ASTM A302 Grade A Mn-Mo Steel
ASTM A302 grade A is a type of ASTM A302 alloy steel. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. It has the lowest strength compared to the other variants of ASTM A302 alloy steel.
The graph bars on the material properties cards below compare ASTM A302 grade A 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
180
Elastic (Young's, Tensile) Modulus
190 GPa 27 x 106 psi
Elongation at Break
22 %
Fatigue Strength
250 MPa 36 x 103 psi
Poisson's Ratio
0.29
Shear Modulus
73 GPa 11 x 106 psi
Shear Strength
370 MPa 53 x 103 psi
Tensile Strength: Ultimate (UTS)
590 MPa 85 x 103 psi
Tensile Strength: Yield (Proof)
350 MPa 51 x 103 psi
Thermal Properties
Latent Heat of Fusion
250 J/g
Maximum Temperature: Mechanical
410 °C 760 °F
Melting Completion (Liquidus)
1460 °C 2670 °F
Melting Onset (Solidus)
1420 °C 2590 °F
Specific Heat Capacity
470 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
51 W/m-K 30 BTU/h-ft-°F
Thermal Expansion
13 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
7.2 % IACS
Electrical Conductivity: Equal Weight (Specific)
8.2 % IACS
Otherwise Unclassified Properties
Base Metal Price
2.4 % relative
Density
7.9 g/cm3 490 lb/ft3
Embodied Carbon
1.5 kg CO2/kg material
Embodied Energy
20 MJ/kg 8.7 x 103 BTU/lb
Embodied Water
48 L/kg 5.8 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
110 MJ/m3
Resilience: Unit (Modulus of Resilience)
330 kJ/m3
Stiffness to Weight: Axial
13 points
Stiffness to Weight: Bending
24 points
Strength to Weight: Axial
21 points
Strength to Weight: Bending
20 points
Thermal Diffusivity
14 mm2/s
Thermal Shock Resistance
17 points
Alloy Composition
| Fe | 97.4 to 98.5 | |
| Mn | 1.0 to 1.3 | |
| Mo | 0.45 to 0.6 | |
| Si | 0.15 to 0.4 | |
| C | 0 to 0.25 | |
| P | 0 to 0.035 | |
| S | 0 to 0.035 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM A302: Standard Specification for Pressure Vessel Plates, Alloy Steel, Manganese-Molybdenum and Manganese-Molybdenum-Nickel
Pressure Vessels: External Pressure Technology, 2nd ed., Carl T. F. Ross, 2011
Properties and Selection: Irons, Steels and High Performance Alloys, ASM Handbook vol. 1, ASM International, 1993
Manufacture and Uses of Alloy Steels, Henry D. Hibbard, 2005
Ferrous Materials: Steel and Cast Iron, Hans Berns and Werner Theisen, 2008
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