Steel ZG65Mn QT-30-35HRC vs ZG65Mn-SR
Steel · ZG65Mn temper comparison
ZG65Mn QT-30-35HRC and ZG65Mn-SR are two conditions of the same steel grade, ZG65Mn: QT-30-35HRC versus SR (stress relieved). The chemistry is identical, so every difference below comes from the condition. ZG65Mn QT-30-35HRC is the stronger of the two: yield strength 830 MPa (120 ksi) against 400 MPa (58 ksi) for ZG65Mn-SR, about 108% more; tensile strength follows at 1,030 MPa (149 ksi) vs 720 MPa (104 ksi). In exchange, ZG65Mn-SR is the more ductile: elongation 11% versus 8% for ZG65Mn QT-30-35HRC, and ZG65Mn QT-30-35HRC is harder (310 HB vs 210 HB). ZG65Mn QT-30-35HRC runs hotter in service (400°C vs 300°C continuous). On the shop floor, ZG65Mn-SR machines more easily (fair vs poor) and ZG65Mn-SR welds better (30 vs 18 out of 100).
ZG65Mn QT-30-35HRCChoose it when strength drives the design, or when the part sees heat.
ZG65Mn-SRChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
ZG65Mn QT-30-35HRC vs ZG65Mn-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)
Elongation at Break
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell C
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 205 GPa29.7 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 165 GPa23.9 Msi · Poisson's Ratio 0.29 · Reduction in Area 20%
Physical
Density and transition temperatures.
Same in both: Density 7.81 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.
Thermal Conductivity
Max Service Temperature (continuous)
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 270 J/g116 BTU/lb · Min Service Temperature -20°C-4 °F
Electrical
Conductivity and insulation.
Electrical Resistivity
Same in both: Electrical Conductivity 8 % IACS
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.62 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 62 / 100 · Brazeability / Solderability 45 / 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 70%
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.
ZG65Mn QT-30-35HRC vs ZG65Mn-SR — frequently asked
Is ZG65Mn QT-30-35HRC stronger than ZG65Mn-SR?
Yes. ZG65Mn QT-30-35HRC has a typical yield strength of 830 MPa (120 ksi) against 400 MPa (58 ksi) for ZG65Mn-SR — about 108% more. Tensile strength is 1,030 MPa (149 ksi) vs 720 MPa (104 ksi).
Which condition does FabDigit quote by default, QT-30-35HRC or SR?
N+T is the default ZG65Mn condition in the FabDigit quote flow (neither QT-30-35HRC 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, ZG65Mn QT-30-35HRC or ZG65Mn-SR?
ZG65Mn-SR. Its machinability rates fair (44/100) against poor (30/100) for ZG65Mn QT-30-35HRC; for welding the order is ZG65Mn-SR first (poor, 30/100) then ZG65Mn QT-30-35HRC (poor, 18/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in ZG65Mn QT-30-35HRC and ZG65Mn-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.