Steel ZG42CrMo-A vs ZG42CrMo-SR
Steel · ZG42CrMo temper comparison
ZG42CrMo-A and ZG42CrMo-SR are two conditions of the same steel grade, ZG42CrMo: A (solution annealed) versus SR (stress relieved). The chemistry is identical, so every difference below comes from the condition. ZG42CrMo-SR is the stronger of the two: yield strength 650 MPa (94.3 ksi) against 380 MPa (55.1 ksi) for ZG42CrMo-A, about 71% more; tensile strength follows at 860 MPa (125 ksi) vs 650 MPa (94.3 ksi). In exchange, ZG42CrMo-A is the more ductile: elongation 18% versus 14% for ZG42CrMo-SR, and ZG42CrMo-SR is harder (255 HB vs 190 HB). On the shop floor, ZG42CrMo-A machines more easily (good vs fair).
ZG42CrMo-AChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
ZG42CrMo-SRChoose it when strength drives the design.
ZG42CrMo-A vs ZG42CrMo-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
Reduction in Area
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 210 GPa30.5 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) 1,420°C2,588 °F · Liquidus Temperature 1,495°C2,723 °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) 12.3 µm/m·K6.8 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Max Service Temperature (continuous) 400°C752 °F · Min Service Temperature -20°C-4 °F
Electrical
Conductivity and insulation.
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: 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 55 / 100 · Brazeability / Solderability 45 / 100 · Polishability 55 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 24 MJ/kg10,318 BTU/lb · Embodied Carbon (primary production) 2 kg CO₂/kg · Embodied Water 45 L/kg5.4 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.
ZG42CrMo-A vs ZG42CrMo-SR — frequently asked
Is ZG42CrMo-SR stronger than ZG42CrMo-A?
Yes. ZG42CrMo-SR has a typical yield strength of 650 MPa (94.3 ksi) against 380 MPa (55.1 ksi) for ZG42CrMo-A — about 71% more. Tensile strength is 860 MPa (125 ksi) vs 650 MPa (94.3 ksi).
Which condition does FabDigit quote by default, A or SR?
QT-240-280HB is the default ZG42CrMo condition in the FabDigit quote flow (neither A 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, ZG42CrMo-A or ZG42CrMo-SR?
ZG42CrMo-A. Its machinability rates good (58/100) against fair (44/100) for ZG42CrMo-SR; for welding the order is ZG42CrMo-A first (fair, 35/100) then ZG42CrMo-SR (poor, 30/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in ZG42CrMo-A and ZG42CrMo-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.