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Steel 51B60-HR vs 51B60 QT-48HRC

Steel · 51B60 temper comparison

51B60-HR and 51B60 QT-48HRC are two conditions of the same steel grade, 51B60: HR (hot rolled) versus QT-48HRC (Q&T 425 °C). The chemistry is identical, so every difference below comes from the condition. 51B60 QT-48HRC is the stronger of the two: yield strength 1,570 MPa (228 ksi) against 490 MPa (71.1 ksi) for 51B60-HR, about 3.2 times as much; tensile strength follows at 1,730 MPa (251 ksi) vs 860 MPa (125 ksi). In exchange, 51B60-HR is the more ductile: elongation 15% versus 9% for 51B60 QT-48HRC, and 51B60 QT-48HRC is harder (460 HB vs 248 HB). On the shop floor, 51B60-HR machines more easily (fair vs poor) and 51B60-HR welds better (poor vs not recommended).

51B60-HRChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.

51B60 QT-48HRCChoose it when strength drives the design.

51B60-HR vs 51B60 QT-48HRC: properties

51B60-HR51B60 QT-48HRC

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

860 MPa125 ksi
1,730 MPa251 ksi

Yield Strength (0.2% offset)

490 MPa71.1 ksi
1,570 MPa228 ksi

Elongation at Break

15%
9%

Reduction in Area

35%
30%

Compressive Strength

870 MPa126 ksi
730 MPa106 ksi

Shear Strength

515 MPa74.7 ksi
1,040 MPa151 ksi

Fatigue Strength (Endurance Limit)

400 MPa58 ksi
700 MPa102 ksi

Fracture Toughness (K_IC)

52 MPa·√m47.3 ksi·√in
50 MPa·√m45.5 ksi·√in

Charpy V-Notch Impact (RT)

13 J9.6 ft·lbf
14 J10.3 ft·lbf

Hardness, Brinell

248 HB
460 HB

Hardness, Rockwell B

100 HRB
92 HRB

Hardness, Vickers

261 HV
485 HV

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) 1,415°C2,579 °F · Liquidus Temperature 1,480°C2,696 °F

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

45 W/m·K26 BTU/hr·ft·°F
46 W/m·K26.6 BTU/hr·ft·°F

Same in both: Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12.3 µm/m·K6.8 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Max Service Temperature (continuous) 250°C482 °F · Min Service Temperature -30°C-22 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

7.6 % IACS
7.8 % IACS

Electrical Resistivity

2.25×10⁻⁷ Ω·m8.86 µΩ·in
2.2×10⁻⁷ Ω·m8.66 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

48 / 100
20 / 100

Machinability Rating (AISI 1212 = 100 %)

50%
22%

Weldability

22 / 100
8 / 100

Formability (cold)

30 / 100
5 / 100

Same in both: Castability 20 / 100 · Brazeability / Solderability 45 / 100 · Polishability 60 / 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 55 L/kg6.6 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.

2005001,0002,0007.588.5Density (g/cm³)Yield strength (MPa) — log scale51B60

51B60-HR vs 51B60 QT-48HRC — frequently asked

Is 51B60 QT-48HRC stronger than 51B60-HR?

Yes. 51B60 QT-48HRC has a typical yield strength of 1,570 MPa (228 ksi) against 490 MPa (71.1 ksi) for 51B60-HR — about 3.2 times as much. Tensile strength is 1,730 MPa (251 ksi) vs 860 MPa (125 ksi).

Which condition does FabDigit quote by default, HR or QT-48HRC?

A is the default 51B60 condition in the FabDigit quote flow (neither HR nor QT-48HRC). 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, 51B60-HR or 51B60 QT-48HRC?

51B60-HR. Its machinability rates fair (48/100) against poor (20/100) for 51B60 QT-48HRC; for welding the order is 51B60-HR first (poor, 22/100) then 51B60 QT-48HRC (not recommended, 8/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 51B60-HR and 51B60 QT-48HRC 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.