Steel 4320-HR vs 4320 Q&T
Steel · 4320 temper comparison
4320-HR and 4320 Q&T are two conditions of the same steel grade, 4320: HR (hot rolled) versus Q&T (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. 4320 Q&T is the stronger of the two: yield strength 900 MPa (131 ksi) against 415 MPa (60.2 ksi) for 4320-HR, about 117% more; tensile strength follows at 1,080 MPa (157 ksi) vs 640 MPa (92.8 ksi). In exchange, 4320-HR is the more ductile: elongation 22% versus 15% for 4320 Q&T, and 4320 Q&T is harder (320 HB vs 187 HB). 4320-HR runs hotter in service (350°C vs 300°C continuous). On the shop floor, 4320-HR machines more easily (50 vs 35 out of 100) and 4320-HR welds better (fair vs poor).
4320-HRChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
4320 Q&TChoose it when strength drives the design.
4320-HR vs 4320 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)
Charpy V-Notch Impact (RT)
Hardness, Brinell
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 · Hardness, Rockwell B 90 HRB
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.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 44 W/m·K25.4 BTU/hr·ft·°F · Specific Heat Capacity 475 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 -60°C-76 °F
Electrical
Conductivity and insulation.
Same in both: 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)
Same in both: Brazeability / Solderability 55 / 100 · Polishability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 31 MJ/kg13,328 BTU/lb · Embodied Carbon (primary production) 2.3 kg CO₂/kg · Embodied Water 50 L/kg6 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.
4320-HR vs 4320 Q&T — frequently asked
Is 4320 Q&T stronger than 4320-HR?
Yes. 4320 Q&T has a typical yield strength of 900 MPa (131 ksi) against 415 MPa (60.2 ksi) for 4320-HR — about 117% more. Tensile strength is 1,080 MPa (157 ksi) vs 640 MPa (92.8 ksi).
Which condition does FabDigit quote by default, HR or Q&T?
HR is the default 4320 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, 4320-HR or 4320 Q&T?
4320-HR, by a small margin. Both rate fair for machinability — 50/100 against 35/100 for 4320 Q&T; for welding the order is 4320-HR first (fair, 40/100) then 4320 Q&T (poor, 30/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 4320-HR and 4320 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.