Stainless Steels are versatile alloys of steel containing from 12% to 30% chromium, and 0% to 20% nickel. The chromium protects the iron against most corrosion. The ability of stainless to form a thin layer of protection on its outside surface, called a "passive film" is the most important characteristic in preventing corrosion.

Various types of stainless steel used in the manufacture of fasteners are listed below

The 18-8 family of Stainless Steels (18% chromium 8% nickel) most commonly used to manufacture fasteners.

302HQ is primarily used as the cold heading alloy due to its lower cold working tendencies. It also has added copper of 3% to 4% which helps minimize tool wear.

303 is primarily used as the machining grade with its added sulfur (.18% to .40%) 303 adds to the life of automatic screw machines.

304 is used to manufacture hot formed products as well as stamped items with a lower carbon content than 303 and 305. It has better corrosion resistance and welding characteristics.

316 has added nickel and especially molybdenum. The molybdenum (called moly) sharply increases corrosion resistance to chlorides and sulfates, including sulfurous acids in the pulp industry. It has superior tensile strength at high temperatures compared to 18-8. 

410 is a chromium alloy which can be hardened by heat treatment. It resists corrosion caused by atmospheric conditions, food acids, mine water and gasoline. It can be headed or machined.