Steel Cr12 Q&T vs Cr12 Q&T 55-58 HRC
Steel · Cr12 temper comparison
Cr12 Q&T and Cr12 Q&T 55-58 HRC are two conditions of the same steel grade, Cr12: Q&T (quenched and tempered) versus Q&T 55-58 HRC (tempered 350–400 °C for higher toughness). The chemistry is identical, so every difference below comes from the condition. Cr12 Q&T is the stronger of the two: yield strength 1,700 MPa (247 ksi) against 1,550 MPa (225 ksi) for Cr12 Q&T 55-58 HRC, about 10% more; tensile strength follows at 1,950 MPa (283 ksi) vs 1,800 MPa (261 ksi). In exchange, Cr12 Q&T 55-58 HRC is the more ductile: elongation 2% versus 1% for Cr12 Q&T, and Cr12 Q&T is harder (61 HRC vs 57 HRC). Cr12 Q&T 55-58 HRC runs hotter in service (300°C vs 180°C continuous).
Cr12 Q&TChoose it when strength drives the design.
Cr12 Q&T 55-58 HRCChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
Cr12 Q&T vs Cr12 Q&T 55-58 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.
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
Charpy V-Notch Impact (RT)
Hardness, Rockwell C
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 210 GPa30.5 Msi · Shear Modulus 81 GPa11.7 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.28 · Hardness, Brinell 240 HB
Physical
Density and transition temperatures.
Same in both: Density 7.7 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,400°C2,552 °F · Liquidus Temperature 1,450°C2,642 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Max Service Temperature (continuous)
Same in both: Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.5 µm/m·K6.4 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -30°C-22 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Corrosion Resistance 26 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Formability (cold)
Same in both: Machinability Rating (AISI 1212 = 100 %) 5% · Castability 25 / 100 · Brazeability / Solderability 35 / 100 · Polishability 70 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 36 MJ/kg15,477 BTU/lb · Embodied Carbon (primary production) 2.6 kg CO₂/kg · Embodied Water 60 L/kg7.2 gal/lb · Typical Recycled Content 45%
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.
Cr12 Q&T vs Cr12 Q&T 55-58 HRC — frequently asked
Is Cr12 Q&T stronger than Cr12 Q&T 55-58 HRC?
Yes. Cr12 Q&T has a typical yield strength of 1,700 MPa (247 ksi) against 1,550 MPa (225 ksi) for Cr12 Q&T 55-58 HRC — about 10% more. Tensile strength is 1,950 MPa (283 ksi) vs 1,800 MPa (261 ksi).
Which condition does FabDigit quote by default, Q&T or Q&T 55-58 HRC?
Annealed is the default Cr12 condition in the FabDigit quote flow (neither Q&T nor Q&T 55-58 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, Cr12 Q&T or Cr12 Q&T 55-58 HRC?
Cr12 Q&T. Its weldability rates not recommended (12/100) against not recommended (5/100) for Cr12 Q&T 55-58 HRC.
Ready to make it?
Upload a CAD file and FabDigit prices the part in Cr12 Q&T and Cr12 Q&T 55-58 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.