Influence of sintering on mechanical response of metal injection moulded parts

Abstract

ABSTRACT Sintering is often the final step during Metal Injection Molding (MIM) and does in an observable way contribute to influencing both the characteristics and performance of final products. In this research paper, the influence of sintering parameters on dimensional stability and mechanical properties of parts having three different shapes is presented and adequately discussed. A CI 90 feedstock having 90 weight percent of Carbonyl Iron powder was prepared by mixing the carbonyl iron powder with an organic binder. The GSGR75 feedstock has 75 weight percent of powder of grinding sludge and graphite. The green samples were subject to thermal debinding at 750°C. The brown samples were sintered at the temperatures of 1100°C, 1200°C, and 1300°C for 60 minutes and in atmospheres of vacuum, argon, and nitrogen. The sintering characteristics of the parts that were produced from the use of the grinding sludge powder (GSGR) were found to be inferior to those produced from the use of the carbonyl iron (CI) powder. This is essentially because of the limited degree of reduction coupled with the presence and distribution of a sizable number of pores. The sintering parameters did exert an influence on the properties of the as-sintered end-product. Distinct empirical relations were developed and verified for the purpose of predicting properties of the sintered product based on the sintering parameters used.