Steel 42CrMo-HR vs 42CrMo Q&T
Steel · 42CrMo temper comparison
42CrMo-HR and 42CrMo Q&T are two conditions of the same steel grade, 42CrMo: HR (hot rolled) versus Q&T (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. 42CrMo Q&T is the stronger of the two: yield strength 960 MPa (139 ksi) against 570 MPa (82.7 ksi) for 42CrMo-HR, about 68% more; tensile strength follows at 1,120 MPa (162 ksi) vs 880 MPa (128 ksi). 42CrMo Q&T is harder — 340 HB against 240 HB for 42CrMo-HR — which matters for wear surfaces and threads. On the shop floor, 42CrMo-HR machines more easily (50 vs 38 out of 100) and 42CrMo-HR forms better (poor vs not recommended).
42CrMo-HRChoose it when the part is machined in volume.
42CrMo Q&TChoose it when strength drives the design, or when surface hardness matters.
42CrMo-HR vs 42CrMo Q&T: 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
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell C
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) 1,416°C2,581 °F · Liquidus Temperature 1,495°C2,723 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 42.6 W/m·K24.6 BTU/hr·ft·°F · Specific Heat Capacity 473 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12.3 µm/m·K6.8 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) -0.61 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: Brazeability / Solderability 55 / 100 · Polishability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 29 MJ/kg12,468 BTU/lb · Embodied Carbon (primary production) 2.3 kg CO₂/kg · Embodied Water 45 L/kg5.4 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.
42CrMo-HR vs 42CrMo Q&T — frequently asked
Is 42CrMo Q&T stronger than 42CrMo-HR?
Yes. 42CrMo Q&T has a typical yield strength of 960 MPa (139 ksi) against 570 MPa (82.7 ksi) for 42CrMo-HR — about 68% more. Tensile strength is 1,120 MPa (162 ksi) vs 880 MPa (128 ksi).
Which condition does FabDigit quote by default, HR or Q&T?
HR is the default 42CrMo 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, 42CrMo-HR or 42CrMo Q&T?
42CrMo-HR, by a small margin. Both rate fair for machinability — 50/100 against 38/100 for 42CrMo Q&T; for welding the order is 42CrMo-HR first (poor, 30/100) then 42CrMo Q&T (poor, 25/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 42CrMo-HR and 42CrMo Q&T 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.