H21 Die Steel / DIN 1.2581 / JIS SKD5
H21 steel is a quintessential high-heat-strength hot-work die steel with exceptionally broad applications. It is frequently selected for moulds demanding high load-bearing capacity, superior thermal strength, and outstanding resistance to tempering, including die-casting moulds, hot-pressing dies, and forming dies.
Product Description
Xiri Tool Steel is a leading supplier of H21 die steel (DIN 1.2581) in China. H21 steel is a classic hot work die steel with tungsten as the main alloying element, and its Chinese grade is 3Cr2W8V. It is renowned for maintaining high strength and hardness (i.e., high thermal strength) even at a working temperature as high as 650°C.
Whether you need H21 flat bars, 1.2581 steel plates, or forged rounds, we provide custom dimensions with machining or grinding services. Our materials are strictly tested to ensure premium metallurgical structure.
H21 steel is a quintessential high-heat-strength hot-work die steel with exceptionally broad applications. It is frequently selected for moulds demanding high load-bearing capacity, superior thermal strength, and outstanding resistance to tempering, including die-casting moulds, hot-pressing dies, and forming dies.
Equivalent Grades of H21 Steel
| USA AISI |
Germany DIN |
Japan JIS |
GOST | China GB |
UK BS |
France AFNOR |
Korea KS |
ISO |
| H21 | 1.2581 | SKD5 | 3X2B8Ф | 3Cr2W8V | BH21 | Z30WCV9 | STD5 | 30WCrV9 |
Chemical Composition of AISI H21 / DIN 1.2581 tool steel
| C | Si | Mn | Cr | P | S | W | V |
| 0.26-0.36 | 0.15-0.50 | 0.15-0.40 | 3.0-3.75 | max 0.030 | max 0.030 | 8.50-10.00 | 0.30-0.60 |
Supply Form & Size Range of H21 / DIN 1.2581 tool steel
We supply H21 / DIN 1.2581 steel in various forms to meet your manufacturing needs:
Round bar: Diameter 10mm – 800mm
Steel Plate / Flat: Thickness 16mm – 400mm x Width 100mm – 800mm
Surface: Black, Peeled, Rough machined or Grinded.
Delivery Condition: Annealed (Hardness 255 HB max.)
Core Performance of H21 1.2581 Tool Steel
Unparalleled Thermal Strength and Hardness: H21’s core appeal lies in its exceptional resistance to tempering softening. At elevated temperatures between 600°C and 650°C, it maintains remarkably high strength and hardness (significantly outperforming many comparable materials in high-temperature hardness). This effectively counters deformation and collapse under thermal cycling stresses, ensuring enduring dimensional stability.
Outstanding Resistance to Thermal Fatigue: Moulds are highly susceptible to thermal stress cracking during repeated heating and cooling cycles. H21’s meticulously optimised alloy composition endows it with exceptional toughness. Combined with high thermal conductivity, this significantly mitigates thermal stress concentration, substantially extending mould service life under the severe challenges of alternating hot and cold conditions while reducing unplanned downtime caused by cracking.
Robust wear and thermal erosion resistance: When stamping molten metals or high-temperature plastics at high speeds, mould surfaces face significant risks of abrasion and adhesive thermal erosion. H21 exhibits outstanding high-temperature wear resistance and resilience against molten metal erosion, maintaining long-lasting surface smoothness. This ensures seamless product ejection with flawless, defect-free surfaces.
Stable and reliable thermal conductivity: As a hot-work tool steel, efficient heat transfer is paramount. H21’s optimised alloy composition delivers balanced thermal conductivity (approximately 8% higher than conventional hot-work steels), rapidly dissipating cavity heat to accelerate cycle times. This simultaneously minimises stress damage risks from excessive internal temperature gradients, significantly enhancing production efficiency and product consistency.
H21 Tool Steel Applications
H21 mould steel is the ideal choice for mould components subjected to severe high-temperature and high-pressure conditions:
Critical high-temperature metal forming applications: Core components (cores, cavities) for die-casting moulds handling aluminium, magnesium, and copper alloys; high-impact and high-wear zones in hot extrusion dies; high-speed precision hot forging dies.
High-Demand Plastic Processing: Core forming components for injection moulds processing high-temperature engineering plastics (e.g., PEEK, LCP) or requiring exceptionally long service life and high surface finish.
Specialised Hot-Work Tools: High-temperature punches, mandrels, hot-shear blades, tungsten wire hot-work dies.
Other Critical Wear- and Heat-Resistant Components: Tools requiring outstanding resistance to high-temperature softening, such as titanium alloy extrusion dies.
Our advantages in Processing H21 Tool Steel
The superior quality of H21 tool steel is no accident. Its exceptional and consistent performance relies on meticulous quality control throughout the entire process:
The Cornerstone of Pure Molten Steel: Control begins at the source, employing carefully selected raw materials and advanced smelting techniques such as vacuum degassing (VD/VOD) or electroslag remelting (ESR). These processes thoroughly eliminate harmful gases (hydrogen, oxygen) and non-metallic inclusions, significantly enhancing the steel’s purity, density, and toughness. This forms the foundation for resistance to thermal fatigue and extended service life.
Precise and Uniform Pre-treatment: Ingots undergo rigorous high-temperature diffusion annealing to ensure highly uniform distribution of key carbide-forming elements like tungsten, molybdenum, and chromium, eliminating dendritic segregation and establishing a homogeneous foundation for subsequent heat treatment.
Scientific and Rigorous Heat Treatment Process: Whether it concerns the precise control of quenching temperatures, the selection of cooling methods (oil quenching or graded quenching), or the stable execution of high-temperature tempering parameters (typically within the 600-650°C range), each step decisively influences the final product’s hardness, toughness, and thermal stability. Strict control over the number of tempering cycles and holding times ensures the attainment of optimal comprehensive mechanical properties and thermal stability.
Rigorous closed-loop quality inspection: Before shipment, finished products undergo multidimensional testing including hardness, impact toughness, metallographic structure (examining carbide morphology, distribution, and grain size), and ultrasonic flaw detection (identifying internal defects). Each specification sheet corresponds to clearly traceable performance data, ensuring every piece of H21 tool steel delivered to customers meets established high standards.
Not sure about the best equivalent for your application?
Why Manufacturers Choose Huangshi Xiri
Huangshi Xiri combines international-standard steel grades, a complete tool steel portfolio, strict quality control and reliable global supply. We match DIN / JIS / AISI equivalents precisely, offer cutting and heat-treatment services, and control every step from smelting to inspection. With stable capacity, on-time delivery and responsive technical support, we help manufacturers reduce risk, save costs and run production with confidence.
Contact Us
Contact Huangshi Xiri today for quotations, grade selection and technical support on tool steel, mold steel and alloy steel. Whether you need samples, cutting-to-size service or long-term supply for your projects, our engineers and sales team are ready to respond quickly with professional advice and reliable solutions for your manufacturing needs.
