Stainless Steel 420C +A vs 420C QT 45-50 HRC
Stainless Steel · 420C temper comparison
420C +A and 420C QT 45-50 HRC are two conditions of the same stainless steel grade, 420C: +A (annealed) versus QT 45-50 HRC. The chemistry is identical, so every difference below comes from the condition. 420C QT 45-50 HRC is the stronger of the two: yield strength 1,300 MPa (189 ksi) against 460 MPa (66.7 ksi) for 420C +A, about 183% more; tensile strength follows at 1,550 MPa (225 ksi) vs 760 MPa (110 ksi). In exchange, 420C +A is the more ductile: elongation 17% versus 6% for 420C QT 45-50 HRC, and 420C QT 45-50 HRC is harder (48 HRC vs 20 HRC). On the shop floor, 420C +A machines more easily (fair vs poor).
420C +AChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
420C QT 45-50 HRCChoose it when strength drives the design.
420C +A vs 420C QT 45-50 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.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Rockwell C
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 215 GPa31.2 Msi · Shear Modulus 83 GPa12 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.28 · Reduction in Area 40% · Compressive Strength 470 MPa68.2 ksi · Shear Strength 460 MPa66.7 ksi · Hardness, Brinell 220 HB · Hardness, Rockwell B 97 HRB
Physical
Density and transition temperatures.
Same in both: Density 7.7 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.
Same in both: Thermal Conductivity 30 W/m·K17.3 BTU/hr·ft·°F · Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 10.5 µm/m·K5.8 µin/in·°F · Latent Heat of Fusion 260 J/g112 BTU/lb · Max Service Temperature (continuous) 400°C752 °F · Min Service Temperature -20°C-4 °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) -0.35 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Formability (cold)
Same in both: Machinability Rating (AISI 1212 = 100 %) 45% · Weldability 20 / 100 · Castability 40 / 100 · Brazeability / Solderability 45 / 100 · Polishability 78 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 50 MJ/kg21,496 BTU/lb · Embodied Carbon (primary production) 3.4 kg CO₂/kg · Embodied Water 90 L/kg10.8 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.
420C +A vs 420C QT 45-50 HRC — frequently asked
Is 420C QT 45-50 HRC stronger than 420C +A?
Yes. 420C QT 45-50 HRC has a typical yield strength of 1,300 MPa (189 ksi) against 460 MPa (66.7 ksi) for 420C +A — about 183% more. Tensile strength is 1,550 MPa (225 ksi) vs 760 MPa (110 ksi).
Which condition does FabDigit quote by default, +A or QT 45-50 HRC?
+A is the default 420C 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, 420C +A or 420C QT 45-50 HRC?
420C +A. Its machinability rates fair (45/100) against poor (22/100) for 420C QT 45-50 HRC.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 420C +A and 420C QT 45-50 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.