Laser-assisted machining of an austenitic stainless steel: P550

Abstract

High-nitrogen, nickel-free stainless steels have much higher yield strength than typical stainless steels, and their high corrosion resistance and high strength makes them especially attractive in medical, aerospace, and oil drilling industries. The high strength also makes these materials difficult to machine owing to high cutting forces, and relatively short tool lives. Laser-assisted machining (LAM) is investigated as an economic alternative for machining these difficult-to-machine materials. In the current study, surface temperature measurements are compared with model predictions to ascertain the accuracy of a thermal model. An experimental matrix is designed to determine the effects of temperature and surface speed, using tool life, cutting forces, surface roughness, and workpiece integrity as metrics to determine optimal processing conditions. Explanation of cutting temperatures and effects on tool life are discussed. Hardness measurements, X-ray diffraction, and microstructural analysis indicate little or no damage of the subsurface of the workpiece. An economic analysis shows the benefits that can be obtained over conventional machining through implementation of LAM in stainless steels.