Materials / Compare

PCB Laminate FR-4 vs. Stainless Steel 17-4PH

Compare PCB Laminate FR-4 vs. Stainless Steel 17-4PH strength, stiffness, weight and thermal properties.

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PCB Laminate FR-4Composite
Stainless Steel 17-4PHWrought
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Mechanical
Yield strengthnot given (tensile used)1,275MPasourcetypical, transverse, sheet/strip
Ultimate tensile strength246–385MPasourcetypical, in-plane: cross direction .. length direction (ASTM D3039)1,379MPasourcetypical, transverse, sheet/strip
Flexural strength531–621MPasourcetypical: cross direction .. length direction (IPC-TM-650 2.4.4B)not sourced
Elongation at breaknot sourced9%sourcetypical, transverse, in 2 in. (50.8 mm)
Young's modulus (stiffness)21.9–25.8GPasourcetypical, in-plane: cross direction .. length direction (ASTM D790-15e2)197GPasourceH 900
Density1,920kg/m³sourcetypical, 50% resin content; another FR-4 producer: Park Nelco N4000-6 (high-Tg multifunctional epoxy), not Isola 370HR7,800kg/m³sourceH 900
Strength to weight164kN·m/kg163kN·m/kg
Stiffness to weight12.4MN·m/kg25.3MN·m/kg2.03x higher
Poisson's ratio0.171–0.177sourcetypical, in-plane: cross direction .. length direction0.272sourceH 900 (column)
Shear modulus10.2GPa77.4GPa7.62x stiffer in shear
Bulk modulus12.2GPa144GPa
Speed of sound3,525m/s5,026m/s
Thermal
Thermal conductivity0.4W/m·Ksourcetypical (ASTM E1952); direction not stated by the sheet17.9W/m·Ksourceat 149 °C (300 °F), H 900
Thermal expansion13–14µm/m·Ksourcetypical, in-plane X/Y-axis, below Tg (IPC-TM-650 2.4.24C)10.8µm/m·Ksourcemean, 21–93 °C (70–200 °F), H 900
100 mm part over a 50 °C swing67.5µm growth54µm growth25% less
Specific heat1,200–1,400J/kg·Ksourcetypical (ASTM E1461); another FR-4 producer: Park Nelco N4000-6 (high-Tg multifunctional epoxy), not Isola 370HR460J/kg·Ksourcemean, 0–100 °C, H 900
Heats up and cools (diffusivity)0.16mm²/s4.99mm²/s31.1x faster
Thermal shock resistance324W/m7,809W/m24.1x more resistant
Glass transition180°Csourcetypical, DSC (IPC-TM-650 2.4.25C)not sourced
Max service temperature130°CsourceUL Relative Thermal Index (UL 796)316°Csourcestrength-retention limit (not oxidation)
Values forIsola 370HR FR-4 laminate (Polyclad PCL-FR-370HR, 180 C Tg multifunctional epoxy, E-glass fabric), copper removed; Isola data sheet Revision C, last updated April 15, 2021. Woven-glass laminate: the sheet gives in-plane values per weave direction (length / cross) and the Z-axis CTE separately; the solver is isotropic per material.Cleveland-Cliffs 17-4 PH, Condition H 900, sheet/strip, transverse (Product Data Bulletin, May 2021)

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.

Questions

Is PCB Laminate FR-4 stronger than Stainless Steel 17-4PH?

Stainless Steel 17-4PH is stronger: its yield strength is 1,275 MPa against tensile strength 315 MPa for PCB Laminate FR-4 (4.04x).

Which is lighter, PCB Laminate FR-4 or Stainless Steel 17-4PH?

PCB Laminate FR-4 is lighter: 1,920 kg/m³ against 7,800 kg/m³ for Stainless Steel 17-4PH.

Which is stiffer, PCB Laminate FR-4 or Stainless Steel 17-4PH?

Stainless Steel 17-4PH is stiffer: Young's modulus 197 GPa against 23.9 GPa for PCB Laminate FR-4, so the same part in Stainless Steel 17-4PH deflects less under the same load.

Which is lighter for the same job, PCB Laminate FR-4 or Stainless Steel 17-4PH?

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

Part that must bePCB Laminate FR-4Stainless Steel 17-4PH
Stiff rod or tie (tension)2.03x heavierlighter
Stiff beam (bending)lighter41% heavier
Stiff panel or platelighter2.01x heavier
Strong rod or tieabout equalabout equal
Strong beamlighter1.6x heavier
Strong panel or platelighter2.02x 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).

Which conducts heat better, PCB Laminate FR-4 or Stainless Steel 17-4PH?

Stainless Steel 17-4PH conducts heat better: 17.9 W/m·K against 0.4 W/m·K for PCB Laminate FR-4.

Which expands less with temperature?

Stainless Steel 17-4PH expands less: 10.8 µm/m·K against 13.5 µm/m·K for PCB Laminate FR-4.

Among 72 materials

1k10k0.1110100Density (kg/m³)Young's modulus (GPa)Plastic PLAPlastic PETGPlastic ABSPlastic TPUPlastic NylonAluminumSteelIronTitaniumSteel AISI 1018Stainless Steel 304Stainless Steel 316Aluminum 6061-T6Aluminum 7075-T6Brass C360Copper C110GlassSteel AISI 1045Steel AISI 4340Steel A992Stainless Steel 303Aluminum 2024-T351Aluminum 5052-H32Aluminum 7050-T7451Titanium Ti-6Al-4VBrass C260Nickel Inconel 718Magnesium AZ31B-H24Zinc Zamak 3Plastic ABS (bulk/injection)Plastic PolycarbonatePlastic POM/AcetalPlastic Nylon PA6Plastic Nylon PA66Plastic PEEKPlastic UHMWPEPlastic HDPEPlastic PolypropylenePlastic PMMAFDM ASAFDM PolycarbonateFDM PAHT-CFFDM HIPSSLA Resin Tough 2000SLS PA12 NylonDMLS AlSi10Mg AluminumDMLS Ti-6Al-4V ELI TitaniumDMLS 316L Stainless SteelDMLS 17-4PH Stainless SteelSiliconCeramic Alumina 96%Ceramic Aluminum NitrideAluminum A380Aluminum 6063-T6Aluminum 1100-OAluminum ADC12Magnesium AZ91DSolder SAC305Plastic PBT GF30Plastic PPS GF40Plastic LCP GF30PCB Laminate FR-4Stainless Steel 17-4PH
Stiffness against density
1k10k101001kDensity (kg/m³)Yield strength (MPa)Plastic PLAPlastic PETGPlastic ABSPlastic TPUPlastic NylonRubberAluminumSteelIronTitaniumSteel AISI 1018Stainless Steel 304Stainless Steel 316Aluminum 6061-T6Aluminum 7075-T6Brass C360Copper C110GlassSteel AISI 1045Steel AISI 4340Steel A992Stainless Steel 303Aluminum 2024-T351Aluminum 5052-H32Aluminum 7050-T7451Titanium Ti-6Al-4VBrass C260Nickel Inconel 718Magnesium AZ31B-H24Zinc Zamak 3Plastic ABS (bulk/injection)Plastic PolycarbonatePlastic POM/AcetalPlastic Nylon PA6Plastic Nylon PA66Plastic PEEKPlastic PTFEPlastic UHMWPEPlastic HDPEPlastic PolypropylenePlastic PMMAFDM ASAFDM PolycarbonateFDM PAHT-CFFDM HIPSSLA Resin Tough 2000SLA Resin Elastic 50ASLS PA12 NylonDMLS AlSi10Mg AluminumDMLS Ti-6Al-4V ELI TitaniumDMLS 316L Stainless SteelDMLS 17-4PH Stainless SteelBrickSiliconCeramic Alumina 96%Aluminum A380Aluminum 6063-T6Aluminum 1100-OAluminum ADC12Magnesium AZ91DSolder SAC305Plastic PBT GF30Plastic PPS GF40Plastic LCP GF30PCB Laminate FR-4Stainless Steel 17-4PH
Strength against density

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