DIEVAR Material Detailed Information
DIEVAR is a high-performance hot work tool steel produced by Uddeholm. It is a premium steel designed for high-temperature applications that require extremely high resistance to thermal fatigue, wear, and oxidation. The steel is used in demanding tooling applications such as die casting, forging, and plastic molding, where high heat resistance and toughness are essential. DIEVAR is especially known for its ability to withstand extreme heat cycling while maintaining outstanding toughness and wear resistance.
Key Features
- Superior Heat Resistance: The steel maintains high hardness and strength even at elevated temperatures, making it ideal for hot working conditions.
- Exceptional Thermal Fatigue Resistance: The steel can endure repeated thermal cycling without cracking or significant wear.
- Good Wear Resistance: The high chromium and vanadium content ensures resistance to abrasive wear.
- Outstanding Toughness: This material can resist fractures, chipping, and cracking under mechanical and thermal stresses.
- High Oxidation Resistance: Dies made from DIEVAR are resistant to oxidation at elevated temperatures, which extends tool life.
Chemical Composition
| Element | Composition (%) |
| Carbon (C) | 0.38 |
| Silicon (Si) | 0.90 |
| Manganese (Mn) | 0.30 |
| Chromium (Cr) | 5.30 |
| Molybdenum (Mo) | 1.80 |
| Vanadium (V) | 0.90 |
| Phosphorus (P) | ≤ 0.025 |
| Sulfur (S) | ≤ 0.020 |
Key Features in Composition:
- High Chromium (Cr) Content: Increases wear resistance and oxidation resistance at high temperatures.
- Molybdenum (Mo): Enhances hot hardness, thermal stability, and strength at elevated temperatures.
- Vanadium (V): Increases carbide formation, improving wear resistance.
- Low Phosphorus (P) & Sulfur (S): Provides improved toughness and reduces brittleness.
Mechanical Properties
| Property | Value |
| Hardness (Annealed) | ≤ 250 HB |
| Hardness (After Heat Treatment) | 48 – 52 HRC |
| Tensile Strength | ~1,700 MPa |
| Yield Strength | ~1,500 MPa |
| Impact Toughness | Very High |
| Wear Resistance | Excellent |
| Thermal Fatigue Resistance | Superior |
| Heat Resistance | Excellent |
Key Features:
- Excellent heat resistance: Withstands high temperatures up to 600-650°C without degradation in strength.
- Superior thermal fatigue resistance: Resistant to cracking and heat checking under cyclic heating conditions.
- Outstanding wear resistance: Perfect for high-wear applications at elevated temperatures.
- High toughness: Can absorb impact and thermal shock, which is essential for tooling exposed to thermal stresses.
DIEVAR vs. Other Hot Work Tool Steels
| Property | DIEVAR | SKD61 (H13) | 1.2344 | 1.2367 |
| Hardness (After Heat Treatment) | 48-52 HRC | 45-50 HRC | 45-50 HRC | 50-52 HRC |
| Thermal Fatigue Resistance | Superior | Moderate | Moderate | High |
| Wear Resistance | Excellent | Good | Good | High |
| Toughness | Very High | High | Moderate | High |
| Oxidation Resistance | Excellent | Good | Good | High |
| Heat Resistance | Superior | Moderate | Moderate | High |
| Applications | Hot work tooling | General tooling | Hot work dies | Hot work tooling |
Why Choose DIEVAR?
- Superior thermal fatigue and heat resistance compared to standard steels like SKD61 and 1.2344.
- Excellent wear and oxidation resistance, ensuring longer tool life in high-temperature environments.
- Better toughness and resistance to cracking under thermal cycling compared to conventional hot work steels.
Applications
DIEVAR is most commonly used in hot work tooling applications where high thermal stress and repeated heating and cooling cycles are common.
Die Casting Molds
- Molds for aluminum, magnesium, and zinc die casting
- Die casting dies for high-temperature alloys
- Shot sleeves and injection nozzles
Hot Forging Dies
- Dies for forging of steels and non-ferrous alloys
- Hot forging press dies
- Trimming tools and punches
Plastic Molding Tools
- Injection mold cavities for high-temperature plastics
- Blow molding tools for engineering thermoplastics
Extrusion Dies
- Dies for extrusion of aluminum, copper, and brass
- Tube and pipe extrusion dies
Other High-Temperature Applications
- Hot stamping dies
- Heavy-duty hot working tools
Heat Treatment Process
Soft Annealing (If Necessary for Machining)
- Heat to 850–900°C, then cool slowly at 10–20°C per hour to 600°C before cooling to room temperature.
Hardening
- Preheat to 600–850°C, then heat to 1,040–1,100°C for hardening.
- Quenching: Use air, vacuum, or oil quenching for optimal results.
Tempering
- Temper at 550–650°C for 2–3 cycles to achieve a hardness of 48-52 HRC, balancing toughness and strength.
Nitriding (Optional)
- Nitriding can be done to increase surface hardness and wear resistance.
Alternative Materials
- SKD61 (H13): Standard hot work steel, offers good heat resistance but with lower thermal fatigue resistance compared to DIEVAR.
- 1.2344: A widely used hot work steel, but DIEVAR offers superior performance in terms of wear resistance and toughness.
- 1.2367: Better than 1.2344 in heat resistance, but DIEVAR still outperforms it in fatigue resistance and oxidation resistance.
- QRO 90 Supreme (Uddeholm): Offers excellent heat resistance, but DIEVAR is a better choice for applications with extreme thermal fatigue requirements.
Conclusion
DIEVAR is a high-performance hot work tool steel known for its outstanding heat resistance, thermal fatigue resistance, wear resistance, and toughness. It is ideal for die casting, forging, extrusion, and high-temperature plastic molding tools, where durability under extreme conditions is critical.
Best Choice for: Hot work tooling exposed to extreme temperatures and thermal cycling
Why Choose DIEVAR? Superior heat resistance, thermal fatigue resistance, wear resistance, and toughness compared to standard hot work steels like H13 (SKD61).
