Evaluation of Dissimilar Welds with the Temper-bead Technique Using ER 316L and ER NiCrMo-3 Electrodes on ASTM A182 F22 Steel

ABSTRACT

An adequate procedure for dissimilar welding must use the buttering of the bevel through the temper-bead technique, in order to establishing a thermal barrier capable to minimize the joint embrittlement. The buttering interface in these welds is indicated as the most critical region of the joint due to the presence of hard phases, which are often found in the coarse region of the heat affected zone (HAZ) and near the fusion line. The present work aims to investigate the feasibility of the Higuchi and Modified Higuchi techniques for the selection of operational parameters for controlled welding by the temper-bead technique, concerning the tempering the HAZ with coarse grains of the first layer deposited on an HSLA (High Strength Low Alloy) steel. The weld overlays were deposited by the combination of two wires, the ER NiCrMo-3 and the ER 316L, which used the GMAW (Gas Metal Arc Welding) process with pulsed current and with conventional current, respectively. The ASTM A182 F22 HSLA steel was used as base metal. The results showed a reduction in the microhardness level of the first layer HAZ by using the temper-bead technique. However, the tempering level achieved is still insufficient to eliminate the use of postweld heat treatment (PWHT).

Key-words
Dissimilar welding; temper-bead technique; Higuchi’s test