Steel ZG230-450-QT vs ZG230-450-SR
Steel · ZG230-450 temper comparison
ZG230-450-QT and ZG230-450-SR are two conditions of the same steel grade, ZG230-450: QT (quenched and tempered) versus SR (stress relieved). The chemistry is identical, so every difference below comes from the condition. ZG230-450-QT is the stronger of the two: yield strength 370 MPa (53.7 ksi) against 240 MPa (34.8 ksi) for ZG230-450-SR, about 54% more; tensile strength follows at 570 MPa (82.7 ksi) vs 460 MPa (66.7 ksi). ZG230-450-QT is harder — 185 HB against 145 HB for ZG230-450-SR — which matters for wear surfaces and threads.
ZG230-450-QTChoose it when strength drives the design, or when surface hardness matters.
ZG230-450-QT vs ZG230-450-SR: 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)
Reduction in Area
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 202 GPa29.3 Msi · Shear Modulus 78 GPa11.3 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Elongation at Break 20%
Physical
Density and transition temperatures.
Same in both: Density 7.82 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,420°C2,588 °F · Liquidus Temperature 1,500°C2,732 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Same in both: 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) 425°C797 °F · Min Service Temperature -29°C-20 °F
Electrical
Conductivity and insulation.
Electrical Resistivity
Same in both: Electrical Conductivity 10 % IACS
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.61 V · Corrosion Resistance 12 / 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: Castability 65 / 100 · Brazeability / Solderability 70 / 100 · Polishability 45 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 26 MJ/kg11,178 BTU/lb · Embodied Carbon (primary production) 2.1 kg CO₂/kg · Embodied Water 50 L/kg6 gal/lb · Typical Recycled Content 75%
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.
ZG230-450-QT vs ZG230-450-SR — frequently asked
Is ZG230-450-QT stronger than ZG230-450-SR?
Yes. ZG230-450-QT has a typical yield strength of 370 MPa (53.7 ksi) against 240 MPa (34.8 ksi) for ZG230-450-SR — about 54% more. Tensile strength is 570 MPa (82.7 ksi) vs 460 MPa (66.7 ksi).
Which condition does FabDigit quote by default, QT or SR?
NT is the default ZG230-450 condition in the FabDigit quote flow (neither QT nor SR). 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, ZG230-450-QT or ZG230-450-SR?
ZG230-450-SR. Its machinability rates good (58/100) against fair (52/100) for ZG230-450-QT; for welding the order is ZG230-450-SR first (very good, 78/100) then ZG230-450-QT (very good, 70/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in ZG230-450-QT and ZG230-450-SR 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.