Physical properties of stainless steel slurry for metal injection molding

To obtain the sound green compacts in metal injection molding (MIM), it is very important to know the optimal injection molding conditions using the slurry flow analysis such as a Flow Analysis Network (FAN) method. The flow analysis method requires several basic parameters including the rheological properties, e.g. viscosity, density and thermal conductivity of the slurry or green compacts. The physical properties of the MIM materials using a stainless steel SUS304 powder have been measured in this study, particularly for the temperature dependence of density, thermal conductivity and viscosity. The slurry viscosity was measured by the capillary test using the injection molding machine. From the experiments, the clear relations were obtained between the parameters and the temperature or share rate. Furthermore, from the flow analysis using the FAN method and the measured parameters, the detailed now pattern was obtained in the wide range of temperatures during slurry filling in the mold cavity. The rheological properties of slurry depending on the temperature were found to be very important factors in the numerical simulation for the optimization of injection molding conditions.