Indian Welding Journal

Nachimani Charde ¹

Affiliations
1 Department of Mechanical Engineering, University Malaya, MY

Abstract

Part 1 of this research introduces the spot welds growth on 304L stainless steel; primarily supported by information such as the chemical property, specimen size, calculated-static resistance, welding lobe, welding schedule, simulation, tensile shear load, indentation, failure mode, and also the elongation during tensile test. In part 2, the analysis is furthered to understand the dynamic resistances, force profiles, electrically generated forging forces, macro and micro structural orientation and also the hardness distribution. Heat development during the welding process is proportionally influenced by the dynamic resistances and therefore several detailed analytical approaches have been included to understand the process variables certainly. Literally the dynamic resistances are proportionally related for the welding current and welding time changes but reversely behaved for the electrode force changes within the welding lobe limits. These resistive changes became the ischolar_main cause of weld growth pertaining to heat variations. So the computations have been carried out from the perspective of welding current against the terminal voltage. On the other end, the force profiles are relatively measured to observe the electrode force variation with respect to the welding current changes. With the changes of process variables, the corresponding weld growth is analysed in terms of dynamic resistances in this experiment. Eventually the micro structural changes show the enrichment of coarsened grains but transformed in phases as results; which lead to slight increment of hardness at the welded areas as Rockwell hardness proves these increments as well.

Keywords

Signal Measurement, Dynamic Resistance, Macro and Microstructure, Hardness Distribution.

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Nachimani Charde ¹

Affiliations
1 Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur, MY

Abstract

Austenitic stainless steel(ASS) is very common material that used in many industries today. Suitable joining method should be of low cost; reliable and long life. In such situation, the industries may prefer to use the resistance spot welding (RSW) for such ASS sheet. The weld quality of RSW joint is usually considered by nugget size which relies on the welding parameters. This paper analyzes the weld nuggets' characteristic of 304L austenitic stainless steel with relevant to its basic welding parameters (current, weld time and force). The entire experiment is carried out by varying the welding current and welding time at first attempt and the welding current and electrode force at second attempt. The increment of current and weld time has resulted proportional increment of nugget diameters; whereas the force increment has resulted reduction of nugget diameters. These results have been relatively compared with simulation results for the proper weld region identification. Eventually the welded joints were characterised by tensile shear test, macro graph and elongation measurement to relate the changes that happened due to the variations of welding parameters.

Keywords

Welding Simulation, Stainless Steel Welding, Tensile Simulation, Elongation Simulation.

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Nachimani Charde ¹

Affiliations
1 Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur, MY

Abstract

Part 1 of this research introduces the spot weld growth on 304L stainless steel, mainly by explaining information: such as the specimen size, static resistance, welding lobe, welding schedule, simulation, tensile shear load, failure mode, and elongation. In part 2, the analysis explains the dynamic resistance, force profile, electrically generated forging force, macro and micro structural orientation and also the hardness distribution. In part 3, the investigation reveals similar and dissimilar thicknesses: pertaining to macrograph orientation, electrode indentation and the weld growth. Three types of different thicknesses are investigated for the macrograph development and subsequently found the symmetrical weld bead geometry despite thicknesses. Electric current increment is mainly analysed in this experiments as it increases the weld size significantly. Strength tests show that the weld geometries have been widened in proportion to the escalation of electric currents. The astonishing factor is that the bead thickness reduction due to electrode indentation does not affect the tensile strengths at all.

Keywords

Spot Welding, Stainless Steel, Dissimilar Thickness, Macrographs, Dissimilar Hardness.

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