Steel 4350-CR vs 4350 Q&T
Steel · 4350 temper comparison
4350-CR and 4350 Q&T are two conditions of the same steel grade, 4350: CR (cold rolled) versus Q&T (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. 4350 Q&T is the stronger of the two: yield strength 1,550 MPa (225 ksi) against 930 MPa (135 ksi) for 4350-CR, about 67% more; tensile strength follows at 1,800 MPa (261 ksi) vs 1,080 MPa (157 ksi). 4350 Q&T is harder — 500 HB against 320 HB for 4350-CR — which matters for wear surfaces and threads. 4350-CR runs hotter in service (350°C vs 200°C continuous). On the shop floor, 4350-CR machines more easily (fair vs poor).
4350-CRChoose it when the part sees heat, or when the part is machined in volume.
4350 Q&TChoose it when strength drives the design, or when surface hardness matters.
4350-CR vs 4350 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)
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell C
Same in both: Elastic (Young's) Modulus 205 GPa29.7 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Elongation at Break 8% · Reduction in Area 25%
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 1,480°C2,696 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 42 W/m·K24.3 BTU/hr·ft·°F · Specific Heat Capacity 475 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 270 J/g116 BTU/lb · Min Service Temperature -40°C-40 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Resistivity 2.5×10⁻⁷ Ω·m9.84 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: 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 45 / 100 · Polishability 70 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 30 MJ/kg12,898 BTU/lb · Embodied Carbon (primary production) 2.2 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.
4350-CR vs 4350 Q&T — frequently asked
Is 4350 Q&T stronger than 4350-CR?
Yes. 4350 Q&T has a typical yield strength of 1,550 MPa (225 ksi) against 930 MPa (135 ksi) for 4350-CR — about 67% more. Tensile strength is 1,800 MPa (261 ksi) vs 1,080 MPa (157 ksi).
Which condition does FabDigit quote by default, CR or Q&T?
HR is the default 4350 condition in the FabDigit quote flow (neither CR nor Q&T). 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, 4350-CR or 4350 Q&T?
4350-CR. Its machinability rates fair (45/100) against poor (20/100) for 4350 Q&T; for welding the order is 4350-CR first (poor, 20/100) then 4350 Q&T (not recommended, 12/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 4350-CR and 4350 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.