The Effect of Nb Addition and Sintering Conditions on AISI-420 Martensitic Stainless Steels Produced by Powder Injection Molding: Microstructural, Mechanical and Corrosion Properties

Abstract

In this research article, the effect of Nb addition and sintering conditions on the microstructural, mechanical and corrosion properties of AISI-420 martensitic stainless steels produced by Powder Injection Molding method was investigated. The feedstock was formed by mixing the alloyed AISI-420 stainless steel powders produced by gas atomization with polymeric binders and shaping processes were carried out using the injection molding method. After the molding process, solvent and thermal binder removal processes were applied and most of the binders used were removed from the structure. The debinded samples were sintered under H2 and Ar atmosphere in the temperature range of 1250-1350 ºC. Samples were subjected to heat treatment after sintering in order to obtain the final properties. Densities of heat-treated samples were measured according to Archimedes principle. Metallographic procedures for determining microstructural developments; tensile testing and hardness measurements to determine mechanical properties; potentiometric measurements were carried out to determine corrosion resistance. It was observed that the final samples reached 99% relative density values, and Nb addition improved all mechanical and corrosion properties. In addition, samples sintered in an H2 sintering atmosphere were found to exhibit the best properties.

Keywords

• powder injection molding
• martensitic stainless steel
• sintering
• mechanical properties