201 stainless steel pipe--S20100 (AISI.ASTM)
The American Iron and Steel Institute uses three digits to designate various standard grades of malleable stainless steel. in:
①Austenitic stainless steel is marked with numbers of 200 and 300 series;
② Ferritic and martensitic stainless steels are represented by numbers in the 400 series.
For example, some of the more common austenitic stainless steels are marked with 201, 304, 316 and 310, ferritic stainless steels are marked with 430 and 446, martensitic stainless steels are marked with 410, 420 and 440C, double Phase (austenitic-ferritic) stainless steels, precipitation-hardening stainless steels, and high alloys with less than 50% iron are usually designated by proprietary or trade names.