Heat treatment and properties of powder forged Fe–Ni–Cu–C–Mo gear materials

The heat treatments of the powder forged Fe‒Ni‒Cu‒C‒Mo materials after forging were studied. The continuous cooling transformation diagram of the powder forged Fe‒Ni‒Cu‒C‒Mo alloys was constructed to guide the selection of cooling process after forging. The quenching Fe‒Ni‒Cu‒C‒Mo specimens were tempered at various temperatures in the low temperature tempering test, and the effects of tempering temperatures on the microstructure and mechanical properties of the Fe‒Ni‒Cu‒C‒Mo materials were investigated. The results show that, when the cooling rate of the Fe–Ni–Cu–C–Mo specimens after forging is more than 7.0 ℃·s⁻¹, the microstructure is the martensite and the hardness tends to be stable. Tempering at 150 and 175 ℃, the carbide is evenly distributed inside the martensite lath, which acts as the precipitation strengthening, and the Fe–Ni–Cu–C–Mo specimens exhibit the excellent tensile properties.