Overview
D2 Tool Steel is a high-carbon, high-chromium cold-work tool steel known for its exceptional wear resistance, hardness, dimensional stability, and edge retention. Classified as an air-hardening tool steel under the AISI system, D2 is one of the most widely used tool steels for industrial cutting, stamping, forming, and wear-resistant applications.
Compared with A2 tool steel, D2 offers significantly higher wear resistance. Compared with M2 high-speed steel, D2 provides better abrasion resistance but lower hot hardness.
D2 is widely used in:
- Industrial Knives
- Punches & Dies
- Stamping Tools
- Shear Blades
- Slitting Knives
- Wear Plates
- Plastic Mold Components
- Precision Cutting Tools
Because of its excellent wear resistance and long service life, D2 remains one of the most popular cold-work tool steels worldwide.
Material Specification
| Property | Value |
|---|---|
| Material Designation | D2 Tool Steel |
| Standard | ASTM A681 |
| UNS Number | T30402 |
| Material Family | High Carbon High Chromium Cold Work Tool Steel |
| Density | 7.70 g/cm³ |
| Magnetic Property | Magnetic |
| Typical Supply Condition | Annealed |
| Standard Forms | Round Bar, Flat Bar, Plate, Block, Tooling Stock |
Chemical Composition
| Element | Content (%) |
|---|---|
| Iron (Fe) | Balance |
| Carbon (C) | 1.40–1.60 |
| Chromium (Cr) | 11.00–13.00 |
| Molybdenum (Mo) | 0.70–1.20 |
| Vanadium (V) | 0.70–1.10 |
| Manganese (Mn) | ≤0.60 |
| Silicon (Si) | ≤0.60 |
| Phosphorus (P) | ≤0.030 |
| Sulfur (S) | ≤0.030 |
The high carbon and chromium content create a large volume of hard carbides, providing exceptional wear resistance.
Mechanical Properties
Annealed Condition
| Property | Value |
|---|---|
| Tensile Strength | 750–950 MPa |
| Yield Strength | 500–700 MPa |
| Hardness | 200–255 HB |
| Elastic Modulus | 210 GPa |
Hardened & Tempered Condition
| Property | Value |
|---|---|
| Hardness | 58–62 HRC |
| Compressive Strength | Excellent |
| Wear Resistance | Outstanding |
| Dimensional Stability | Excellent |
Vacuum Heat Treated Condition
| Property | Value |
|---|---|
| Hardness | 60–62 HRC |
| Edge Retention | Outstanding |
| Service Life | Excellent |
Physical Properties
| Property | Value |
|---|---|
| Density | 7.70 g/cm³ |
| Melting Point | 1420–1460°C |
| Thermal Conductivity | 20 W/m·K |
| Electrical Resistivity | 0.70 μΩ·m |
| Thermal Expansion Coefficient | 10.4 × 10⁻⁶/K |
| Specific Heat Capacity | 460 J/kg·K |
Corrosion Resistance
| Environment | Performance |
|---|---|
| Indoor Environment | Good |
| Dry Atmosphere | Good |
| Humid Environment | Moderate |
| Outdoor Environment | Moderate |
| Marine Environment | Poor |
| Chemical Environment | Moderate |
Although D2 contains high chromium, most chromium is tied up in carbides, so it is not considered a true stainless steel.
Recommended surface treatments:
- Black Oxide
- PVD Coating
- TiN Coating
- TiCN Coating
- DLC Coating
- Nitriding
- Hard Chrome Plating
Weldability
| Welding Process | Rating |
|---|---|
| TIG Welding | Poor |
| MIG Welding | Poor |
| Arc Welding | Poor |
| Laser Repair Welding | Fair |
| Tool Steel Repair Welding | Fair |
D2 has limited weldability due to its high carbon and alloy content.
Recommended:
- Preheat Required
- Controlled Cooling Required
- Post-Weld Tempering Required
Machinability
| Process | Rating |
|---|---|
| CNC Turning | Fair |
| CNC Milling | Fair |
| Drilling | Fair |
| Grinding | Excellent |
| EDM Machining | Outstanding |
| Wire Cutting | Outstanding |
Machinability Comparison
| Material | Machinability |
|---|---|
| 1045 Steel | Excellent |
| 4140 Steel | Good |
| D2 Tool Steel | Fair |
| A2 Tool Steel | Good |
| M2 Tool Steel | Fair |
D2 is commonly machined in the annealed condition and hardened afterward.
Heat Treatment
Annealing
| Parameter | Value |
|---|---|
| Temperature | 870–900°C |
| Cooling Method | Furnace Cool |
Preheating
| Parameter | Value |
|---|---|
| Temperature | 650–760°C |
Hardening
| Parameter | Value |
|---|---|
| Temperature | 1010–1040°C |
| Cooling Medium | Air Cooling |
Tempering
| Parameter | Value |
|---|---|
| Temperature | 150–540°C |
| Cycles | Double Temper Recommended |
Hardness After Heat Treatment
| Condition | Hardness |
|---|---|
| Annealed | 200–255 HB |
| Hardened | 60–64 HRC |
| Hardened & Tempered | 58–62 HRC |
Nitriding
| Property | Value |
|---|---|
| Surface Hardness | 70+ HRC |
| Wear Resistance | Exceptional |
International Equivalent Grades
| Standard | Equivalent Grade |
|---|---|
| ASTM / AISI (USA) | D2 |
| UNS | T30402 |
| GB/T (China) | Cr12Mo1V1 |
| EN (Europe) | X153CrMoV12 |
| DIN (Germany) | 1.2379 |
| JIS (Japan) | SKD11 |
| ISO | X153CrMoV12 |
Available Forms
| Product Type | Availability |
|---|---|
| Round Bar | Yes |
| Flat Bar | Yes |
| Tool Steel Plate | Yes |
| Precision Ground Plate | Yes |
| Mold Blocks | Yes |
| Tooling Stock | Yes |
| Forgings | Yes |
Typical Applications
Tool & Die Industry
- Blanking Dies
- Punching Dies
- Forming Dies
- Cold Work Dies
Blade Manufacturing
- Industrial Knives
- Slitting Knives
- Shear Blades
- Circular Cutters
Metal Stamping Industry
- Punches
- Dies
- Trimming Tools
- Progressive Dies
Plastic Mold Industry
- Wear Inserts
- Mold Components
- Ejector Systems
Industrial Machinery
- Wear Plates
- Guide Rails
- Precision Wear Parts
Paper & Packaging Industry
- Slitting Tools
- Cutting Blades
- Trim Knives
Manufacturing Characteristics
| Manufacturing Process | Rating |
|---|---|
| CNC Turning | Good |
| CNC Milling | Good |
| Precision Grinding | Outstanding |
| Wire EDM | Outstanding |
| EDM Machining | Outstanding |
| Vacuum Heat Treatment | Outstanding |
| PVD Coating | Outstanding |
| Nitriding | Outstanding |
Advantages
Exceptional Wear Resistance
One of the best cold-work tool steels available.
Outstanding Edge Retention
Ideal for industrial cutting applications.
Excellent Dimensional Stability
Maintains accuracy after heat treatment.
High Compressive Strength
Suitable for stamping and forming operations.
Long Tool Life
Reduces maintenance and replacement costs.
Air-Hardening Capability
Lower distortion than oil-hardening steels.
Limitations
Lower Toughness Than A2
Can chip under severe impact loading.
Limited Weldability
Difficult to repair by conventional welding.
Moderate Corrosion Resistance
Not a true stainless steel.
More Difficult Machining
Requires machining before hardening.
Comparison with Other Tool Steels
| Property | D2 | A2 | O1 | M2 | SKD11 |
|---|---|---|---|---|---|
| Wear Resistance | Outstanding | Excellent | Good | Excellent | Outstanding |
| Toughness | Moderate | Excellent | Good | Good | Moderate |
| Hardness | 62 HRC | 60 HRC | 60 HRC | 65 HRC | 62 HRC |
| Dimensional Stability | Excellent | Excellent | Good | Excellent | Excellent |
| Cost | Moderate | Moderate | Lower | Higher | Moderate |
Comparison with Engineering Materials
| Material | Hardness Potential | Wear Resistance | Toughness |
|---|---|---|---|
| D2 Tool Steel | 62 HRC | Outstanding | Moderate |
| A2 Tool Steel | 60 HRC | Excellent | Better |
| M2 Tool Steel | 65 HRC | Excellent | Good |
| 4140 Steel | 58 HRC | Good | Excellent |
| 4340 Steel | 60 HRC | Good | Outstanding |
| SKD11 | 62 HRC | Outstanding | Moderate |
Available Surface Finishes
Raw Finishes
- Annealed Finish
- Ground Finish
- Precision Machined Finish
Functional Finishes
- Vacuum Hardened Finish
- Precision Ground Finish
- Wire EDM Finish
- Nitrided Finish
Protective Finishes
- Black Oxide
- TiN Coating
- TiCN Coating
- DLC Coating
- Hard Chrome Plating
Frequently Asked Questions (FAQ)
What is D2 tool steel?
D2 is a high-carbon, high-chromium cold-work tool steel known for exceptional wear resistance and long tool life.
What is D2 steel used for?
Typical applications include:
- Punches
- Dies
- Industrial Knives
- Shear Blades
- Wear Parts
- Cutting Tools
Is D2 stainless steel?
No. Although D2 contains approximately 12% chromium, it is not considered stainless steel because much of the chromium forms carbides.
What hardness can D2 achieve?
- Hardened: 60–64 HRC
- Hardened & Tempered: 58–62 HRC
What is the equivalent material to D2?
Common equivalents include:
- SKD11 (Japan)
- 1.2379 (Germany)
- Cr12Mo1V1 (China)
- X153CrMoV12 (Europe)
What is the difference between D2 and A2?
| Property | D2 | A2 |
|---|---|---|
| Wear Resistance | Higher | Lower |
| Toughness | Lower | Higher |
| Edge Retention | Better | Good |
Can D2 be nitrided?
Yes. Nitriding can increase surface hardness above 70 HRC.
Is D2 good for knives?
Yes. D2 is widely used for industrial and high-performance cutting tools due to excellent edge retention.
Why is D2 widely used in stamping dies?
Because it combines:
- High Hardness
- Exceptional Wear Resistance
- Long Tool Life
- Dimensional Stability
- Good Cost Performance
Does GCNOV provide custom manufacturing services for D2 steel?
Yes. GCNOV provides:
- CNC Machining
- Tool & Die Manufacturing
- Wire EDM
- Precision Grinding
- Vacuum Heat Treatment
- Nitriding
- PVD Coating
- Prototype Development
- Low-Volume Production
- Mass Production