Steel L6 Q&T 42-46 HRC vs L6 Q&T 58-62 HRC
Steel · L6 temper comparison
L6 Q&T 42-46 HRC and L6 Q&T 58-62 HRC are two conditions of the same steel grade, L6: Q&T 42-46 HRC (oil quenched from 845–870 °C, tempered ~510–540 °C) versus Q&T 58-62 HRC (oil quenched, low temper ~175–205 °C). The chemistry is identical, so every difference below comes from the condition. L6 Q&T 58-62 HRC is the stronger of the two: yield strength 1,900 MPa (276 ksi) against 1,250 MPa (181 ksi) for L6 Q&T 42-46 HRC, about 52% more; tensile strength follows at 2,250 MPa (326 ksi) vs 1,420 MPa (206 ksi). In exchange, L6 Q&T 42-46 HRC is the more ductile: elongation 10% versus 1.5% for L6 Q&T 58-62 HRC, and L6 Q&T 42-46 HRC is harder (415 HB vs 197 HB). L6 Q&T 42-46 HRC runs hotter in service (450°C vs 175°C continuous). On the shop floor, L6 Q&T 42-46 HRC machines more easily (poor vs not recommended).
L6 Q&T 42-46 HRCChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
L6 Q&T 58-62 HRCChoose it when strength drives the design.
L6 Q&T 42-46 HRC vs L6 Q&T 58-62 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.
L6 Q&T 42-46 HRCL6 Q&T 58-62 HRC
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 207 GPa30 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Hardness, Rockwell B 92 HRB
Physical
Density and transition temperatures.
Same in both: Density 7.87 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,420°C2,588 °F · Liquidus Temperature 1,480°C2,696 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 38 W/m·K22 BTU/hr·ft·°F · Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12.5 µm/m·K6.9 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -50°C-58 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 7 % IACS · Electrical Resistivity 2.5×10⁻⁷ Ω·m9.84 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V · Corrosion Resistance 11 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Polishability
Same in both: Castability 30 / 100 · Brazeability / Solderability 40 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 33 MJ/kg14,187 BTU/lb · Embodied Carbon (primary production) 2.4 kg CO₂/kg · Embodied Water 60 L/kg7.2 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.
L6 Q&T 42-46 HRC vs L6 Q&T 58-62 HRC — frequently asked
Is L6 Q&T 58-62 HRC stronger than L6 Q&T 42-46 HRC?
Yes. L6 Q&T 58-62 HRC has a typical yield strength of 1,900 MPa (276 ksi) against 1,250 MPa (181 ksi) for L6 Q&T 42-46 HRC — about 52% more. Tensile strength is 2,250 MPa (326 ksi) vs 1,420 MPa (206 ksi).
Which condition does FabDigit quote by default, Q&T 42-46 HRC or Q&T 58-62 HRC?
A is the default L6 condition in the FabDigit quote flow (neither Q&T 42-46 HRC nor Q&T 58-62 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 is easier to machine, L6 Q&T 42-46 HRC or L6 Q&T 58-62 HRC?
L6 Q&T 42-46 HRC. Its machinability rates poor (25/100) against not recommended (5/100) for L6 Q&T 58-62 HRC; for welding the order is L6 Q&T 42-46 HRC first (not recommended, 10/100) then L6 Q&T 58-62 HRC (not recommended, 3/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in L6 Q&T 42-46 HRC and L6 Q&T 58-62 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.