Production of high performance automobile parts by the metal injection molding (MIM) process

Abstract

Effects of various processing parameters in the metal injection molding (MIM) process were investigated in order to study the fabrication of selected automobile part, splined coupling, through MIM process. 430L stainless steel powder and 40 vol% PAN-250 binder were mixed in a twin-screw kneader. The motor speed of 122 rpm was selected. The optimized molding conditions for tensile specimens and splined coupling were selected. The optimized debinding condition for tensile specimens was debinding temperature of 310-360 ํC in flowing air with fan for 30 hours which achieved 94-99% extraction. The sintering conditions of 1195 ํC in N2+70%H2 atmosphere and 1250 ํC, 1300 ํC, 1350 ํC in hydrogen atmosphere were used. At 1195 ํC, the sintering was not complete. At 1250 ํC, 1300 ํC and 1350 ํC, the sintering reached final stage and achieved the maximum density of 95.82% theoretical density. Physical and mechanical properties of the sintered tensile specimens were tested and the results were discussed. The splined coupling could be formed though MIM process. However, sintered splined couplings had some distortions resulting in dimensional control problem.