Plastic TPU vs. Stainless Steel 303

Compare Plastic TPU vs. Stainless Steel 303 strength, stiffness, weight and thermal properties.

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Mechanical
Try it on a partA bracket to run stress or thermal on, free in your browser	Open in LessCAD	Open in LessCAD
Yield strength	not given (tensile used)	275MPasourceOutokumpu typical (product P = hot rolled plate, transverse)
Ultimate tensile strength	23.7MPasourcetypical, stress at break	585MPasourceOutokumpu typical
Flexural strength	4.1MPasourcetypical	not sourced
Elongation at break	not sourced	35%sourceOutokumpu typical, A5
Young's modulus (stiffness)	0.067GPasourcetypical	200GPasourceat RT (Table 12)
Density	1,220kg/m³sourcetypical	7,900kg/m³sourceat RT
Strength to weight	19.4kN·m/kg	34.8kN·m/kg1.79x higher
Stiffness to weight	0.0549MN·m/kg	25.3MN·m/kg461x higher
Poisson's ratio	not sourced	0.3sourcedesign value (structural stainless steels)
Shear modulus	not sourced	76.9GPa
Bulk modulus	not sourced	167GPa
Speed of sound	234m/s	5,032m/s
Thermal
Thermal conductivity	not sourced	15W/m·Ksourceat RT
Thermal expansion	not sourced	16µm/m·Ksourcemean, 20–100 °C
100 mm part over a 50 °C swing	not sourced	80µm growth
Specific heat	not sourced	500J/kg·Ksourceat RT
Heats up and cools (diffusivity)	not sourced	3.8mm²/s
Thermal shock resistance	not sourced	902W/m
Melting point	217°Csourcetypical	not sourced
Max service temperature	50.3°CsourceHDT 0.455 MPa (printed specimens)	871°Csourcecontinuous, scaling limit
Values for	Ultimaker TPU 95A, 3D-printed specimens, XY (flat); Ultimaker S5 Pro, engineering intent profile, 0.15 mm layer height, AA 0.4 print core, 100% infill, Cura 4.9, printed one-at-a-time, conditioned >=24 h at room temperature. TDS (file v5.00), April 29, 2022.	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

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.

Plastic TPU is 3D printed: its properties depend on build direction and print settings; these are typical values.

Questions

Is Plastic TPU stronger than Stainless Steel 303?

Stainless Steel 303 is stronger: its yield strength is 275 MPa against tensile strength 23.7 MPa for Plastic TPU (11.6x).

Which is lighter, Plastic TPU or Stainless Steel 303?

Plastic TPU is lighter: 1,220 kg/m³ against 7,900 kg/m³ for Stainless Steel 303.

Which is stiffer, Plastic TPU or Stainless Steel 303?

Stainless Steel 303 is stiffer: Young's modulus 200 GPa against 0.067 GPa for Plastic TPU, so the same part in Stainless Steel 303 deflects less under the same load.

Which is lighter for the same job, Plastic TPU or Stainless Steel 303?

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

Part that must be	Plastic TPU	Stainless Steel 303
Stiff rod or tie (tension)	461x heavier	lighter
Stiff beam (bending)	8.44x heavier	lighter
Stiff panel or plate	2.22x heavier	lighter
Strong rod or tie	1.79x heavier	lighter
Strong beam	lighter	26% heavier
Strong panel or plate	lighter	1.9x 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).

Among 72 materials

Stiffness against density

Strength against density