Advantages of Stainless Steel Fasteners
Stainless Steel Fasteners are, most importantly, corrosion resistant. They have an excellent life cycle, are environmentally friendly and are 100% Recyclable. They are also resistant to high heat as well as extremely cold temperatures making stainless steel fasteners the material of choice for almost any application!
What is Stainless Steel?
Stainless Steel is a generic term given to a large range of corrosion resistant steel alloys. Elements of these alloys can include chromium, nickel, iron, manganese, silicon, carbon, nitrogen, sulphur, phosphorous, molybdenum, titanium, niobium, copper, tungsten and vanadium. When the proportions are changed, the characteristics of the resultant alloy change.
Why is Stainless Steel corrosion resistant?
Stainless steel is a low carbon steel that contains 10.5% or more chromium by weight. Chromium gives the steel its anti-corrosion property by allowing the formulation of an invisible chromium-oxide film on its surface which is known as a passive layer. This layer or film can self-repair if damaged mechanically or chemically when it has available oxygen, even in small quantities. The corrosion resistance of stainless steel may be enhanced by increasing the chromium content together with the addition of other elements to the alloy such as nickel, molybdenum and titanium.
Can Stainless Steel corrode?
Yes it can! Stainless steel is corrosion-resistant but not corrosion-proof and corrosion can occur if the material is installed or handled incorrectly. The corrosion may be limited to visual damage only or could be as serious as functional loss of the alloy material through pitting or crevice corrosion. It follows that in these circumstances the many advantages of stainless steel alloys are lost. Corrosion can be the result of various factors but typically it is caused by a lack of available oxygen which prevents the formation of the natural and self-repairing barrier of chromium-oxide on the surface of stainless steel material. The use of tools and drills made from conventional steel during the installation of stainless steel fasteners may also lead to problems. Even the hardest of tools can produce debris that leaves minute steel particles on the stainless steel fastener surfaces or in pre-drilled holes. It is these particles that often rust when exposed to moisture or oxygen and can result in a stained or tarnished finish to the stainless steel material.
How can extraneous corrosion be prevented?
Keeping the surface of stainless steel clean and contaminant free is one of the best ways of preventing extraneous corrosion from occurring. Using appropriate sealant products during the installation of stainless steel fasteners located in damp or wet environments as well as tools made from stainless steel are also useful in preventing extraneous corrosion.
How many different types of Stainless Steel are available?
Because of the large number and combinations of elements used to make stainless steel alloys, the number of different types or grades is almost limitless.
How are Stainless Steels categorized?
Stainless steels can be found in four different categories: Austenitic (300 series), Martensitic (400 series), Precipitation Hardenable (17-4PH, 455), and Ferritic (430, 443).
What is the difference between these groups?
The main difference lies in the type of hardening.
What about Stainless Steel and magnetism?
Each stainless steel alloy shows different magnetic characteristics. Only the Austenitic (304, 316, 316L) stainless steels are largely non-magnetic but it is common for stainless steel fasteners to show a small degree of magnetism which is a result of work-hardening during the manufacturing process. All other stainless steel alloys are magnetic to some degree.
What is passivation?
Passivation is the removal of iron particles from the surface of stainless steel. The removal of iron particles facilitates the interaction of the chromium in the steel with oxygen which produces the formation of the passive chromium-oxide film layer. This thin and invisible layer protects material from further corrosion by its ability to self-repair. If the material is scratched and the passive film disrupted, more oxide will form and cover the exposed surface. For deep scratches, material can be manually passivated again.