Intro_to_ Penetrant.pdfVIP

PENETRANT TESTING Introduction ? This module is intended to provide an introduction to the NDT method of penetrant testing. ? Penetrant Testing, or PT, is a nondestructive testing method that builds on the principle of Visual Inspection. ? PT increases the “seeability” of small discontinuities that the human eye might not be able to detect alone. Outline ? General Introduction ? Penetrant Materials and Considerations ? Basic Steps in Penetrant Testing ? Common Equipment ? Advantages and Limitations ? Summary ? Glossary of Terms How Does PT Work? ? In penetrant testing, a liquid with high surface wetting characteristics is applied to the surface of a component under test. ? The penetrant “penetrates” into surface breaking discontinuities via capillary action and other mechanisms. ? Excess penetrant is removed from the surface and a developer is applied to pull trapped penetrant back the surface. ? With good inspection technique, visual indications of any discontinuities present become apparent. What Makes PT Work? ? Every step of the penetrant process is done to promote capillary action. ? This is the phenomenon of a liquid rising or climbing when confined to small openings due to surface wetting properties of the liquid. ? Some examples: ? Plants and trees draw water up from the ground to their branches and leaves to supply their nourishment. ? The human body has miles of capillaries that carry life sustaining blood to our entire body. Basic Process of PT 1) Clean Dry Component 4) Apply Developer 2) Apply Penetrant 3) Remove Excess 5) Visual Inspection 6) Post Clean Component What Can Be Inspected Via PT? Almost any material that has a relatively smooth, non- porous surface on which discontinuities or defects are suspected. What Can NOT be Inspected Via PT? ?Components with rough surfaces, such as sand castings, that trap and hold penetrant. ?Porous ceramics ?Wood and other fibrous materials. ?Plastic parts t