What is stainless steel? Stainless steel is not a
single alloy, but a part of a large family of alloys
with different properties for each member. The
stainless steel family is quite large and specialized.
There are hundreds of grades and sub grades, and
each is designed for a special application.
What exactly is required for iron to be transformed
into stainless steel? Chromium is the magic
element. Stainless steel must contain at least
10.5% chromium to provide adequate resistance to
rusting. And, the more chromium the alloy contains,
the better the corrosion resistance. However, it is
important to remember there is an upper limit to the
amount of chromium the iron can hold. Because of
this, additional alloying elements are necessary to
develop corrosion resistance to specific medias.
By definition, stainless steel must contain a minimum
of 50% iron. If it contains less iron, the alloy
is named for the next major element. For example,
if the iron is replaced with nickel, so the iron is less
than 50%, it is identified as a nickel alloy.