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Stainless Steel 1.4578-A vs 1.4578-C900

Stainless Steel · 1.4578 temper comparison

1.4578-A and 1.4578-C900 are two conditions of the same stainless steel grade, 1.4578: A (solution annealed) versus C900. The chemistry is identical, so every difference below comes from the condition. 1.4578-C900 is the stronger of the two: yield strength 700 MPa (102 ksi) against 235 MPa (34.1 ksi) for 1.4578-A, about 198% more; tensile strength follows at 950 MPa (138 ksi) vs 540 MPa (78.3 ksi). In exchange, 1.4578-A is the more ductile: elongation 45% versus 12% for 1.4578-C900, and 1.4578-C900 is harder (280 HB vs 150 HB). 1.4578-A runs hotter in service (425°C vs 290°C continuous). On the shop floor, 1.4578-A welds better (very good vs good).

1.4578-AChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.

1.4578-C900Choose it when strength drives the design.

1.4578-A vs 1.4578-C900: properties

1.4578-A1.4578-C900

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

200 GPa29 Msi
195 GPa28.3 Msi

Tensile Strength (Ultimate)

540 MPa78.3 ksi
950 MPa138 ksi

Yield Strength (0.2% offset)

235 MPa34.1 ksi
700 MPa102 ksi

Elongation at Break

45%
12%

Reduction in Area

70%
42%

Compressive Strength

240 MPa34.8 ksi
720 MPa104 ksi

Shear Strength

380 MPa55.1 ksi
580 MPa84.1 ksi

Fatigue Strength (Endurance Limit)

240 MPa34.8 ksi
370 MPa53.7 ksi

Fracture Toughness (K_IC)

180 MPa·√m164 ksi·√in
100 MPa·√m91 ksi·√in

Charpy V-Notch Impact (RT)

150 J111 ft·lbf
40 J29.5 ft·lbf

Hardness, Brinell

150 HB
280 HB

Hardness, Vickers

160 HV
295 HV

Same in both: Shear Modulus 77 GPa11.2 Msi · Bulk Modulus 140 GPa20.3 Msi · Poisson's Ratio 0.3 · Hardness, Rockwell B 80 HRB

Physical

Density and transition temperatures.

Same in both: Density 8 g/cm³0.29 lb/in³ · Melting Point (Solidus) 1,385°C2,525 °F · Liquidus Temperature 1,425°C2,597 °F

Thermal

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

Max Service Temperature (continuous)

425°C797 °F
290°C554 °F

Same in both: Thermal Conductivity 15 W/m·K8.7 BTU/hr·ft·°F · Specific Heat Capacity 500 J/kg·K0.12 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 16.5 µm/m·K9.2 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -196°C-321 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

7.5×10⁻⁷ Ω·m29.5 µΩ·in
7.6×10⁻⁷ Ω·m29.9 µΩ·in

Same in both: Electrical Conductivity 2.3 % IACS

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

72 / 100
69 / 100

Same in both: Galvanic Potential (seawater, vs SCE) -0.07 V

Manufacturability

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

Machinability

42 / 100
45 / 100

Weldability

70 / 100
58 / 100

Formability (cold)

92 / 100
40 / 100

Same in both: Machinability Rating (AISI 1212 = 100 %) 45% · Brazeability / Solderability 70 / 100 · Polishability 80 / 100

Sustainability

Primary-production footprint per kilogram.

Same in both: Embodied Energy (primary production) 55 MJ/kg23,646 BTU/lb · Embodied Carbon (primary production) 5 kg CO₂/kg · Embodied Water 110 L/kg13.2 gal/lb · Typical Recycled Content 60%

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 scale1.4578

1.4578-A vs 1.4578-C900 — frequently asked

Is 1.4578-C900 stronger than 1.4578-A?

Yes. 1.4578-C900 has a typical yield strength of 700 MPa (102 ksi) against 235 MPa (34.1 ksi) for 1.4578-A — about 198% more. Tensile strength is 950 MPa (138 ksi) vs 540 MPa (78.3 ksi).

Which condition does FabDigit quote by default, A or C900?

A is the default 1.4578 condition in the FabDigit quote flow. The other condition is available on request or by drawing note — specify it in the material field or the part notes and the quote is priced for it.

Which welds better, 1.4578-A or 1.4578-C900?

1.4578-A. Its weldability rates very good (70/100) against good (58/100) for 1.4578-C900.

Ready to make it?

Upload a CAD file and FabDigit prices the part in 1.4578-A and 1.4578-C900 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.