NDT Method
Difference Between MPI and Dye Penetrant Testing
Compare magnetic particle inspection and dye penetrant testing, and learn which method suits your material.
Overview
Magnetic particle inspection and dye penetrant testing both detect surface-breaking defects, but they work differently. MPI uses magnetic fields and only works on ferromagnetic (steel) materials, detecting slightly sub-surface cracks as well. PT uses a penetrating dye and works on any non-porous material, including aluminium and stainless steel.
The material dictates the choice: MPI for steel, PT for non-magnetic materials.
When to Use Each
- MPI — ferromagnetic steel components
- PT — aluminium, stainless and non-magnetic materials
- MPI — detects slightly sub-surface cracks
- PT — highly sensitive to fine surface cracks
Frequently Asked Questions
Related Services
NDT Australia provides these services nationwide with certified, mobile inspectors and clear, compliant reporting.