Steel 20MoCr4 CH-QT vs 20MoCr4 +U
Steel · 20MoCr4 temper comparison
20MoCr4 CH-QT and 20MoCr4 +U are two conditions of the same steel grade, 20MoCr4: CH-QT (carburized, direct/reheat quenched and low-temperature tempered) versus +U (hot rolled). The chemistry is identical, so every difference below comes from the condition. 20MoCr4 CH-QT is the stronger of the two: yield strength 680 MPa (98.6 ksi) against 450 MPa (65.3 ksi) for 20MoCr4 +U, about 51% more; tensile strength follows at 950 MPa (138 ksi) vs 700 MPa (102 ksi). In exchange, 20MoCr4 +U is the more ductile: elongation 16% versus 11% for 20MoCr4 CH-QT, and 20MoCr4 CH-QT is harder (300 HB vs 215 HB). 20MoCr4 +U runs hotter in service (300°C vs 180°C continuous). On the shop floor, 20MoCr4 +U machines more easily (fair vs poor) and 20MoCr4 +U welds better (fair vs poor).
20MoCr4 CH-QTChoose it when strength drives the design.
20MoCr4 +UChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
20MoCr4 CH-QT vs 20MoCr4 +U: 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
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
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 · Reduction in Area 45% · Charpy V-Notch Impact (RT) 45 J33.2 ft·lbf
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 1,500°C2,732 °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 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.5 µm/m·K6.4 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -40°C-40 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 7.8 % 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
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Polishability
Same in both: Castability 20 / 100 · Brazeability / Solderability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 33 MJ/kg14,187 BTU/lb · Embodied Carbon (primary production) 2.2 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.
20MoCr4 CH-QT vs 20MoCr4 +U — frequently asked
Is 20MoCr4 CH-QT stronger than 20MoCr4 +U?
Yes. 20MoCr4 CH-QT has a typical yield strength of 680 MPa (98.6 ksi) against 450 MPa (65.3 ksi) for 20MoCr4 +U — about 51% more. Tensile strength is 950 MPa (138 ksi) vs 700 MPa (102 ksi).
Which condition does FabDigit quote by default, CH-QT or +U?
+AC is the default 20MoCr4 condition in the FabDigit quote flow (neither CH-QT nor +U). 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, 20MoCr4 CH-QT or 20MoCr4 +U?
20MoCr4 +U. Its machinability rates fair (52/100) against poor (15/100) for 20MoCr4 CH-QT; for welding the order is 20MoCr4 +U first (fair, 50/100) then 20MoCr4 CH-QT (poor, 15/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 20MoCr4 CH-QT and 20MoCr4 +U 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.