Steel is the most common fastener material due to its strength properties. Many stainless steel fasteners are non-magnetic or less magnetic than regular steel fasteners. Stainless steel is steel combined with alloying elements, principally chromium, to enhance corrosion resistance and impart other desired properties depending upon the alloying elements in use and their proportions. The DIN/ISO denotation for a very similar grade is A4-70. It is used in more severe corrosive environments than 304 stainless steel, as such it is used in more industrial settings, like process chemicals, textiles, bleaches, salt water and rubber. It is on the low middle end of the grade scale. The second most common stainless steel grade, this material is stronger than grade 2, slightly weaker than grade 5,or generally as strong as medium to low carbon steel. The corrosion resistance and ease of fabrication are why this grade is used in food industry machines, appliances, architectural trim and aquatic fasteners. The DIN/ISO denotation for an extremely similar grade is A2-70. The most common stainless steel grade, comparable in strength to grade 2 materials, yet slightly weaker and easy to weld. This finish should not be used in marine or high salt spray environments. Slightly less corrosion resistant than yellow zinc, it is a versatile finish that is best used indoors. It is a popular finish because of its protection, value, and ease of coating. The zinc protects the steel from corrosion and the chromate layer protects the zinc from degrading.

It is an electroplated zinc layer covered with a chromate post-treatment. This finish, also know as zinc plating, zinc chromate or dichromate provides good corrosion resistance and is the standard for many hardware fasteners. This most basic finish can be used when protection is not an issue or indoors. This finish is susceptible to rusting and corrosion in exterior environments. Often the surface has been oiled which improves lubricity. Nothing has been done to this bare metal surface to improve appearance or corrosion resistance, which is very low if the material is steel.

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