Stainless Steel 420F Q&T 28-32 HRC vs 420F Q&T 40-45 HRC
Stainless Steel · 420F temper comparison
420F Q&T 28-32 HRC and 420F Q&T 40-45 HRC are two conditions of the same stainless steel grade, 420F: Q&T 28-32 HRC (oil quench, high temper ≈650 °C) versus Q&T 40-45 HRC (oil quench, temper ≈500 °C). The chemistry is identical, so every difference below comes from the condition. 420F Q&T 40-45 HRC is the stronger of the two: yield strength 1,180 MPa (171 ksi) against 800 MPa (116 ksi) for 420F Q&T 28-32 HRC, about 48% more; tensile strength follows at 1,400 MPa (203 ksi) vs 1,000 MPa (145 ksi). In exchange, 420F Q&T 28-32 HRC is the more ductile: elongation 16% versus 11% for 420F Q&T 40-45 HRC, and 420F Q&T 28-32 HRC is harder (290 HB vs 220 HB). 420F Q&T 28-32 HRC runs hotter in service (500°C vs 450°C continuous). On the shop floor, 420F Q&T 28-32 HRC machines more easily (fair vs poor).
420F Q&T 28-32 HRCChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
420F Q&T 40-45 HRCChoose it when strength drives the design.
420F Q&T 28-32 HRC vs 420F Q&T 40-45 HRC: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all stainless 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 stainless 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.
420F Q&T 28-32 HRC420F Q&T 40-45 HRC
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Same in both: Elastic (Young's) Modulus 200 GPa29 Msi · Shear Modulus 78 GPa11.3 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.28 · Shear Strength 430 MPa62.4 ksi · Hardness, Rockwell B 97 HRB
Physical
Density and transition temperatures.
Same in both: Density 7.75 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,450°C2,642 °F · Liquidus Temperature 1,510°C2,750 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 24.9 W/m·K14.4 BTU/hr·ft·°F · Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 10.3 µm/m·K5.7 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -30°C-22 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 3.1 % IACS · Electrical Resistivity 5.5×10⁻⁷ Ω·m21.7 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.3 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Same in both: Weldability 12 / 100 · Formability (cold) 25 / 100 · Castability 35 / 100 · Brazeability / Solderability 35 / 100 · Polishability 50 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 45 MJ/kg19,347 BTU/lb · Embodied Carbon (primary production) 3.4 kg CO₂/kg · Embodied Water 130 L/kg15.6 gal/lb · Typical Recycled Content 65%
Strength versus weight
Yield strength against density for every stainless steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
420F Q&T 28-32 HRC vs 420F Q&T 40-45 HRC — frequently asked
Is 420F Q&T 40-45 HRC stronger than 420F Q&T 28-32 HRC?
Yes. 420F Q&T 40-45 HRC has a typical yield strength of 1,180 MPa (171 ksi) against 800 MPa (116 ksi) for 420F Q&T 28-32 HRC — about 48% more. Tensile strength is 1,400 MPa (203 ksi) vs 1,000 MPa (145 ksi).
Which condition does FabDigit quote by default, Q&T 28-32 HRC or Q&T 40-45 HRC?
Annealed is the default 420F condition in the FabDigit quote flow (neither Q&T 28-32 HRC nor Q&T 40-45 HRC). 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, 420F Q&T 28-32 HRC or 420F Q&T 40-45 HRC?
420F Q&T 28-32 HRC. Its machinability rates fair (42/100) against poor (28/100) for 420F Q&T 40-45 HRC.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 420F Q&T 28-32 HRC and 420F Q&T 40-45 HRC 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.