DMLS 17-4PH Stainless Steel vs. Plastic PETG

Compare DMLS 17-4PH Stainless Steel vs. Plastic PETG strength, stiffness, weight and thermal properties.

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DMLS 17-4PH Stainless Steel3D printed metal (DMLS)

Mechanical
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Yield strength	861MPasourcemean, as built, horizontal (N=72)	46.2MPasourcetypical
Ultimate tensile strength	886MPasourcemean, as built, horizontal (N=72)	46.2MPasourcetypical, peak stress (= stress at yield)
Flexural strength	not sourced	78.9MPasourcetypical
Elongation at break	19.9%sourcemean at break, as built, horizontal	7.6%sourcetypical
Young's modulus (stiffness)	197GPasourcebase material: wrought 17-4 PH, Condition H 900 (Cleveland-Cliffs)	1.94GPasourcetypical
Density	7,790kg/m³sourcemean part density (ISO 3369)	1,270kg/m³sourcetypical
Strength to weight	110kN·m/kg3.04x higher	36.4kN·m/kg
Stiffness to weight	25.3MN·m/kg16.6x higher	1.53MN·m/kg
Poisson's ratio	0.272sourcebase material: wrought 17-4 PH, all conditions (Cleveland-Cliffs)	not sourced
Shear modulus	77.4GPa	not sourced
Bulk modulus	144GPa	not sourced
Speed of sound	5,029m/s	1,236m/s
Thermal
Thermal conductivity	17.9W/m·Ksourcebase material: wrought 17-4 PH, Condition H 900, at 149 °C (Cleveland-Cliffs)	0.21W/m·Ksourcebase material: Eastman Eastar Copolyester 6763 (PETG), typical
Thermal expansion	10.4µm/m·Ksourcemean 25-100 °C, ASTM E228, AFTER atmospheric heat treatment (as-built value not published)	51µm/m·Ksourcebase material: Eastman Eastar Copolyester 6763 (PETG), typical
100 mm part over a 50 °C swing	52µm growth4.9x less	255µm growth
Specific heat	460J/kg·Ksourcebase material: wrought 17-4 PH, Condition A, 0-100 °C (Cleveland-Cliffs)	1,300J/kg·Ksourcebase material: Eastman Eastar Copolyester 6763 (PETG), DSC at 60 °C (lowest temperature listed)
Heats up and cools (diffusivity)	5mm²/s39.3x faster	0.127mm²/s
Thermal shock resistance	5,474W/m	not sourced
Glass transition	not sourced	77.4°Csourcetypical
Max service temperature	not sourced	76.2°CsourceHDT 0.455 MPa (printed specimens)
Values for	EOS StainlessSteel 17-4PH IndustryLine (powder 9011-0041), EOS M 290, 40 µm, default job 17-4PH_040_StainlessM291_100, as built, horizontal; ISO 6892 & ASTM E8M	Ultimaker PETG, 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 v1.00, April 29, 2022.

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 17-4PH Stainless Steel and Plastic PETG are 3D printed: their properties depend on build direction and print settings; these are typical values.

Questions

Is DMLS 17-4PH Stainless Steel stronger than Plastic PETG?

DMLS 17-4PH Stainless Steel is stronger: its yield strength is 861 MPa against 46.2 MPa for Plastic PETG (18.6x).

Which is lighter, DMLS 17-4PH Stainless Steel or Plastic PETG?

Plastic PETG is lighter: 1,270 kg/m³ against 7,790 kg/m³ for DMLS 17-4PH Stainless Steel.

Which is stiffer, DMLS 17-4PH Stainless Steel or Plastic PETG?

DMLS 17-4PH Stainless Steel is stiffer: Young's modulus 197 GPa against 1.94 GPa for Plastic PETG, so the same part in DMLS 17-4PH Stainless Steel deflects less under the same load.

Which is lighter for the same job, DMLS 17-4PH Stainless Steel or Plastic PETG?

For the same stiffness or strength: DMLS 17-4PH Stainless Steel is lighter for a stiff rod or tie (tension), stiff beam (bending), strong rod or tie, strong beam; Plastic PETG is lighter for a stiff panel or plate, strong panel or plate.

Part that must be	DMLS 17-4PH Stainless Steel	Plastic PETG
Stiff rod or tie (tension)	lighter	16.6x heavier
Stiff beam (bending)	lighter	1.64x heavier
Stiff panel or plate	31% heavier	lighter
Strong rod or tie	lighter	3.04x heavier
Strong beam	lighter	15% heavier
Strong panel or plate	42% 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 17-4PH Stainless Steel or Plastic PETG?

DMLS 17-4PH Stainless Steel conducts heat better: 17.9 W/m·K against 0.21 W/m·K for Plastic PETG.

Which expands less with temperature?

DMLS 17-4PH Stainless Steel expands less: 10.4 µm/m·K against 51 µm/m·K for Plastic PETG.

Among 59 materials

Stiffness against density

Strength against density