Sources used:
- ASNT Introduction to Nondestructive Testing
- ASNT Ultrasonic Testing overview
Why Buyers Ask PT vs MT
Searches like "PT vs MT searching for pores" usually come from buyers or inspectors who need a simple answer before placing an order. The correct answer depends on the material, the defect location, the surface condition and the acceptance standard.
PT and MT are both useful, but neither is a universal substitute for RT or UT.
What PT Is Good At
PT means liquid penetrant testing. It is used to reveal surface-breaking indications on non-porous surfaces. It can be used on many metallic materials, including non-magnetic stainless steels, when the surface is suitable.
PT is useful for checking surface cracks, laps, seams or open surface discontinuities. If a pore is open to the surface, PT may reveal it. If the pore is fully internal, PT will not find it.
