Effect of welding parameters (heat input) on mechanical behavior and microstructure of submerged arc welded HSLA steel joints

Abstract

The welding heat input has a great influence on the weldments properties. This article describes the effect of heat input (controlled by welding current, Voltage and welding speed) on the microstructure and Mechanical behavior (Tensile properties, Hardness and Toughness) of high strength low alloy (HSLA- SAILMA 300 HI) steel weldments produced by submerged arc welding (SAW). The SAW process was used for welding of 20 mm thick high strength low alloy (HSLA- SAILMA 300 HI) steel plates. The weld joints were prepared by varying the welding current (630-870A), Voltage (26-33 V) and welding speed (250-330 mm/min). The increase in the heat input affects the proportions of different micro constituents both in the weld metal and heat affected zone (HAZ). It is observed that the tensile strength (UTS, YS), toughness and hardness decreases with increase in heat input on other hand % elongation, % reduction in area increases. The hardness has been found to vary from the base metal to weld centre line and peak hardness was found in the HAZ. The hardness of the weld metal was largely uniform. © 2012 Praise Worthy Prize S.r.l. - All rights reserved.