Effect of thermal debinding and sintering parameters on the mechanical properties of 4605 MIM compact using the RSM

Abstract

ABSTRACT In metal injection moulding (MIM) process, improper debinding or sintering process is mainly responsible for forming defects in final parts. In this study, the effects of thermal debinding and sintering parameters on the physical and mechanical properties of low alloy steel parts produced by the MIM process are investigated. For this reason, the design of experiments was done using the central composite design (CCD) method with parameters of 3–7 °C/min for heating rate, 1–3 h for sintering time, and 1200–1300 °C for temperature. The density, strength, hardness, and elongation of the sintered parts were measured for each experiment. The results showed that among the process variables, the heating rate has the most significant effect on the properties mentioned above. Also, the impact of sintering temperature showed to be more significant than the sintering time. Finally, it was observed that with the increase in the thermal debinding rate from 3 to 7 °C/min, the relative density decreased by 3%, and elongation decreased from 10 to 4%. As for the strength, there is an optimum point of heating rate after which, with the increase of heating rate (from 5 to 7 °C/min), the strength decreases significantly by 70 MPa.