# Magnetic Flux

Written by Jerry Ratzlaff on . Posted in Corrosion Engineering

Magnetic flux, abbreviated as $$\Phi$$ or $$\Phi_B$$, is a method that can detect wall thickness from corrosion and pitting without affecting the pipe.  The magnetic flux through some surface is porportional to the number of field lines passing through that surface.

## Magnetic Flux formulas

 $$\large{ \Phi_B = B \; A }$$ $$\large{ \Phi_B = B \; A \; cos\;\theta }$$

### Where:

 Units English Metric $$\large{ \Phi_B }$$  (Greek symbol Phi) = magnetic flux $$\large{\frac{Wb}{in^2}}$$ $$\large{\frac{Wb}{mm^2}}$$ $$\large{ \theta }$$ = angle between a perpendicular vector to the area and the magnertic field $$\large{deg}$$ $$\large{rad}$$ $$\large{ A }$$ = area perpendicular to magnetic field B $$\large{ft^2}$$ $$\large{m^2}$$ $$\large{ B }$$ = magnetic field density per unit area $$\large{ T}$$ $$\large{ T}$$