The Influence and Mechanism of Residual Stress on the Corrosion Behavior of Welded Structures

Linyue Bai,Lei Gao,Kebin Jiang

doi:10.1590/1980-5373-mr-2018-01660

Abstract

To study the influence of residual stress on the corrosion behavior of welded structures, methods such as residual stress measurement, microstructure observation, and corrosion morphology observation were used. The energy transformation model and corrosion-resistance constant model were utilized to reveal the mechanism of residual stress on the welded structures’ corrosion behavior. The results show that the fusion line was the region that is most heavily affected by corrosion and sustains more serious corrosion damage than other areas, resulting in the welded structure becoming a high-incidence area for corrosion cracking and failure. Residual tensile stress could reduce the activation energy and surface atomic density, and therefore decrease the corrosion resistance of the welded structures. The residual compressive stress decreased the activation energy needed by metal atoms to convert into metal ions in welded structures, and simultaneously increased the surface atomic density. The corrosion resistance of the welded structures ultimately increased owing to the combined influence of changes in activation energy and surface atomic density.

Highlights

Due to good connection performance and excellent air tightness, welding fabrication has been extensive applied in the manufacturing of steel structures[1,2,3,4]
The influences on the corrosion resistance of welded structures by residual tensile stress and residual compressive stress are different, which increases the complexity of the investigation on the influence and mechanism of residual stress on the corrosion behavior
The high-level residual tensile stress increases the internal energy of the structure and decreases the activation energy needed by the metal atoms to convert into metal ions, thereby decreasing the corrosion resistance of heat affected zone (HAZ)

Summary

Introduction

Due to good connection performance and excellent air tightness, welding fabrication has been extensive applied in the manufacturing of steel structures[1,2,3,4]. The welding residual stress has great influence on the corrosion resistance of welded structures while the structures serve in a corrosive environment, effecting their security and service life[5,6,7,8]. Methods such as heat treatment and vibratory stress relief (VSR) are usually used to eliminate the residual stress in welded structures to reduce its effects on the structures[9,10,11].

Results

Discussion

Conclusion