ASTM A372 Grade H Alloy Steel
ASTM A372 grade H steel is an alloy steel formulated for primary forming into wrought products. It has a moderately low embodied energy among wrought alloy steels in the same category. In addition, it has a moderately low electrical conductivity and a fairly low base cost.
The properties of ASTM A372 grade H steel include three common variations. This page shows summary ranges across all of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare ASTM A372 grade H steel to: wrought alloy steels in the same category (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
Brinell Hardness
200 to 280
Elastic (Young's, Tensile) Modulus
190 GPa 27 x 106 psi
Elongation at Break
20 to 22 %
Fatigue Strength
310 to 380 MPa 45 to 55 x 103 psi
Poisson's Ratio
0.29
Shear Modulus
73 GPa 11 x 106 psi
Shear Strength
410 to 570 MPa 60 to 83 x 103 psi
Tensile Strength: Ultimate (UTS)
650 to 910 MPa 95 to 130 x 103 psi
Tensile Strength: Yield (Proof)
430 to 550 MPa 63 to 80 x 103 psi
Thermal Properties
Latent Heat of Fusion
250 J/g
Maximum Temperature: Mechanical
410 °C 780 °F
Melting Completion (Liquidus)
1460 °C 2660 °F
Melting Onset (Solidus)
1420 °C 2580 °F
Specific Heat Capacity
470 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
45 W/m-K 26 BTU/h-ft-°F
Thermal Expansion
13 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
7.2 % IACS
Electrical Conductivity: Equal Weight (Specific)
8.3 % IACS
Otherwise Unclassified Properties
Base Metal Price
2.3 % relative
Density
7.8 g/cm3 490 lb/ft3
Embodied Carbon
1.5 kg CO2/kg material
Embodied Energy
20 MJ/kg 8.4 x 103 BTU/lb
Embodied Water
49 L/kg 5.9 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
130 to 160 MJ/m3
Resilience: Unit (Modulus of Resilience)
500 to 810 kJ/m3
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
23 to 32 points
Strength to Weight: Bending
21 to 27 points
Thermal Diffusivity
12 mm2/s
Thermal Shock Resistance
19 to 27 points
Alloy Composition
Among alloy steels, the composition of ASTM A372 grade H steel is notable for containing comparatively high amounts of manganese (Mn) and chromium (Cr). Manganese is used to improve hardenability, hot workability, and surface quality. There is some loss of ductility and weldability, however. Chromium is used to improve corrosion resistance and most mechanical properties (particularly at higher temperatures).
| Fe | 97.3 to 98.3 | |
| Mn | 0.75 to 1.1 | |
| Cr | 0.4 to 0.65 | |
| C | 0.3 to 0.4 | |
| Si | 0.15 to 0.35 | |
| Mo | 0.15 to 0.25 | |
| P | 0 to 0.015 | |
| S | 0 to 0.010 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM A372: Standard Specification for Carbon and Alloy Steel Forgings for Thin-Walled Pressure Vessels
Pressure Vessels: External Pressure Technology, 2nd ed., Carl T. F. Ross, 2011
ASM Specialty Handbook: Carbon and Alloy Steels, J. R. Davis (editor), 1996
Manufacture and Uses of Alloy Steels, Henry D. Hibbard, 2005
CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015
Steels: Processing, Structure, and Performance, 2nd ed., George Krauss, 2015