Defect Analysis of 316LSS during the Powder Injection Moulding Process

Abstract

Austenitic Stainless Steel Has a FCC Structure at Room Temperature and the Temperature Range of the Austenite Phase Depends upon its Composition. 316L SS Is Widely Used in Medical, Marine, Industrial, Sporting and Aerospace Applications due to its Excellent Combination of Mechanical Properties and Corrosion Resistance. this Study Presents the Defects Observed during Optimization of the Processing Parameters for the Fabrication of Powder Injection Molding (PIM) of 316L SS Parts. in this Study, Five Formulations of Feedstock Containing 60-71vol% of Metal Powder Were Prepared Using a Wax-Based Binder. Green Samples Were Injection-Moulded, Followed by Binder Removal by Solvent and Thermal Means. Paraffin Wax (major Binder) Was Extracted at Various Temperatures in Order to Determine the Solvent Extraction Temperature. the Thermal De-Binding Was Performed Successfully at a Temperature of 450°C by Varying the Heating Rate from 1°C/min -10°C/min. SEM Results Showed Complete Removal of the Plastic Binder. Test Samples Were Sintered at Various Temperatures and Atmospheres. the Defects Observed during Solvent Extraction Were Swelling, Cracks and, at the Thermal De-Binding Step, Collection of Binder, Swelling and Holes. Sintered Samples Showed a Loss of Dimensional Control. these Types of Defect Were Considered to Be due to Inappropriate Heating Rates, Temperature and Dwell Time at each Process Step.