Ferrite Testing

Accurate Measurement of
Stainless Steels

Ferrite testing is a fast, inexpensive, and accurate way to measure delta ferrite content in austenitic and duplex stainless steels. Proper ferrite content provides a balance between ductility, toughness, corrosion resistance and crack prevention.

Heat, pressure and caustic environments require materials and welds with very high metallurgical integrity. A correct ferrite measurement can help to avoid both solidification cracking and corrosion in stainless steel welds, pipes, plates, pressure vessels and petrochemical components.  

When ferrite content is too high, stainless steel can lose ductility, toughness, and corrosion resistance – especially at high temperatures. If ferrite content is too low, stainless steel welds become susceptible to hot cracking or solidification cracks.

In duplex stainless steel welds, a deficit of ferrite content can also reduce weld strength and contribute to the development of stress corrosion cracks.

Ferrite Test Process

Using the magnetic induction method, with highly accurate digital readings and in situ instrument calibration checks, trained BTS technicians can report readings individually or in ranges to meet customer specifications.

Baker Testing can measure and report ferrite content of welds and components during fabrication and for in-service applications with two different test methods, depending on code or customer requirements.

Alternately, high sensitivity low Mu permeability standards measure ferrite content between a series of calibrated standards. Test measurements can be reported by ferrite number (FN) or by ferrite percentage in conformance with welding procedures, customer drawings, and specifications by direct reading or conversion.

Experience, Expertise, Code Conformance

Photographs courtesy of Olympus