DB6 Die Blocks Tool Steel
DB6 Die Blocks Tool Steel is a high-quality hot-work tool steel mainly used for manufacturing large die blocks and heavy-duty tooling that operate under high temperature and pressure conditions. It is specially designed to provide high strength, excellent toughness, and resistance to thermal cracking, making it suitable for demanding industrial applications where tools are exposed to repeated heating and cooling cycles.
DB6 steel contains alloying elements such as chromium, molybdenum, and vanadium, which enhance its heat resistance, wear resistance, and durability. These properties allow the steel to maintain its performance even in extreme working environments. It also offers good hardenability and uniform hardness across large sections, which is very important for die blocks used in heavy forging operations.
Because of its strong mechanical properties, DB6 die block steel is commonly used in the production of forging dies, hammer dies, press dies, die holders, and large industrial molds. It is widely applied in industries such as automotive, heavy engineering, and metal forming, where reliable and long-lasting tooling materials are essential.
Main characteristics and applications
Ni – Cr – Mo die steel characterized by high level hardenability and toughness, good resistance to repeated thermal and good wear resistance.
Main applications:
- hammer and press forging dies.
- rams for power hammers.
- hot mill rolls.
- very hard cold work dies and punches.
It is advisable to use the blocks for dies treated at various hardness limits according to the depth cavity complying with the indications given below.
Comparable standards
| DIN | W.Nr | AFNOR | AISI/ASTM | JIS |
|---|---|---|---|---|
| 56NiCrMoV7<\/td> | 1.2714<\/td> | ~55NCD07-05<\/td> | DB-6<\/td> | SKT-4<\/td> |
Chemical composition (typical; in weight %)
| C | Si | Mn | P (Max) | S (Max) | Cr | Mo | Ni | V |
|---|---|---|---|---|---|---|---|---|
| 0.50-0.60<\/td> | 0.10-0.40<\/td> | 0.60-0.95<\/td> | 0.03<\/td> | 0.03<\/td> | 0.80-1.20<\/td> | 0.35-0.55<\/td> | 1.50-1.80<\/td> | 0.05-0.15<\/td> |
Critical points
Production technology
US specification
Delivery condition
Physical properties (reference values)
| Property | 20°C | 100°C | 200°C | 500°C |
|---|---|---|---|---|
| Thermal expansion coefficient (10⁻⁶/K) | 12.1<\/td> | 12.4<\/td> | —<\/td> | 14.0<\/td> |
| Thermal conductivity (W/m·K)<\/td> | 36.7<\/td> | 36.9<\/td> | —<\/td> | 35.7<\/td> |
| Young's modulus (kN/mm²)<\/td> | 212<\/td> | 208<\/td> | —<\/td> | 175<\/td> |
Tempering curve / Heat treatment
| Treatment | Temperature (°C) | Holding Time | Cooling | Comments |
|---|---|---|---|---|
| Annealing<\/td> | 700 – 720<\/td> | Min. 2 min/mm<\/td> | Air or furnace<\/td> | In order to obtain hardness lower than 240 HB (23 HRC) to improve machinability<\/td> |
| Stress relieving<\/td> | 600 – 650 (max 30°C below tempering temp)<\/td> | Min. 2 min/mm<\/td> | Air or furnace<\/td> | To be carried out after machining to eliminate residual stresses induced by mechanical working<\/td> |
| Hardening<\/td> | Initial preheating: 350-450°C Second preheating: 650-750°C Hardening: 850-870°C<\/td> | Min. 1 min/mm<\/td> | Oil<\/td> | —<\/td> |
| Tempering<\/td> | 550 – 600°C (minimum 3 hours) 2nd tempering at same or 20°C lower<\/td> | —<\/td> | Air<\/td> | Usual service hardness: 44-52 HRC. Before tempering, preheat to 200-300°C<\/td> |
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