Simplified Selection of Stainless Steels

Three parameters are important to consider when selecting a particular grade of stainless steel for a given application. These parameters are in order of decreasing importance:

Corrosion resistance. This is the most important property to consider when selecting a stainless steel. Actually, the corrosion resistance is always the primary reason when considering Fe-Cr-Ni alloys. For best results, the maximum allowable corrosion rate, usually 50 μm/year (2 mils per year), along with an exact knowledge of the corrosive environment, must be known.

Mechanical strength. The mechanical strength is the second most important parameter, especially for designing structural applications.

Fabrication. The capabilities of the stainless steel to be machined, welded, cold worked, and heat treated are, in combination with the two previous parameters, an important parameter to take into account from a technical and a cost-assesment point of view.

 

Based on an approach developed by the company Carpenter Specialty Alloys8, it is possible  to summarize the selection process graphically (Figure 1), plotting the grade of the  stainless steel as a function of both corrosion resistance and mechanical strength.

 

 

 

 

Stainless Steel Application Guidelines