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Steel A372 Grade M vs AR500

Steel · grade comparison

Steel A372 Grade M and AR500 are both steel grades. AR500 is the stronger of the two: yield strength 1,350 MPa (196 ksi) against 725 MPa (105 ksi) for A372 Grade M, about 86% more; tensile strength follows at 1,650 MPa (239 ksi) vs 860 MPa (125 ksi). In exchange, A372 Grade M is the more ductile: elongation 16% versus 9% for AR500, and AR500 is harder (500 HB vs 262 HB). A372 Grade M runs hotter in service (400°C vs 250°C continuous). On the shop floor, A372 Grade M machines more easily (fair vs not recommended), AR500 welds better (fair vs poor), and A372 Grade M sits in a lower cost tier (standard, $$) than AR500 (high, $$$$).

A372 Grade MChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.

AR500Choose it when strength drives the design, or when it will be welded.

A372 Grade M vs AR500: properties

A372 Grade MAR500

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

860 MPa125 ksi
1,650 MPa239 ksi

Yield Strength (0.2% offset)

725 MPa105 ksi
1,350 MPa196 ksi

Elongation at Break

16%
9%

Reduction in Area

45%
30%

Compressive Strength

725 MPa105 ksi
1,400 MPa203 ksi

Shear Strength

520 MPa75.4 ksi
1,000 MPa145 ksi

Fatigue Strength (Endurance Limit)

385 MPa55.8 ksi
700 MPa102 ksi

Fracture Toughness (K_IC)

100 MPa·√m91 ksi·√in
50 MPa·√m45.5 ksi·√in

Charpy V-Notch Impact (RT)

45 J33.2 ft·lbf
35 J25.8 ft·lbf

Hardness, Brinell

262 HB
500 HB

Hardness, Rockwell C

26 HRC
50 HRC

Hardness, Vickers

275 HV
525 HV

Same in both: Elastic (Young's) Modulus 205 GPa29.7 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29

Physical

Density and transition temperatures.

Melting Point (Solidus)

1,425°C2,597 °F
1,420°C2,588 °F

Liquidus Temperature

1,495°C2,723 °F
1,500°C2,732 °F

Same in both: Density 7.85 g/cm³0.28 lb/in³

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

42 W/m·K24.3 BTU/hr·ft·°F
40 W/m·K23.1 BTU/hr·ft·°F

Specific Heat Capacity

475 J/kg·K0.11 BTU/lb·°F
470 J/kg·K0.11 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

12.3 µm/m·K6.8 µin/in·°F
12 µm/m·K6.7 µin/in·°F

Max Service Temperature (continuous)

400°C752 °F
250°C482 °F

Min Service Temperature

-30°C-22 °F
-40°C-40 °F

Same in both: Latent Heat of Fusion 270 J/g116 BTU/lb

Electrical

Conductivity and insulation.

Electrical Conductivity

7.8 % IACS
7.5 % IACS

Electrical Resistivity

2.2×10⁻⁷ Ω·m8.66 µΩ·in
2.3×10⁻⁷ Ω·m9.06 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.61 V
-0.62 V

Corrosion Resistance

12 / 100
13 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

40 / 100
12 / 100

Machinability Rating (AISI 1212 = 100 %)

48%
10%

Weldability

28 / 100
45 / 100

Formability (cold)

20 / 100
15 / 100

Brazeability / Solderability

45 / 100
—

Polishability

60 / 100
55 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Carbon (primary production)

2.2 kg CO₂/kg
2.3 kg CO₂/kg

Embodied Water

60 L/kg7.2 gal/lb
55 L/kg6.6 gal/lb

Typical Recycled Content

30%
25%

Same in both: Embodied Energy (primary production) 30 MJ/kg12,898 BTU/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

110 kN·m/kg
210 kN·m/kg

Modulus of Resilience

1,282 kJ/m³
4,445 kJ/m³

Thermal Diffusivity

11.3 mm²/s
10.8 mm²/s

Thermal Shock Resistance Index

14
27

Same in both: Specific Stiffness (E / density) 26.1 MN·m/kg

Strength versus weight

Yield strength against density for every steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

2005001,0002,0007.588.5Density (g/cm³)Yield strength (MPa) — log scaleAR500A372 Grade M

Manufacturing and finishing

CapabilityA372 Grade MAR500
CNC machining—Yes
Sheet metal—Yes
Default condition—Q&T
Relative cost$$ Standard$$$$ High
Min. machined wall—0.8 mm
Best machined surface—Ra 1.6 µm
AlCrN—Yes
AlTiN—Yes
Black Oxide—Yes
CVD Al2O3—Yes
CVD TiCN—Yes
CVD TiN—Yes
Cerakote—Yes
Chrome Plating—Yes
CrN—Yes
DLC—Yes
E-Coating—Yes
HVOF Coating—Yes
Hot-Dip Galvanizing—Yes
MoS2—Yes
Multilayer CVD—Yes
Nickel Plating—Yes
PTFE Coating—Yes
Painting—Yes

They share 9 finishes: Copper Plating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Manganese Phosphate, Plasma Spray, Silver Plating, Zinc Phosphate.

A372 Grade M vs AR500 — frequently asked

Is AR500 stronger than A372 Grade M?

Yes. AR500 has a typical yield strength of 1,350 MPa (196 ksi) against 725 MPa (105 ksi) for A372 Grade M — about 86% more. Tensile strength is 1,650 MPa (239 ksi) vs 860 MPa (125 ksi).

Which is cheaper, A372 Grade M or AR500?

A372 Grade M is the lower-cost material: it sits in the standard tier ($$) while AR500 is high ($$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.

Which is easier to machine, A372 Grade M or AR500?

A372 Grade M. Its machinability rates fair (40/100) against not recommended (12/100) for AR500; for welding the order is AR500 first (fair, 45/100) then A372 Grade M (poor, 28/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in A372 Grade M and AR500 side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.

Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.