Ferralium® is the original super duplex stainless steel. Langley Alloys developed it through the 1960s and submitted a patent application in 1967.
At that time Langley Alloys operated a foundry, forge, rolling mills, laboratory and valve manufacturing business, so trial alloys could be used in our own products. When the patent was granted in 1969, the developmental 'Langalloy 40R' was re-branded as Ferralium®.
How the metallurgy works
Ferralium® uses the mixed austenitic-ferritic microstructure to combine high strength with excellent corrosion performance. Two features are central to its development:
- elevated nitrogen content, which increases pitting corrosion resistance;
- higher copper content, which slows down pitting corrosion if it starts.
Together these give Ferralium® superior corrosion resistance over similar alloys.