13–14µm/m·Ksourcethe bare laminate's (fr4-370hr), in-plane X/Y-axis, below Tg (IPC-TM-650 2.4.24C)
12µm/m·Ksourcenominal (constructional data, no temperature range stated)
100 mm part over a 50 °C swing
67.5µm growth
60µm growth12% less
Specific heat
not sourced
460–480J/kg·Ksourcebase material: EN S275JR unalloyed structural steel (the EN counterpart of A36), typical, 50/100 °C
Heats up and cools (diffusivity)
not sourced
13mm²/s
Thermal shock resistance
not sourced
5,390W/m
Values for
A whole circuit board read as one orthotropic plate: the JEDEC high-K thermal test board (JESD51-7, "2s2p"), 0.062 in (1.575 mm) thick with two internal solid copper planes 0.0014 in (1 oz) thick, as Texas Instruments SZZA017A Table 1 gives it. Copper C110 and the Isola 370HR laminate from this library; the layers conduct in parallel along the board and in series through it (boardStackup.ts). Its two 0.0028 in trace layers cover little of the board and are left out; vias are ignored. Mechanical values are the bare laminate's.
ASTM A992 W-shapes; Fy/Fu specified minimums from AISC publications (AISC 360-16 Commentary; Modern Steel Construction); elastic constants AISC 360; physical constants from the bauforumstahl structural-steel EPD, which names A992 among covered product standards.
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 Board FR-4, 2 copper planes stronger than Steel A992?
Steel A992 is stronger: its yield strength is 385 MPa against tensile strength 315 MPa for PCB Board FR-4, 2 copper planes (22%).
Which is stiffer, PCB Board FR-4, 2 copper planes or Steel A992?
Steel A992 is stiffer: Young's modulus 200 GPa against 23.9 GPa for PCB Board FR-4, 2 copper planes, so the same part in Steel A992 deflects less under the same load.
Which expands less with temperature?
Steel A992 expands less: 12 µm/m·K against 13.5 µm/m·K for PCB Board FR-4, 2 copper planes.