Weldability and liquation cracking behavior of ZhS6U superalloy during electron-beam welding

Arash Khakzadshahandashti; Mohammad Reza Rahimipour; Kourosh Shirvani; Mansour Razavi

doi:10.1007/s12613-019-1730-z

Volume 26 Issue 2

Feb. 2019

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Article Navigation > International Journal of Minerals, Metallurgy and Materials > 2019 > 26(2): 251-259

Arash Khakzadshahandashti, Mohammad Reza Rahimipour, Kourosh Shirvani, and Mansour Razavi, Weldability and liquation cracking behavior of ZhS6U superalloy during electron-beam welding, Int. J. Miner. Metall. Mater., 26(2019), No. 2, pp. 251-259. https://doi.org/10.1007/s12613-019-1730-z

Cite this article as:

Arash Khakzadshahandashti, Mohammad Reza Rahimipour, Kourosh Shirvani, and Mansour Razavi, Weldability and liquation cracking behavior of ZhS6U superalloy during electron-beam welding, Int. J. Miner. Metall. Mater., 26(2019), No. 2, pp. 251-259. https://doi.org/10.1007/s12613-019-1730-z

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Research Article

Weldability and liquation cracking behavior of ZhS6U superalloy during electron-beam welding

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Corresponding author:
Mohammad Reza Rahimipour E-mail: m-rahimi@merc.ac.ir
Received: 19 April 2018; Revised: 18 July 2018; Accepted: 30 July 2018

Abstract

Abstract

The weldability of the ZhS6U nickel-based superalloy, which is prone to solidification cracking during electron-beam welding (EBW) repair processes, was investigated. The effects of two different pre-weld heat-treatment cycles on the final microstructure before and after welding were examined. Welds were made on flat coupons using an EBW machine, and the two heat-treatment cycles were designed to reduce γ' liquation before welding. Microstructural features were also examined by optical and scanning electron microscopy. The results showed that the change in the morphology and size of the γ' precipitates in the pre-weld heat-treatment cycles changed the ability of the superalloy to release the tensile stresses caused by the matrix phase cooling after EBW. The high hardness in the welded coupons subjected to the first heat-treatment cycle resulted in greater resistance to stress release by the base alloy, and the concentration of stress in the base metal caused liquation cracks in the heat-affected zone and solidification cracks in the weld area.
- weldability;
- ZhS6U superalloy;
- electron beam welding;
- heat-affected zone;
- liquation cracking;
- pre-weld heat treatment

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References

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