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Steel FB780-CR vs FB780 TMCP

Steel · FB780 temper comparison

FB780-CR and FB780 TMCP are two conditions of the same steel grade, FB780: CR (cold rolled) versus TMCP (thermomechanically controlled processed). The chemistry is identical, so every difference below comes from the condition. Both yield at about 685 MPa — the mechanical properties are the same, and the difference is in how the stock is processed and what it is certified to (cold rolled versus thermomechanically controlled processed). FB780 TMCP is the more ductile: elongation 15% versus 12% for FB780-CR. FB780 TMCP runs hotter in service (400°C vs 300°C continuous).

FB780 TMCPChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.

FB780-CR vs FB780 TMCP: properties

FB780-CRFB780 TMCP

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

835 MPa121 ksi
810 MPa117 ksi

Yield Strength (0.2% offset)

685 MPa99.4 ksi
700 MPa102 ksi

Elongation at Break

12%
15%

Reduction in Area

44%
52%

Shear Strength

510 MPa74 ksi
495 MPa71.8 ksi

Fatigue Strength (Endurance Limit)

405 MPa58.7 ksi
395 MPa57.3 ksi

Fracture Toughness (K_IC)

100 MPa·√m91 ksi·√in
115 MPa·√m105 ksi·√in

Charpy V-Notch Impact (RT)

50 J36.9 ft·lbf
85 J62.7 ft·lbf

Hardness, Brinell

250 HB
240 HB

Hardness, Rockwell B

100 HRB
98 HRB

Hardness, Vickers

263 HV
252 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) 1,495°C2,723 °F · Liquidus Temperature 1,520°C2,768 °F

Thermal

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

Thermal Conductivity

42 W/m·K24.3 BTU/hr·ft·°F
44 W/m·K25.4 BTU/hr·ft·°F

Max Service Temperature (continuous)

300°C572 °F
400°C752 °F

Min Service Temperature

-40°C-40 °F
-60°C-76 °F

Same in both: Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12.5 µm/m·K6.9 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb

Electrical

Conductivity and insulation.

Electrical Conductivity

8.2 % IACS
8.5 % IACS

Electrical Resistivity

2.1×10⁻⁷ Ω·m8.27 µΩ·in
2.03×10⁻⁷ Ω·m7.99 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Same in both: Galvanic Potential (seawater, vs SCE) -0.65 V · Corrosion Resistance 12 / 100

Manufacturability

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

Machinability

40 / 100
43 / 100

Machinability Rating (AISI 1212 = 100 %)

48%
52%

Weldability

78 / 100
80 / 100

Formability (cold)

57 / 100
52 / 100

Polishability

55 / 100
45 / 100

Same in both: Brazeability / Solderability 50 / 100

Sustainability

Primary-production footprint per kilogram.

Same in both: Embodied Energy (primary production) 27 MJ/kg11,608 BTU/lb · Embodied Carbon (primary production) 2.1 kg CO₂/kg · Embodied Water 40 L/kg4.8 gal/lb · Typical Recycled Content 25%

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 scaleFB780

FB780-CR vs FB780 TMCP — frequently asked

What is the difference between FB780-CR and FB780 TMCP?

FB780-CR and FB780 TMCP are two conditions of the same steel grade, FB780: CR (cold rolled) versus TMCP (thermomechanically controlled processed). The chemistry is identical, so every difference below comes from the condition. Both yield at about 685 MPa — the mechanical properties are the same, and the difference is in how the stock is processed and what it is certified to (cold rolled versus thermomechanically controlled processed).

Which condition does FabDigit quote by default, CR or TMCP?

HR is the default FB780 condition in the FabDigit quote flow (neither CR nor TMCP). 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.

When should I choose FB780-CR over FB780 TMCP?

Pick FB780 TMCP when the part is bent, formed or impact-loaded, or when the part sees heat.

Ready to make it?

Upload a CAD file and FabDigit prices the part in FB780-CR and FB780 TMCP 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.