Steel P4-ANN vs P4 CARB-HT
Steel · P4 temper comparison
P4-ANN and P4 CARB-HT are two conditions of the same steel grade, P4: ANN (annealed) versus CARB-HT (carburized, hardened & tempered). The chemistry is identical, so every difference below comes from the condition. P4 CARB-HT is the stronger of the two: yield strength 1,150 MPa (167 ksi) against 300 MPa (43.5 ksi) for P4-ANN, about 3.8 times as much; tensile strength follows at 1,400 MPa (203 ksi) vs 500 MPa (72.5 ksi). In exchange, P4-ANN is the more ductile: elongation 25% versus 8% for P4 CARB-HT, and P4 CARB-HT is harder (730 HV vs 128 HV). P4-ANN runs hotter in service (400°C vs 200°C continuous). On the shop floor, P4-ANN machines more easily (good vs not recommended) and P4-ANN welds better (fair vs poor).
P4-ANNChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
P4 CARB-HTChoose it when strength drives the design.
P4-ANN vs P4 CARB-HT: 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)
Charpy V-Notch Impact (RT)
Hardness, Vickers
Same in both: Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Hardness, Brinell 122 HB · Hardness, Rockwell B 69 HRB
Physical
Density and transition temperatures.
Same in both: Density 7.8 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,420°C2,588 °F · Liquidus Temperature 1,490°C2,714 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 26 W/m·K15 BTU/hr·ft·°F · Specific Heat Capacity 460 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 250 J/g107 BTU/lb · Min Service Temperature -30°C-22 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 2.9 % IACS · Electrical Resistivity 6×10⁻⁷ Ω·m23.6 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Polishability
Same in both: Castability 30 / 100 · Brazeability / Solderability 50 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 32 MJ/kg13,758 BTU/lb · Embodied Carbon (primary production) 2.4 kg CO₂/kg · Embodied Water 60 L/kg7.2 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.
P4-ANN vs P4 CARB-HT — frequently asked
Is P4 CARB-HT stronger than P4-ANN?
Yes. P4 CARB-HT has a typical yield strength of 1,150 MPa (167 ksi) against 300 MPa (43.5 ksi) for P4-ANN — about 3.8 times as much. Tensile strength is 1,400 MPa (203 ksi) vs 500 MPa (72.5 ksi).
Which condition does FabDigit quote by default, ANN or CARB-HT?
ANN is the default P4 condition in the FabDigit quote flow. 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, P4-ANN or P4 CARB-HT?
P4-ANN. Its machinability rates good (60/100) against not recommended (12/100) for P4 CARB-HT; for welding the order is P4-ANN first (fair, 45/100) then P4 CARB-HT (poor, 15/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in P4-ANN and P4 CARB-HT 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.