Effects of Austenitizing Temperature and Cooling Rate on the Mechanical Properties of 36MnVS4 Steel for Automobile Engine Connecting Rod

Abstract

The relationship between microstructure and mechanical properties of 36MnVS4 steel was studied. Different prior austenite grain sizes were obtained by austenitizing at 850, 950 and 1050 °C, respectively, and different ferrite contents were obtained by different cooling rates. Austenitizing temperature mainly influenced the grain size. With the austenitizing temperature increasing, grain size increased and the phase transformation starting temperature increased. Also, the strength increased and the plasticity and toughness decreased. Cooling rate mainly influenced the microstructure percentage. With the cooling rate increasing, ferrite percentage decreased and pearlite percentage increased. And meanwhile, the strength increased and ductility and toughness decreased. Microstructure had a significant influence on fracture splitting properties. With the grain size increasing, fracture splitting properties were markedly improved. With the ferrite percentage increasing and pearlite percentage decreasing, fracture splitting properties were worsened.