Stainless steels are iron-based alloys containing
a minimum of about 10.5% chromium - thereby giving it the characteristic
of "stainlessness" or corrosion resistance. Many industries,
from household appliance manufacturers to builders, have adopted
stainless steel in their products for just this reason, as well
as for its attractive appearance, low maintenance and high strength.
Depending upon the mix of alloys used in the process of making
stainless steel, the results can characterized as follows:
• Austenitic Stainless Steel, containing at least 16%
chromium and 6% nickel, is most suitable for use in items
that are subject to extreme temperatures. Austenitics offer
the greatest corrosion resistance of all the stainless groups.
The most common grades in this family are 304 and 316.
• Ferritic Stainless Steel, consisting primarily of
grade 430, generally has less chromium and thereby offers
only moderate corrosion resistance. They are used primarily
for decorative trim, sinks, and automotive applications.
• Martensitic Stainless Steels are straight chromium
steels that do not contain nickel. They are magnetic and can
be hardened by heat treating. The martensitic grades are mainly
used where hardness, strength, and wear resistance are required.
Other groups include Duplex Stainless Steels,
combining aspects of both Austenitic and Ferritic, and Precipitation
Hardening Stainless Steels, a specialized family which has
very high strength achieved by adding elements such as copper.