Processing of Water-atomised 316L Stainless Steel Powder Using Metal-injection Processes

A water-atomised 316L stainless steel (SS) powder has been evaluated for physical and mechanical properties in a metal-injection moulding (MIM) process using the locally-based binder system palm stearin (PS). The results of the powder characterisation and feedstock preparation assays essentially conform to MIM processing standard requirements. Injection moulding was conducted successfully using a powder loading of 0.62. Solvent extraction and thermal methods were used for binder de-binding. The results show that water-atomised powder could be sintered to 95% of its theoretical density under tested sintering conditions (1360°C, 1 hour). Specimens composed of water-atomised powder exhibited large shrinkage due to the lower green density that is associated with the poor packing properties of the powder. The sintered specimen of water-atomised 316L SS that used the PS-based binder system nearly achieved Metal Powder Industries Federation (MPIF) Standard 35.