Steel 20NiCrMo7-CH vs 20NiCrMo7 +S
Steel · 20NiCrMo7 temper comparison
20NiCrMo7-CH and 20NiCrMo7 +S are two conditions of the same steel grade, 20NiCrMo7: CH (carburized and hardened) versus +S (treated for high shearability). The chemistry is identical, so every difference below comes from the condition. 20NiCrMo7-CH is the stronger of the two: yield strength 950 MPa (138 ksi) against 390 MPa (56.6 ksi) for 20NiCrMo7 +S, about 144% more; tensile strength follows at 1,250 MPa (181 ksi) vs 600 MPa (87 ksi). In exchange, 20NiCrMo7 +S is the more ductile: elongation 21% versus 10% for 20NiCrMo7-CH, and 20NiCrMo7-CH is harder (380 HB vs 178 HB). 20NiCrMo7 +S runs hotter in service (350°C vs 180°C continuous). On the shop floor, 20NiCrMo7 +S machines more easily (good vs not recommended) and 20NiCrMo7 +S welds better (fair vs not recommended).
20NiCrMo7-CHChoose it when strength drives the design.
20NiCrMo7 +SChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
20NiCrMo7-CH vs 20NiCrMo7 +S: 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) 1,420°C2,588 °F · Liquidus Temperature 1,495°C2,723 °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 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.7 µm/m·K6.5 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -40°C-40 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 8 % IACS · Electrical Resistivity 2.2×10⁻⁷ Ω·m8.66 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V · Corrosion Resistance 11 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Formability (cold)
Polishability
Same in both: Machinability Rating (AISI 1212 = 100 %) 60% · Brazeability / Solderability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 34 MJ/kg14,617 BTU/lb · Embodied Carbon (primary production) 2.3 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.
20NiCrMo7-CH vs 20NiCrMo7 +S — frequently asked
Is 20NiCrMo7-CH stronger than 20NiCrMo7 +S?
Yes. 20NiCrMo7-CH has a typical yield strength of 950 MPa (138 ksi) against 390 MPa (56.6 ksi) for 20NiCrMo7 +S — about 144% more. Tensile strength is 1,250 MPa (181 ksi) vs 600 MPa (87 ksi).
Which condition does FabDigit quote by default, CH or +S?
+A is the default 20NiCrMo7 condition in the FabDigit quote flow (neither CH nor +S). 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, 20NiCrMo7-CH or 20NiCrMo7 +S?
20NiCrMo7 +S. Its machinability rates good (55/100) against not recommended (12/100) for 20NiCrMo7-CH; for welding the order is 20NiCrMo7 +S first (fair, 46/100) then 20NiCrMo7-CH (not recommended, 10/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 20NiCrMo7-CH and 20NiCrMo7 +S 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.