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Steel X65-MO vs X65-N

Steel · X65 temper comparison

X65-MO and X65-N are two conditions of the same steel grade, X65: MO (TMCP, offshore service) versus N (normalized). The chemistry is identical, so every difference below comes from the condition. Both yield at about 500 MPa — the mechanical properties are the same, and the difference is in how the stock is processed and what it is certified to (TMCP, offshore service versus normalized). X65-MO is the more ductile: elongation 32% versus 28% for X65-N.

X65-MOChoose it when the part is bent, formed or impact-loaded.

X65-MO vs X65-N: properties

X65-MOX65-N

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

580 MPa84.1 ksi
590 MPa85.6 ksi

Yield Strength (0.2% offset)

500 MPa72.5 ksi
485 MPa70.3 ksi

Elongation at Break

32%
28%

Reduction in Area

72%
68%

Compressive Strength

500 MPa72.5 ksi
495 MPa71.8 ksi

Shear Strength

355 MPa51.5 ksi
350 MPa50.8 ksi

Fracture Toughness (K_IC)

230 MPa·√m209 ksi·√in
200 MPa·√m182 ksi·√in

Charpy V-Notch Impact (RT)

280 J207 ft·lbf
160 J118 ft·lbf

Hardness, Brinell

182 HB
185 HB

Hardness, Rockwell B

90 HRB
89 HRB

Hardness, Vickers

192 HV
195 HV

Same in both: Elastic (Young's) Modulus 207 GPa30 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Fatigue Strength (Endurance Limit) 270 MPa39.2 ksi

Physical

Density and transition temperatures.

Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,425°C2,597 °F · Liquidus Temperature 1,505°C2,741 °F

Thermal

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

Min Service Temperature

-45°C-49 °F
-40°C-40 °F

Same in both: Thermal Conductivity 47 W/m·K27.2 BTU/hr·ft·°F · 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 · Latent Heat of Fusion 270 J/g116 BTU/lb · Max Service Temperature (continuous) 250°C482 °F

Electrical

Conductivity and insulation.

Same in both: Electrical Conductivity 8.6 % IACS · Electrical Resistivity 2×10⁻⁷ Ω·m7.87 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Same in both: Galvanic Potential (seawater, vs SCE) -0.68 V · Corrosion Resistance 12 / 100

Manufacturability

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

Machinability

54 / 100
57 / 100

Machinability Rating (AISI 1212 = 100 %)

58%
60%

Weldability

90 / 100
82 / 100

Formability (cold)

72 / 100
62 / 100

Same in both: Brazeability / Solderability 45 / 100 · Polishability 40 / 100

Sustainability

Primary-production footprint per kilogram.

Same in both: Embodied Energy (primary production) 25 MJ/kg10,748 BTU/lb · Embodied Carbon (primary production) 2 kg CO₂/kg · Embodied Water 40 L/kg4.8 gal/lb · Typical Recycled Content 20%

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 scaleX65

X65-MO vs X65-N — frequently asked

What is the difference between X65-MO and X65-N?

X65-MO and X65-N are two conditions of the same steel grade, X65: MO (TMCP, offshore service) versus N (normalized). The chemistry is identical, so every difference below comes from the condition. Both yield at about 500 MPa — the mechanical properties are the same, and the difference is in how the stock is processed and what it is certified to (TMCP, offshore service versus normalized).

Which condition does FabDigit quote by default, MO or N?

M is the default X65 condition in the FabDigit quote flow (neither MO nor N). 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 welds better, X65-MO or X65-N?

X65-MO. Its weldability rates excellent (90/100) against very good (82/100) for X65-N.

Ready to make it?

Upload a CAD file and FabDigit prices the part in X65-MO and X65-N 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.