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Stainless Steel CA15M vs CA40F

Stainless Steel · grade comparison

Stainless Steel CA15M and CA40F are both stainless steel grades. Both yield at about 550 MPa — strength does not separate them. CA15M is the more ductile: elongation 22% versus 14% for CA40F, and CA40F is harder (240 HB vs 225 HB). On the shop floor, CA40F machines more easily (good vs fair) and CA15M welds better (fair vs poor).

CA15MChoose it when the part is bent, formed or impact-loaded, or when it will be welded.

CA40FChoose it when the part is machined in volume.

CA15M vs CA40F: properties

CA15MCA40F

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Shear Modulus

78 GPa11.3 Msi
77 GPa11.2 Msi

Tensile Strength (Ultimate)

725 MPa105 ksi
760 MPa110 ksi

Yield Strength (0.2% offset)

550 MPa79.8 ksi
570 MPa82.7 ksi

Elongation at Break

22%
14%

Reduction in Area

55%
25%

Compressive Strength

560 MPa81.2 ksi
580 MPa84.1 ksi

Shear Strength

450 MPa65.3 ksi
460 MPa66.7 ksi

Fatigue Strength (Endurance Limit)

330 MPa47.9 ksi
300 MPa43.5 ksi

Fracture Toughness (K_IC)

80 MPa·√m72.8 ksi·√in
50 MPa·√m45.5 ksi·√in

Charpy V-Notch Impact (RT)

40 J29.5 ft·lbf
12 J8.9 ft·lbf

Hardness, Brinell

225 HB
240 HB

Hardness, Rockwell C

20 HRC
22 HRC

Hardness, Vickers

235 HV
250 HV

Same in both: Elastic (Young's) Modulus 200 GPa29 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.28

Physical

Density and transition temperatures.

Same in both: Density 7.61 g/cm³0.27 lb/in³ · Melting Point (Solidus) 1,450°C2,642 °F · Liquidus Temperature 1,510°C2,750 °F

Thermal

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

Thermal Expansion (CTE, 20–100 °C)

10.8 µm/m·K6 µin/in·°F
10.3 µm/m·K5.7 µin/in·°F

Max Service Temperature (continuous)

650°C1,202 °F
620°C1,148 °F

Min Service Temperature

-30°C-22 °F
-20°C-4 °F

Same in both: Thermal Conductivity 24.2 W/m·K14 BTU/hr·ft·°F · Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Latent Heat of Fusion 270 J/g116 BTU/lb

Electrical

Conductivity and insulation.

Same in both: Electrical Conductivity 3 % IACS · Electrical Resistivity 5.7×10⁻⁷ Ω·m22.4 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.3 V
-0.35 V

Corrosion Resistance

45 / 100
35 / 100

Manufacturability

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

Machinability

45 / 100
58 / 100

Machinability Rating (AISI 1212 = 100 %)

45%
65%

Weldability

40 / 100
15 / 100

Formability (cold)

10 / 100
5 / 100

Castability

70 / 100
68 / 100

Brazeability / Solderability

45 / 100
30 / 100

Polishability

70 / 100
45 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Carbon (primary production)

4 kg CO₂/kg
4.3 kg CO₂/kg

Embodied Water

130 L/kg15.6 gal/lb
220 L/kg26.4 gal/lb

Same in both: Embodied Energy (primary production) 53 MJ/kg22,786 BTU/lb · Typical Recycled Content 75%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

95 kN·m/kg
100 kN·m/kg

Modulus of Resilience

756 kJ/m³
812 kJ/m³

Thermal Shock Resistance Index

8
9

Same in both: Specific Stiffness (E / density) 26.3 MN·m/kg · Thermal Diffusivity 6.9 mm²/s

Strength versus weight

Yield strength against density for every stainless steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

3005007001,0001,5002,0007.27.47.67.888.2Density (g/cm³)Yield strength (MPa) — log scaleCA15MCA40F

Manufacturing and finishing

CapabilityCA15MCA40F
Default condition——
Relative cost$$$ Premium$$$ Premium
Min. machined wall——
Best machined surface——

Both take the same 7 finishes: Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Pickling, Plasma Spray, Silver Plating.

CA15M vs CA40F — frequently asked

What is the difference between CA15M and CA40F?

Stainless Steel CA15M and CA40F are both stainless steel grades. Both yield at about 550 MPa — strength does not separate them. CA15M is the more ductile: elongation 22% versus 14% for CA40F, and CA40F is harder (240 HB vs 225 HB).

Which is cheaper, CA15M or CA40F?

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

Which is easier to machine, CA15M or CA40F?

CA40F. Its machinability rates good (58/100) against fair (45/100) for CA15M; for welding the order is CA15M first (fair, 40/100) then CA40F (poor, 15/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in CA15M and CA40F 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.