Corrosion Resistant Alloys

NAS 335X

  • JIS
  • UNSN08020
  • DIN/EN

NAS 335X is a stainless steel with extremely high corrosion resistance to sulfuric acid. It can be used in a wide range of sulfuric acid environments, including high concentration, high temperature environments. It possesses excellent intergranular corrosion resistance and stress corrosion cracking resistance.

Products & Materials

NAS 335XProductsPDF(252KB)

Chemical Composition 20Cr-33Ni-2.5Mo-3Cu-0.4Nb
Product shape
Workability Cold and hot workability are approximately equal to those of Type 304, 316, and other standard austenitic stainless steels.
Weldability TIG welding, MIG welding, and shielded metal arc welding are applicable in the same manner as with standard austenitic stainless steels. However, because NAS 335X is an Nb-added stainless steel, the welding heat input should be reduced as far as possible.
Use of ER320 or ER320LR welding electrodes is recommended.
Machinability The machinability of NAS 335X is basically the same as that of standard austenitic stainless steels. In machining, a high speed steel tool or ultrahard tool should be used. It is also advisable to use a slower feed rate and deeper cutting depth.
Heat Treatment Stabilizing heat treatment of NAS 335X should be performed at the temperature range from 925 to 1010℃ followed by being quenched in water or rapidly cooled by other means. (Conditions provided in ASTM A480/A480M)
Pickling Pickling is performed under the same conditions as with Type 304, using a mixture acid of nitric acid and hydrofluoric acid.
Applications Sulfuric acid plants, various types of chemical and petrochemical plants