Steel 15B21 Normalized vs 15B21 Q&T 25-32 HRC
Steel · 15B21 temper comparison
15B21 Normalized and 15B21 Q&T 25-32 HRC are two conditions of the same steel grade, 15B21: Normalized versus Q&T 25-32 HRC (quenched and tempered, SAE J429 Grade 5 / class 8.8 level). The chemistry is identical, so every difference below comes from the condition. 15B21 Q&T 25-32 HRC is the stronger of the two: yield strength 720 MPa (104 ksi) against 310 MPa (45 ksi) for 15B21 Normalized, about 132% more; tensile strength follows at 880 MPa (128 ksi) vs 470 MPa (68.2 ksi). In exchange, 15B21 Normalized is the more ductile: elongation 30% versus 16% for 15B21 Q&T 25-32 HRC, and 15B21 Q&T 25-32 HRC is harder (285 HB vs 137 HB). 15B21 Normalized runs hotter in service (400°C vs 300°C continuous). On the shop floor, 15B21 Normalized welds better (excellent vs fair).
15B21 NormalizedChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
15B21 Q&T 25-32 HRCChoose it when strength drives the design.
15B21 Normalized vs 15B21 Q&T 25-32 HRC: 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.
15B21 Normalized15B21 Q&T 25-32 HRC
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
Hardness, Rockwell B
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) 1,425°C2,597 °F · Liquidus Temperature 1,515°C2,759 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 51 W/m·K29.5 BTU/hr·ft·°F · Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.7 µm/m·K6.5 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -20°C-4 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 10 % IACS · Electrical Resistivity 1.7×10⁻⁷ Ω·m6.69 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.61 V · Corrosion Resistance 10 / 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 75 / 100 · Polishability 55 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 25 MJ/kg10,748 BTU/lb · Embodied Carbon (primary production) 2 kg CO₂/kg · Embodied Water 30 L/kg3.6 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.
15B21 Normalized vs 15B21 Q&T 25-32 HRC — frequently asked
Is 15B21 Q&T 25-32 HRC stronger than 15B21 Normalized?
Yes. 15B21 Q&T 25-32 HRC has a typical yield strength of 720 MPa (104 ksi) against 310 MPa (45 ksi) for 15B21 Normalized — about 132% more. Tensile strength is 880 MPa (128 ksi) vs 470 MPa (68.2 ksi).
Which condition does FabDigit quote by default, Normalized or Q&T 25-32 HRC?
HR is the default 15B21 condition in the FabDigit quote flow (neither Normalized nor Q&T 25-32 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 welds better, 15B21 Normalized or 15B21 Q&T 25-32 HRC?
15B21 Normalized. Its weldability rates excellent (85/100) against fair (45/100) for 15B21 Q&T 25-32 HRC.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 15B21 Normalized and 15B21 Q&T 25-32 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.