Forming Performance of 1Cr18Ni9Ti Stainless Steel Laser Oscillating Welding Joints

Laser oscillating welding tests of 1Cr18Ni9Ti stainless steel were carried out by using different oscillating frequencies and oscillating amplitudes, and the effects of different oscillating laser process parameters on the porosity and macroscopic morphologies of the welds, the microstructure and mechanical properties of the joints were studied. The results show that compared with the oscillating frequency, increasing the oscillating amplitude effectively reduces the porosity of the weld. The porosity decreases to 0.19% under 100 Hz frequency and 1.5 mm amplitude. With the increase of the oscillating frequency, the width of nail head decreases firstly and then changes little. With the increase of the oscillating amplitude, the width of nail rod gradually increases, while the weld penetration decreases. There are little differences in the microstructures of the welds under different oscillating frequencies and amplitudes, which are mainly composed of skeletal and strip ferrite and austenite.The upper weld edge has more strip ferrite than the weld center, while the lower weld transition zone has finer microstructure than the upper weld edge. The hardness of the weld and base metal has little differences, and the average hardness of the welds has no obvious changes under different oscillating parameters. The tensile fractures of the joints are mainly at the base metal, and the macroscopic necking phenomenons and microscopic dimple characteristics of the fractures indicate that plastic fracture mainly occurs during tensile process.