Tooling heat treatment uses precise control of heating, holding, and cooling to achieve the ideal microstructure in tool steel or high-speed steel – a high-hardness martensitic matrix with fine, uniformly distributed carbides – thereby achieving the optimal balance between hardness and toughness.

Typical Process Flow:

1. Preheating Stage – Gradual heating to 600-850°C reduces thermal stress and prevents cracking of complex-shaped tools.
2. Austenitizing Stage – Heating to target austenitizing temperature (HSS: 1180-1240°C, tool steel: 1000-1100°C) to fully dissolve carbides.
3. Quenching Stage – Rapid cooling (oil, gas, or step quenching) to form high-hardness martensite.
4. Cryogenic Treatment (Optional) – Treatment at -80°C to -196°C reduces retained austenite, improving hardness and dimensional stability.
5. Tempering Stage – 1-3 tempering cycles (HSS: 540-570°C, tool steel: 150-600°C) to eliminate quenching stress and adjust final hardness.

The choice of tempering cycles and temperature directly affects final tool performance and must be precisely determined according to the specific application.

Tooling heat treatment demands high precision and process stability:

1. Vacuum High-Pressure Gas Quenching – High-purity nitrogen or argon at high pressure provides rapid cooling, achieving oxidation-free, distortion-free high-quality quenching.
2. Cryogenic Treatment – Liquid nitrogen cools workpieces to -196°C, significantly reducing retained austenite, improving hardness and dimensional stability – especially for precision gauges and high-accuracy dies.
3. Plasma Nitriding/Carburizing – Surface hardening of dies improves surface hardness and wear resistance while maintaining matrix toughness.
4. Digital Process Control – Sensors and control systems enable precise heating rate control, automatic determination of austenitizing holding time, real-time cooling rate adjustment, and complete process data traceability.

Heat treatment of tooling and cutting tools is a core process determining tool performance and service life. As high-end manufacturing demands ever-higher precision and longer tool life, advanced technologies such as vacuum heat treatment, cryogenic treatment, and digital control will see broader application.

Rexin China factory provides vacuum hardening furnaces, box hardening furnaces, pit hardening furnaces, tempering furnaces, and cryogenic treatment equipment for the tooling industry, supporting wholesale supply and custom manufacturing. Contact our engineering team for more information or to request a quote.