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Steel 34MnB5 vs P690QH

Steel · grade comparison

Steel 34MnB5 and P690QH are both steel grades. P690QH is the stronger of the two: yield strength 740 MPa (107 ksi) against 420 MPa (60.9 ksi) for 34MnB5, about 76% more; tensile strength follows at 830 MPa (120 ksi) vs 620 MPa (89.9 ksi). P690QH is the more ductile: elongation 17% versus 14% for 34MnB5, and P690QH is harder (260 HB vs 185 HB). 34MnB5 conducts heat better (44 W/m·K vs 36 W/m·K). On the shop floor, 34MnB5 machines more easily (good vs fair), P690QH welds better (65 vs 55 out of 100), and P690QH sits in a lower cost tier (budget, $) than 34MnB5 (standard, $$).

34MnB5Choose it when the part is machined in volume.

P690QHChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.

34MnB5 vs P690QH: properties

34MnB5P690QH

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Shear Modulus

80 GPa11.6 Msi
81 GPa11.7 Msi

Bulk Modulus

160 GPa23.2 Msi
166 GPa24.1 Msi

Poisson's Ratio

0.29
0.3

Tensile Strength (Ultimate)

620 MPa89.9 ksi
830 MPa120 ksi

Yield Strength (0.2% offset)

420 MPa60.9 ksi
740 MPa107 ksi

Elongation at Break

14%
17%

Reduction in Area

45%
55%

Shear Strength

400 MPa58 ksi
500 MPa72.5 ksi

Fatigue Strength (Endurance Limit)

280 MPa40.6 ksi
380 MPa55.1 ksi

Fracture Toughness (K_IC)

55 MPa·√m50.1 ksi·√in
130 MPa·√m118 ksi·√in

Charpy V-Notch Impact (RT)

40 J29.5 ft·lbf
100 J73.8 ft·lbf

Hardness, Brinell

185 HB
260 HB

Hardness, Rockwell B

89 HRB
—

Hardness, Vickers

195 HV
273 HV

Compressive Strength

—
740 MPa107 ksi

Hardness, Rockwell C

—
26 HRC

Same in both: Elastic (Young's) Modulus 210 GPa30.5 Msi

Physical

Density and transition temperatures.

Melting Point (Solidus)

1,420°C2,588 °F
1,425°C2,597 °F

Liquidus Temperature

1,495°C2,723 °F
1,500°C2,732 °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

44 W/m·K25.4 BTU/hr·ft·°F
36 W/m·K20.8 BTU/hr·ft·°F

Specific Heat Capacity

470 J/kg·K0.11 BTU/lb·°F
460 J/kg·K0.11 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

12.5 µm/m·K6.9 µin/in·°F
12 µm/m·K6.7 µin/in·°F

Latent Heat of Fusion

250 J/g107 BTU/lb
270 J/g116 BTU/lb

Min Service Temperature

-40°C-40 °F
0°C32 °F

Same in both: Max Service Temperature (continuous) 400°C752 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

8 % IACS
6.6 % IACS

Electrical Resistivity

2.2×10⁻⁷ Ω·m8.66 µΩ·in
2.6×10⁻⁷ Ω·m10.2 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.6 V
-0.61 V

Corrosion Resistance

11 / 100
13 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

55 / 100
40 / 100

Machinability Rating (AISI 1212 = 100 %)

60%
45%

Weldability

55 / 100
65 / 100

Formability (cold)

60 / 100
40 / 100

Same in both: Brazeability / Solderability 45 / 100 · Polishability 55 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

25 MJ/kg10,748 BTU/lb
30 MJ/kg12,898 BTU/lb

Embodied Carbon (primary production)

2 kg CO₂/kg
2.3 kg CO₂/kg

Embodied Water

40 L/kg4.8 gal/lb
60 L/kg7.2 gal/lb

Same in both: Typical Recycled Content 25%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

79 kN·m/kg
106 kN·m/kg

Modulus of Resilience

420 kJ/m³
1,304 kJ/m³

Thermal Diffusivity

11.9 mm²/s
10 mm²/s

Thermal Shock Resistance Index

10
12

Same in both: Specific Stiffness (E / density) 26.8 MN·m/kg

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 scale34MnB5P690QH

Manufacturing and finishing

Capability34MnB5P690QH
Sheet metalYes—
Default conditionCR—
Relative cost$$ Standard$ Budget
Min. machined wall——
Best machined surface——
Black OxideYes—
CerakoteYes—
Chrome PlatingYes—
E-CoatingYes—
Hot-Dip GalvanizingYes—
Nickel PlatingYes—
PTFE CoatingYes—
PaintingYes—
Powder CoatingYes—
Tin PlatingYes—
Zinc PlatingYes—
Zinc-Flake (Dip-Spin) CoatingYes—
Zinc-Nickel PlatingYes—

They share 9 finishes: Copper Plating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Manganese Phosphate, Plasma Spray, Silver Plating, Zinc Phosphate.

34MnB5 vs P690QH — frequently asked

Is P690QH stronger than 34MnB5?

Yes. P690QH has a typical yield strength of 740 MPa (107 ksi) against 420 MPa (60.9 ksi) for 34MnB5 — about 76% more. Tensile strength is 830 MPa (120 ksi) vs 620 MPa (89.9 ksi).

Which is cheaper, 34MnB5 or P690QH?

P690QH is the lower-cost material: it sits in the budget tier ($) while 34MnB5 is standard ($$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.

Which is easier to machine, 34MnB5 or P690QH?

34MnB5. Its machinability rates good (55/100) against fair (40/100) for P690QH; for welding the order is P690QH first (good, 65/100) then 34MnB5 (good, 55/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 34MnB5 and P690QH 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.