Classification of stainless steel:

1. Classified stainless steel according to the rate of corrosion:

The stainless steel resistant is base on ability of corrosion in different environments. Accordingly to that property and depending corrosive environments, stainless steel in general is classified according to the corrosion rate as follows:

In corrosive environments: freshwater, air ...


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2.Classified Stainless steel according to the structure of the steel:

Based on the influence of alloying elements to the structure of the steel, we divided stainless steel into two groups: stable austenite structure elements (characterized by content of Ni) and stable ferrite structure (Characterized by content of Cr). This definition is shown in the Schaeffler diagram of the structure of stainless steel with vertical axis is % of Ni equivalent, horizontal axis is %  of Cr equivalent.

Schaeffler diagram for stainless steel structure



According to the diagram of the stainless steel structure, there are three main groups of stainless steel (single phase) is: stainless steel mactensite, stainless steel austenite and ferrite stainless steel. In addition, there are other related stainless steel groups but they have a little use in our life.