Thermal conductivity against densityHigher and further left: spreads more heat for its weightThermal expansion against thermal conductivityLower and further right: warps less when heated
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Sources6 documents: Outokumpu, Niagara LaSalle, U.S. Department of Defense, Steel Construction Institute, Ovako, Carpenter Technology
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
Steel AISI 1018
AISI 1018 cold drawn bar (Niagara LaSalle, cold-finished bar producer)
1
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
MIL-HDBK-5J, Metallic Materials and Elements for Aerospace Vehicle Structures (2003)U.S. Department of DefenseSteel AISI 1018 · Young's modulus (stiffness): base material: AISI 1025 plain carbon steel (MIL-HDBK-5J design value; ASTM A108 bar is the cold-finished carbon-steel bar spec that also covers 1018)Steel AISI 1018 · Density: base material: AISI 1025 plain carbon steel (MIL-HDBK-5J design value; ASTM A108 bar is the cold-finished carbon-steel bar spec that also covers 1018)Steel AISI 1018 · Poisson's ratio: base material: AISI 1025 plain carbon steel (MIL-HDBK-5J design value; ASTM A108 bar is the cold-finished carbon-steel bar spec that also covers 1018)Steel AISI 1018 · Thermal conductivity: base material: AISI 1025 plain carbon steel (MIL-HDBK-5J design value; ASTM A108 bar is the cold-finished carbon-steel bar spec that also covers 1018)Steel AISI 1018 · Specific heat: base material: AISI 1025 plain carbon steel (MIL-HDBK-5J design value; ASTM A108 bar is the cold-finished carbon-steel bar spec that also covers 1018)
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Design Manual for Structural Stainless Steel, 4th Edition (P413)Steel Construction Institutearchived copyStainless Steel 303 · Poisson's ratio: design value (structural stainless steels)
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S275JR Steel GradeOvakoSteel AISI 1018 · Thermal expansion: base material: unalloyed carbon steel, Ovako family table (S275JR, 'none alloyed structural steels', C <= 0.21%); mean 20-300 °C
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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 Stainless Steel 303 stronger than Steel AISI 1018?
Steel AISI 1018 is stronger: its yield strength is 372 MPa against 275 MPa for Stainless Steel 303 (35%).
Which is lighter, Stainless Steel 303 or Steel AISI 1018?
Steel AISI 1018 is lighter: 7,861 kg/m³ against 7,900 kg/m³ for Stainless Steel 303.
Which is stiffer, Stainless Steel 303 or Steel AISI 1018?
Stainless Steel 303 is stiffer: Young's modulus 200 GPa against 200 GPa for Steel AISI 1018, so the same part in Stainless Steel 303 deflects less under the same load.
Which is lighter for the same job, Stainless Steel 303 or Steel AISI 1018?
For the same stiffness or strength: Steel AISI 1018 is lighter for a strong rod or tie, strong beam, strong panel or plate.
Part that must be
Stainless Steel 303
Steel AISI 1018
Stiff rod or tie (tension)
about equal
about equal
Stiff beam (bending)
about equal
about equal
Stiff panel or plate
about equal
about equal
Strong rod or tie
36% heavier
lighter
Strong beam
23% heavier
lighter
Strong panel or plate
17% 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, Stainless Steel 303 or Steel AISI 1018?
Stainless Steel 303 stretches further before it breaks: 35% elongation at break against 15% for Steel AISI 1018.
Thermal
Which conducts heat better, Stainless Steel 303 or Steel AISI 1018?
Steel AISI 1018 conducts heat better: 51.9 W/m·K against 15 W/m·K for Stainless Steel 303.
Which expands less with temperature?
Steel AISI 1018 expands less: 12 µm/m·K against 16 µm/m·K for Stainless Steel 303.