Standards : X40CrMoV5

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Total Weight: 0.00 kg
Element Typical Content (%)
Carbon (C)0.26 – 0.36
Tungsten (W)8.5 – 10.5
Chromium (Cr)3.0 – 5.0
Vanadium (V)0.20 – 0.50
Molybdenum (Mo)≤ 0.50
Silicon (Si)0.20 – 1.00
Manganese (Mn)0.20 – 0.60
Phosphorus (P)≤ 0.030
Sulfur (S)≤ 0.030
BalanceIron (Fe)

Grade Brief

H21 steel is a tungsten-based hot work tool steel (AISI H21, ASTM A681) used in applications requiring high hot strength, good toughness, and resistance to thermal fatigue. It belongs to the H21–H26 tungsten hot work series, with alloying elements tungsten, chromium, vanadium, and carbon. Compared to chromium hot work steels (H10–H19), H21 offers:

  • Higher hardening temperature.
  • Better hot hardness and wear resistance.
  • Improved resistance to distortion under air hardening.

Preheating before service minimizes breakage, while reduced carbon improves toughness and thermal shock resistance.

Mode of Supply

Kuber Multi Metals is the largest stockiest and supplier of H21 tool steel in flat, square and round bar. We provide steel in all sizes as your requirements. H21 die steel is available in flat, square and round shape. Consult our team who will assist you for H21 steel query.

P20-Round
ROUND
SQUARE
P20-Flat
FLAT

Steel Properties

Hot work steel with good toughness include tungsten Chromium Carbon Vanadium usually is working hardness is 40.0 to 55.0 HRC size available in round, flat and square.

Mechanical Properties
Property Value
Hardness (as hardened)50 – 55 HRC
Hardness (tempered @ 600 °C)~45 HRC
Tensile Strength (UTS)~ 1,400 – 1,600 MPa
Yield Strength (0.2% proof)~ 1,100 – 1,200 MPa
Elongation (%)10 – 12
Impact Strength (Charpy V-notch)~ 25 J

Physical Properties

Depending on the precise composition and heat treatment of the H21/ DIN 2581/ AISI H21 steel, the physical attributes may differ somewhat. Its always advisable to refer to the manufacturer’s specifications for accurate information.

Physical Properties
Property Value
Density7.85 g/cm³
Modulus of Elasticity (E)210 GPa
Thermal Conductivity25 W/m·K
Specific Heat Capacity460 J/kg·K
Thermal Expansion (20–600 °C)11.4 ×10⁻⁶ /°C
Machinability

The tungsten percentage in H21/ DIN 2581/ AISI H21 steels makes them harder to manufacture when compared to water hardening low alloy steels, which have 100% machinability whereas H21/ DIN 2581/ AISI H21 has 55%.

Heat Treatment & Processes

Annealing

Heat to 820–870 °C, hold, then furnace cool at ≤10 °C/hr to ~600 °C, then air cool. Results in hardness ~220 HB.

Hardening

Preheat in two steps: 650–750 °C and 850–900 °C. Austenitize at 1,050–1,100 °C, hold uniformly. Quench in still air or oil (for thin sections).

Tempering

Temper immediately after quenching at 550–650 °C. Usually tempered twice. Final hardness: ~50–55 HRC.

Equivalent Grades

Standard Equivalent Grade
AISI / SAEH21
UNST20821
ASTMA681 H21
DINX30WCrV9-3
W.-Nr.1.2581
JISSKD5

Application

Hot forging dies, Hot shear blades, Extrusion tools and mandrels, Die casting dies, Punches and hot trimming dies, Rolls for hot rolling mills.

Conclusion

H21 tool steel is a tungsten-modified hot work steel suited to high-performance work that requires toughness, hot hardness, and thermal fatigue resistance. It is highly resistant to wear and hard to distort in air hardening in high temperature conditions, and it has much better stability than chromium hot work steels. H21 is a favorite in hot work environments, gaining its strength, toughness, and heat resistance to be used in forging dies, extrusion tooling, die casting, and hot shear appliances to achieve durability and reliability.

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