What is ferrite testing?
Ferrite is a compound of mainly iron mixed with one or more other metals. Ferrite testing is used on austenitic metals to determine the ferrite content. Austenite is simply another composition of iron usually with chromium and nickel. There is usually a specified range that the ferrite value should be between, depending on the material being tested. Having too high of a ferrite content will make the metal corrode more easily, as well as reduce the toughness. If the ferrite content is too low however, the piece is more susceptible to hot-cracking.
The testing is done easily with a small handheld instrument which, when placed on the test material, will take a reading and display the amount of ferrite present. The surface of the material must be cleaned before the test occurs as the machine can only get results from the surface of the test piece and if anything is blocking the actual material the reading will not be correct. The result will either be given as a percent, or a ferrite number.
Ferrite testing is necessary on many parts, some of which include weld materials like butt and fillet joints, stainless weld overlays, castings, forgings, and welded cladding on boilers and pressure vessels.
AXIS is able to provide Ferrite Testing for Manufacturer items and can be an integral part of your Third Party Quality Control Program.
Until Next Week,
For Links to previous Non-Destructive Testing Blogs