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Steel C60E +AC vs C60E +U

Steel · C60E temper comparison

C60E +AC and C60E +U are two conditions of the same steel grade, C60E: +AC (spheroidize annealed) versus +U (hot rolled). The chemistry is identical, so every difference below comes from the condition. C60E +U is the stronger of the two: yield strength 420 MPa (60.9 ksi) against 340 MPa (49.3 ksi) for C60E +AC, about 24% more; tensile strength follows at 780 MPa (113 ksi) vs 620 MPa (89.9 ksi). In exchange, C60E +AC is the more ductile: elongation 23% versus 13% for C60E +U, and C60E +U is harder (230 HB vs 185 HB). C60E +AC runs hotter in service (400°C vs 350°C continuous). On the shop floor, C60E +AC machines more easily (good vs fair).

C60E +ACChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.

C60E +UChoose it when strength drives the design.

C60E +AC vs C60E +U: properties

C60E +ACC60E +U

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

620 MPa89.9 ksi
780 MPa113 ksi

Yield Strength (0.2% offset)

340 MPa49.3 ksi
420 MPa60.9 ksi

Elongation at Break

23%
13%

Reduction in Area

45%
30%

Compressive Strength

350 MPa50.8 ksi
630 MPa91.4 ksi

Shear Strength

400 MPa58 ksi
600 MPa87 ksi

Fatigue Strength (Endurance Limit)

280 MPa40.6 ksi
330 MPa47.9 ksi

Fracture Toughness (K_IC)

60 MPa·√m54.6 ksi·√in
45 MPa·√m41 ksi·√in

Charpy V-Notch Impact (RT)

35 J25.8 ft·lbf
12 J8.9 ft·lbf

Hardness, Brinell

185 HB
230 HB

Hardness, Rockwell C

11 HRC
28 HRC

Hardness, Vickers

195 HV
285 HV

Same in both: Elastic (Young's) Modulus 210 GPa30.5 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29

Physical

Density and transition temperatures.

Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,420°C2,588 °F · Liquidus Temperature 1,480°C2,696 °F

Thermal

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

Thermal Conductivity

49 W/m·K28.3 BTU/hr·ft·°F
46 W/m·K26.6 BTU/hr·ft·°F

Max Service Temperature (continuous)

400°C752 °F
350°C662 °F

Same in both: Specific Heat Capacity 480 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.3 µm/m·K6.3 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -20°C-4 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

11 % IACS
10 % IACS

Electrical Resistivity

1.6×10⁻⁷ Ω·m6.3 µΩ·in
1.8×10⁻⁷ Ω·m7.09 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Same in both: Galvanic Potential (seawater, vs SCE) -0.62 V · Corrosion Resistance 10 / 100

Manufacturability

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

Machinability

55 / 100
45 / 100

Machinability Rating (AISI 1212 = 100 %)

65%
55%

Weldability

28 / 100
22 / 100

Formability (cold)

50 / 100
28 / 100

Same in both: Castability 45 / 100 · Brazeability / Solderability 55 / 100 · Polishability 65 / 100

Sustainability

Primary-production footprint per kilogram.

Same in both: Embodied Energy (primary production) 26 MJ/kg11,178 BTU/lb · Embodied Carbon (primary production) 2.1 kg CO₂/kg · Embodied Water 55 L/kg6.6 gal/lb · Typical Recycled Content 30%

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 scaleC60E

C60E +AC vs C60E +U — frequently asked

Is C60E +U stronger than C60E +AC?

Yes. C60E +U has a typical yield strength of 420 MPa (60.9 ksi) against 340 MPa (49.3 ksi) for C60E +AC — about 24% more. Tensile strength is 780 MPa (113 ksi) vs 620 MPa (89.9 ksi).

Which condition does FabDigit quote by default, +AC or +U?

+QT is the default C60E condition in the FabDigit quote flow (neither +AC nor +U). The other condition is available on request or by drawing note — specify it in the material field or the part notes and the quote is priced for it.

Which is easier to machine, C60E +AC or C60E +U?

C60E +AC. Its machinability rates good (55/100) against fair (45/100) for C60E +U; for welding the order is C60E +AC first (poor, 28/100) then C60E +U (poor, 22/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in C60E +AC and C60E +U 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.