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ASTM A372 Grade J Alloy Steel

ASTM A372 grade J steel is an alloy steel formulated for primary forming into wrought products. It has a moderately low embodied energy and a moderately low base cost among wrought alloy steels in the same category.

The properties of ASTM A372 grade J steel include five 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 J 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 310

Elastic (Young's, Tensile) Modulus

190 GPa 27 x 106 psi

Elongation at Break

17 to 22 %

Fatigue Strength

310 to 570 MPa 45 to 82 x 103 psi

Poisson's Ratio

0.29

Shear Modulus

73 GPa 11 x 106 psi

Shear Strength

410 to 630 MPa 60 to 91 x 103 psi

Tensile Strength: Ultimate (UTS)

650 to 1020 MPa 95 to 150 x 103 psi

Tensile Strength: Yield (Proof)

430 to 850 MPa 63 to 120 x 103 psi

Thermal Properties

Latent Heat of Fusion

250 J/g

Maximum Temperature: Mechanical

420 °C 790 °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

44 W/m-K 26 BTU/h-ft-°F

Thermal Expansion

13 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

7.3 % IACS

Electrical Conductivity: Equal Weight (Specific)

8.4 % IACS

Otherwise Unclassified Properties

Base Metal Price

2.4 % relative

Density

7.8 g/cm3 490 lb/ft3

Embodied Carbon

1.5 kg CO2/kg material

Embodied Energy

20 MJ/kg 8.6 x 103 BTU/lb

Embodied Water

51 L/kg 6.1 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

130 to 170 MJ/m3

Resilience: Unit (Modulus of Resilience)

500 to 1930 kJ/m3

Stiffness to Weight: Axial

13 points

Stiffness to Weight: Bending

24 points

Strength to Weight: Axial

23 to 36 points

Strength to Weight: Bending

21 to 29 points

Thermal Diffusivity

12 mm2/s

Thermal Shock Resistance

19 to 30 points

Alloy Composition

Among alloy steels, the composition of ASTM A372 grade J steel is notable for containing comparatively high amounts of chromium (Cr) and manganese (Mn). Chromium is used to improve corrosion resistance and most mechanical properties (particularly at higher temperatures). Manganese is used to improve hardenability, hot workability, and surface quality. There is some loss of ductility and weldability, however.

Iron (Fe) 96.7 to 97.8
Chromium (Cr) 0.8 to 1.2
Manganese (Mn) 0.75 to 1.1
Carbon (C) 0.35 to 0.5
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

Manufacture and Uses of Alloy Steels, Henry D. Hibbard, 2005

Steels: Processing, Structure, and Performance, 2nd ed., George Krauss, 2015