LPW Technology Ltd, Runcorn, UK, has published its newest case study, ‘Nitrogen vs Argon Atomisation of 17-4 PH Stainless Steel and their respective Effects on AM Processing’. The study joins the current case studies in the LPW Technical Library, available via the company’s website, along with a number of brochures and technical tools, and looks in-depth at the role of atomisation gas choice in determining the ultimate microstructure and mechanical properties of fabricated parts in Selective Laser Melting (SLM), using 17-4 PH stainless steel metal powder to these effects demonstrate across four total builds.
According to the study, atomising 17-4 PH with argon delivers a powder with the desired martensitic microstructure, whereas nitrogen gas atomisation will deliver an austenitic microstructure. Whether the powder is atomised using argon or nitrogen, subsequent processing of the powder with an argon SLM processing gas will still deliver a martensitic part that can be heat treated to produce enhanced mechanical properties.
However, using argon for both atomisation and processing will deliver optimum hardness, ultimate tensile strength and yield strength values, reports LPW. Using nitrogen for both processes will result in an austenitic microstructure with no observed increase in desired mechanical properties.
“It’s important to understand the effect that powder production methods and AM processing parameters can have on the resulting component microstructure,” stated Dr Rob Deffley, LPW’s Research & Development Manager. “LPW’s highly-trained team understands the behaviour of powders processed under different conditions and can recommend the appropriate powder to achieve the required mechanical properties. This latest case study addresses a question we have been asked by several AM end users and adds further intelligence to our portfolio of technical information.”