Analytical Model for Angular Distortion in Multilayer Welding under Constraints

Woo-Jae Seong,Hee-Keun Lee,Sang-Cheol Park

doi:10.3390/app10051848

Woo-Jae Seong, Hee-Keun Lee + Show 1 more

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https://doi.org/10.3390/app10051848

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Abstract

We propose an analytical model for the fast prediction of angular distortion that is caused by practical multilayer (or multi-pass) butt welding under constraints. To this end, the relationships between angular distortion, bead size, thickness, and degree of constraint are derived by analyzing the welding deformation mechanism and considering the bead-on-plate welding experimental results. Prediction curves are then obtained while considering the geometry of the butt welding joint. We verify the formulas through experiments under various constraint conditions, with different welding joint geometries, heat inputs, and thicknesses. The proposed model can not only predict angular distortion in butt joints of various shapes, but also allows for providing restraint methods and welding sequences for minimizing distortion.

Highlights

Welding large structures is essential in constructing ships, heavy machinery, nuclear power plants, platforms, among others
As the inherent strain at the welding joint includes plasticity, the plastic region is identical to the region where the inherent strain is distributed, and the inherent strain region can be considered as the plastic region
We conducted V butt welding experiments to examine whether the predictions that are based

Summary

Introduction

Welding large structures is essential in constructing ships, heavy machinery, nuclear power plants, platforms, among others. For structures whose mechanical parts require precision work, including rack and pinion jacking systems and large platforms as representative examples, strict criteria should be satisfied during construction. Deformation in the welding of thick structures is largely due to transverse angular distortion, but is controllable. It is necessary to predict and minimize the distortion before construction. Okerblom [1] proposed a formula for predicting the angular distortion through a bead-on-plate experiment. The obtained angular distortion was proportional to the heat input and melting efficiency, and inversely proportional to the square of thickness. The heat input is expressed as the product of current and voltage divided by the travel speed

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