Ferrite Content Test (FCT) is a non-destructive testing (NDT) method used to measure the amount of delta ferrite in austenitic and duplex stainless steel welds, weld overlays, and cladding.
How it works
A magnetic-induction probe is placed on the surface and the instrument reads the ferrite content directly, expressed as a Ferrite Number (FN) or as percent ferrite. We use a Fischer FERITSCOPE DMP30 checked against reference standards, so readings can be taken quickly on finished welds, overlays and cladding without sectioning the item.
What it tells you
- Weld quality in austenitic stainless steel — too little ferrite increases the risk of hot cracking during welding, while too much reduces corrosion resistance and toughness.
- Phase balance in duplex stainless steel — confirming that the ferrite–austenite balance in welds and heat-affected zones is within the range the specification requires.
- Overlays and cladding — checking that dilution from the base metal has not pushed the ferrite content outside the acceptable range.
Where it fits
Like hardness testing, ferrite content testing characterises the material rather than searching for flaws. It is normally specified alongside PMI, which confirms the alloy grade, and a flaw-detection method such as liquid penetrant or ultrasonic testing.
Ferrite content testing with CAST
We perform ferrite content testing on site and at our Bintulu facility on stainless steel welds, weld overlays and cladding, and report the results in FN or percent ferrite against your specification.
Call +6086 348 938, email cast@ctne.com.my, or tell us about your inspection.