The Effect of Heat input on the Mechanical Properties of MIG Welded Dissimilar Joints K.Monika 1 , M.Bala Chennaiah 2 , Dr.P.Nanda Kumar 3 , Dr.K.Prahalada Rao 4 1 V.R.Siddhartha Engineering College, Vijayawada. 2 Assistant Professor in ME Department, V.R.Siddhartha Engineering College,Vijayawada. 3 Professor, B K R Institute of Science & Technology, SPSR Nellore, A.P. 4 Professor in ME Department,JNTU College of Engineering, Anathapuram, AP . Abstract The effect of heat input on the mechanical properties of MIG welded dissimilar joints is studied. Two dissimilar joints (IS2062-IS 45 C8) and (IS2062-IS 103 Cr 1) are prepared by Gas Metal Arc Welding and mechanical properties are observed. But these mechanical properties are varied with respect to the heat input. This heat input is depending upon voltage, current and speed flow rate of wire. In this present work input is considered into two conditions. i) low heat input dissimilar joints i.e. in IS 2062-IS 45 C8 (3.6189 kj/mm )and in IS 2062-IS 103 Cr 1 (4.01973 kj/mm) ii)high heat input dissimilar joints i.e. in IS 2062-IS 45 C8 (3.1421kj/mm)and in IS 2062-IS 103 Cr 1 (3.70537 kj/mm) are taken and study the mechanical properties and finally compare the heat input which is suitable in dissimilar joints for the present working conditions. Key words— Metal Inert Gas Welding (MIG); Heat Affected Zone (HAZ); Weld Zone (WZ); Base Metal (BM); 1. Introduction Joining of dissimilar metals is carried out since ancient times. Nowadays, joining dissimilar metals has become indispensable in the field of manufacturing and construction of equipment, machinery and products. Different kinds of metals feature different chemical, physical, and metallurgical properties. Joining dissimilar metals is, therefore, to compose different properties of metals in order to maximize the performance with minimum cost. Firstly we have do edge preparation for single V butt joint in order to proceed further for MIG (Metal Inert Gas) Welding. When welding two dissimilar materials, there are a number of aspects that need to be addressed, in addition to those associated with welding similar materials. The joining of dissimilar metals by arc welding requires careful consideration of aspects like selection of filler wire to optimize dilution & alloying, melting temperature ranges of the metals, their thermal conductivities, co-efficient of thermal expansion, weld metal-base metal interaction and joint design. Then Dye Penetrate test is to be carried out in order to find out the weld defects. In the view of the fact that Arc welding processes like GMAW offer a wide Spectrum of thermal energy for joining different thicknesses of steels, it was considered important that undertaking the present study would be beneficial in gaining an understanding about the Mechanical Properties that affect the service performance of these welded joints made using different heat input combinations i.e. Low heat input and High heat input. And then dissimilar joints are to be conducted for Mechanical properties tests (tensile, hardness). So, there is a comparison between the joints i.e. tensile and hardness test values in Low heat input and High heat input. The dissimilarity of the metals may arise due to the difference in chemical composition. The chemical composition of the steel affects weldability and other mechanical properties. Several elements are purposefully added in the production of structural steel, but other undesirable elements may be present in the scrap materials used to make the steel. Carbon and other elements that increase harden ability increase the risk of “cold” cracking, and therefore higher preheat and inter pass temperatures, better hydrogen control, and sometimes post heat are necessary to avoid cold cracking. 1406 International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 www.ijert.org IJERTV2IS90549 Vol. 2 Issue 9, September - 2013