Steel 15B35 vs 45B
Steel · grade comparison
Steel 15B35 and 45B are both steel grades. 15B35 is the stronger of the two: yield strength 620 MPa (89.9 ksi) against 400 MPa (58 ksi) for 45B, about 55% more. In exchange, 45B is the more ductile: elongation 16% versus 13% for 15B35, and 15B35 is harder (217 HB vs 197 HB). 45B runs hotter in service (400°C vs 350°C continuous).
15B35Choose it when strength drives the design.
45BChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
15B35 vs 45B: 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.
Elastic (Young's) Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Same in both: Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Reduction in Area 40%
Physical
Density and transition temperatures.
Melting Point (Solidus)
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Liquidus Temperature 1,495°C2,723 °F
Thermal
How each material carries heat and how hot it can run.
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Latent Heat of Fusion
Max Service Temperature (continuous)
Min Service Temperature
Same in both: Thermal Conductivity 46 W/m·K26.6 BTU/hr·ft·°F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.61 V · Corrosion Resistance 10 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability Rating (AISI 1212 = 100 %)
Formability (cold)
Brazeability / Solderability
Same in both: Machinability 55 / 100 · Weldability 40 / 100 · Polishability 55 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Water
Same in both: Embodied Energy (primary production) 25 MJ/kg10,748 BTU/lb · Embodied Carbon (primary production) 1.9 kg CO₂/kg · Typical Recycled Content 30%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
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.
Manufacturing and finishing
| Capability | 15B35 | 45B |
|---|---|---|
| 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 45B — frequently asked
Is 15B35 stronger than 45B?
Yes. 15B35 has a typical yield strength of 620 MPa (89.9 ksi) against 400 MPa (58 ksi) for 45B — about 55% more. Tensile strength is 730 MPa (106 ksi) vs 700 MPa (102 ksi).
Which is cheaper, 15B35 or 45B?
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.
When should I choose 15B35 over 45B?
Pick 15B35 when strength drives the design. Pick 45B when the part is bent, formed or impact-loaded, or when the part sees heat.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 15B35 and 45B 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.