Improving Structural Integrity with Boron-based Additives for 3D Printed 420 Stainless Steel

This paper explores the possibility of attaining fully dense parts with a powder-based 3D printing method by sintering, instead of following the standard protocol of infiltrating bronze. The possible ingredients that can be added to improve the densification are explored, which will also enhance the structural integrity of 3D printed 420 stainless steels (SS). As studied with the powder metallurgy (P/M) community in the past half of a century, a small addition of ingredients (sintering aid) into a base metal powder enhances densification and improves the final structural integrity. Numerous P/M works have suggested possible ingredients as sintering aids. However, these P/M works were not carried out with a consistent set of experimental conditions. Thus, in this study, we have constrained our base powder to be 420 SS, common for 3DP, with the average size of 30 micron, which were sintered between 1150 and 1250 °C after the powder were mixed with the sintering ingredients. Each sintered sample was analyzed in terms of the final density attained, the amount of ingredient mixed and the sintering temperature.