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Steel P265GH vs Q345R

Steel · grade comparison

Steel P265GH and Q345R are both steel grades, both pressure vessel steel. Q345R is the stronger of the two: yield strength 370 MPa (53.7 ksi) against 295 MPa (42.8 ksi) for P265GH, about 25% more; tensile strength follows at 550 MPa (79.8 ksi) vs 465 MPa (67.4 ksi). Q345R is harder — 160 HB against 140 HB for P265GH — which matters for wear surfaces and threads. P265GH conducts electricity better (10 % IACS vs 8.6 % IACS).

Q345RChoose it when strength drives the design, or when surface hardness matters.

P265GH vs Q345R: properties

P265GHQ345R

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

211 GPa30.6 Msi
206 GPa29.9 Msi

Shear Modulus

81 GPa11.7 Msi
79 GPa11.5 Msi

Poisson's Ratio

0.3
0.29

Tensile Strength (Ultimate)

465 MPa67.4 ksi
550 MPa79.8 ksi

Yield Strength (0.2% offset)

295 MPa42.8 ksi
370 MPa53.7 ksi

Elongation at Break

26%
24%

Reduction in Area

52%
50%

Compressive Strength

295 MPa42.8 ksi
370 MPa53.7 ksi

Shear Strength

280 MPa40.6 ksi
330 MPa47.9 ksi

Fatigue Strength (Endurance Limit)

205 MPa29.7 ksi
240 MPa34.8 ksi

Charpy V-Notch Impact (RT)

70 J51.6 ft·lbf
90 J66.4 ft·lbf

Hardness, Brinell

140 HB
160 HB

Hardness, Rockwell B

76 HRB
84 HRB

Hardness, Vickers

147 HV
168 HV

Same in both: Bulk Modulus 160 GPa23.2 Msi · Fracture Toughness (K_IC) 100 MPa·√m91 ksi·√in

Physical

Density and transition temperatures.

Melting Point (Solidus)

1,495°C2,723 °F
1,440°C2,624 °F

Liquidus Temperature

1,520°C2,768 °F
1,510°C2,750 °F

Same in both: Density 7.85 g/cm³0.28 lb/in³

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

50 W/m·K28.9 BTU/hr·ft·°F
48 W/m·K27.7 BTU/hr·ft·°F

Specific Heat Capacity

461 J/kg·K0.11 BTU/lb·°F
480 J/kg·K0.11 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

12 µm/m·K6.7 µin/in·°F
11.8 µm/m·K6.6 µin/in·°F

Min Service Temperature

-10°C14 °F
-20°C-4 °F

Same in both: Latent Heat of Fusion 270 J/g116 BTU/lb · Max Service Temperature (continuous) 400°C752 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

10 % IACS
8.6 % IACS

Electrical Resistivity

1.7×10⁻⁷ Ω·m6.69 µΩ·in
2×10⁻⁷ Ω·m7.87 µΩ·in

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

66 / 100
62 / 100

Machinability Rating (AISI 1212 = 100 %)

63%
65%

Weldability

90 / 100
85 / 100

Formability (cold)

76 / 100
70 / 100

Brazeability / Solderability

70 / 100
60 / 100

Polishability

50 / 100
45 / 100

Castability

—
45 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Carbon (primary production)

2 kg CO₂/kg
2.1 kg CO₂/kg

Embodied Water

40 L/kg4.8 gal/lb
35 L/kg4.2 gal/lb

Typical Recycled Content

25%
22%

Same in both: Embodied Energy (primary production) 25 MJ/kg10,748 BTU/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

59 kN·m/kg
70 kN·m/kg

Specific Stiffness (E / density)

26.9 MN·m/kg
26.2 MN·m/kg

Modulus of Resilience

206 kJ/m³
332 kJ/m³

Thermal Diffusivity

13.8 mm²/s
12.7 mm²/s

Thermal Shock Resistance Index

9
11

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.

2005001,0002,0007.588.5Density (g/cm³)Yield strength (MPa) — log scaleQ345RP265GH

Manufacturing and finishing

CapabilityP265GHQ345R
Default conditionHRHR
Relative cost$$ Standard$$ Standard
Min. machined wall0.8 mm0.8 mm
Best machined surfaceRa 1.6 µmRa 1.6 µm

Both are offered for CNC machining and Sheet metal. Both take the same 38 finishes: AlCrN, AlTiN, Black Oxide, CVD Al2O3, CVD TiCN, CVD TiN, Cerakote, Chrome Plating, Copper Plating, CrN, DLC, E-Coating and 26 more.

P265GH vs Q345R — frequently asked

Is Q345R stronger than P265GH?

Yes. Q345R has a typical yield strength of 370 MPa (53.7 ksi) against 295 MPa (42.8 ksi) for P265GH — about 25% more. Tensile strength is 550 MPa (79.8 ksi) vs 465 MPa (67.4 ksi).

Which is cheaper, P265GH or Q345R?

Both sit in the same relative cost tier ($$, standard); the part price will be decided by machining time, tolerance and quantity rather than by the material.

Which welds better, P265GH or Q345R?

P265GH. Its weldability rates excellent (90/100) against excellent (85/100) for Q345R.

Ready to make it?

Upload a CAD file and FabDigit prices the part in P265GH and Q345R 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.