Influence of Vibratory Stress Relief on Residual Stresses in Bridge Structural Members Weldments

Aurimas Jurčius,Algirdas Vaclovas Valiulis,Olegas Černašėjus

doi:10.3846/bjrbe.2011.31

Aurimas Jurčius, Algirdas Vaclovas Valiulis + Show 1 more

Open Access

https://doi.org/10.3846/bjrbe.2011.31

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Abstract

The welding process can join two similar materials with a bond that has mechanical properties comparable to the original material. Unfortunately, this process induces residual stresses in the weldment, which, if left untreated, can cause distortion of the part, premature fatigue failure or cracking along the weld. In a cases of cracking in steel bridge structural members were attributed to metal fatigue. The majority of these fatigue cracks are initiated adjacent to a weld. A post-weld heat treatment is the traditional method of relieving these stresses, but is costly and a time consuming process. Heat treatment is required for weldments, which have heavy fatigue loading since the post-weld heat treatment reduces the residual stresses in the weldment and generates more uniform mechanical properties. Vibratory stress relief techniques could be used to substitute the heat treatment for these types of weldments and save time and money. The purpose of this paper is to provide a brief overview of the generation, measurement, and reduction of residual stresses. Residual stresses in the weld bead were measured by means of X-ray diffraction, neutron diffraction, ultrasonic technique, hole drilling and numerical methods. In addition, welded specimens were subjected to mechanical testing with purpose of determination of VSR effect on weld and heat-affected zone metal.

Highlights

The rapid expansion of the industrial steel constructions, steel bridges, etc. has increased the demand for steel structures workability requirements
The analysis of X-ray and neutron diffraction indicates that the vibratory stress relief (VSR) treatment during welding reduced the peak of residual stresses more than 60%
Different residual stress measurement techniques confirmed that the effect of vibration during welding reduces peaks of residual welding stresses by approx 60%, after welding – approx 40%, and thermal relief reduces peaks by approx 62%

Summary

Introduction

The rapid expansion of the industrial steel constructions, steel bridges, etc. has increased the demand for steel structures workability requirements. Thermal treatment process involves maintaining the high temperature in a structure followed by a slow cooling and a resulting reduction of residual stresses (According ASM Handbook 2002; Žiliukas, Surantas 2010). A vibratory stress relief (VSR) technique for the relief of residual welding stresses has been successfully applied worldwide for over 30 years. This method, compared to the thermal treatment, is much less energy, labour and time consuming intensive (Aoki et al 2005; Wang et al 2008). The practical problem arises when there is a need to assess the change in residual stresses in a real structure after applying VSR method. Many difficulties arise when assessing the effect of vibration energy to residual stresses in a real bridge structural member or other structure

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