Steel ER312 vs ER70S-3
Steel · grade comparison
Steel ER312 and ER70S-3 are both steel grades. ER312 is the stronger of the two: yield strength 570 MPa (82.7 ksi) against 460 MPa (66.7 ksi) for ER70S-3, about 24% more; tensile strength follows at 780 MPa (113 ksi) vs 550 MPa (79.8 ksi). In exchange, ER70S-3 is the more ductile: elongation 28% versus 25% for ER312, and ER312 is harder (250 HB vs 160 HB). ER70S-3 runs hotter in service (400°C vs 315°C continuous) and ER70S-3 conducts heat better (48 W/m·K vs 16 W/m·K). On the shop floor, ER70S-3 machines more easily (good vs poor) and ER70S-3 sits in a lower cost tier (budget, $) than ER312 (high, $$$$).
ER312Choose it when strength drives the design.
ER70S-3Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
ER312 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.
Elastic (Young's) Modulus
Shear Modulus
Bulk Modulus
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 B
Hardness, Rockwell C
Hardness, Vickers
Same in both: 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
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Latent Heat of Fusion
Max Service Temperature (continuous)
Same in both: Min Service Temperature -30°C-22 °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
Castability
Same in both: Polishability 55 / 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)
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 | ER312 | ER70S-3 |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$$ High | $ Budget |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Both take the same 9 finishes: Copper Plating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Manganese Phosphate, Plasma Spray, Silver Plating, Zinc Phosphate.
ER312 vs ER70S-3 — frequently asked
Is ER312 stronger than ER70S-3?
Yes. ER312 has a typical yield strength of 570 MPa (82.7 ksi) against 460 MPa (66.7 ksi) for ER70S-3 — about 24% more. Tensile strength is 780 MPa (113 ksi) vs 550 MPa (79.8 ksi).
Which is cheaper, ER312 or ER70S-3?
ER70S-3 is the lower-cost material: it sits in the budget tier ($) while ER312 is high ($$$$). 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, ER312 or ER70S-3?
ER70S-3. Its machinability rates good (58/100) against poor (25/100) for ER312; for welding the order is ER70S-3 first (excellent, 95/100) then ER312 (excellent, 90/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in ER312 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.