Hardened H21 Tool Steel
Hardened SAE-AISI H21 is SAE-AISI H21 steel in the hardened (H) condition. The graph bars on the material properties cards below compare hardened SAE-AISI H21 to: tool steels (top), all iron alloys (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.
Mechanical Properties
Elastic (Young's, Tensile) Modulus
200 GPa 29 x 106 psi
Poisson's Ratio
0.29
Rockwell C Hardness
55
Shear Modulus
76 GPa 11 x 106 psi
Tensile Strength: Ultimate (UTS)
1790 MPa 260 x 103 psi
Thermal Properties
Latent Heat of Fusion
250 J/g
Melting Completion (Liquidus)
1630 °C 2960 °F
Melting Onset (Solidus)
1580 °C 2880 °F
Specific Heat Capacity
440 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
27 W/m-K 16 BTU/h-ft-°F
Thermal Expansion
11 µm/m-K
Otherwise Unclassified Properties
Base Metal Price
23 % relative
Density
8.5 g/cm3 530 lb/ft3
Embodied Carbon
4.5 kg CO2/kg material
Embodied Energy
68 MJ/kg 29 x 103 BTU/lb
Embodied Water
72 L/kg 8.6 gal/lb
Common Calculations
PREN (Pitting Resistance)
19
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
23 points
Strength to Weight: Axial
58 points
Strength to Weight: Bending
38 points
Thermal Diffusivity
7.1 mm2/s
Thermal Shock Resistance
59 points
Alloy Composition
| Fe | 87.6 to 93.8 | |
| W | 8.5 to 10 | |
| Cr | 3.0 to 3.8 | |
| V | 0.3 to 0.6 | |
| Si | 0.15 to 0.5 | |
| C | 0.28 to 0.36 | |
| Mn | 0.15 to 0.4 | |
| Ni | 0 to 0.3 | |
| Cu | 0 to 0.25 | |
| P | 0 to 0.030 | |
| S | 0 to 0.030 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Further Reading
SAE J437: Selection and Heat Treatment of Tool and Die Steels
ASTM A681: Standard Specification for Tool Steels Alloy
Tool Steels: Properties and Performance, Rafael A. Mesquita (editor), 2016
ASM Specialty Handbook: Carbon and Alloy Steels, J. R. Davis (editor), 1996