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D6 Tool Steel | 1.2436 | SKD2 | T30406: Properties, Process, Uses
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D6 Tool Steel is a high-carbon, high-chromium material recognized for its outstanding durability and resistance to wear, making it perfect for challenging cold work tasks. This article delves into its essential characteristics, thermal treatment methods, and typical applications.
What Is D6 Tool Steel?
D6 tool steel is a high-carbon, 12% chromium tungsten alloy designed for cold work applications. Known for its high wear resistance and excellent toughness, it is often used in tools, dies, and molds requiring durability in harsh conditions. D6 offers superior hardenability and dimensional stability compared to other cold work steels like D3. With a hardness range of 55-62 HRC after heat treatment, D6 is well-suited for high-stress environments requiring precision and longevity.
SteelPro Group provides D6 tool steel that conforms to the ASTM A681-199 standard for cold work tool steels. We offer D6 steel in various forms such as round bars, plates, and blocks. Our services include heat treatment, cutting, grinding, milling, turning, and custom machining to meet your specific requirements.
Chemical Composition of D6 Tool Steel
D6 tool steel features a balanced chemical composition that combines high carbon for hardness, chromium for wear resistance, and tungsten for added toughness and durability. This alloy is designed for demanding applications requiring excellent abrasion resistance and dimensional stability. The table below outlines its precise chemical makeup.
| Element | Composition (%) |
| Carbon (C) | 2.05 |
| Chromium (Cr) | 12.5 |
| Iron (Fe) | 83.05 |
| Manganese (Mn) | 0.8 |
| Silicon (Si) | 0.3 |
| Tungsten (W) | 1.3 |
Mechanical Properties of D6 Tool Steel
D6 tool steel is renowned for its exceptional compressive strength, robust hardness, and reliable elastic modulus, making it suitable for high-stress applications. Its mechanical attributes guarantee longevity and resistance to deformation when subjected to stress. The table below presents a comprehensive summary of its essential mechanical features.
| Property | Metric Value | Imperial Value |
| Compressive Strength | 1,320 MPa | 191,000 psi |
| Modulus of Elasticity | 194 GPa | 28,100 ksi |
| Hardness (HRC) | 46 HRC | 46 HRC |
Physical Properties of D6 Tool Steel
D6 tool steel offers high density, low thermal expansion, and efficient heat conductivity, ensuring stability and performance in precision applications. Its moderate specific heat capacity supports consistent operation under thermal stress. The following is an overview of its main physical characteristics.
| Property | Metric Value | Imperial Value |
| Density | 7.67 g/cm³ | 0.277 lb/in³ |
| Thermal Expansion Coefficient (21–400 °C / 69.8–752 °F) | 10.8 µm/m °C | 6 µin/in °F |
| Thermal Conductivity (20 °C / 68 °F) | 20.5 W/m K | 142 BTU·in/hr·ft²·°F |
| Specific Heat Capacity (20 °C / 68 °F) | 0.460 J/g-°C | 0.110 BTU/lb-°F |
Heat Treatment of D6 Tool Steel
D6 tool steel is typically supplied in annealed or pre-hardened condition, offering ease of machining and minimal distortion during heat treatment.We specialize in providing D6 tool steel in custom heat-treated forms, ensuring the material is tailored to specific client requirements.
Annealing
- Heat at 50-100°C (122-212°F) per hour.
- Heat to 830-870°C (1526-1598°F) and soak for 1 hour per 25.4 mm (1 inch).
- Cool slowly in a furnace or air-cool in a controlled environment.
Gradual heating avoids thermal shock. Soaking ensures uniform temperature throughout, and slow cooling relieves internal stresses and maintains dimensional stability.
Stress Relieving
- Heat to 650-700°C (1202-1292°F) before hardening.
- Cool slowly in air or a furnace.
Stress relieving is necessary to eliminate residual stresses from machining or forming, ensuring the steel won’t crack or warp during hardening.
Hardening
- Preheat to 760-800°C (1400-1472°F).
- Heat to 1000-1050°C (1832-1922°F) for austenitizing and soak for 1 hour per 25.4 mm (1 inch).
- Quench in oil, air, or salt baths.
Preheating ensures uniform heating before austenitizing. Quenching in different media affects cooling rates, which in turn influences hardness and the risk of distortion.Oil quenching results in slower cooling, increasing hardness but with a higher risk of cracking, while air cooling is faster and can result in lower hardness but less distortion. Salt baths offer controlled cooling for a more uniform hardness.
Tempering
- Heat to 500-600°C (932-1112°F) and soak for 1 hour per 25.4 mm (1 inch).
- Secondary tempering may be required.
Tempering reduces brittleness and increases toughness. The cooling rate and temperature range during tempering determine the final hardness.
A second tempering cycle at a higher temperature may be necessary to further refine mechanical properties and ensure the steel achieves the desired balance of strength and toughness.
D6 Tool Steel Product Forms
At SteelPro Group, we specialize in providing high-quality D6 tool steel in a range of standard product forms and sizes. The table below outlines the typical dimensions available for D6 tool steel products. If you need tailored dimensions, we have the capability to meet your exact requirements with accuracy and adaptability.
| Product Form | Typical Dimensions (Metric) | Typical Dimensions (Imperial) |
| Round Bars | Diameters: 16 mm to 200 mm | Diameters: 0.63 in to 7.87 in |
| Square Bars | Thickness: 20 mm to 200 mm | Thickness: 0.79 in to 7.87 in |
| Width: 30 mm to 150 mm | Width: 1.18 in to 5.91 in | |
| Flat Bars | Thickness: 10 mm to 120 mm | Thickness: 0.39 in to 4.72 in |
| Width: 30 mm to 610 mm | Width: 1.18 in to 24.02 in | |
| Blocks | Thickness: 100 mm to 500 mm | Thickness: 3.94 in to 19.69 in |
| Width: 100 mm to 500 mm | Width: 3.94 in to 19.69 in | |
| Plates | Thickness: 20 mm to 200 mm | Thickness: 0.79 in to 7.87 in |
| Width: Up to 1000 mm | Width: Up to 39.37 in |
D6 Tool Steel Applications
D6 steel is ideal for applications that involve high stress, wear, and demanding operational conditions. Its strength and dimensional stability during heat treatment ensure it performs effectively in both cold and hot working environments.
- Cutting Tools: Punches, dies, and shear blades for high-precision cutting operations.
- Forming Dies: Used in automotive and aerospace industries for stamping and forming.
- Extrusion Dies: Ideal for extrusion of metals, plastics, and rubber, handling high pressure and wear.
- Cold Work Tooling: Includes cutting tools, stamping dies, and forming tools.
- Rolls for Steel Processing: Rolls for sheet and strip steel production, resistant to thermal cracking and wear.
- Plastic Molds: Injection molds requiring high precision and wear resistance.
- Hot Work Tools: Forging dies and hot shear blades for use in elevated temperature environments.
D6 Tool Steel: Customized Solutions & Services
At SteelPro Group, we offer high-quality D-2 and D6 Tool Steel in round bars, plates, blocks, and square bars, with precise dimensions to meet your specific needs. Whether you need standard or custom sizes, we can deliver with fast turnaround times.
Our expert services include heat treatment, precision cutting, grinding, milling, and tempering, ensuring your D6 steel is tailored to perfection for your application. Contact us today to discover how we can help optimize your tooling solutions.
