The EN material number according to EN 10027-2 is a unique number and is primarily based on the chemical composition and is primarily used in Europe. However, there are also other systems which are explained below.
The regulations for pressure equipment in Europe and America have traditionally introduced different designations for materials, each of which follows a different system. Materials differ not only in their chemical composition, but also in other delivery conditions or heat treatments, which give the materials different properties and must therefore be designated differently.
EN-Material Numbers in acc. to EN 10027-2
The material numbers and short names for steels are initially on behalf of DIN and since 1992 with the adoption of the German system into the European standardisation system on behalf of the European standardisation CEN/ECISS as European Steel Registration Office.
The material short names for correct name formation are defined in EN 10027-1. The allocation of material numbers, which are primarily identified by their chemical composition in according to EN 10027-2. The classification of steel grades according to EN 10020, on the basis of chemical composition into unalloyed, stainless and other alloyed steels, as well as into main grades, defined by main property or application characteristics of the unalloyed, stainless and other alloyed steels.
Example:
Short name: X2CrNiMo17-12-2
EN-Material Number: 1.4571
Grade and Class
Grade and Class designation is found in ASME and ASTM specifications. When more than one material is specified in standard, they may be separated first by types, which are distinguished by Roman numerals. This first subdivision shall be based upon some major property, composition, or application of the item. Designate further subdivision by grades according to some pertinent property or properties and identify by Arabic numbers. If necessary, make additional division into classes, identified by capital letters.
Examples: ASTM A-182 Grade F12 Class 1, ASTM A-516 Grade 60, ASTM A-106 Grade B
AISI
The American Iron and Steel Institute, (AISI), developed designations such as 304, 316L etc and published compositions for steels. These are NOT specifications, but steel grade composition ranges only. These grades were used by the American Society Testing and Materials, (ASTM), to identify grades in a wide range of standards they published for stainless products, such as sheets and plates (ASTM A240), forgings (ASTM A-182) and tubes (ASTM A-269).
The compositions of the AISI grades were made more specific with the introduction of the ‘Unified Numbering System’, jointly established by ASTM e.g. 316 being UNS S31000, F316L being UNS S31603
UNS
Most ASTM and ASME standards list the steel grades by their UNS, (Unified Numbering system), numbers but also make reference, where appropriate to the more general AISI, (American Iron and Steel Institute), grade designations. These grade numbering systems are widely used in the USA, where they originated and are recognised by most stainless steel specifiers and users. Where UNS grade numbers are used, these are universal, regardless of the product type or the standard in which they appear.
This five digit number, preceded by the letter ‘S’ for most stainless steels, identified the specific variant of the grade e.g. 316 being UNS S31600, 316L being UNS S31603. The letter “L” usually stands for low or lower carbon.
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