SAE 904L stainless steel
904L is an austenitic stainless steel. It is softer than 316L,[1] but its molybdenum addition gives it superior resistance to localized attack (pitting and crevice corrosion) by chlorides and greater resistance reducing acids; in particular, its copper addition gives it useful corrosion resistance to all concentrations of sulfuric acid. Its high alloying content also gives it greater resistance to chloride stress corrosion cracking, but it is still susceptible. Its low carbon content makes it resistant to sensitization by welding and which prevents intergranular corrosion.[2][3][4][5]
It has applications in piping systems, pollution control equipment, heat exchangers, and bleaching systems.[6]
Omega SA experimented with 904L or 'Uranus Steel' with the PloProf dive watches in 1971–72. The inspiration came from French deep sea diving company COMEX, who used this steel in their diving bells due to superior corrosion resistance in salt water.[7] In 1985, Rolex began to utilize 904L grade steel in its watches.[8] Beside its corrosion resistance, watch manufacturers, such as Rolex, also choose this variety of stainless steel because it takes a higher polish than 316L grade stainless steel commonly used by other watch brands such as Seiko, Omega, and Tudor
Composition[edit]
- Nickel, 23–28%
- Chromium, 19–23%
- Carbon, 0.02% maximum
- Copper, 1–2%
- Molybdenum, 4–5%
- Manganese, 2% maximum
- Silicon, 1.0% maximum
- Iron, (balance)
Other names[edit]
- UNS N08904
- EN 1.4539
- SUS 904L
- SS2562
See also[edit]
References[edit]
- ^ "What Is The Difference Between 316L And 904L Stainless Steel?". Fratello Watches. Retrieved 23 December 2023.
- ^ "904L Datasheet" (PDF). Atlas Steels.
- ^ "904L Datasheet" (PDF). Rolled Alloys.
- ^ "904L Datasheet" (PDF). ATI Metals.
- ^ "Stainless Steel - Grade 904L (UNS N08904)". AZoM.com. 2001-11-07. Retrieved 2017-06-02.
- ^ "Stainless Steel 904L Manufacturer, Supplier, Stockist, Exporter". Ritinox Overseas. Retrieved 2017-06-02.
- ^ "The Seamaster Chronicles - Part 1". monochrome-watches.com. 2018-11-16. Retrieved 2020-12-23.
- ^ Jahn Karsybaev (9 April 2016), Watches: How to Design, Manufacture and Build a Brand, Lulu.com, p. 48, ISBN 978-1-365-03518-0