Notch aspects of RSP steel microstructure

Abstract

For a rather long time, basic research projects have been focused on examinations of mechanical properties for Rapid Solidification Powder (RSP) steels. These state-of-art steels are commonly known as “powdered steels“. In fact, they combine distinctive attributes of conventional steel alloys with unusual resistance of construction material manufactured by so called “pseudo-powdered” metallurgy.Choice of suitable materials for experimental verification was carried out based on characteristic application of so called “modern steel”. First, groups of stainless and tool steel types (steel grades ČSN 17 and 19) were selected. These provided representative specimens for the actual comparison experiment. For stainless steel type, two steel types were chosen: hardenable X47Cr14 (ČSN 17 029) stainless steel and non-hardenable X2CrNiMo18-14-3 (ČSN 17 350) steel. They are suitable e.g. for surgical tools and replacements (respectively). For tooling materials, C80U (ČSN 19 152) carbon steel and American D2 highly-alloyed steel (ČSN “equivalent” being 19 572 steel) were chosen for the project. Finally, the M390 Böhler steel was chosen as representative of powdered (atomized) steels. The goal of this paper is to discuss structural aspects of modern stainless and tool steel types and to compare them against the steel made by the RSP method. Based on the paper's results, impact of powdered steel structural characteristics on the resistance to crack initiation shall be evaluated.