Description
D7 Tool Steel: Detailed Overview
D7 tool steel is a high-carbon, high-chromium alloy tool steel known for its exceptional hardness, wear resistance, and ability to retain sharp edges under extreme conditions. It is ideal for use in high-stress, cold-working environments where resistance to wear, abrasion, and deformation is crucial.
Introduction to D7 Tool Steel
D7 is a high-carbon, high-chromium alloy steel that offers superior wear resistance, hardness, and toughness. This tool steel is designed for extreme applications where high performance under wear and stress conditions is required. The steel’s composition helps it maintain hardness and strength even at elevated temperatures.
Key Features of D7 Tool Steel:
- Exceptional Hardness: Capable of achieving extremely high hardness through heat treatment.
- Superior Wear Resistance: Outstanding resistance to wear and abrasion, even in high-stress applications.
- High Strength: Excellent tensile strength and durability.
- Heat Resistance: Maintains mechanical properties at elevated temperatures.
- Edge Retention: Ideal for applications that require sharp edges and cutting tools.
Applications of D7 Tool Steel
D7 tool steel is used in demanding applications that require high hardness and wear resistance, particularly in cold-work environments. Its excellent wear resistance makes it ideal for tools and dies used in metal cutting, forming, and stamping operations.
Typical Applications Include:
- Cutting Tools: Circular saws, shear blades, punches, and reamers.
- Cold-Working Dies: Stamping, forming, and extrusion dies.
- Knives and Blades: Industrial blades and knives that require superior wear resistance.
- Wear-Resistant Components: Rollers, bearings, and machine parts exposed to abrasive materials.
- Molds: Injection molds for plastics and other materials.
Equivalent Grades of D7 Tool Steel
D7 tool steel is recognized under various international standards to ensure compatibility across regions and industries.
| Standard | Equivalent Grade |
|---|---|
| DIN | 1.2439 |
| EN | X210CrW12 |
| AISI/SAE | D7 |
| BS | BO1 |
Chemical Composition of D7 Tool Steel
The chemical composition of D7 tool steel is designed to provide excellent wear resistance, high hardness, and edge retention. Below is the typical composition:
| Element | Composition (%) |
|---|---|
| Carbon (C) | 2.00 – 2.30 |
| Silicon (Si) | 0.10 – 0.40 |
| Manganese (Mn) | 0.10 – 0.40 |
| Chromium (Cr) | 12.00 – 13.00 |
| Vanadium (V) | 0.30 – 0.50 |
| Tungsten (W) | 0.70 – 1.00 |
The high levels of carbon and chromium in D7 steel contribute to its superior hardness and wear resistance.
Mechanical Properties of D7 Tool Steel
The mechanical properties of D7 tool steel are essential for understanding its suitability for various high-performance applications. Typical values are:
| Property | Value (Typical) |
|---|---|
| Tensile Strength (MPa) | 950 – 1200 |
| Yield Strength (MPa) | 800 – 1000 |
| Elongation (%) | ≥ 6 |
| Impact Toughness (J) | ≥ 25 (at room temp) |
| Hardness (HB) | 260 – 320 |
These values indicate the steel’s excellent ability to withstand wear, stress, and deformation in harsh conditions.
Heat Treatment of D7 Tool Steel
To optimize the performance of D7 tool steel, heat treatment processes are crucial:
- Hardening: Heat to 950 – 1000°C followed by quenching in oil or air to achieve maximum hardness.
- Tempering: Heat to 150 – 300°C after hardening to reduce brittleness and enhance toughness.
- Annealing: Heat to 800 – 850°C followed by slow furnace cooling to soften the material for machining.
These heat treatments help D7 achieve the desired balance of hardness and toughness for specific applications.
Hardness of D7 Tool Steel
D7 tool steel can achieve extremely high hardness through proper heat treatment. Typical hardness values are:
- Annealed Condition: 230 – 260 HB
- After Hardening and Tempering: Up to 64 HRC
These hardness levels make D7 tool steel particularly resistant to wear and deformation, even under extreme conditions.
Physical Properties of D7 Tool Steel
D7’s physical properties are essential for understanding its performance in different operating environments. Key values include:
| Property | Value |
|---|---|
| Density (g/cm³) | 7.7 – 7.9 |
| Melting Point (°C) | 1420 – 1450 |
| Thermal Conductivity (W/m·K) | 25 – 30 |
| Specific Heat Capacity (J/kg·K) | 400 – 450 |
These properties ensure that D7 tool steel maintains its performance under high-stress, high-temperature conditions.
Forging Properties of D7 Tool Steel
D7 can be forged at temperatures ranging from 1050 – 1150°C. After forging, slow cooling is recommended to prevent internal stresses and distortion.
Stress Relieving for D7 Tool Steel
Stress relieving is performed by heating the steel to 600 – 650°C to remove internal stresses from machining or forming. This process improves dimensional stability and reduces the risk of cracking during service.
Machinability of D7 Tool Steel
D7 tool steel has moderate machinability in its annealed condition. Due to its high hardness after heat treatment, careful management of cutting speeds and tool wear is necessary during machining.
Welding of D7 Tool Steel
Welding D7 tool steel is challenging due to its high carbon content. Preheating to 200 – 300°C and post-weld heat treatment are necessary to minimize the risk of cracking and maintain weld integrity.
Supply Cities:
Mumbai Ahmedabad, Amaravathi, Ambattur, Bangalore, Belgaum, Chennai, Chittoor, Coimbatore, Dindigul, Mysore, Nellore, Hyderabad, Kochi, Mangalore, Tirupur, Tuticorin, Madurai, Andhra Pradesh, Karnataka, Puducherry, Kerala, Tamil Nadu, Telangana, Visakhapatnam, Kochi, Kerala, Hubli-Dharwad, Karnataka, Ghaziabad Kolkata.
