Stainless Steel 420HC-A vs 420HC-QT45
Stainless Steel · 420HC temper comparison
420HC-A and 420HC-QT45 are two conditions of the same stainless steel grade, 420HC: A (solution annealed) versus QT45 (hardened and tempered to 42–46 HRC). The chemistry is identical, so every difference below comes from the condition. 420HC-QT45 is the stronger of the two: yield strength 1,200 MPa (174 ksi) against 345 MPa (50 ksi) for 420HC-A, about 3.5 times as much; tensile strength follows at 1,450 MPa (210 ksi) vs 660 MPa (95.7 ksi). In exchange, 420HC-A is the more ductile: elongation 22% versus 8% for 420HC-QT45, and 420HC-QT45 is harder (435 HV vs 205 HV). 420HC-A runs hotter in service (425°C vs 350°C continuous). On the shop floor, 420HC-A machines more easily (fair vs poor).
420HC-AChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
420HC-QT45Choose it when strength drives the design.
420HC-A vs 420HC-QT45: 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.
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, Vickers
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 · Hardness, Brinell 195 HB · Hardness, Rockwell B 92 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 265 J/g114 BTU/lb · Min Service Temperature -40°C-40 °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 %)
Formability (cold)
Same in both: Weldability 30 / 100 · Brazeability / Solderability 35 / 100 · Polishability 75 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 46 MJ/kg19,776 BTU/lb · Embodied Carbon (primary production) 3 kg CO₂/kg · Embodied Water 250 L/kg30 gal/lb · Typical Recycled Content 45%
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.
420HC-A vs 420HC-QT45 — frequently asked
Is 420HC-QT45 stronger than 420HC-A?
Yes. 420HC-QT45 has a typical yield strength of 1,200 MPa (174 ksi) against 345 MPa (50 ksi) for 420HC-A — about 3.5 times as much. Tensile strength is 1,450 MPa (210 ksi) vs 660 MPa (95.7 ksi).
Which condition does FabDigit quote by default, A or QT45?
A is the default 420HC 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, 420HC-A or 420HC-QT45?
420HC-A. Its machinability rates fair (45/100) against poor (25/100) for 420HC-QT45.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 420HC-A and 420HC-QT45 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.