Steel 4621-HR vs 4621 QT28-32
Steel · 4621 temper comparison
4621-HR and 4621 QT28-32 are two conditions of the same steel grade, 4621: HR (hot rolled) versus QT28-32 (Q&T 28–32 HRC). The chemistry is identical, so every difference below comes from the condition. 4621 QT28-32 is the stronger of the two: yield strength 790 MPa (115 ksi) against 350 MPa (50.8 ksi) for 4621-HR, about 126% more; tensile strength follows at 950 MPa (138 ksi) vs 570 MPa (82.7 ksi). In exchange, 4621-HR is the more ductile: elongation 27% versus 17% for 4621 QT28-32, and 4621 QT28-32 is harder (293 HB vs 170 HB). On the shop floor, 4621-HR machines more easily (good vs fair).
4621-HRChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
4621 QT28-32Choose it when strength drives the design.
4621-HR vs 4621 QT28-32: 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 205 GPa29.7 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 1,500°C2,732 °F
Thermal
How each material carries heat and how hot it can run.
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) 12 µm/m·K6.7 µin/in·°F · Latent Heat of Fusion 260 J/g112 BTU/lb · Max Service Temperature (continuous) 400°C752 °F · Min Service Temperature -60°C-76 °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).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.61 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Formability (cold)
Same in both: Weldability 45 / 100 · Brazeability / Solderability 60 / 100 · Polishability 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) 2.4 kg CO₂/kg · Embodied Water 62 L/kg7.4 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.
4621-HR vs 4621 QT28-32 — frequently asked
Is 4621 QT28-32 stronger than 4621-HR?
Yes. 4621 QT28-32 has a typical yield strength of 790 MPa (115 ksi) against 350 MPa (50.8 ksi) for 4621-HR — about 126% more. Tensile strength is 950 MPa (138 ksi) vs 570 MPa (82.7 ksi).
Which condition does FabDigit quote by default, HR or QT28-32?
ANN is the default 4621 condition in the FabDigit quote flow (neither HR nor QT28-32). 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, 4621-HR or 4621 QT28-32?
4621-HR. Its machinability rates good (55/100) against fair (42/100) for 4621 QT28-32.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 4621-HR and 4621 QT28-32 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.