Laser beam cladding at high processing speed

Abstract

Laser beam cladding is a versatile method for the deposition of functional surface layers, the generation of prototypes, and the repair welding of components. It is a thermal process characterized by a highly localized high intensity energy input. The powder-fed laser beam cladding process uses CO2 and, more recently, Nd:YAG and direct diode lasers at a processing speed typically within 0.3 to 1.5 m/min. The present work investigates the extension of process parameters towards significantly higher speed and thermal efficiency. In this study, a focused YAG laser beam produces a very small melt pool, and the interaction time is in the range of milliseconds. High heating and cooling rates determine microstructure and properties of the clad layers. With minimal overall heat input, functional layers with a thickness of tenths of millimeters are obtained, and the surface area processed per time unit is increased.