Which NDE (x-ray, mag particle, dye penetrant, UT) method is used for different metals?

Question

What NDE method is more appropriate for stainless steel, carbon steel, copper, zinc, titanium, etc? In other words, given the type of metal, how do I choose the correct NDE method?

What does eddy current do? How is it better than say mag. particle?

Thank you.

Answer 1

Radiographic methods can be used for any materials.
For welds that are inaccessable to the radiographic equipment, ultrasonic inspection of welds is substituted, such as for structural welds in hard to access places.
Magnetic particle inspection and eddy current testing can be used for any magnetic materials, such as all the carbon steels and the ferritic stainless steels.
Liquid penetrant inspection is used in lieu of magnetic particle inspection for non-magnetic materials, such as all the austenitic stainless steels.

All NDT methods have advantages and limitations for detecting various types of weld indications, for example:

Magnetic particle testing (MT) is used for detecting short length and shallow surface breaking indications. Its sensitivity, however, is severely reduced in detection of indications through coatings, and MT is difficult to use outside on wet surfaces.
Eddy current is used for detecting surface breaking indications through coating thickness as great as 2 mm (0.08 in.), and it can be used on wet surfaces. Because, however, only the area under test is being inspected, several scans must be employed for complete coverage.
Ultrasonic testing (UT) is used for detecting volumetric indications. It is generally not as sensitive as MT for detection of fine, surface-breaking indications, and UT requires a higher level of operator skill.
Radiographic testing (RT) is used for volumetric detection of indications. It cannot, however, detect lamellar indications. RT also requires special safety precautions.

See the following website for some great info:

http://www.asnt.org/publications/materialseval/solution/feb98solution/feb98sol.htm

Answer 2

This is like the 3rd question on NDE today. Does somebody have a project due?

Typically the material doesn't matter as much as far as it's composition, what matters is how big is the part (how thick and how much acreage do I have to look at?). Dye pen inspection is great for covering a lot of ground but doesn't always find small cracks. Eddy current is the opposite, it uses induced currents in the inspection metal and looks for voltage spikes. It can be very time consuming but is usually the best way to find small cracks and discontinuities in thin metals.

Here's a website.

http://www.ndt-ed.org/EducationResources/CommunityCollege/EddyCurrents/Introduction/IntroductiontoET.htm

Answer 3

THAT... is weird and wonderful. it particularly is a stable theory to apply that for it. i might shop on with stuff i did no longer actual positioned on, like curtains or blankets or in spite of, because of the opportunity of stench like another person suggested.... PTA and Easter Eggs. Who woulda thunk it?