Session: CS-22-02 Temper Bead Welding Advancements for Repair and Replacement

Paper Number: 106089

106089 - Evaluating Impact Toughness Properties in Grade 22 Steel Hazs After Pwht and Temper Bead Welding (Tbw) 

Welding of thick low alloy steel components without elevated preheat imposes rapid cooling rates that may promote martensite formation in the coarse-grained heat affected zone (CGHAZ). Freshly formed martensite contains a distorted and supersaturated matrix with high dislocation densities. As a result, fracture and impact toughness properties of these regions are inherently low and post weld tempering procedures are typically required. Conventional post-weld heat treatment (PWHT) involves extended isothermal holds at elevated temperature which allows for considerable softening of the martensitic structure but has been found to have a minor effect on improving impact toughness. In contrast, short-term tempering processes with rapid heating and cooling rates and short times at elevated temperature have been shown to greatly improve impact toughness through a shift in the kinetics of martensite tempering and refined carbide distributions of significant number densities. Temper bead welding (TBW) was developed for in-service repair of thick steel components where PWHT was impractical or not possible.  With temper bead welding, the heat-affected-zone is tempered by one or more rapid re-heat cycles from overlapping weld beads or weld layers. This study compares the Charpy V-notch impact toughness and fracture morphology of the CGHAZ in the as-welded condition, with conventional PWHT, single temper bead reheat, and multiple temper bead reheats for an SA-387 Grade 22 alloy steel.

 

Presenting Author: Eun Jang Ohio State University

Presenting Author Biography: Eun Jang is a PhD-seeking graduate research associate in the Welding Engineering department at Ohio State University. He received his bachelor’s degree in Welding Engineering in May 2019. Eun’s research interests include the evaluation of process-microstructure-property relationships in the HAZ of welded low alloy steels.

Authors:

Eun Jang Ohio State University
Boian Alexandrov Ohio State University
Steve Mccracken Electric Power Research Institute
Darren Barborak Electric Power Research Institute