Corrosion Resistant Alloys
NAS 75N
- JISー
- UNSS32760
- DIN/EN1.4501
Super Duplex Stainless Steel
NAS 75N is a super duplex stainless steel with a pitting resistance equivalent (PRE) number of more than 40, and provides excellent corrosion resistance and strength properties. In comparison with UNS S32205, SUS 329J3L, and SUS 329J4L (NAS 64), it offers superior localized corrosion resistance, and thus is suitable for use in chemical plants, seawater desalination plants, and similar severe environments. Nippon Yakin supplies this product in plate form.
*PRE=%Cr+3.3X%Mo+16X%N| Chemical Composition | 25Cr-7Ni-3.6Mo-0.6Cu-0.6W-0.27N |
|---|---|
| Product shape |
 Coil Sheet Plate |
| Workability | The high-temperature strength of NAS 75N is basically the same as Type 430 in the range of 950~1150℃. It should be noted that the strength increases abruptly below 900℃. Solution annealing should be done after hot working. Regarding cold workability, care is required as proof stress is high and elongation is low in comparison with Type 304. |
| Weldability | Various welding methods are applicable in the same manner as with the standard austenitic stainless steels, including shielded metal arc welding, TIG welding, and plasma welding. Use of welding electrodes for UNS S32760 is recommended. Preheating and postheating are not necessary. In welding, the interpass temperature should be no more than 100℃ in order to prevent formation of intermetallic compounds. |
| Heat Treatment | Solution annealing of NAS 75N should be performed at 1100℃ and higher followed by being quenched in water or rapidly cooled by other means. (Conditions provided in ASTM A480/A480M) |
| Pickling | A mixture of nitric acid and fluoric acid is used in pickling. However, because descaling is somewhat difficult in comparison with Type 304, alkali immersion before acid pickling, and if possible, shot blasting are extremely effective. |
| Applications | Chemical plant, Chemical tanker, Seawater desalination system, Seawater pump |
| Certification | It is possible to manufacture UNS S32760 in accordance with the NORSOK standard below. The thickness is up to 40mm. •NORSOK M-650 •NORSOK M-630 MDS D55 |