Core Chemical Composition System
Base Carbon Content: Carbon content is controlled within the 0.3%–0.6% range to balance hardness, wear resistance, and toughness, while avoiding brittleness caused by excessive carbon.
Key Alloying Elements:
Chromium (Cr): 4.75%–12.0%; enhances oxidation resistance and hardenability (e.g., H13 typically contains 4.75%–5.50% Cr).
Molybdenum (Mo): 1.10%–3.50%; inhibits temper brittleness and improves high-temperature strength.
Vanadium (V): 0.30%–2.50%; refines grain structure and significantly reduces the tendency for thermal fatigue cracking.
Auxiliary Elements: Silicon (Si) ≤1.0% improves deoxidation; Nickel (Ni) ≤0.30% enhances matrix toughness; Tungsten (W) improves red hardness.
Material Characteristics of Mainstream Commercial Grades
H13 (4Cr5MoSiV1): A balanced material containing 5% Cr, 1% Mo, and 1% V; it maintains a hardness above HRC 45 at 600°C. It is a standard choice for die casting and hot forging applications. Suzhou Changyuhe H13 hot-work die steel is common on the market, with prices starting at 5.80 Yuan.
DIEVAR: A high-performance material designed with high Molybdenum (2.1%) content; it offers superior thermal cracking resistance compared to H13, along with outstanding toughness, thermal strength, and ductility. Suzhou Changshuo DIEVAR hot-work die steel is priced at 12.00 Yuan/kg.
5CrMnMo: A low-alloy material with 0.50%–0.60% carbon content; it uses Manganese to replace Nickel for optimized hardenability and is suitable for small-to-medium hammer forging dies and hot trimming dies.
SKD61: Corresponds to the national standard 4Cr5MoSiV1; refined via vacuum degassing, it achieves a hardness of 56–58 HRC after quenching and is widely used in aluminum and zinc alloy die casting. 3Cr2W8V: A high-tungsten (8%) grade offering excellent high-temperature resistance but relatively poor toughness; it is currently being gradually replaced by newer grades.
