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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).

Iron (Fe) 97.3 to 98.3
Manganese (Mn) 0.75 to 1.1
Chromium (Cr) 0.4 to 0.65
Carbon (C) 0.3 to 0.4
Silicon (Si) 0.15 to 0.35
Molybdenum (Mo) 0.15 to 0.25
Phosphorus (P) 0 to 0.015
Sulfur (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