Effect of Particle Size Distribution and Powder Loading on Processing and Properties of 17-4PH MIM Feedstock

摘要

17-4PH precipitation hardened stainless steel is one of the most popular alloys used in Metal Injection Moulding and in emerging 3D printing applications today. It is known that the properties achieved can vary significantly depending on chemistry, particle size, powder loading and other process variables that affect final density and phase structure. In this paper the results of a systematic study on the effects of gas atomised particle size distribution and powder loading in a proprietary polyoxymethylene-based binder system, on sintering behaviour and properties of 17-4PH are reported. Various size fractions (90%-10μm, 90%-22μm and -32μm) of gas atomised powder were extracted from the same production campaign and used for moulding test samples. The relative merits of different size distributions are discussed in terms of injection and sintering performance, carbon control, shrinkage ratio and surface roughness.