according to ISO 3506
More than 97 % of all fasteners made from stainless steels are produced from this steel composition group. They are characterised by impressive corrosion resistance and excellent mechanical properties.
Austenitic stainless steels are divided into 5 main groups whose chemical compositions are as follows:
1) Stabilized against intergranular corrosion through addition of titanium, possibly niobium, tantalum.
2) Sulfur may be replaced by selenum.
3) If the nickel content is below 8 %, the min. manganese content shall be 5 %.
4) There is no min. limit to the copper content, provided that the nickel content is greater than 8 %.
5) If the chromium content is below 17 %, the min. nickel content should be 12 %.
6) For austenitic stainless steels having a max. carbon content of 0,03 %, nitrogen may be present to a max. of 0,22 %.
7) This shall contain titanium ≥ 5 x C up to 0,8 % max. for stabilization and be marked appropriately as specified in this table, or shall contain niobium (columbium) and / or tantalum ≥ 10 x C up to 1 % maximum for stabilization and be marked approprately as specified in this table.
8) At the discretion of the manufacturer, the carbon content may be higher where required in order to obtain the specified mechanical properties at larger diameters, but shall not exceed 0,12 % for austenitic steels.