Dissimilar metal welding is widely applied to meet the rquirement of transition in mechanical properties and/or difference in working conditions. For instance, even though AISI 304 and AISI 316L are both belong to austenitic stainless steels, but they are applied in different working environment. AISI 304 is used at high temperature applications, whereas AISI 316L is used at low temperature. Repair welding is able to return a part back to its normal service life if weld failure happened due to service deterioration or defects during fabrication stage. However, repetitive heat input due to repair welding will cause changes in welded structure and properties. In this article, the effect of repetitive repair welding of dissimilar austenitic stainless steel pipes to the microhardness, tensile strength, microstructure and quality of the weldment has been reviewed.

No abstract

No abstract

This paper presents an experimental investigation on effect of welding parameter to repair welding of dissimilar material using Gas Metal Arc Welding (GMAW) machine. Taguchi Method has been used to analyse the statistical analysis by using Minitab Software. Repair welding getting more popular nowadays due to saving cost and prolong the material service life. The effect of repair welding of dissimilar material on mechanical properties have been studied. Statistical analysis using Taguchi Method by Minitab Software with three times repetition of L9 orthogonal array. Setting up GMAW machine with current (150A-170A), voltage (17V-21V) and jig rotational speed (50rpm-100rpm) were prepared with 3.00mm of Stainless Steel 304L and 3.60mm Carbon Steel 1387.Result shows that voltage gave a huge impact to tensile testing and micro hardness of second repair welding. While current and jig rotational speed gave less impact to responses. The benefit shown have caused repair welding to be accepted and applied in the industry. Regular and total maintenance is able to contribute to the savings while producing good preventive maintenance schedule.

Abstract-Lightweight trend leads to new trend of welding in which optimizing tubes or pipes thicknesses due to its respective workloads. Thinner tube can be used in parts with low working loads and thicker tube for high working loads parts. In order to obtain a good weld, controlling the process parameters such as welding current and welding speed become very crucial as it significantly influences the mechanical properties. Thus, the purpose of this study is to investigate the process-properties relationship of welded mild steel tube of dissimilar thickness by using Metal Inert Gas (MIG) orbital welding. The effects of weld current and jig rotational speed to the tensile properties of welded mild steel tubes were studied. MIG welding was used to weld 26.70 mm diameter of mild steel tubes, which has dissimilar inner diameter of 2.87 mm and 3.90 mm, respectively. The mechanical properties were tested using Universal Tensile Machine (UTM) Instron 8802 model. Design of Experiment (DoE) was used to design the experiment as well as to analyze the data. It was found out that, tensile properties of welded tubes increase with increasing of welding current between 60 and 80 A. On the other hand, increasing in jig rotational speed between 40 and 50 rpm decreases the tensile properties of the welded tubes. Empirical mathematical model was generated and verified.Index Terms-Mild steel, orbital welding, metal inert gas welding, tensile strength and empirical mathematical modeling.