Evaluating the GMAW Joint with a Constant Heat Input

Abstract

The most important aspect of the overall welding process is determining the welding parameters which are usually described in a form of Welding Procedure Specification –WPS. WPS is written by an experienced welding engineer. Following the WPS in the welding application is expected to provide optimum joint properties for a certain applied load and environment conditions. One of the most important parameter which is frequently prescribed in WPS is heat input. This paper is presented based on the curiosity toprove the equal heat input does not always produce identical joint. An actual experiment method of constant heat input welding was implemented by varying welding speed with adjusted electric current. The tensile test then is carried out to the weldments to analyze the effect of the varied welding parameters. Finite Element Method (FEM) was used to acuminate the analysis. Using the FEM the temperature history of desired position can be obtained. This temperature history is an important additional data to give a technical reason why the tensile strength is as what exhibited by data from tensile test. The tensile test shows that with higher electric current the higher tensile strength is obtained. From temperature history, which is emulated by FEM, the higher electric current originates faster cooling rate. This faster cooling rate produces harder joint and in turn provides higher tensile strength which is confirmed by the tensile test.