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Plastic Nylon PA6 vs. Steel AISI 1045

Compare Plastic Nylon PA6 vs. Steel AISI 1045 strength, stiffness, weight and thermal properties.

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Plastic Nylon PA6Bulk polymer (molded or machined)
Steel AISI 1045Wrought
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Mechanical
Yield strength90MPasourcetypical, dry531MPasourceproducer-stated, cold drawn
Ultimate tensile strengthnot sourced627MPasourceproducer-stated, cold drawn
Elongation at break10%sourcenominal strain at break, dry12%sourcein 2 in (50.8 mm)
Young's modulus (stiffness)3.5GPasourcetypical, dry210GPasourcetypical
Density1,130kg/m³sourcetypical6.9x lighter7,800kg/m³sourcetypical
Strength to weight79.6kN·m/kg17% higher68.1kN·m/kg
Stiffness to weight3.1MN·m/kg26.9MN·m/kg8.69x higher
Poisson's ratio0.4sourcebase material: unfilled polyamide (PA), conditioned, maker design-guide family value (Covestro Table 3-1)0.3sourcetypical
Shear modulus1.25GPa80.8GPa64.6x stiffer in shear
Bulk modulus5.83GPa175GPa
Speed of sound1,760m/s5,189m/s
Thermal
Thermal conductivity0.33W/m·Ksourcetypical40–45W/m·Ksourcetypical range, ambient
Thermal expansion102µm/m·Ksourcelongitudinal, 23-55 °C12µm/m·Ksourcetypical, mean 20-300 °C
100 mm part over a 50 °C swing510µm growth60µm growth8.5x less
Specific heat1,700J/kg·Ksourcetypical460–480J/kg·Ksourcetypical range, 50/100 °C
Heats up and cools (diffusivity)0.172mm²/s11.6mm²/s67.5x faster
Thermal shock resistance49.9W/m6,269W/m126x more resistant
Melting point220°CsourceDSCnot sourced
Max service temperature87°CsourceIEC 60216 temperature index, 20000 hnot sourced
Values forBASF Ultramid B3S (PA6, unreinforced injection-moulding grade), Product Information 02/2026, dry values (ISO methods)AISI 1045 cold drawn bar (Niagara LaSalle) for mechanical; Ovako C45 (lists 'SAE 1045' as a similar designation) for physical constants

Every value links to the document that states it. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.

Questions

Is Plastic Nylon PA6 stronger than Steel AISI 1045?

Steel AISI 1045 is stronger: its yield strength is 531 MPa against 90 MPa for Plastic Nylon PA6 (5.9x).

Which is lighter, Plastic Nylon PA6 or Steel AISI 1045?

Plastic Nylon PA6 is lighter: 1,130 kg/m³ against 7,800 kg/m³ for Steel AISI 1045.

Which is stiffer, Plastic Nylon PA6 or Steel AISI 1045?

Steel AISI 1045 is stiffer: Young's modulus 210 GPa against 3.5 GPa for Plastic Nylon PA6, so the same part in Steel AISI 1045 deflects less under the same load.

Which is lighter for the same job, Plastic Nylon PA6 or Steel AISI 1045?

For the same stiffness or strength: Plastic Nylon PA6 is lighter for a stiff panel or plate, strong rod or tie, strong beam, strong panel or plate; Steel AISI 1045 is lighter for a stiff rod or tie (tension), stiff beam (bending).

Part that must bePlastic Nylon PA6Steel AISI 1045
Stiff rod or tie (tension)8.69x heavierlighter
Stiff beam (bending)12% heavierlighter
Stiff panel or platelighter1.76x heavier
Strong rod or tielighter17% heavier
Strong beamlighter2.11x heavier
Strong panel or platelighter2.84x heavier

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 conducts heat better, Plastic Nylon PA6 or Steel AISI 1045?

Steel AISI 1045 conducts heat better: 42.5 W/m·K against 0.33 W/m·K for Plastic Nylon PA6.

Which expands less with temperature?

Steel AISI 1045 expands less: 12 µm/m·K against 102 µm/m·K for Plastic Nylon PA6.

Among 59 materials

1k10k0.1110100Density (kg/m³)Young's modulus (GPa)Plastic PLAPlastic PETGPlastic ABSPlastic TPUPlastic NylonAluminumSteelIronTitaniumSteel AISI 1018Stainless 304Stainless 316Aluminum 6061-T6Aluminum 7075-T6Brass C360Copper C110GlassSteel AISI 4340Steel A992Stainless 303Stainless 17-4PHAluminum 2024-T351Aluminum 5052-H32Aluminum 7050-T7451Titanium Ti-6Al-4VBrass C260Nickel Inconel 718Magnesium AZ31B-H24Zinc Zamak 3Plastic ABS (bulk/injection)Plastic PolycarbonatePlastic POM/AcetalPlastic Nylon PA66Plastic PEEKPlastic UHMWPEPlastic HDPEPlastic PolypropylenePlastic PMMAFDM ASAFDM PolycarbonateFDM PAHT-CFFDM HIPSSLA Resin Tough 2000SLS PA12 NylonDMLS AlSi10Mg AluminumDMLS Ti-6Al-4V ELI TitaniumDMLS 316L Stainless SteelDMLS 17-4PH Stainless SteelPlastic Nylon PA6Steel AISI 1045
Stiffness against density
1k10k101001kDensity (kg/m³)Yield strength (MPa)Plastic PLAPlastic PETGPlastic ABSPlastic TPUPlastic NylonRubberAluminumSteelIronTitaniumSteel AISI 1018Stainless 304Stainless 316Aluminum 6061-T6Aluminum 7075-T6Brass C360Copper C110GlassSteel AISI 4340Steel A992Stainless 303Stainless 17-4PHAluminum 2024-T351Aluminum 5052-H32Aluminum 7050-T7451Titanium Ti-6Al-4VBrass C260Nickel Inconel 718Magnesium AZ31B-H24Zinc Zamak 3Plastic ABS (bulk/injection)Plastic PolycarbonatePlastic POM/AcetalPlastic Nylon PA66Plastic PEEKPlastic PTFEPlastic UHMWPEPlastic HDPEPlastic PolypropylenePlastic PMMAFDM ASAFDM PolycarbonateFDM PAHT-CFFDM HIPSSLA Resin Tough 2000SLA Resin Elastic 50ASLS PA12 NylonDMLS AlSi10Mg AluminumDMLS Ti-6Al-4V ELI TitaniumDMLS 316L Stainless SteelDMLS 17-4PH Stainless SteelBrickPlastic Nylon PA6Steel AISI 1045
Strength against density

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