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Steel 34MnB5 vs P420QH

Steel · grade comparison

Steel 34MnB5 and P420QH are both steel grades. P420QH is the stronger of the two: yield strength 470 MPa (68.2 ksi) against 420 MPa (60.9 ksi) for 34MnB5, about 12% more. P420QH is the more ductile: elongation 22% versus 14% for 34MnB5, and P420QH is harder (195 HB vs 185 HB). 34MnB5 conducts heat better (44 W/m·K vs 39 W/m·K). On the shop floor, P420QH welds better (68 vs 55 out of 100) and P420QH sits in a lower cost tier (budget, $) than 34MnB5 (standard, $$).

P420QHChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.

34MnB5 vs P420QH: properties

34MnB5P420QH

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
165 GPa23.9 Msi

Poisson's Ratio

0.29
0.3

Tensile Strength (Ultimate)

620 MPa89.9 ksi
590 MPa85.6 ksi

Yield Strength (0.2% offset)

420 MPa60.9 ksi
470 MPa68.2 ksi

Elongation at Break

14%
22%

Reduction in Area

45%
60%

Shear Strength

400 MPa58 ksi
360 MPa52.2 ksi

Fracture Toughness (K_IC)

55 MPa·√m50.1 ksi·√in
100 MPa·√m91 ksi·√in

Charpy V-Notch Impact (RT)

40 J29.5 ft·lbf
90 J66.4 ft·lbf

Hardness, Brinell

185 HB
195 HB

Hardness, Rockwell B

89 HRB
92 HRB

Hardness, Vickers

195 HV
205 HV

Compressive Strength

—
470 MPa68.2 ksi

Hardness, Rockwell C

—
12 HRC

Same in both: Elastic (Young's) Modulus 210 GPa30.5 Msi · Fatigue Strength (Endurance Limit) 280 MPa40.6 ksi

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
39 W/m·K22.5 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
-20°C-4 °F

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

Electrical

Conductivity and insulation.

Electrical Conductivity

8 % IACS
7.2 % IACS

Electrical Resistivity

2.2×10⁻⁷ Ω·m8.66 µΩ·in
2.4×10⁻⁷ Ω·m9.45 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.6 V
-0.62 V

Corrosion Resistance

11 / 100
13 / 100

Manufacturability

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

Machinability

55 / 100
48 / 100

Machinability Rating (AISI 1212 = 100 %)

60%
58%

Weldability

55 / 100
68 / 100

Formability (cold)

60 / 100
45 / 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
29 MJ/kg12,468 BTU/lb

Embodied Carbon (primary production)

2 kg CO₂/kg
2.1 kg CO₂/kg

Embodied Water

40 L/kg4.8 gal/lb
45 L/kg5.4 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
75 kN·m/kg

Modulus of Resilience

420 kJ/m³
526 kJ/m³

Thermal Diffusivity

11.9 mm²/s
10.8 mm²/s

Thermal Shock Resistance Index

10
9

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 scale34MnB5P420QH

Manufacturing and finishing

Capability34MnB5P420QH
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 P420QH — frequently asked

Is P420QH stronger than 34MnB5?

Yes. P420QH has a typical yield strength of 470 MPa (68.2 ksi) against 420 MPa (60.9 ksi) for 34MnB5 — about 12% more. Tensile strength is 590 MPa (85.6 ksi) vs 620 MPa (89.9 ksi).

Which is cheaper, 34MnB5 or P420QH?

P420QH 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 P420QH?

34MnB5. Its machinability rates good (55/100) against fair (48/100) for P420QH; for welding the order is P420QH first (good, 68/100) then 34MnB5 (good, 55/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 34MnB5 and P420QH 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.