INFLUENCE OF ARGON GAS MIXTURES OM PROPERTIES OF WELDS IN HYDRO MECHANICAL GATES

Abstract

Since the development of Gas Metal Arc Welding (GMAW), the process is gaining popularity in applications where Shielded Metal Arc Welding has been the standard process. It has renewed interest and focused attention on developing ways to enhance its effectiveness. Application of the process can be used in fabrication and erection of Hydro-Mechanical Gates. Therefore, some investigations have been carried out on welding of structural steel to evaluate the feasibility of the process with different shielding gases and their mixtures, with particular reference to effect on mechanical properties, which are important in hydro-mechanical gates. Based on the experimental investigation it has been found that ultimate tensile strength, yield strength, fatigue life improves with addition Of CO2 in argon. Mixtures of 20% CO2 in argon gives reasonably good results on mechanical properties. With these gas mixtures the fractional porosity contents are low and absorbed energy during charpy impact test of the weld metal is reasonably high. However no conclusive trend have been found for hardness and weld bead geometry with different types of shielding gases and gas mixtures.