Stainless Steels


  • JISSUS 303
  • UNSS30300
  • DIN/EN

NAS 303AM (SUS 303, UNS S30300) is a high free-machining austenitic stainless steel in which machinability is improved by adding sulfur to Type 304. Although sulfur is an alloying element that reduces corrosion resistance, the corrosion resistance of NAS 303AM is close to that of Type 304 in mildly corrosion atmosphere. Nippon Yakin supplies this product in plate form.

Products & Materials

NAS 303AM Spec Sheet PDF(693KB)

Product shape
Machinability This material's machinability is controlled by dispersed sulfides. NAS 303AM has excellent machinability. NAS 303AM’s excellent machinability enables remarkable extension of tool life, good surface finish, and other advantages during machining operations.
1.Drill speed test
As the result of the drill speed test, a much higher cutting speed can be obtained with NAS 303AM in comparison with that of Type 304. As the chips of NAS 303AM are extremely small and brittle in comparison with those of Type 304. Load of the drill is also smaller in case of NAS 303AM.
2.Drill cutting resistance test
In the results of the drill cutting resistance test, at the same feed rate, the maximum torque and the maximum thrust load of NAS 303AM are both much lower in comparison with those of Type 304, and drilling is also possible at a far faster drill feed rate than that at which the drill fractured with Type 304. Thus, the productivity of NAS 303AM in cutting work is greatly improved.
3.Drill life test
The number of holes that can be drilled with one drill under these test conditions with Type 304 is 1 hole (the drill fractured while drilling 2nd hole). In contrast, with NAS 303AM, the maximum number of 625 holes are drilled without drill fracture.
With NAS 303AM, tool life is greatly improved thanks to the low load on the cutting tool.
Corrosion resistance 1.Salt Spray Test (SST)
In the salt spray test, rust is not observed with NAS 303AM.
2.Pitting potential measurement
In the pitting potential measurements, the pitting potential of NAS 303AM shows a lower value than Type 304 but a higher value than Type 430, indicating that NAS 303AM has comparatively high pitting corrosion resistance.
Bending Formability NAS 303AM is not suitable for bending forming and similar processing, as its ductility is lower than that of Type 304 due to its high sulfur content.
Weldability NAS 303AM is not recommended for applications requiring welding.
Heat Treatment ・Solution heat treatment: 1010~1150℃; Water cooling
Pickling A mixed acid of nitric acid and hydrofluoric acid is used in pickling. Please avoid over-pickling. In some cases surface roughening may occur.