Heat Treatment Guide for Tool Die Steel Performance

Heat treatment is one of the most critical processes in enhancing the mechanical properties of tool die steel. Whether used in plastic mold manufacturing, cutting tools, forging dies, stamping molds, or high-pressure casting applications, correctly applied heat treatment can significantly improve steel performance, extend tool life, and reduce production costs.

Key Heat Treatment Processes for Tool Die Steel

1. Annealing

Annealing softens tool steel to make it easier to machine.

Purpose: Relieve internal stresses and improve machinability
Temperature Range: 760–800°C (varies by steel grade)
Cooling: Slow furnace cooling

2. Normalizing

Often used before hardening to prepare a uniform microstructure.

Purpose: Refine grain structure
Temperature Range: Approx. 30–50°C above critical temperature
Cooling: Air cooling

3. Quenching (Hardening)

Hardens the steel to improve wear resistance.

Purpose: Increase hardness
Temperature Range: Based on steel carbon/alloy content
Cooling Medium: Oil, air, or salt bath

Tips for Achieving the Best Heat Treatment Results

✅ Preheat steel gradually to avoid thermal shock
✅ Use protective atmosphere to avoid surface decarburization
✅ Perform double or triple tempering after hardening
✅ Control heating rate based on material thickness
✅ Always use hardness testing after tempering
✅ Avoid overheating—grain growth reduces tool strength

Choosing the right heat treatment process is essential for maximizing the performance of tool die steel. From improving hardness to preventing deformation, proper heat treatment ensures longer mold life, increased production efficiency, and cost savings.