Study on Microstructure and Properties of Welded Joints with Low Strength Backing Layer for WELDOX960

Abstract:

The welding of WELDOX960 ultra-high strength steel must consider not only the strength but also the toughness of the welding zone. In this paper, a new welding process with low strength matching backing layer is studied, that is, we choose ER50-6 wire for backing welding, use T union gm120 wire for MAG welding filling, and complete the cover welding. We prepared two groups of welding samples of ER50-6 wire backing welding and T union gm120 wire backing welding. Then we test the samples by optical metallography, tensile test, impact test and hardness test. The results show that the properties of the two kinds of backing weld can meet the requirements. The basic structure of the weld outside the backing layer of the two welding methods is similar, which are acicular ferrite and carbide. Using ER50-6 welding wire as backing, the microstructure of the weld is uniform and fine ferrite grain and a small amount of pearlite. Using T union GM120 high strength steel as backing, the microstructure of the weld is acicular ferrite and carbide. The toughness of ER50-6 is higher than that of T union GM120, and the hardness is lower than that of T union GM120.The research results have been successfully applied to the welding of large tonnage truck crane boom, and the enterprise has achieved high economic benefits.

• Periodical: Key Engineering Materials (Volume 904)
• Pages: 154-158
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.904.154
• Online since: November 2021
• Authors: Zhi Ling Wang*
• Keywords: Backing Weld, Ultra High Strength Steel, Weld Microstructure, Welded Joints

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