DMLS 316L Stainless Steel vs. Plastic Polypropylene

Compare DMLS 316L Stainless Steel vs. Plastic Polypropylene strength, stiffness, weight and thermal properties.

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DMLS 316L Stainless Steel3D printed metal (DMLS)

Plastic PolypropyleneBulk polymer (molded or machined)

Mechanical
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Yield strength	530MPasourcetypical, as manufactured, horizontal	33MPasourcetypical, tensile stress at yield ISO 527
Ultimate tensile strength	640MPasourcetypical, as manufactured, horizontal	not sourced
Elongation at break	40%sourcetypical at break, as manufactured, horizontal	not sourced
Young's modulus (stiffness)	185GPasourcetypical, as built, horizontal (XY); EOSINT M280-400W / M290-400W, 316L_Surface 1.0, 20 µm (2014 sheet)	1.45GPasourcetypical, tensile modulus ISO 527
Density	7,900kg/m³sourcepart density (ISO 3369, not labelled min or typical), EOS M 290, 40 µm FlexLine	900kg/m³sourcetypical, 23 °C ISO 1183-1
Strength to weight	67.1kN·m/kg1.83x higher	36.7kN·m/kg
Stiffness to weight	23.4MN·m/kg14.5x higher	1.61MN·m/kg
Poisson's ratio	0.3sourcebase material: austenitic stainless steels incl. 1.4404 (316L), design value	0.42sourcebase material: polypropylene homopolymer family (INEOS Olefins & Polymers USA, Typical Engineering Properties of Polypropylene)
Shear modulus	71.2GPa139x stiffer in shear	0.511GPa
Bulk modulus	154GPa	3.02GPa
Speed of sound	4,839m/s	1,269m/s
Thermal
Thermal conductivity	16.2W/m·Ksourcebase material: wrought 316/316L (Cleveland-Cliffs), at 100 °C	0.17–0.22W/m·Ksourcebase material: polypropylene homopolymer family (INEOS Olefins & Polymers USA, Typical Engineering Properties of Polypropylene)
Thermal expansion	15.7µm/m·Ksourcemean 25-100 °C, ASTM E228	80–100µm/m·Ksourcebase material: polypropylene homopolymer family (INEOS Olefins & Polymers USA, Typical Engineering Properties of Polypropylene)
100 mm part over a 50 °C swing	78.6µm growth5.73x less	450µm growth
Specific heat	500J/kg·Ksourcebase material: wrought 316/316L (Cleveland-Cliffs), 0-100 °C	not sourced
Heats up and cools (diffusivity)	4.1mm²/s	not sourced
Thermal shock resistance	2,067W/m72.3x more resistant	28.6W/m
Max service temperature	not sourced	90°CsourceHDT 0.45 MPa (ISO 75B), unannealed
Values for	EOS StainlessSteel 316L (powder 9011-0032), EOS M 290, ParameterSet 316L 20µm Surface M290/400W, as manufactured, horizontal; ISO 6892-1	LyondellBasell Moplen HP501H polypropylene homopolymer (general purpose), typical ISO values

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.

DMLS 316L Stainless Steel is 3D printed: its properties depend on build direction and print settings; these are typical values.

Questions

Is DMLS 316L Stainless Steel stronger than Plastic Polypropylene?

DMLS 316L Stainless Steel is stronger: its yield strength is 530 MPa against 33 MPa for Plastic Polypropylene (16.1x).

Which is lighter, DMLS 316L Stainless Steel or Plastic Polypropylene?

Plastic Polypropylene is lighter: 900 kg/m³ against 7,900 kg/m³ for DMLS 316L Stainless Steel.

Which is stiffer, DMLS 316L Stainless Steel or Plastic Polypropylene?

DMLS 316L Stainless Steel is stiffer: Young's modulus 185 GPa against 1.45 GPa for Plastic Polypropylene, so the same part in DMLS 316L Stainless Steel deflects less under the same load.

Which is lighter for the same job, DMLS 316L Stainless Steel or Plastic Polypropylene?

For the same stiffness or strength: DMLS 316L Stainless Steel is lighter for a stiff rod or tie (tension), stiff beam (bending), strong rod or tie; Plastic Polypropylene is lighter for a stiff panel or plate, strong beam, strong panel or plate.

Part that must be	DMLS 316L Stainless Steel	Plastic Polypropylene
Stiff rod or tie (tension)	lighter	14.5x heavier
Stiff beam (bending)	lighter	29% heavier
Stiff panel or plate	1.74x heavier	lighter
Strong rod or tie	lighter	1.83x heavier
Strong beam	38% heavier	lighter
Strong panel or plate	2.19x 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 conducts heat better, DMLS 316L Stainless Steel or Plastic Polypropylene?

DMLS 316L Stainless Steel conducts heat better: 16.2 W/m·K against 0.195 W/m·K for Plastic Polypropylene.

Which expands less with temperature?

DMLS 316L Stainless Steel expands less: 15.7 µm/m·K against 90 µm/m·K for Plastic Polypropylene.

Among 59 materials

Stiffness against density

Strength against density