Steel equivalent grades are the counterpart designations for a particular standard steel grade type. For example, the different grades used by the American Iron Steel Institute (AISI) in classifying various types of steel have their own corresponding grades in other international standards.
Different countries and organizations, such as the European Union, have established a standard method in categorizing various steel products based on their chemical composition and mechanical properties. These standards include the United States' "AISI," Germany's "DIN and "W.N," France's "AFNOR," Japan's "JIS," Italy's "UNI," Sweden's "SIS," the United Kingdom's "BSI," E.U.'s "EURONORM," Spain's "UNE" and Russia's "GOST." Steel equivalent grades across these international classification systems provide a convenient way of referencing what particular steel grade type can be substituted for another steel product.
Steel grade can be categorized into three types: austenitic, ferritic and ferritic-austenitic. For the AISI austenitic 302 stainless steel grade designation, its steel equivalent grade is X 5 CrNi 18 7 in DIN, 1.4319 in W.N., Z 10 Cn 18-09 in AFNOR, SUS 302 in JIS, X 10 CrNi 1809 in UNI, 23 31 in SIS, 302S25 in BSI, X 10 CrNi 18 9 in EURONORM, X 10 Crni 18-09 in UNE and 12KH18N9 in GOST.
For the AISI ferritic 409 designation, its equivalent grade is X 6 CrTi 12 in DIN, 1.4512 in W.N., Z 6 CT 12 in AFNOR, SUH 409 in JIS, X 6 CrTi 12 in UNI, 409S19 in BSI and X 5 CrTi 12 in EURONORM. For the AISI ferritic-austenitic UNS31803 steel grade designation, its equivalent grade in DIN and W.N. are X 2 CrNiMoN 22 5 and 1.4462, respectively.