Steel A633 Grade C vs A656 Grade 80
Steel · grade comparison
Steel A633 Grade C and A656 Grade 80 are both steel grades. A656 Grade 80 is the stronger of the two: yield strength 590 MPa (85.6 ksi) against 385 MPa (55.8 ksi) for A633 Grade C, about 53% more; tensile strength follows at 680 MPa (98.6 ksi) vs 530 MPa (76.9 ksi). In exchange, A633 Grade C is the more ductile: elongation 25% versus 18% for A656 Grade 80, and A656 Grade 80 is harder (215 HB vs 160 HB). A633 Grade C runs hotter in service (400°C vs 350°C continuous). On the shop floor, A633 Grade C machines more easily (good vs fair) and A633 Grade C welds better (82 vs 72 out of 100).
A633 Grade CChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
A656 Grade 80Choose it when strength drives the design.
A633 Grade C vs A656 Grade 80: 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.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Hardness, Rockwell C
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 · Fracture Toughness (K_IC) 100 MPa·√m91 ksi·√in
Physical
Density and transition temperatures.
Melting Point (Solidus)
Liquidus Temperature
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
Max Service Temperature (continuous)
Min Service Temperature
Same in both: Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12 µm/m·K6.7 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.62 V · 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) 62 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
Same in both: Embodied Energy (primary production) 25 MJ/kg10,748 BTU/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) 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.
Manufacturing and finishing
| Capability | A633 Grade C | A656 Grade 80 |
|---|---|---|
| Default condition | — | — |
| Relative cost | $ Budget | $ Budget |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Both take the same 9 finishes: Copper Plating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Manganese Phosphate, Plasma Spray, Silver Plating, Zinc Phosphate.
A633 Grade C vs A656 Grade 80 — frequently asked
Is A656 Grade 80 stronger than A633 Grade C?
Yes. A656 Grade 80 has a typical yield strength of 590 MPa (85.6 ksi) against 385 MPa (55.8 ksi) for A633 Grade C — about 53% more. Tensile strength is 680 MPa (98.6 ksi) vs 530 MPa (76.9 ksi).
Which is cheaper, A633 Grade C or A656 Grade 80?
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, A633 Grade C or A656 Grade 80?
A633 Grade C. Its machinability rates good (58/100) against fair (48/100) for A656 Grade 80; for welding the order is A633 Grade C first (very good, 82/100) then A656 Grade 80 (very good, 72/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in A633 Grade C and A656 Grade 80 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.