Monday, January 16, 2012

Standardisation of Metallic Materials

Classification of Steels:

In the Euronorm, steels are classified according to their chemical composition and their characteristics as working materials.

Classification as per alloying components:

Unalloyed steels:  

The content of various alloying components specified in the table should be less than the limits specified.

Alloyed Steels

The percentage content of at least one of the elements specified in the table should be equal to or greater than the limit specified.

Classification according to working characteristics

Basic Steels are steels of low purity and uniformity of grain structure. They are unalloyed and not intended for heat treatment (quenching and tempering/surface hardening).

High grade Steels are purer and of better surface quality than basic steels. They may be alloyed or unalloyed. Unalloyed high grade steels are ordinary structural steels which can be folded and cold formed, steel rods and rod wires which can be drawn and sheets which can be deep drawn. Alloyed high grade steels are fine grain structural steels with high elastic limits. They are used as free cutting steels for sheets, strips, springs and parts subjects to wear.

Superrefined Steels are very low in non-metallic inclusions. Unalloyed superrefined steels are suited to heat treatment. Alloyed superrefined steels are fine grain structural steels with a guaranteed elastic limit of at least 420 N/mm2. They are used as structural steels, tool steels and steels with tailor made characteristics.

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