Steel C25-IH vs C25 +QT
Steel · C25 temper comparison
C25-IH and C25 +QT are two conditions of the same steel grade, C25: IH (induction hardened) versus +QT (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. C25 +QT is the stronger of the two: yield strength 410 MPa (59.5 ksi) against 265 MPa (38.4 ksi) for C25-IH, about 55% more; tensile strength follows at 610 MPa (88.5 ksi) vs 440 MPa (63.8 ksi). C25-IH is harder — 390 HB against 180 HB for C25 +QT — which matters for wear surfaces and threads. C25 +QT runs hotter in service (400°C vs 200°C continuous). On the shop floor, C25 +QT machines more easily (good vs poor), C25 +QT welds better (very good vs fair), and C25 +QT forms better (fair vs not recommended).
C25-IHChoose it when surface hardness matters.
C25 +QTChoose it when strength drives the design, or when the part sees heat.
C25-IH vs C25 +QT: 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.
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: 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) 1,425°C2,597 °F · Liquidus Temperature 1,515°C2,759 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Max Service Temperature (continuous)
Same in both: Specific Heat Capacity 480 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.9 µm/m·K6.6 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
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.61 V · Corrosion Resistance 10 / 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 30 / 100 · Brazeability / Solderability 75 / 100 · Polishability 55 / 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 28%
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.
C25-IH vs C25 +QT — frequently asked
Is C25 +QT stronger than C25-IH?
Yes. C25 +QT has a typical yield strength of 410 MPa (59.5 ksi) against 265 MPa (38.4 ksi) for C25-IH — about 55% more. Tensile strength is 610 MPa (88.5 ksi) vs 440 MPa (63.8 ksi).
Which condition does FabDigit quote by default, IH or +QT?
+N is the default C25 condition in the FabDigit quote flow (neither IH nor +QT). 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, C25-IH or C25 +QT?
C25 +QT. Its machinability rates good (57/100) against poor (25/100) for C25-IH; for welding the order is C25 +QT first (very good, 75/100) then C25-IH (fair, 50/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in C25-IH and C25 +QT 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.