Stainless steels for fasteners do not follow the same designation as other structural steels; that is, we will not encounter fasteners in AISI 304 and AISI 316, simply because they are subject to a different standard.

The fasteners we sell are in A2 and A4, where the letter A indicates the general composition of the steel groups (CrNi and CrNiMo Austenitic steels) and the numerical digit represents the type of alloy.

In fact, A2 corresponds to a group of nickel-chromium stainless steels that include: AISI 304, AISI 304L, and AISI 305; while A4 corresponds to AISI 316 and AISI 316L nickel-chromium-molybdenum steels.

For simplicity, it is common to say that A2 is AISI 304 for fasteners, and A4 is AISI 316.