Corrosion resistance is an important factor in the selection of stainless steel fasteners

Stainless steel fasteners don’t rust or corrode, thanks to their high chromium content. This causes the metal to create a protective layer of chromium oxide that prevents corrosion.
This layer can even regenerate if it becomes compromised by oxygen in the use environment. This is one reason why stainless steels are preferred over plated fasteners in corrosive applications.
Corrosion Resistance
Corrosion resistance is an important factor in the selection of stainless steel fasteners. In a typical use environment, stainless fasteners are protected from corrosion by a passive layer of chromium oxide. This layer is not only resistant to rust but also to many corrosive chemicals, including hydrofluoric acid and sulfuric acid.
However, this layer can be damaged if the fastener is subjected to physical distortion or stresses. It is for this reason that it is crucial to specify a grade with the right corrosion resistance properties.
For example, type 304 with 18% chromium and 8% nickel is suitable for most general applications. Other grades in the 300 series offer different chemistries and corrosion-resistance properties. For example, type 430 offers lower corrosion-resistance but is often used for decorative trim because it has a smoother finish that closely resembles chromium plated material. It can also be heat-treated to work harden and become mildly magnetic. This makes it appropriate for certain mechanical and electrical applications.
Durability
Stainless steel fasteners are more durable than traditional metals. The chromium element in these types of fasteners reacts with oxygen to form a layer of chromium oxide that acts as an additional barrier against corrosion. This layer can even regenerate if damaged.
There are many different grades of stainless steel fasteners. These are distinguished by their alloy composition, hardening processes and other characteristics. These classifications help users select the correct fastener for their specific needs.
Austentic grades, such as 304 and 316 stainless steel fasteners, are commonly used for general applications. These grades are non-magnetic and work-harden during cold forming and machining. These alloys contain 18% chromium and 8% nickel and are resistant to corrosion in most environments, including mild chloride type conditions. However, if the fasteners are subject to heat during welding, this can precipitate chromium carbides in the grain boundaries. This is referred to as sensitization. Grades with low carbon content, such as 304L and 316L, are available to minimize this effect.
Flexibility
There are many types of stainless steel fasteners. Some are better suited to certain environments than others. For example, those that are used to connect companion flanges in a piping system may need to withstand more corrosion than those used for ordinary applications.
Stainless steels with more than 10% chromium are more resistant to corrosion than other iron-based alloys. The chromium oxide layer that covers the surface of the metal prevents corrosive agents from coming into direct contact with the metal. This helps protect the fastener from damage and makes it very resilient.
Stainless steels can be austenitic (commonly SS 302, 304, and 316) which are non-magnetic and cannot be heat treated, martensitic (which have a low carbon content of up to 0.8% and may contain molybdenum), or ferritic which is magnetic and has a lower chromium and nickel composition. The type of head on the fastener is also important and can change the amount of torque they can withstand.
Cost
While they may seem insignificant, fasteners play a critical role. Choosing the right ones will allow your project to run smoothly and sustainably. Stainless steel fasteners are an effective choice in a wide range of applications because they offer high corrosion resistance and durability. They also tend to be cheaper than other fastener materials and do not require a protective coating.
Stainless steel fasteners come in many types and grades. However, most commonly used fasteners are made of austenitic grades 304 and 316. These are often referred to as 18-8 stainless due to their composition of 18% chromium and 8% nickel. They also have low carbon levels to prevent precipitation of chromium carbides at the grain boundaries.
Choosing the right type of stainless steel for your application will help you avoid costly mistakes and ensure that the material will perform as expected. You should also consider additional factors such as environmental conditions when deciding on the ideal fastener grade.