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Steel E120C-K4 vs ER70S-6

Steel · grade comparison

Steel E120C-K4 and ER70S-6 are both steel grades. E120C-K4 is the stronger of the two: yield strength 800 MPa (116 ksi) against 460 MPa (66.7 ksi) for ER70S-6, about 74% more; tensile strength follows at 880 MPa (128 ksi) vs 560 MPa (81.2 ksi). In exchange, ER70S-6 is the more ductile: elongation 27% versus 17% for E120C-K4, and E120C-K4 is harder (270 HB vs 160 HB). ER70S-6 conducts heat better (49 W/m·K vs 40 W/m·K). On the shop floor, ER70S-6 machines more easily (good vs fair), ER70S-6 welds better (excellent vs very good), and ER70S-6 sits in a lower cost tier (budget, $) than E120C-K4 (premium, $$$).

E120C-K4Choose it when strength drives the design.

ER70S-6Choose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.

E120C-K4 vs ER70S-6: properties

E120C-K4ER70S-6

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

880 MPa128 ksi
560 MPa81.2 ksi

Yield Strength (0.2% offset)

800 MPa116 ksi
460 MPa66.7 ksi

Elongation at Break

17%
27%

Reduction in Area

55%
65%

Shear Strength

530 MPa76.9 ksi
340 MPa49.3 ksi

Fatigue Strength (Endurance Limit)

370 MPa53.7 ksi
240 MPa34.8 ksi

Charpy V-Notch Impact (RT)

70 J51.6 ft·lbf
130 J95.9 ft·lbf

Hardness, Brinell

270 HB
160 HB

Hardness, Rockwell C

27 HRC
—

Hardness, Vickers

285 HV
170 HV

Compressive Strength

—
460 MPa66.7 ksi

Fracture Toughness (K_IC)

—
120 MPa·√m109 ksi·√in

Hardness, Rockwell B

—
84 HRB

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

Physical

Density and transition temperatures.

Density

7.8 g/cm³0.28 lb/in³
7.85 g/cm³0.28 lb/in³

Melting Point (Solidus)

1,425°C2,597 °F
1,470°C2,678 °F

Liquidus Temperature

1,500°C2,732 °F
1,520°C2,768 °F

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

40 W/m·K23.1 BTU/hr·ft·°F
49 W/m·K28.3 BTU/hr·ft·°F

Specific Heat Capacity

470 J/kg·K0.11 BTU/lb·°F
480 J/kg·K0.11 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

12.3 µm/m·K6.8 µin/in·°F
12 µm/m·K6.7 µin/in·°F

Latent Heat of Fusion

250 J/g107 BTU/lb
270 J/g116 BTU/lb

Min Service Temperature

-51°C-60 °F
-30°C-22 °F

Same in both: Max Service Temperature (continuous) 400°C752 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

2.4×10⁻⁷ Ω·m9.45 µΩ·in
1.6×10⁻⁷ Ω·m6.3 µΩ·in

Electrical Conductivity

—
10.5 % IACS

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

14 / 100
10 / 100

Galvanic Potential (seawater, vs SCE)

—
-0.65 V

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

35 / 100
58 / 100

Machinability Rating (AISI 1212 = 100 %)

40%
65%

Weldability

80 / 100
95 / 100

Formability (cold)

25 / 100
60 / 100

Polishability

55 / 100
45 / 100

Brazeability / Solderability

—
65 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

32 MJ/kg13,758 BTU/lb
28 MJ/kg12,038 BTU/lb

Embodied Carbon (primary production)

2.5 kg CO₂/kg
2.1 kg CO₂/kg

Embodied Water

60 L/kg7.2 gal/lb
45 L/kg5.4 gal/lb

Typical Recycled Content

40%
25%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

113 kN·m/kg
71 kN·m/kg

Specific Stiffness (E / density)

26.3 MN·m/kg
26.1 MN·m/kg

Modulus of Resilience

1,561 kJ/m³
516 kJ/m³

Thermal Diffusivity

10.9 mm²/s
13 mm²/s

Thermal Shock Resistance Index

14
11

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.

2005001,0002,0007.588.5Density (g/cm³)Yield strength (MPa) — log scaleER70S-6E120C-K4

Manufacturing and finishing

CapabilityE120C-K4ER70S-6
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.

E120C-K4 vs ER70S-6 — frequently asked

Is E120C-K4 stronger than ER70S-6?

Yes. E120C-K4 has a typical yield strength of 800 MPa (116 ksi) against 460 MPa (66.7 ksi) for ER70S-6 — about 74% more. Tensile strength is 880 MPa (128 ksi) vs 560 MPa (81.2 ksi).

Which is cheaper, E120C-K4 or ER70S-6?

ER70S-6 is the lower-cost material: it sits in the budget tier ($) while E120C-K4 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, E120C-K4 or ER70S-6?

ER70S-6. Its machinability rates good (58/100) against fair (35/100) for E120C-K4; for welding the order is ER70S-6 first (excellent, 95/100) then E120C-K4 (very good, 80/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in E120C-K4 and ER70S-6 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.