Steel ER120S-1 vs ER70S-3
Steel · grade comparison
Steel ER120S-1 and ER70S-3 are both steel grades. ER120S-1 is the stronger of the two: yield strength 810 MPa (117 ksi) against 460 MPa (66.7 ksi) for ER70S-3, about 76% more; tensile strength follows at 880 MPa (128 ksi) vs 550 MPa (79.8 ksi). In exchange, ER70S-3 is the more ductile: elongation 28% versus 18% for ER120S-1, and ER120S-1 is harder (270 HB vs 160 HB). ER70S-3 conducts heat better (48 W/m·K vs 38 W/m·K). On the shop floor, ER70S-3 machines more easily (good vs fair), ER70S-3 welds better (excellent vs good), and ER70S-3 sits in a lower cost tier (budget, $) than ER120S-1 (premium, $$$).
ER120S-1Choose it when strength drives the design.
ER70S-3Choose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
ER120S-1 vs ER70S-3: 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)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell C
Hardness, Vickers
Hardness, Rockwell B
Same in both: Elastic (Young's) Modulus 205 GPa29.7 Msi · Shear Modulus 79 GPa11.5 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Liquidus Temperature
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Latent Heat of Fusion
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 · Max Service Temperature (continuous) 400°C752 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Galvanic Potential (seawater, vs SCE)
Corrosion Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Brazeability / Solderability
Polishability
Castability
Sustainability
Primary-production footprint per kilogram.
Embodied Water
Same in both: Embodied Energy (primary production) 32 MJ/kg13,758 BTU/lb · Embodied Carbon (primary production) 2.4 kg CO₂/kg · Typical Recycled Content 25%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
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 | ER120S-1 | ER70S-3 |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$ Premium | $ 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.
ER120S-1 vs ER70S-3 — frequently asked
Is ER120S-1 stronger than ER70S-3?
Yes. ER120S-1 has a typical yield strength of 810 MPa (117 ksi) against 460 MPa (66.7 ksi) for ER70S-3 — about 76% more. Tensile strength is 880 MPa (128 ksi) vs 550 MPa (79.8 ksi).
Which is cheaper, ER120S-1 or ER70S-3?
ER70S-3 is the lower-cost material: it sits in the budget tier ($) while ER120S-1 is premium ($$$). 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, ER120S-1 or ER70S-3?
ER70S-3. Its machinability rates good (58/100) against fair (35/100) for ER120S-1; for welding the order is ER70S-3 first (excellent, 95/100) then ER120S-1 (good, 65/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in ER120S-1 and ER70S-3 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.