Steel 8637-A vs 8637 QT28-32HRC
Steel · 8637 temper comparison
8637-A and 8637 QT28-32HRC are two conditions of the same steel grade, 8637: A (solution annealed) versus QT28-32HRC. The chemistry is identical, so every difference below comes from the condition. 8637 QT28-32HRC is the stronger of the two: yield strength 860 MPa (125 ksi) against 400 MPa (58 ksi) for 8637-A, about 115% more; tensile strength follows at 965 MPa (140 ksi) vs 660 MPa (95.7 ksi). In exchange, 8637-A is the more ductile: elongation 22% versus 19% for 8637 QT28-32HRC, and 8637 QT28-32HRC is harder (285 HB vs 187 HB).
8637-AChoose it when the part is bent, formed or impact-loaded.
8637 QT28-32HRCChoose it when strength drives the design.
8637-A vs 8637 QT28-32HRC: 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 · Compressive Strength 870 MPa126 ksi · Fracture Toughness (K_IC) 90 MPa·√m81.9 ksi·√in · Hardness, Rockwell C 30 HRC · Hardness, Vickers 300 HV
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) 12.2 µm/m·K6.8 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Max Service Temperature (continuous) 400°C752 °F · Min Service Temperature -40°C-40 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 7.5 % IACS · Electrical Resistivity 2.3×10⁻⁷ Ω·m9.06 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.61 V · Corrosion Resistance 12 / 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 65 / 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 65 L/kg7.8 gal/lb · Typical Recycled Content 35%
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.
8637-A vs 8637 QT28-32HRC — frequently asked
Is 8637 QT28-32HRC stronger than 8637-A?
Yes. 8637 QT28-32HRC has a typical yield strength of 860 MPa (125 ksi) against 400 MPa (58 ksi) for 8637-A — about 115% more. Tensile strength is 965 MPa (140 ksi) vs 660 MPa (95.7 ksi).
Which condition does FabDigit quote by default, A or QT28-32HRC?
QT28-32HRC is the default 8637 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, 8637-A or 8637 QT28-32HRC?
8637-A. Its machinability rates good (58/100) against fair (50/100) for 8637 QT28-32HRC; for welding the order is 8637-A first (fair, 40/100) then 8637 QT28-32HRC (fair, 35/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 8637-A and 8637 QT28-32HRC 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.