Residual stress distributions in laser and gas-metal-arc welded high-strength steel plates

Abstract

S700 is a high-strength steel recently developed by Tata Steel. This paper describes the residual stress distributions in a multi-pass gas-metal-arc weld (GMAW), a single pass autogenous laser weld (ALW) and a multi-pass ultra-narrow gap laser weld (NGLW) in 13 mm thick high-strength (S700) steel plates, as measured by X-ray diffraction and the contour method. The relationships between microstructural variation and residual stress distributions were investigated. It was found that solid-sate phase transformations from austenite to ferrite, bainite and martensite changed both the magnitude and distribution of residual stresses in the three different welded specimens. The width of the regions sustaining tensile stress in each specimen decreased in the following order: GMAW > ALW > ultra-NGLW.

This paper is part of a Themed Issue on Measurement, modelling and mitigation of residual stress.

Keywords:

• As welded condition
• Bainite
• Hardness
• Martensite
• Solid-state phase transformation
• 2G welding position

Acknowledgements

The authors acknowledge financial support of the work by Tata Steel, and by The University of Manchester through the provision of a scholarship. The authors are grateful for laser welding experimental support, which was provided by Mr Damian Crosby, Dr Yanfeng Du and Dr Xianfeng Shen. The authors greatly appreciate help provided by Mr Paul English on the GMAW work. The authors would like to express their appreciation to Dr Zhu Liu and Mr Yiqiang Chen for their assistance in providing materials characterisation facilities. The authors are grateful to Mr Ian Winstanley for his help with EDM cutting, and to Dr Matthew Roy who supported the hardness testing and contour method measurements.

ORCID

W. Guo http://orcid.org/0000-0002-9011-1024