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Stainless Steel Alloy 20 vs S35125

Stainless Steel · grade comparison

Stainless Steel Alloy 20 and S35125 are both stainless steel grades. Alloy 20 is the stronger of the two: yield strength 310 MPa (45 ksi) against 270 MPa (39.2 ksi) for S35125, about 15% more. In exchange, S35125 is the more ductile: elongation 45% versus 40% for Alloy 20. S35125 runs hotter in service (1,100°C vs 500°C continuous). On the shop floor, Alloy 20 machines more easily (fair vs poor), Alloy 20 welds better (80 vs 70 out of 100), and S35125 sits in a lower cost tier (high, $$$$) than Alloy 20 (specialty, $$$$$).

Alloy 20Choose it when strength drives the design, or when the part is machined in volume.

S35125Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.

Alloy 20 vs S35125: properties

Alloy 20S35125

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

193 GPa28 Msi
195 GPa28.3 Msi

Shear Modulus

74 GPa10.7 Msi
75 GPa10.9 Msi

Tensile Strength (Ultimate)

620 MPa89.9 ksi
600 MPa87 ksi

Yield Strength (0.2% offset)

310 MPa45 ksi
270 MPa39.2 ksi

Elongation at Break

40%
45%

Reduction in Area

60%
55%

Shear Strength

415 MPa60.2 ksi
400 MPa58 ksi

Fatigue Strength (Endurance Limit)

260 MPa37.7 ksi
250 MPa36.3 ksi

Charpy V-Notch Impact (RT)

190 J140 ft·lbf
130 J95.9 ft·lbf

Hardness, Brinell

160 HB
165 HB

Hardness, Vickers

—
175 HV

Same in both: Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.3 · Hardness, Rockwell B 85 HRB

Physical

Density and transition temperatures.

Density

8.08 g/cm³0.29 lb/in³
7.95 g/cm³0.29 lb/in³

Melting Point (Solidus)

1,370°C2,498 °F
1,330°C2,426 °F

Liquidus Temperature

1,425°C2,597 °F
1,385°C2,525 °F

Thermal

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

Thermal Conductivity

12 W/m·K6.9 BTU/hr·ft·°F
11.5 W/m·K6.6 BTU/hr·ft·°F

Specific Heat Capacity

500 J/kg·K0.12 BTU/lb·°F
460 J/kg·K0.11 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

14.8 µm/m·K8.2 µin/in·°F
15 µm/m·K8.3 µin/in·°F

Latent Heat of Fusion

285 J/g123 BTU/lb
—

Max Service Temperature (continuous)

500°C932 °F
1,100°C2,012 °F

Same in both: Min Service Temperature -196°C-321 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

1.6 % IACS
1.7 % IACS

Electrical Resistivity

1.08×10⁻⁶ Ω·m42.5 µΩ·in
1×10⁻⁶ Ω·m39.4 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.08 V
—

Corrosion Resistance

80 / 100
72 / 100

Manufacturability

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

Machinability

38 / 100
25 / 100

Machinability Rating (AISI 1212 = 100 %)

40%
28%

Weldability

80 / 100
70 / 100

Formability (cold)

72 / 100
60 / 100

Castability

55 / 100
—

Brazeability / Solderability

60 / 100
55 / 100

Polishability

75 / 100
65 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

100 MJ/kg42,992 BTU/lb
90 MJ/kg38,693 BTU/lb

Embodied Carbon (primary production)

7.5 kg CO₂/kg
6.8 kg CO₂/kg

Embodied Water

200 L/kg24 gal/lb
250 L/kg30 gal/lb

Typical Recycled Content

45%
40%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

77 kN·m/kg
75 kN·m/kg

Specific Stiffness (E / density)

23.9 MN·m/kg
24.5 MN·m/kg

Modulus of Resilience

249 kJ/m³
187 kJ/m³

Thermal Diffusivity

3 mm²/s
3.1 mm²/s

Thermal Shock Resistance Index

3
2

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 scaleAlloy 20S35125

Manufacturing and finishing

CapabilityAlloy 20S35125
CNC machiningYes—
Sheet metalYes—
Default conditionAnnealed—
Relative cost$$$$$ Specialty$$$$ High
Min. machined wall0.8 mm—
Best machined surfaceRa 1.6 µm—
AlCrNYes—
AlTiNYes—
Black OxideYes—
CVD Al2O3Yes—
CVD TiCNYes—
CVD TiNYes—
CerakoteYes—
Chrome PlatingYes—
CrNYes—
DLCYes—
ElectropolishingYes—
HVOF CoatingYes—
MoS2Yes—
Multilayer CVDYes—
Nickel PlatingYes—
PTFE CoatingYes—
PaintingYes—
Passivation (Stainless Steel)Yes—

They share 7 finishes: Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Pickling, Plasma Spray, Silver Plating.

Alloy 20 vs S35125 — frequently asked

Is Alloy 20 stronger than S35125?

Yes. Alloy 20 has a typical yield strength of 310 MPa (45 ksi) against 270 MPa (39.2 ksi) for S35125 — about 15% more. Tensile strength is 620 MPa (89.9 ksi) vs 600 MPa (87 ksi).

Which is cheaper, Alloy 20 or S35125?

S35125 is the lower-cost material: it sits in the high tier ($$$$) while Alloy 20 is specialty ($$$$$). 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, Alloy 20 or S35125?

Alloy 20. Its machinability rates fair (38/100) against poor (25/100) for S35125; for welding the order is Alloy 20 first (very good, 80/100) then S35125 (very good, 70/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in Alloy 20 and S35125 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.