Multi layered cladded pressure vessel

Date 09-14-2003 21:23

I have a multi layered, cladded and insulated pressure vessel to get thickness reading on. The insulation will not be removed,we will have internal access and the 3 layers are 516 gr 70 and the cladding is 304L. The orig. combined thickness is about 3 15/16" on the 3 carbon steel layers and 1/4" 304L cladding. I know of a few methods to achive this non destructively but I am open to new ideas. Any input would be appreciated. Thanks and have a good one!

By G.S.Crisi (****)

Date 09-15-2003 18:12

Anyone knows of a method for measuring non destructively the thickness of a vessel other than Ultrasonic? I'll be glad to know it if it exists.
Before Ultrasonic testing was invented, the method employed was to drill a hole on the vessel wall, measure the thickness by means of a deepness caliper, tap the hole and plug it up with a stainless steel bolt.
Giovanni S. Crisi
Sao Paulo - Brazil

By insp76

Date 09-17-2003 12:48

Crisi, there is another method that exist "Eddy current" that can be used for thickness readings.

By G.S.Crisi (****)

Date 09-19-2003 13:50

Thank you insp76. I've learned something new. I read once that a day in your life is useless if you havn't learned something new in it.
Giovanni S. Crisi

By insp76

Date 09-19-2003 16:43

Crisi, I feel the same way about it and that is the main reason for my post. There are so many new methods out there and I like to keep up with them as much as I can. When you are using UT for dissimilar metals, in this case ss cladding over carbon steel you have two different velocities to deal with. This is not a problem, you simply calibrate to the ss and take your thickness reading from the second pip on the screen that shows up because of the different velocity. The eddy current method requires a mock up of the required thickness of the cladding and shell to calbrate but is very accurate. Thanks and have a good one!