Optimized Annealing Process of M2 High Speed Steel Wires

The effect of annealing process parameters including heating temperature,holding time and isothermal transformation on microstructure and mechanical properties of M2 high speed steel wires processed by different isothermal annealing processes was investigated.The process was optimized on this basis.The results show that excessive high temperature and long time could cause the coarsening of primary carbides,reducing the plasticity.Excesssive short isothermal transformation time went against the forming of pearlite,and made the plasticity decreaesed.The appropriate annealing process of M2 wires was heating at 880 ℃ for 2 h and then furnace-cooled to 760 ℃ for 5 h.Fine and spherical primary carbides were formed in annealed sorbite after annealing with those parameters which cause the wires obtaining good plasticity.