Fasteners are a crucial part of everyday life. Well, it is a minute part but plays a massive role.
You might not even notice, but you are surrounded by fasteners. If you think about it, you might wonder how frequent screws, bolts, and nuts are.
However, being metals, the fasteners get attacked by corrosion. Nonetheless, the corrosion is preventable with proper measures.
What are fasteners?
Fasteners are a hardware device that joins or holds the material together. Although fasteners are used for non-permanent joints, permanent joints are also used in some cases.
The non-permanent fasteners include screws, bolts, nuts, and washers. Besides, the permanent fasteners cover soldering, welding, and riveting.
But then why are non-permanent fasteners popular? The permanent fasteners damage the joints during the unfastening process, while non-permanent ones don’t.
Types of Corrosions
Metal corrosion is a non-reversible process. It is beneficial to use preventive measures to avoid any life threats it may bring with corrosion.
There are mainly two types of fastener corrosion.
Direct Chemical Attack
A direct chemical attack occurs if the fastener material is soluble in the present environment. Fastener corrosion is common in the oil and gas industry.
A proper coating of a solvent is applied to the fastener to avoid any risks of corrosion.
Electrochemical Corrosion
During the electrochemical corrosion, a small electric current flows through the fastener. This happens when two different metals come in contact or there is the presence of atmospheric oxygen.
Electrochemical corrosion is divided into the following categories.
Galvanic Corrosion
In galvanic corrosion, two different metals come in contact with each other in the presence of moisture.
When they come in contact, a chemical reaction occurs. The chemical reaction damages both metals and makes them weak.
As a result, the holding capacity of the fastener reduces.
Stress Corrosion
A fastener experiences stress corrosion when the said material is under tension. Putting pressure, exceeding the capability of the fastener, will weaken the metal.
Small cracks would emerge in the fastener’s structure.
The weakening of the metal initiates on the tensile stressed part of the metal in a corrosive environment and further spreads to the whole.
Crevice Corrosion
A crevice is a small crack or space in a material. Small cracks of the fasteners act as a space for moisture retention.
The said moisture reacts with the metal. If the number of joints increases, so does the space between the fasteners. Thus, increasing the risk factor.
Crevices that are not properly ventilated are prone to corrosion. Crevice corrosion is more harmful than others because it is not detected until the damage is done.
Uniform Corrosion
It is the most common fastener corrosion. In this case, the fastener becomes red, and the damage is distributed along the entire length.
It makes the unfastening process difficult. You might have heard rusting of metal. That is what uniform corrosion is.
Prevention of Fastener Corrosion
It is salient to take preventive measures before any damage occurs. There are three most common ways to prevent fastener corrosion.
Use Appropriate Metals
The use of metal fasteners depends on environmental factors. A non-reactive metal is preferred in a humid environment.
If the fastener is attached to a metal, it should have a similar electric potential. This would reduce the electricity flow between the metals. Hence, slowing the rate of corrosion.
Suitable Surface Coating
It is predominant to coat the metal with a non-reactive material. This would insulate the metal and create a shield between the environment and the metal.
You could use either dielectric coating, non-conductive paint, or insulation.
Proper Installation Technique
Improper installation would exert uneven and excess pressure on the fastener. High tension would cause stress corrosion in the fastener.
Further, to avoid corrosion, avoid accidentally scratching on the material.
Summing Up
It is crucial to use corrosion preventive measures for fasteners. They might look all shiny in the beginning, but you might not even notice when they start to pose a threat.
If you are using a fastener for any purpose, ensure it is of top-notch quality. Try to buy fasteners from a trusted industry. Bhavya Industries is a leading fastener producer in Punjab. We provide high-quality services and products to our customers.
