameters and the welding process on the weld quality.
Vickers microhardness tests were used to determine the hardness distribution of the welded zone and tensile testing was conducted to quantify the strength of the welded area to the base metal in order to establish the optimal process parameters...