Different Classes of Stainless Steel

From our automobiles to our flatware, stainless steel is a tremendously versatile metal found in everyday life. Just like its many uses, stainless steel comes in many forms. The most common in our industry is American Iron and Steel Institute’s AISI classification 304, or Austenitic stainless steel, which is used in the manufacture of kitchen sinks and accessories; however, it is necessary to know all 304 grade stainless steel products are not created equally.

Certainly the most common stainless steel used in sinks is 18/8, which means that there is 18 percent chromium and 8 percent nickel by weight; 18/10 is another option. The chromium creates an invisible barrier — or passive film — to oxygen and moisture.

It fights against most corrosion — or what most would know as red rust. That’s why it is called “stain-less” steel. This layer is very thin and invisible to the eye, and when scratched, it quickly reforms itself. It is very important to remember the chromium content must be 18 percent to ensure adequate safeguards against rust. Equally as important is the nickel content, as it ensures better resistance to stress corrosion or cracking.