DMLS 17-4PH Stainless Steel vs. Plastic PEEK

Q: Is DMLS 17-4PH Stainless Steel stronger than Plastic PEEK?

DMLS 17-4PH Stainless Steel is stronger: its yield strength is 861 MPa against 98 MPa for Plastic PEEK (8.78x).

Q: Which is lighter, DMLS 17-4PH Stainless Steel or Plastic PEEK?

Plastic PEEK is lighter: 1,300 kg/m³ against 7,790 kg/m³ for DMLS 17-4PH Stainless Steel.

Q: Which is stiffer, DMLS 17-4PH Stainless Steel or Plastic PEEK?

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

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

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; Plastic PEEK is lighter for a stiff panel or plate, strong beam, strong panel or plate.

Q: Which conducts heat better, DMLS 17-4PH Stainless Steel or Plastic PEEK?

DMLS 17-4PH Stainless Steel conducts heat better: 17.9 W/m·K against 0.29 W/m·K for Plastic PEEK.

Q: Which expands less with temperature?

DMLS 17-4PH Stainless Steel expands less: 10.4 µm/m·K against 55 µm/m·K for Plastic PEEK.

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

Change either side

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

Plastic PEEKBulk polymer (molded or machined)

Mechanical
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Yield strength	861MPasourcemean, as built, horizontal (N=72)	98MPasourcetypical, tensile yield
Ultimate tensile strength	886MPasourcemean, as built, horizontal (N=72)	not sourced
Compressive strength	not sourced	125MPasourcetypical, 23 C
Flexural strength	not sourced	165MPasourcetypical, flexural stress at yield, 23 C
Elongation at break	19.9%sourcemean at break, as built, horizontal	25%sourcetypical, at break
Young's modulus (stiffness)	197GPasourcebase material: wrought 17-4 PH, Condition H 900 (Cleveland-Cliffs)	4GPasourcetypical (nominal)
Density	7,790kg/m³sourcemean part density (ISO 3369)	1,300kg/m³sourcetypical (crystalline)
Strength to weight	110kN·m/kg47% higher	75.4kN·m/kg
Stiffness to weight	25.3MN·m/kg8.22x higher	3.08MN·m/kg
Poisson's ratio	0.272sourcebase material: wrought 17-4 PH, all conditions (Cleveland-Cliffs)	0.38sourcetypical
Shear modulus	77.4GPa53.4x stiffer in shear	1.45GPa
Bulk modulus	144GPa	5.56GPa
Speed of sound	5,029m/s	1,754m/s
Thermal
Thermal conductivity	17.9W/m·Ksourcebase material: wrought 17-4 PH, Condition H 900, at 149 °C (Cleveland-Cliffs)	0.29W/m·Ksourcetypical, average, 23 C
Thermal expansion	10.4µm/m·Ksourcemean 25-100 °C, ASTM E228, AFTER atmospheric heat treatment (as-built value not published)	55µm/m·Ksourceaverage of flow/cross-flow, below Tg (<143 C)
100 mm part over a 50 °C swing	52µm growth5.29x less	275µm growth
Specific heat	460J/kg·Ksourcebase material: wrought 17-4 PH, Condition A, 0-100 °C (Cleveland-Cliffs)	2,200J/kg·Ksourcetypical, 23 °C, DSC (Victrex PEEK 450G TDS, revision Jul 2012)
Heats up and cools (diffusivity)	5mm²/s49.3x faster	0.101mm²/s
Thermal shock resistance	5,474W/m68.3x more resistant	80.1W/m
Melting point	not sourced	343°Csourcetypical, DSC
Glass transition	not sourced	143°Csourceonset (midpoint 150 C)
Max service temperature	not sourced	240°CsourceUL 746B RTI, mechanical strength (continuous use index)
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	Victrex PEEK 450G (unreinforced, injection moulded), Victrex TDS rev. March 2026; Poisson from Victrex fluid-management flyer (2020-07)

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

Questions

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

DMLS 17-4PH Stainless Steel is stronger: its yield strength is 861 MPa against 98 MPa for Plastic PEEK (8.78x).

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

Plastic PEEK is lighter: 1,300 kg/m³ against 7,790 kg/m³ for DMLS 17-4PH Stainless Steel.

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

DMLS 17-4PH Stainless Steel is stiffer: Young's modulus 197 GPa against 4 GPa for Plastic PEEK, 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 PEEK?

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; Plastic PEEK is lighter for a stiff panel or plate, strong beam, strong panel or plate.

Part that must be	DMLS 17-4PH Stainless Steel	Plastic PEEK
Stiff rod or tie (tension)	lighter	8.22x heavier
Stiff beam (bending)	lighter	17% heavier
Stiff panel or plate	1.63x heavier	lighter
Strong rod or tie	lighter	47% heavier
Strong beam	41% heavier	lighter
Strong panel or plate	2.02x 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 PEEK?

DMLS 17-4PH Stainless Steel conducts heat better: 17.9 W/m·K against 0.29 W/m·K for Plastic PEEK.

Which expands less with temperature?