Effect of a nickel-based alloy cladding layer on the strength and toughness of the high-strength steel laser-MAG hybrid welding joint

In this article, a 6 mm thick high-strength steel (HSS) was butt laser-MAG welded using nickel alloy wires as the cladding layer. By preparing the cladding layer on the groove, the microstructure and properties of the weld were adjusted. OM, XRD, SEM, and tensile and impact experiments were used to study the structure and mechanical properties of the welded joints. The results show that the weld structure with the cladding layer corresponds to austenite, while the microstructure of the conventional laser arc hybrid welded joint is a combination of austenite and martensite. Additionally, the tensile specimens of the welded joint are fractured at the weld. The fracture strength of the nickel alloy layer is 809 MPa, and the fracture strength of the conventional laser arc hybrid welded joint is 1149 MPa. The low temperature toughness (−40 °C) of conventional laser arc hybrid welded joint is 6.2J. The low temperature toughness (−40 °C) of prefabricated welded joints with laser-filled cladding has increased to 40.8 J, and this proves to be an effective method to improve the low temperature toughness of the welded joint. (paper)