Understanding Steel Grades and Their Importance

What is “Grade”?

European Standard EN 10025, which is governed by the European Committee for Iron and Steel Standardization (ECISS), a subset of the European Committee for Standardization (CEN).

In line with the European Standard classifications, structural steels must be referenced using standard symbols including but not limited to S, 235, J2, K2, C, Z, W, JR, and JO, where:

• S - Structural Steel
• 235 - Minimum yield strength (Reh) in MPa at 16mm
• JR - Longitudinal Charpy V-notch impacts 27 J at +20°C
• J0 - 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
• +AR - Supplied condition as rolled
• +N - Supplied condition as normalised or normalised rolled

For example, S235JR+AR, S355J2+N, S275JR+AR, S275J0 and its.

The EU standard classifications are not a global standard and therefore a number of corresponding grades with the same chemical and mechanical properties may be used in other parts of the world.

US standard: American Society for Testing and Materials (ASTM)
German standard: Deutsches Institut für Normung (DIN) (German Institute for Standardisation)
Russian standard: GOST (Russian: ГОСТ - Государственный стандарт) ets.