Experimental Study on Static and Dynamic Mechanical Behavior of 20CrMnTi Gear Steel

Dry high-speed cutting of spiral bevel gear is a non-linear dynamic process, involving partial high cutting temperature, high shear fracture, and high strain rate and so on. The accurate description of gear materials' mechanical characteristics in such physical environment is the foundation of dry high-speed cutting numerical simulation. But so far, no papers have been found in this regard. In this paper, based on the static high temperature tensile tests and Split Hopkinson Tension Bar(SHTB) high strain rate tensile tests, the static and dynamic mechanical behavior of the automobile gear steel 20CrMnTi in forged and normalized condition is studied; the elastic modulus, yield limit and ultimate strength are obtained; the Johnson-Cook material constitutive model is established. Experimental results show that 20CrMnTi gear steel has demonstrated a comparatively obvious yield phenomenon both in static and high strain rate state, has emerged rather obvious necking phenomenon before fracture; it has showed a certain degree of temperature softening effect and strain rate hardening effect and its yield limit has a certain sensitivity to temperature and strain rate.