Influence of GMAW Process Parameters and Selection Techniques on the Quality of a Welded Joint

摘要

INTRODUCTION MIG welding [8] can be used as a manual welding operation as well as automatic process. Main advantage of the MIG welding is automatic continuous feeding filler wire. It can also be used to join unalloyed steel, aluminum alloy and stainless steels. Robotic MIG welding is found to be a very effective tool to attain required quality, higher productivity, better working condition, and semiskilled operators can cooperate. MIG welding The use of robotic welding increases the productivity and the quality of the welded joints. Semiskilled operator can operate the machine. But operator should have a proper knowledge of programming of the machine. Specific design of work piece, equipment, shielding gas, electrode size and type of equipment are discussed in this study. Due to flexibility [6] and higher speed, the MIG welding is one of the widely used processes among all the welding processes. Input process parameters such as weld current, voltage and preheat temperature are optimized in order to attain output properties such as tensile strength and percentage elongation. Here grey based Taguchi analysis is used to optimize the parameters and mathematical equation is formed by using a Regression analysis. Results shows that preheat temperature are most affecting factors on the tensile strength. Quality of the welded joints [2] can be measured in terms of bead geometry. There are many input process parameters of MIG welding which affects this quality of weld. Here in order to optimize the different process parameters such as weld current, work piece thickness, voltage and wire feed rate, the Taguchi optimization is used with L27 array. For the same result, mathematical model was also developed. Voltage and weld current affects most on quality. Different input parameters [10] such as welding current, voltage, and welding speed are optimized to attain the output parameters such as fatigue strength, microstructure and its related properties. MIG welding with above parameters is carried out for joining of various similar and dissimilar metals. Results show that MIG welding can be applied to many similar and dissimilar materials. Input parameters of the TIG [21] welding such as current, time, speed, variation of oxide fluxes, electrode diameter and gas flow rate are optimized by using L9 orthogonal array in Taguchi technique in order to improve the output properties such as tensile strength, hardness and depth of weld.[29] Many input parameters of MIG welding are affected on the quality output parameters of a welded joint such as welding bead geometry, distortion, different mechanical properties and penetration. Now a day different techniques of optimization such as design of experiments, network analysis and algorithm is adopted by many researcher. The weld bead dimension [39] and bead mechanical