Laser Oscillating of Nickel Alloyed Welds on Press-Hardened Steel

Abstract

Laser oscillating welding was employed to fabricate Al-Si coated press-hardened steel (PHS) to improve the element homogeneity in the fusion zone. Laser oscillating welding was employed with various oscillation amplitudes (0 mm, 0.5 mm and 1.3 mm) in this present. Ni foil of 0.06 mm thickness was used as an interlayer between two tailored PHS welded. The weld morphology, elemental profile, microstructure and tensile strength of welded joints were studied. The results showed that full penetration weld without any weld defects were achieved for any oscillation amplitudes, and weld width increased with increasing oscillation amplitudes. With the oscillation amplitudes increased, Ni and Al had an uneven elemental profile due to strong stirring force, but the Ni and Al content in the weld was decreased and Ni had a sharp descent compared to Al element. Only few δ-ferrite was presented in fusion line with the oscillation amplitudes increased to 1.3 mm. The oscillation amplitudes did not have an effect on the tensile properties, which was similar to that of base metal. But if keeping increasing the oscillation amplitudes or reducing the thickness of Ni interlayer, it has a potential risk to form more and more δ ferrite such that deteriorate the mechnical properties of welded joints.