Maximum tensile force in a metric bolt
Preload and load reserve for a metric bolt tightened to a prescribed tensile stress (fraction of yield strength).
Preload, F_i = σₜ·Aₜ32.36 kN
Yield load, F₀.₂ = Aₜ·Rₚ₀.₂53.93 kN
Load reserve, P_b = F₀.₂ − F_i21.57 kN
Tensile stress, σₜ384 MPa
Tensile stress area, Aₜ84.26 mm²
Ultimate tensile strength, Rₘ800 MPa
Yield strength, Rₚ₀.₂640 MPa
Pitch, P1.75 mm
Pitch diameter, d₂10.863 mm
Root diameter, d₃9.853 mm
Method & references
- Maximum tensile force / preload for a metric bolt tightened to a prescribed fraction of yield strength.
The computation is a literal port of the original client-side JavaScript from /calculators/e3_6d.htm. Results are verified equal to the original by an automated golden-master test. No formula has been re-derived or “improved”.