Mechanical and corrosion resistance of laser cladding Ni-based alloy of steel plate under variable defocusing.

The laser-clad nickel-base superalloy Ni35 powder is tested on Q235 steel by YLS-3000 fiber laser. Under other conditions, the defocus amount (30 mm and 50 mm) is changed to observe the effect of it to the mechanical heat stability of the cladding layer. Compared with the substrate, the cladding layer formed by laser cladding exhibits better mechanical properties and corrosion resistance as a whole. The mixed morphology of the cladding layer and the matrix is similar to "mushroom shape"; With the defocus amount increasing, the fusion angle α between the cladding layer and the substrate is increased, and the microstructure becomes more refined, thereby the hardness of the cladding layer is increased, and the corrosion resistance is enhanced. After heat treatment to 600 °C, the crystal grains are further refined, and both the maximum and the average hardness of the cladding layer are increased. The cladding layer exhibits favorable stability. The cladding layers at 30 mm and 50 mm defocusing exhibit good mechanical thermal stability, corrosion resistance, and high temperature adaptability. The cladding layer with high defocusing performance is superior. [ABSTRACT FROM AUTHOR]