Steel A572 Gr 42 vs A656
Steel · grade comparison
Steel A572 Gr 42 and A656 are both steel grades, both structural steel. A656 is the stronger of the two: yield strength 580 MPa (84.1 ksi) against 320 MPa (46.4 ksi) for A572 Gr 42, about 81% more; tensile strength follows at 660 MPa (95.7 ksi) vs 460 MPa (66.7 ksi). In exchange, A572 Gr 42 is the more ductile: elongation 26% versus 16% for A656, and A656 is harder (215 HB vs 140 HB). A572 Gr 42 runs hotter in service (400°C vs 350°C continuous) and A572 Gr 42 conducts electricity better (10 % IACS vs 9 % IACS). On the shop floor, A572 Gr 42 welds better (excellent vs very good).
A572 Gr 42Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
A656Choose it when strength drives the design.
A572 Gr 42 vs A656: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Shear Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Hardness, Rockwell C
Same in both: Elastic (Young's) Modulus 200 GPa29 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Reduction in Area 50%
Physical
Density and transition temperatures.
Melting Point (Solidus)
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Liquidus Temperature 1,510°C2,750 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Min Service Temperature
Same in both: Latent Heat of Fusion 270 J/g116 BTU/lb
Electrical
Conductivity and insulation.
Electrical Conductivity
Same in both: Electrical Resistivity 1.9×10⁻⁷ Ω·m7.48 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Galvanic Potential (seawater, vs SCE)
Same in both: Corrosion Resistance 12 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Brazeability / Solderability
Polishability
Same in both: Formability (cold) 65 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Typical Recycled Content
Same in both: Embodied Carbon (primary production) 2 kg CO₂/kg · Embodied Water 40 L/kg4.8 gal/lb
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
Same in both: Specific Stiffness (E / density) 25.5 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.
Manufacturing and finishing
| Capability | A572 Gr 42 | A656 |
|---|---|---|
| Default condition | HR | HR |
| Relative cost | $ Budget | $ Budget |
| Min. machined wall | 0.8 mm | 0.8 mm |
| Best machined surface | Ra 1.6 µm | Ra 1.6 µm |
Both are offered for CNC machining and Sheet metal. Both take the same 38 finishes: AlCrN, AlTiN, Black Oxide, CVD Al2O3, CVD TiCN, CVD TiN, Cerakote, Chrome Plating, Copper Plating, CrN, DLC, E-Coating and 26 more.
A572 Gr 42 vs A656 — frequently asked
Is A656 stronger than A572 Gr 42?
Yes. A656 has a typical yield strength of 580 MPa (84.1 ksi) against 320 MPa (46.4 ksi) for A572 Gr 42 — about 81% more. Tensile strength is 660 MPa (95.7 ksi) vs 460 MPa (66.7 ksi).
Which is cheaper, A572 Gr 42 or A656?
Both sit in the same relative cost tier ($, budget); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which is easier to machine, A572 Gr 42 or A656?
A572 Gr 42. Its machinability rates good (58/100) against fair (50/100) for A656; for welding the order is A572 Gr 42 first (excellent, 85/100) then A656 (very good, 75/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in A572 Gr 42 and A656 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.