1.2379 tool steel, also known internationally as D2 steel, is a high carbon, high chromium cold work tool steel grade renowned for its exceptional wear resistance, high compressive strength, and excellent dimensional stability. It is widely used in various tooling applications including blanking dies, punches, shear blades, and forming tools.
At SAKYSTEEL, we specialize in supplying 1.2379 tool steel in round bar, flat bar, and forged blocks with guaranteed quality and precise chemical composition. In this article, we provide a complete chemical and mechanical property analysis of 1.2379 steel and explore its heat treatment, applications, and comparison with other tool steels.
The chemical composition is the foundation of the mechanical properties and heat treatability of tool steel. According to DIN EN ISO 4957, the standard chemical composition of 1.2379 (D2) tool steel is as follows:
| Element | Content (%) |
|---|---|
| Carbon (C) | 1.50 – 1.60 |
| Chromium (Cr) | 11.00 – 13.00 |
| Molybdenum (Mo) | 0.70 – 1.00 |
| Vanadium (V) | 0.80 – 1.20 |
| Manganese (Mn) | 0.15 – 0.45 |
| Silicon (Si) | 0.10 – 0.60 |
| Phosphorus (P) | ≤ 0.03 |
| Sulfur (S) | ≤ 0.03 |
These alloying elements create a strong carbide network in the microstructure, significantly increasing tool life in wear-prone environments.
| Property | Typical Value (Annealed) | Hardened Condition |
|---|---|---|
| Hardness | ≤ 255 HB | 58 – 62 HRC |
| Tensile Strength | 700 – 950 MPa | Up to 2000 MPa |
| Compressive Strength | - | High |
| Impact Toughness | Moderate | Moderate |
The heat treatment process significantly influences the performance of D2 tool steel.
The tempering process ensures toughness and reduces brittleness after quenching.
1.2379 tool steel is widely used for:
Due to its high wear resistance and edge retention, 1.2379 is especially suited for long production runs and high-pressure operations.
| Steel Grade | Wear Resistance | Toughness | Hardness Range (HRC) | Corrosion Resistance |
|---|---|---|---|---|
| 1.2379 / D2 | Very High | Medium | 58–62 | Medium |
| A2 | High | High | 57–61 | Low |
| O1 | Moderate | High | 57–62 | Low |
| M2 (HSS) | Very High | Medium | 62–66 | Medium |
SAKYSTEEL engineers often recommend 1.2379 where tooling requires both dimensional stability and wear resistance in high-volume manufacturing.
1.2379 is not recommended for welding due to its high carbon content and risk of cracking. If welding is unavoidable:
Machining 1.2379 in its annealed condition is easier than after hardening. Carbide tools are recommended due to the presence of hard carbides.
To enhance the surface hardness and corrosion resistance, 1.2379 tool steel can undergo:
These treatments extend tool life, especially in high-friction applications.
| Form | Available Size Range |
|---|---|
| Round Bar | Ø 20 mm – 400 mm |
| Flat Bar / Plate | Thickness 10 mm – 200 mm |
| Forged Block | Custom Sizes |
| Precision Ground | On request |
We provide customized cutting and heat treatment services as per project requirements.
| Country | Standard / Grade |
|---|---|
| Germany | DIN 1.2379 |
| USA | AISI D2 |
| Japan | JIS SKD11 |
| UK | BS BH21 |
| France | Z160CDV12 |
| ISO | X153CrMoV12 |
This equivalency allows global sourcing of this material with comparable quality.
1.2379 / D2 tool steel is a premium choice for high-performance tooling applications due to its:
For industries demanding durability, precision, and cost-effective tooling, 1.2379 remains a reliable steel grade. Whether for die manufacturing or cold forming, it performs consistently under pressure.
At SAKYSTEEL, we guarantee top-quality 1.2379 tool steel with precise chemical composition and tight dimensional tolerances. Contact us for stock availability, pricing, and custom machining services.
Q1: What is the maximum hardness of 1.2379 after heat treatment?
A: Up to 62 HRC depending on quenching and tempering process.
Q2: Can 1.2379 be used in hot working conditions?
A: No, it is designed for cold work applications.
Q3: Is D2 steel magnetic?
A: Yes, in its hardened condition, it is ferromagnetic.
Q4: What are common alternatives to 1.2379?
A: A2 and M2 tool steels are often used depending on the toughness or hot hardness required.