Steel A48 Class 20 vs A48 Class 40
Steel · grade comparison
Steel A48 Class 20 and A48 Class 40 are both steel grades. A48 Class 40 is the stronger of the two: tensile strength 293 MPa (42.5 ksi) against 152 MPa (22 ksi) for A48 Class 20, about 93% more. A48 Class 40 is the more ductile: elongation 0.6% versus 0.5% for A48 Class 20, and A48 Class 40 is harder (235 HB vs 156 HB). A48 Class 40 is stiffer (125 GPa vs 80 GPa) and A48 Class 40 runs hotter in service (400°C vs 350°C continuous). On the shop floor, A48 Class 20 machines more easily (excellent vs good).
A48 Class 20Choose it when the part is machined in volume.
A48 Class 40Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.
A48 Class 20 vs A48 Class 40: 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.
Elastic (Young's) Modulus
Shear Modulus
Bulk Modulus
Tensile Strength (Ultimate)
Elongation at Break
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Yield Strength (0.2% offset)
Charpy V-Notch Impact (RT)
Same in both: Poisson's Ratio 0.26
Physical
Density and transition temperatures.
Density
Liquidus Temperature
Same in both: Melting Point (Solidus) 1,150°C2,102 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Same in both: Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Latent Heat of Fusion 220 J/g94.6 BTU/lb · Min Service Temperature -30°C-22 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 2.2 % IACS · Electrical Resistivity 8×10⁻⁷ Ω·m31.5 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.61 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Castability
Brazeability / Solderability
Polishability
Same in both: Formability (cold) 3 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Thermal Diffusivity
Same in both: Thermal Shock Resistance Index 9
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 | A48 Class 20 | A48 Class 40 |
|---|---|---|
| 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.
A48 Class 20 vs A48 Class 40 — frequently asked
Is A48 Class 40 stronger than A48 Class 20?
Yes. A48 Class 40 has a typical tensile strength of 293 MPa (42.5 ksi) against 152 MPa (22 ksi) for A48 Class 20 — about 93% more.
Which is cheaper, A48 Class 20 or A48 Class 40?
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, A48 Class 20 or A48 Class 40?
A48 Class 20. Its machinability rates excellent (90/100) against good (65/100) for A48 Class 40; for welding the order is A48 Class 20 first (poor, 25/100) then A48 Class 40 (poor, 20/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in A48 Class 20 and A48 Class 40 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.