BASF Ultradur B 4300 G6 (PBT, 30% glass fibre), injection moulding grade; product information sheet 09/2026, typical values for uncoloured product at 23 °C.
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 Plastic PBT GF30 stronger than Steel A992?
Steel A992 is stronger: its yield strength is 385 MPa against tensile strength 140 MPa for Plastic PBT GF30 (2.75x).
Which is lighter, Plastic PBT GF30 or Steel A992?
Plastic PBT GF30 is lighter: 1,530 kg/m³ against 7,850 kg/m³ for Steel A992.
Which is stiffer, Plastic PBT GF30 or Steel A992?
Steel A992 is stiffer: Young's modulus 200 GPa against 9.8 GPa for Plastic PBT GF30, so the same part in Steel A992 deflects less under the same load.
Which is lighter for the same job, Plastic PBT GF30 or Steel A992?
For the same stiffness or strength: Plastic PBT GF30 is lighter for a stiff beam (bending), stiff panel or plate, strong rod or tie, strong beam, strong panel or plate; Steel A992 is lighter for a stiff rod or tie (tension).
Part that must be
Plastic PBT GF30
Steel A992
Stiff rod or tie (tension)
3.98x heavier
lighter
Stiff beam (bending)
lighter
14% heavier
Stiff panel or plate
lighter
1.88x heavier
Strong rod or tie
lighter
1.87x heavier
Strong beam
lighter
2.61x heavier
Strong panel or plate
lighter
3.09x 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, Plastic PBT GF30 or Steel A992?
Steel A992 conducts heat better: 48 W/m·K against 0.27 W/m·K for Plastic PBT GF30.
Which expands less with temperature?
Steel A992 expands less: 12 µm/m·K against 25 µm/m·K for Plastic PBT GF30.