D2 tool steel is a high-carbon, high-chromium cold work tool steel known for its exceptional hardness, wear resistance, and toughness. Heres a comprehensive description:
Composition
- Carbon (C) 1.40-1.60%
- Chromium (Cr) 11.00-13.00%
- Molybdenum (Mo) 0.70-1.20%
- Vanadium (V) 0.10-0.30%
- Manganese (Mn) 0.60-0.90%
- Silicon (Si) 0.60-0.90%
- Phosphorus (P) and Sulfur (S) Max 0.03% each
Properties
- Hardness D2 tool steel is known for its high hardness, typically reaching 60-62 HRC (Rockwell Hardness C) after heat treatment.
- Wear Resistance Excellent resistance to abrasion and wear, making it suitable for applications involving high friction.
- Toughness While it is hard and wear-resistant, it has moderate toughness, meaning it can resist chipping and cracking under stress but may be more brittle compared to some other tool steels.
- Edge Retention Retains a sharp edge for extended periods, which is beneficial for cutting and shaping applications.
- Dimensional Stability Good stability during heat treatment, which helps in maintaining the precision of tools and dies.
Applications
- Cutting Tools Widely used in manufacturing cutting tools such as knives, shear blades, and dies for cold working.
- Dies and Molds Suitable for making dies and molds that require high wear resistance and dimensional accuracy.
- Punches and Dies Employed in various stamping and punching applications.
- Forming Tools Used for tools involved in cold forming processes due to its durability and wear resistance.
Heat Treatment
- Annealing Typically done at around 850-900C (1562-1652F), followed by slow cooling to relieve stresses and improve machinability.
- Hardening Heat to 1020-1040C (1868-1904F), followed by quenching in oil or air.
- Tempering Usually performed at temperatures between 150-200C (302-392F) to achieve the desired hardness and toughness while reducing brittleness.
Advantages
- High Wear Resistance Ideal for applications that involve high wear and tear.
- Precision Maintains its shape and dimensions well during operation.
- Versatility Effective in a range of cold work applications, making it a popular choice for toolmakers.
Disadvantages
- Brittleness Can be prone to chipping or cracking under excessive stress due to its high hardness.
- Machinability Harder to machine compared to some other tool steels, especially in the hardened state.
Standards and Grades
- Standards D2 is commonly referenced in standards such as ASTM A681 and DIN 1.2379.
- Grades It is often available in various forms, including bars, plates, and sheets.
D2 tool steel is highly valued for its ability to withstand high levels of wear and maintain precision, making it a preferred material for many cutting and forming tools used in industrial applications.