Objectives Scope of Project Introduction

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1.3 Objectives

The objectives of this project are:- a To investigate the microstructural samples and characteristics of resistance spot welds on aluminum sheet metal. b To examine the mechanical behavior at different welding parameters. c To evaluate the hardness of the samples in order to determine the influence of welding parameters.

1.4 Scope of Project

Here, scope act as the guidance that limits this research is doing without loss the focusing. It is capable to bring the project to their objective without run out by doing work that not relate to the objective. Welding process has done using Miller Spot Welding machine SSW-2040ATT. Material used is 6061 Aluminum Alloy sheets with thickness 1.0mm and 1.5mm. The joint design was lab joining. 4 CHAPTER 2 LITERATURE REVIEW

2.1 Introduction

A lot research has been done on joining dissimilar metal through various purpose and application. The famous is about study the resistance and parameter because it had related to the most application requirement. Several finding that has been gathering are as follow: Research has been done by Bowers, Sorensen and Eagar 1990 about mathematical model predicts current distribution as a function of electrode geometry. His finding about the research is it important to note that the mathematical model developed herein is a first level approach to understand the trends produced in current distribution as affected by electrode geometry. It is most interesting that the experimental results support the predictions derived from the model, despite the model not incorporating such factors as contact resistance, alloying and deformation of the electrode tips and the temperature dependence of electrical conductivity of the electrode material. Yet, the experimental results support the predictions derived from the modeling effort. The shifted lobe position and longer electrode life obtained merely by changing the electrode geometry indicate that geometry is a controlling process for a given set of welding parameters. Sun and Khaleel 2004 was research about whether spot welding between aluminum and steel can be achieved using a transition material. Both experimental welding trials 5 and finite element simulations were used in determining the optimal electrode combinations and welding parameters. The nugget formation process was then examined using consecutive metallurgical cross-sectioning and finite element analyses. The finding show that two distinct fusion zones formed during the spot welding process of aluminum to steel using a transition aluminum-clad steel strip. The nugget on the steel side is a regular, elliptical weld with dendrite grain structure inside the nugget region. The nugget on the aluminum side is the top half of the elliptical shape. Son and Kim 2006 was study the numerical analysis of the resistance spot welding process. This research is used 2D axisymmetric Finite Element Method FEM model that has been developed to analyze the transient thermal behaviors of Resistance Spot Welding RSW process. In this model, the temperature dependent material properties, phase change and convectional boundary conditions were taken account for the improvement of the calculated accuracy, but the determination of the contact resistance at the surface is moderately simplified in order to reduce the calculating time through the analysis. The finding show the developed model has been employed the thermal history of the whole process including cooling and temperature distributions for any position in the weldment. Shamsul and Hisyam 2007 was study the Spot Welding of Austenitic Stainless Steel Type 304. In this study, austenitic stainless steel types 304 were welded by resistance spot welding. The research is about the relationship of nugget diameter, welding current and hardness distribution along welding zone. The finding shows Austenitic stainless steel AISI-304 is an extremely important commercial alloy due to its excellent corrosion resistance, high strength, good ductility and toughness. In this study, two plates of these steel were placed as a lap joint and spot welded using varied welding current. 6

2.2 Resistance Welding