Evaluation of double-layer weld deposition technique on ASTM A182 F22 steel without post-weld heat treatment

Abstract

The present work evaluates the mechanical and metallurgical behavior of ASTM A182 F22 steel heat-affected zone (HAZ) through the double-layer weld deposition technique, with different welding energies between the first and second layers. This methodology leads to the reduction of hardness levels in the HAZ and can exempt the need for post-weld heat treatment on low-alloy steel after buttering welding. The welding was performed by the automated GMAW process in flat position. As the filler metal, the AWS ER309L, ER 80S-G and ER NiCrMo-3 (Inconel 625) alloys were applied on ASTM A182 F22 steel. The analysis of the refining and/or tempering in coarse-grained HAZ (CGHAZ) of the first layer was performed by metallographic tests and microhardness measurements. The tempering of the first-layer CGHAZ is dependent on the correct overlap of the weld layers, weld bead geometry and the highest imposed heat of the second layer. The results revealed that the Higuchi technique is effective for obtaining welding parameters for the second-layer deposition that promotes thermal treating of the hard region of the first-layer HAZ. However, this technique was not able to reduce the hardness values at the 250 HV level required by NACE 0175 for the test conditions in this work.