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Steel standards are systems for classifying, evaluating and specifying the chemical, mechanical and metallurgical properties of different types of steels and ferrous alloys that are used in the production of components, machinery and constructions.  Steels are classified by a large variety of criteria such as:

Composition e.g. carbon, low-alloy, or stainless steel; method of manufacturing such as open hearth, basic oxygen process, or electric arc furnace methods; finishing method such as hot rolling, cold rolling and various surface finishing and plating techniques; product form e.g. bar, wire, plate, sheet, strip, tubing or structural shape; deoxidation practice such as killed, semi-killed, capped or rimmed steel; microstructure such as ferritic, pearlitic and martensitic and heat treatment such as annealing, quenching and tempering.

There are a number of classification and designation systems accepted and used worldwide, which are developed and standardised either nationally and internationally by Standard Development Organisations (SDOs) or by specific vertical industries or suppliers.

Some of the more frequently used steel standard and classification systems include:

AISI (American Iron and Steel Institute) steel standards, which are traditionally used in the US and abroad.

EN (Euronorm), which is a harmonised system of metal and steel standards of European countries.  Although it is accepted and effectively used in all European countries, “obsolete” national systems, such as German DIN, British BS, French AFNOR and Italian UNI are commonly used and often found in many documents and specifications.

Japanese JIS steel standards, which are widely used in Asia and Pacific regions.  JIS steel specifications have also often been used as a base for other national systems such as Korean, Chinese, and Taiwanese standards.  Steel standards of newly industrial countries such as Chinese GB and YB, Indian IS and Brazilian NBR, although sometimes less developed and detailed, are increasingly being used due to global sourcing.  The same applies for Russian GOST, which is practically the de facto standard for the whole Community of Independent States.

Symbols used in European Standards e.g. hot rolled products of structural steel BS EN 10025:2004:

SStructural Steel

E… Engineering Steel

H… Hollow Steel

…JR.. Longitudinal Charpy V-notch impacts 27 J at +20°C

…JO.. Longitudinal Charpy V-notch impacts 27 J at 0°C

…J2.. Longitudinal Charpy V-notch impacts 27 J at -20°C

…K2.. Longitudinal Charpy V-notch impacts 40 J at -20°C

.235… Minimum yield strength (Reh) in MPa at 16mm

.275… Minimum yield strength (Reh) in MPa at 16mm

.355… Minimum yield strength (Reh) in MPa at 16mm

Test certification is not mandatory in BS EN 10025 and must be specified when ordering from Tomrods.