Copper C10100 vs. Stainless Steel 303

Compare Copper C10100 vs. Stainless Steel 303 strength, stiffness, weight and thermal properties.

Mechanical	Copper C10100	Stainless Steel 303
Yield strength	69MPa1	Outokumpu typical275MPa23.99x stronger
Ultimate tensile strength	221MPa1	Outokumpu typical585MPa22.65x stronger
Elongation at break	45%129% more ductile	Outokumpu typical35%2
Young's modulus (stiffness)	117GPa1	at RT200GPa21.71x stiffer
Density	8,941kg/m³1	at RT7,900kg/m³213% lighter
Strength to weight	7.72kN·m/kg	34.8kN·m/kg4.51x higher
Stiffness to weight	13.1MN·m/kg	25.3MN·m/kg1.93x higher
Poisson's ratio	0.343	design value0.34
Shear modulus	43.7GPa	76.9GPa1.76x stiffer in shear
Bulk modulus	122GPa	167GPa37% higher
Speed of sound	3,621m/s	5,032m/s39% faster

Stiffness against densityHigher and further left: stiffer for its weight

Strength against densityHigher and further left: stronger for its weight

Thermal	Copper C10100	Stainless Steel 303
Thermal conductivity	391W/m·K126.1x more heat through a fin	at RT15W/m·K2
Thermal expansion	16.9µm/m·K1	mean16µm/m·K2
100 mm part over a 50 °C swing	84.5µm growth	80µm growth6% less
Specific heat	385J/kg·K1	at RT500J/kg·K230% higher
Heats up and cools (diffusivity)	114mm²/s29.9x faster	3.8mm²/s
Thermal shock resistance	8,992W/m9.97x more resistant	902W/m
Melting point	melting point1,083°C1	not sourced
Max service temperature	not sourced	continuous871°C5

Thermal conductivity against densityHigher and further left: spreads more heat for its weight

Thermal expansion against thermal conductivityLower and further right: warps less when heated

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Sources5 documents: Copper Development Association, Outokumpu, Wieland, Steel Construction Institute, Carpenter Technology

Copper C10100: C10100 oxygen-free electronic (OFE) copper, annealed to 0.050 mm grain size (OS050), 0.04 in. flat products, copper.org typical values
Stainless Steel 303: 1.4305 / UNS S30300, Outokumpu typical values (hot rolled, solution annealed) from 'Steel Grades, Properties and Global Standards'; max service from Carpenter CarTech 303 datasheet

1
C10100 Alloy (copper.org)Copper Development Associationarchived copyCopper C10100 · Yield strength: typical, 0.5% extension under load, 0.04 in. flatCopper C10100 · Ultimate tensile strength: typical, 0.04 in. flatCopper C10100 · Elongation at break: typical, 0.04 in. flatCopper C10100 · Young's modulus (stiffness): typicalCopper C10100 · Density: nominalCopper C10100 · Thermal conductivity: typical, 20 °CCopper C10100 · Thermal expansion: typical, mean 20-100 °CCopper C10100 · Specific heat: typical, 20 °CCopper C10100 · Melting point: melting point (liquidus = solidus, pure copper)
2
Steel Grades, Properties and Global StandardsOutokumpuarchived copyStainless Steel 303 · Yield strength: Outokumpu typical (product P = hot rolled plate, transverse)Stainless Steel 303 · Ultimate tensile strength: Outokumpu typicalStainless Steel 303 · Elongation at break: Outokumpu typical, A5Stainless Steel 303 · Young's modulus (stiffness): at RT (Table 12)Stainless Steel 303 · Density: at RTStainless Steel 303 · Thermal conductivity: at RTStainless Steel 303 · Thermal expansion: mean, 20–100 °CStainless Steel 303 · Specific heat: at RT
3
Wieland-K09 (Cu-OFE, C10100) Data SheetWielandCopper C10100 · Poisson's ratio: reference value at room temperature (Wieland-K09 = Cu-OFE = C10100, rolled products)
4
Design Manual for Structural Stainless Steel, 4th Edition (P413)Steel Construction Institutearchived copyStainless Steel 303 · Poisson's ratio: design value (structural stainless steels)
5
Carpenter Stainless Type 303 Data SheetCarpenter Technologyarchived copyStainless Steel 303 · Max service temperature: continuous, scaling limit

Each number points to the document that states it, with the exact basis. Values without a number are computed from the sourced ones. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.

Questions

Mechanical

Is Copper C10100 stronger than Stainless Steel 303?

Stainless Steel 303 is stronger: its yield strength is 275 MPa against 69 MPa for Copper C10100 (3.99x).

Which is lighter, Copper C10100 or Stainless Steel 303?

Stainless Steel 303 is lighter: 7,900 kg/m³ against 8,941 kg/m³ for Copper C10100.

Which is stiffer, Copper C10100 or Stainless Steel 303?

Stainless Steel 303 is stiffer: Young's modulus 200 GPa against 117 GPa for Copper C10100, so the same part in Stainless Steel 303 deflects less under the same load.

Which is lighter for the same job, Copper C10100 or Stainless Steel 303?

For the same stiffness or strength: Stainless Steel 303 is lighter for a stiff rod or tie (tension), stiff beam (bending), stiff panel or plate, strong rod or tie, strong beam, strong panel or plate.

Part that must be	Copper C10100	Stainless Steel 303
Stiff rod or tie (tension)	1.93x heavier	lighter
Stiff beam (bending)	48% heavier	lighter
Stiff panel or plate	35% heavier	lighter
Strong rod or tie	4.51x heavier	lighter
Strong beam	2.84x heavier	lighter
Strong panel or plate	2.26x heavier	lighter

For the same stiffness or strength, mass scales with density over stiffness (or strength) raised to a power set by how the part is loaded: 1 for a rod in tension, 1/2 for a beam in bending, 1/3 for a panel (the standard material-selection indices).

Which is more ductile, Copper C10100 or Stainless Steel 303?

Copper C10100 stretches further before it breaks: 45% elongation at break against 35% for Stainless Steel 303.

Thermal

Which conducts heat better, Copper C10100 or Stainless Steel 303?

Copper C10100 conducts heat better: 391 W/m·K against 15 W/m·K for Stainless Steel 303.

Which expands less with temperature?

Stainless Steel 303 expands less: 16 µm/m·K against 16.9 µm/m·K for Copper C10100.