Steel 15Kh-HR vs 15Kh Q&T
Steel · 15Kh temper comparison
15Kh-HR and 15Kh Q&T are two conditions of the same steel grade, 15Kh: HR (hot rolled) versus Q&T (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. 15Kh Q&T is the stronger of the two: yield strength 540 MPa (78.3 ksi) against 330 MPa (47.9 ksi) for 15Kh-HR, about 64% more; tensile strength follows at 750 MPa (109 ksi) vs 540 MPa (78.3 ksi). In exchange, 15Kh-HR is the more ductile: elongation 24% versus 14% for 15Kh Q&T, and 15Kh Q&T is harder (217 HB vs 170 HB). On the shop floor, 15Kh-HR machines more easily (good vs fair).
15Kh-HRChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
15Kh Q&TChoose it when strength drives the design.
15Kh-HR vs 15Kh Q&T: 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
Charpy V-Notch Impact (RT)
Hardness, Brinell
Same in both: Elastic (Young's) Modulus 212 GPa30.7 Msi · Shear Modulus 82 GPa11.9 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Shear Strength 460 MPa66.7 ksi · Fatigue Strength (Endurance Limit) 350 MPa50.8 ksi · Fracture Toughness (K_IC) 80 MPa·√m72.8 ksi·√in · Hardness, Rockwell C 20 HRC · Hardness, Vickers 228 HV
Physical
Density and transition temperatures.
Same in both: Density 7.82 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 42 W/m·K24.3 BTU/hr·ft·°F · Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.9 µm/m·K6.6 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Max Service Temperature (continuous) 200°C392 °F · Min Service Temperature -40°C-40 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 8.2 % IACS · Electrical Resistivity 2.1×10⁻⁷ Ω·m8.27 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.6 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 %)
Same in both: Weldability 55 / 100 · Formability (cold) 60 / 100 · Castability 30 / 100 · Brazeability / Solderability 65 / 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) 1.9 kg CO₂/kg · Embodied Water 45 L/kg5.4 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.
15Kh-HR vs 15Kh Q&T — frequently asked
Is 15Kh Q&T stronger than 15Kh-HR?
Yes. 15Kh Q&T has a typical yield strength of 540 MPa (78.3 ksi) against 330 MPa (47.9 ksi) for 15Kh-HR — about 64% more. Tensile strength is 750 MPa (109 ksi) vs 540 MPa (78.3 ksi).
Which condition does FabDigit quote by default, HR or Q&T?
Q&T is the default 15Kh 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, 15Kh-HR or 15Kh Q&T?
15Kh-HR. Its machinability rates good (55/100) against fair (45/100) for 15Kh Q&T.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 15Kh-HR and 15Kh Q&T 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.