Influence Of Process Gas Composition On Laser Cladding Process Characteristics

The influence of process gas composition on characteristics of laser cladding processes is studied in detail at the example of a 60 HRC nickel based self fluxing alloy powder. Typically pure nitrogen, argon or helium are used as process gases in laser cladding processes. Besides mixtures of these gases also addition of hydrogen, carbon dioxide and oxygen are applied studying their influence on thermal emission, weld penetration depth and homogeneity, powder usage and crack formation. Use of identical composition of carrier gas and laser process gas is compared to use of different carrier and laser process gases. Oxygen addition increases thermal emission, but does not result in increased weld penetration depth or crack formation tendency. Thereby homogeneity of weld penetration is improved in comparison to use of pure argon. Also, maximum hardness of claddings is achieved when adding oxygen.