DMLS 17-4PH Stainless Steel vs. Plastic HDPE

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

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

Plastic HDPEBulk polymer (molded or machined)

Mechanical
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Yield strength	861MPasourcemean, as built, horizontal (N=72)	24MPasourcetypical, tensile stress at yield 23 °C, 50 mm/min ISO 527
Ultimate tensile strength	886MPasourcemean, as built, horizontal (N=72)	not sourced
Elongation at break	19.9%sourcemean at break, as built, horizontal	not sourced
Young's modulus (stiffness)	197GPasourcebase material: wrought 17-4 PH, Condition H 900 (Cleveland-Cliffs)	0.9GPasourcetypical, tensile modulus 23 °C ISO 527
Density	7,790kg/m³sourcemean part density (ISO 3369)	950kg/m³sourcetypical, ISO 1183
Strength to weight	110kN·m/kg4.37x higher	25.3kN·m/kg
Stiffness to weight	25.3MN·m/kg26.7x higher	0.947MN·m/kg
Poisson's ratio	0.272sourcebase material: wrought 17-4 PH, all conditions (Cleveland-Cliffs)	0.4–0.45sourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE)
Shear modulus	77.4GPa245x stiffer in shear	0.316GPa
Bulk modulus	144GPa	2GPa
Speed of sound	5,029m/s	973m/s
Thermal
Thermal conductivity	17.9W/m·Ksourcebase material: wrought 17-4 PH, Condition H 900, at 149 °C (Cleveland-Cliffs)	0.4–0.49W/m·Ksourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE)
Thermal expansion	10.4µm/m·Ksourcemean 25-100 °C, ASTM E228, AFTER atmospheric heat treatment (as-built value not published)	120µm/m·Ksourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE)
100 mm part over a 50 °C swing	52µm growth11.5x less	600µm growth
Specific heat	460J/kg·Ksourcebase material: wrought 17-4 PH, Condition A, 0-100 °C (Cleveland-Cliffs)	2,250J/kg·Ksourcebase material: high-density polyethylene family (INEOS Olefins & Polymers USA, Typical Engineering Properties of HDPE)
Heats up and cools (diffusivity)	5mm²/s24x faster	0.208mm²/s
Thermal shock resistance	5,474W/m96.3x more resistant	56.9W/m
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	LyondellBasell Hostalen 23050 B high density polyethylene, 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 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 HDPE?

DMLS 17-4PH Stainless Steel is stronger: its yield strength is 861 MPa against 24 MPa for Plastic HDPE (35.9x).

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

Plastic HDPE is lighter: 950 kg/m³ against 7,790 kg/m³ for DMLS 17-4PH Stainless Steel.

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

DMLS 17-4PH Stainless Steel is stiffer: Young's modulus 197 GPa against 0.9 GPa for Plastic HDPE, 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 HDPE?

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 HDPE is lighter for a stiff panel or plate, strong panel or plate.

Part that must be	DMLS 17-4PH Stainless Steel	Plastic HDPE
Stiff rod or tie (tension)	lighter	26.7x heavier
Stiff beam (bending)	lighter	1.8x heavier
Stiff panel or plate	36% heavier	lighter
Strong rod or tie	lighter	4.37x heavier
Strong beam	lighter	33% heavier
Strong panel or plate	37% 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 HDPE?

DMLS 17-4PH Stainless Steel conducts heat better: 17.9 W/m·K against 0.445 W/m·K for Plastic HDPE.

Which expands less with temperature?

DMLS 17-4PH Stainless Steel expands less: 10.4 µm/m·K against 120 µm/m·K for Plastic HDPE.

Among 59 materials

Stiffness against density

Strength against density