Optimization of submerged arc welding process parameters for overlay welding

Selected from Soldagem & Inspeção 2016 21(1) 115–124.

Abstract

In this work, we evaluated the influence of welding variables on weld beads applied by the submerged arc process (SAW) with conventional current, aiming future application in overlays against corrosion. Segments of steel API 5L Gr B pipe as substrate, a 1.13 mm-diameter electrode wire of nickel alloy, classification AWS ERNiCrMo-4 (Hastelloy C-276) as filler metal, and a flux neutral, basic and crowded were used. The variables voltage, wire feed speed and contact tip to work distance (CTWD) were analysed, with the remaining parameters constant by an experimental design with full factorial design in two-level and central points. Statistically significant and predictor mathematical models for response dilution and average current were obtained. However, for the response reinforcement/width, the model was characterized as statistically significant, but not predictive, and containing a lack of fit. The CTWD was the most significant variable reducing the dilution.

Keywords:

• Submerged arc welding
• weld overlay
• nickel alloy
• factorial design

Notes

Selected from Soldagem & Inspeção 2016 21(1) 115–124.

1. P is related to the level of significance of a particular variable analysed in a regression model. For a variable to be statistically significant in a model with 90% confidence, the relation P ≤ 0.1 must be satisfied.