①Forging. GCr15 steel has better forging performance and the forging temperature range of tungsten steel mold is wide. The forging process regulations are generally: heating 1050~1100℃, initial forging temperature 1020~1080℃, final forging temperature 850℃, and air cooling after forging. The forged structure should be a fine flake spheroidal body. Such a structure can be spheroidized and annealed without normalizing.
②Normalize the fire. The normalizing heating temperature of GCr15 steel is generally 900~920℃, and the cooling rate cannot be less than 40~50℃/min. Small mold bases can be cooled in still air; larger mold bases can be cooled by air blast or spray; large mold bases with a diameter of more than 200mm can be cooled in hot oil, and taken out for air cooling when the surface temperature is about 200°C. The internal stress formed by the latter cooling method of the tungsten steel mold is relatively large and easy to crack. It should be spheroidized annealed immediately or a stress relief annealing process should be added.
③Spheroidizing annealing. The spheroidizing annealing process specifications for GCr15 steel are generally: tungsten steel mold heating temperature 770~790℃, holding temperature 2~4h, isothermal temperature 690~720℃, isothermal time 4~6h. After annealing, the structure is fine and uniform spherical pearlite with a hardness of 217~255HBS and good cutting performance. GCr15 steel has good hardenability (the critical hardening diameter for oil quenching is 25mm), and the depth of the hardened layer obtained under oil quenching is similar to that of carbon tool steel through water quenching.
Post time: Aug-23-2024
