Magnetic Particle calculators.

N = D² / (4λ), λ = c / f

Worked example 10 mm, 5 MHz probe on steel N = 21.19 mm reliable far field from 3N = 63.56 mm

index = g/2 + t · tan θ

Worked example 25 mm wall, 3 mm gap, 30° bevel, 60° root index 44.80 mm cap width 29.56 mm

d = √((c · t / 2)² − S²)

Worked example PCS 70 mm, 15.1 µs, probe delay 2.5 µs d = 12.51 mm half path 37.17 mm

Ug = F · t / d

Worked example F 3 mm, OFD 20 mm, SOD 600 mm Ug = 0.100 mm ASME V limit at 25 mm: 0.508 mm

δ = 1 / √(π f μ σ)

Worked example 304 stainless steel at 100 kHz δ = 1.35 mm 32.9 % of the surface field at 1.5 mm

P_f = S_f · 2t / D

Worked example NPS 20 X52, corrosion 3 mm × 150 mm P_safe = 9.80 MPa Modified B31G, failure at 13.62 MPa