One problem was that magnesium (Mg) combined with tin (Sn) during billet reheat, which resulted in low strength, such as tensile strength, and poor machinability.
The results show that the pre-hardened plastic-mould steel belongs to a little lowmachinability steel because of much hard inclusion existing in microstructure and its high strength and hardness.
结果表明，这类材料属较难加工材料，这主要是由于钢中存在大量硬质点，且材料具有较高强度和硬度所致。
3
High strength, low thermal conductivity, high ductility and high work hardening tendency of stainless steels are the main factors that make their machinability difficult.