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Influence of Cold-Wire Submerged Arc Welding on the Toughness of Microalloyed Steel
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- Author(s) / Creator(s)
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The structural performance of microalloyed steel weld joints is essentially dependent on the microstructural characteristics of the heat-affected zone (HAZ). However, the microstructure is adversely impacted by the heat input of the welding process. As such, an X70 microalloyed steel was welded via a recently developed welding process, i.e., tandem submerged arc welding (TSAW) with an additional cold wire (cold-wire TSAW), and compared with the conventional TSAW process in terms of the HAZ microstructure and toughness. The heat introduced to the weldment is essentially reduced by addition of a cold wire in the welding process, which changed the properties in the HAZ. The results of fracture toughness testing using single-edge notched tension (SENT) testing, a recently developed test method, and Charpy V-notch (CVN) impact testing showed an improvement in the toughness of the HAZ of the cold-wire TSAW weld. This improvement was attributed to the formation of a lower fraction of M-A constituents and smaller ferrite/bainite grains with higher boundary misorientation angle, due to the reduced heat input by cold wire addition. Furthermore, the microstructural analysis indicated that the morphology and inter-spacing of the M-A constituents within the CGHAZ play a significant role on the toughness of the HAZ.
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- Date created
- 2018-01-01
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- Type of Item
- Article (Published)