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Steel 15B35 vs 20B46

Steel · grade comparison

Steel 15B35 and 20B46 are both steel grades. 20B46 is the stronger of the two: yield strength 880 MPa (128 ksi) against 620 MPa (89.9 ksi) for 15B35, about 42% more; tensile strength follows at 1,030 MPa (149 ksi) vs 730 MPa (106 ksi). 20B46 is the more ductile: elongation 16% versus 13% for 15B35, and 20B46 is harder (311 HB vs 217 HB). 20B46 runs hotter in service (400°C vs 350°C continuous) and 15B35 conducts electricity better (9.5 % IACS vs 8 % IACS). On the shop floor, 15B35 machines more easily (good vs fair) and 15B35 welds better (fair vs poor).

15B35Choose it when the part is machined in volume, or when it will be welded.

20B46Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.

15B35 vs 20B46: properties

15B3520B46

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

730 MPa106 ksi
1,030 MPa149 ksi

Yield Strength (0.2% offset)

620 MPa89.9 ksi
880 MPa128 ksi

Elongation at Break

13%
16%

Reduction in Area

40%
52%

Compressive Strength

620 MPa89.9 ksi
890 MPa129 ksi

Shear Strength

440 MPa63.8 ksi
620 MPa89.9 ksi

Fatigue Strength (Endurance Limit)

330 MPa47.9 ksi
465 MPa67.4 ksi

Charpy V-Notch Impact (RT)

25 J18.4 ft·lbf
40 J29.5 ft·lbf

Hardness, Brinell

217 HB
311 HB

Hardness, Rockwell B

96 HRB
—

Fracture Toughness (K_IC)

—
70 MPa·√m63.7 ksi·√in

Hardness, Rockwell C

—
32 HRC

Hardness, Vickers

—
327 HV

Same in both: Elastic (Young's) Modulus 205 GPa29.7 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29

Physical

Density and transition temperatures.

Melting Point (Solidus)

1,425°C2,597 °F
1,420°C2,588 °F

Liquidus Temperature

1,495°C2,723 °F
1,490°C2,714 °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

46 W/m·K26.6 BTU/hr·ft·°F
44 W/m·K25.4 BTU/hr·ft·°F

Specific Heat Capacity

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

Thermal Expansion (CTE, 20–100 °C)

11.9 µm/m·K6.6 µin/in·°F
12.2 µm/m·K6.8 µin/in·°F

Latent Heat of Fusion

247 J/g106 BTU/lb
250 J/g107 BTU/lb

Max Service Temperature (continuous)

350°C662 °F
400°C752 °F

Min Service Temperature

-30°C-22 °F
-40°C-40 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

9.5 % IACS
8 % IACS

Electrical Resistivity

1.8×10⁻⁷ Ω·m7.09 µΩ·in
2.2×10⁻⁷ Ω·m8.66 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.61 V
-0.65 V

Corrosion Resistance

10 / 100
12 / 100

Manufacturability

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

Machinability

55 / 100
45 / 100

Machinability Rating (AISI 1212 = 100 %)

65%
45%

Weldability

40 / 100
30 / 100

Formability (cold)

55 / 100
30 / 100

Brazeability / Solderability

60 / 100
45 / 100

Polishability

55 / 100
60 / 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)

1.9 kg CO₂/kg
2.3 kg CO₂/kg

Embodied Water

40 L/kg4.8 gal/lb
55 L/kg6.6 gal/lb

Same in both: Typical Recycled Content 30%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

93 kN·m/kg
131 kN·m/kg

Modulus of Resilience

938 kJ/m³
1,889 kJ/m³

Thermal Diffusivity

12.3 mm²/s
11.9 mm²/s

Thermal Shock Resistance Index

14
18

Same in both: Specific Stiffness (E / density) 26.1 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 scale15B3520B46

Manufacturing and finishing

Capability15B3520B46
Default condition——
Relative cost$ Budget$ Budget
Min. machined wall——
Best machined surface——

Both take the same 9 finishes: Copper Plating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Manganese Phosphate, Plasma Spray, Silver Plating, Zinc Phosphate.

15B35 vs 20B46 — frequently asked

Is 20B46 stronger than 15B35?

Yes. 20B46 has a typical yield strength of 880 MPa (128 ksi) against 620 MPa (89.9 ksi) for 15B35 — about 42% more. Tensile strength is 1,030 MPa (149 ksi) vs 730 MPa (106 ksi).

Which is cheaper, 15B35 or 20B46?

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

Which is easier to machine, 15B35 or 20B46?

15B35. Its machinability rates good (55/100) against fair (45/100) for 20B46; for welding the order is 15B35 first (fair, 40/100) then 20B46 (poor, 30/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 15B35 and 20B46 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.