Semi-empirical model of deposit size and porosity in 420 stainless steel and 4140 steel using laser engineered net shaping

Laser engineered net shaping (LENS™) samples were fabricated from two technologically important steel alloys, 420 and 4140, in order to study how processing parameters such as powder feed rate and laser traverse velocity affected porosity and deposit dimensions. For both steels, it was found that many possible combinations of laser traverse velocity and powder feed rate will result in negligible porosity provided that the ratio of powder feed rate to laser traverse velocity does not exceed a maximum level. Based on measurements of deposit size and shape in the various experiments, a semi-empirical model is presented that predicts the trend in deposit sizes for various processing parameters.