Ferrite Testing - FT

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Ferrite testing is a non-destructive testing method which provides critical data for austenitic stainless steel and duplex materials. The delta ferrite percentage or number allows a technical assessment of material corrosion susceptibility, mechanical properties, service suitability, and service reliability. To perform proper ferrite testing, both a minimum material thickness and a minimum specimen size are required. Test results are interpreted in accordance with current specifications and/or customer requirements.


  • Austenitic stainless steel/Duplex stainless steels
  • Welds (tubing, etc.)
  • Normal construction steel with Austenitic chrome alloy steel welded cladding (e.g. boilers, vessels)
  • Weldments, castings, forgings, weld overlays, wrought materials
  • Weld materials
  • Butt/fillet welds
  • Category A-D welds
  • Stainless weld overlays on non-ferrous interfaces
  • In-service and in-construction components


  • Rapid and accurate analysis
  • Highly portable digital technology
  • Variable calibration in both Ferrite Number and % Ferrite using AWS Standards
  • Testing instrument meets all requirements of ANSI/AWS A4.2 and DIN EN ISO 8249
  • Calibration is traceable to internationally approved IIW secondary calibration standards


  • Not recommended where the material is at temperatures greater than 50 °C (125 °F)
  • Surface preparation is very important for result accuracy
  • Both a minimum material thickness and a minimum specimen size are required
  • Shape of the specimen may have a negative effect on the results obtained (correction calculations can be performed in some instances)