Role of beam interaction time in laser cladding process

Abstract

This paper discusses the microstructure and mechanical properties of a Co based alloy coating, produced by CO2 laser cladding technique, for steam turbine applications. The role of the laser beam interaction time, the so called dwell time, has been investigated. It has been realised that the beam interaction time has a significant effect on the solidification and microstructure development process. The results indicated that the laser cladded zone exhibited a fine microstructure and a higher hardness after a short interaction time compared with a coarse structure and lower hardness after a long interaction time. Since the dilution of the base material into the cladding was significantly low after a short interaction time, the clad could retain a significant amount of strength after a long exposure time, which is a unique feature for the turbine industries.