Steel G18Mo5-F vs G18Mo5-SR
Steel · G18Mo5 temper comparison
G18Mo5-F and G18Mo5-SR are two conditions of the same steel grade, G18Mo5: F (as fabricated) versus SR (stress relieved). The chemistry is identical, so every difference below comes from the condition. G18Mo5-SR is the stronger of the two: yield strength 275 MPa (39.9 ksi) against 260 MPa (37.7 ksi) for G18Mo5-F, about 6% more. G18Mo5-SR is the more ductile: elongation 26% versus 16% for G18Mo5-F, and G18Mo5-F is harder (150 HB vs 140 HB). G18Mo5-SR runs hotter in service (480°C vs 400°C continuous).
G18Mo5-SRChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.
G18Mo5-F vs G18Mo5-SR: 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
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, Vickers
Same in both: Shear Modulus 81 GPa11.7 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) 1,425°C2,597 °F · Liquidus Temperature 1,505°C2,741 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 42 W/m·K24.3 BTU/hr·ft·°F · Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12.2 µm/m·K6.8 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -10°C14 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.62 V · Corrosion Resistance 12 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Same in both: Castability 70 / 100 · Brazeability / Solderability 45 / 100 · Polishability 45 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 28 MJ/kg12,038 BTU/lb · Embodied Carbon (primary production) 2.2 kg CO₂/kg · Embodied Water 60 L/kg7.2 gal/lb · Typical Recycled Content 70%
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.
G18Mo5-F vs G18Mo5-SR — frequently asked
Is G18Mo5-SR stronger than G18Mo5-F?
Yes. G18Mo5-SR has a typical yield strength of 275 MPa (39.9 ksi) against 260 MPa (37.7 ksi) for G18Mo5-F — about 6% more. Tensile strength is 490 MPa (71.1 ksi) vs 480 MPa (69.6 ksi).
Which condition does FabDigit quote by default, F or SR?
N+T is the default G18Mo5 condition in the FabDigit quote flow (neither F nor SR). 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, G18Mo5-F or G18Mo5-SR?
G18Mo5-SR. Its machinability rates good (60/100) against fair (52/100) for G18Mo5-F; for welding the order is G18Mo5-SR first (very good, 74/100) then G18Mo5-F (good, 65/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in G18Mo5-F and G18Mo5-SR 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.