How to Choose the Right Fastener
In industrial applications such as food, gas, and petrochemicals, the productivity of the systems is dependent on how effectively all the components are fitted together. The fasteners used to connect companion flanges such as screws, bolts, and nuts are crucial to ensuring different parts such as bearings and mountings remain in the right positions for optimal safety.
If you fail to use the right fasteners, the system could suffer from problems such as leaks and unnecessary vibrations. They could also culminate to a disastrous failure of your machine. This leads us to one major question: "How can you select the right fasteners?" Here are the four criteria to assist you in picking the right fasteners.
1. Know the Application of Interest
Before you can start looking for fasteners or call the supplier for inquiries, it is important to know the nature of your system. Today, there are so many applications for industrial fasteners and there is need to know what you are looking for. For example, whether you need Chrome Molly or mild steel fasteners, the determining factor is the application. Therefore, you need to read the instructions of your machine guide or ask the technician about the right fasteners. Only, go for the fasteners designed for your system or closely resemble your application.
2. Proof stress
Proof of stress is the overall strength of the alloy used to make the fasteners. It is measured in pounds per square inch (psi). In the manufacturing niche, low carbon steel and pure steel are the common materials that have the lowest proof of stress. They have low strength of about 60,000 psi.
Although steel fasteners are available in multiple grades, it is only four that are common in most industries. Here are some of these fasteners:
- Grade 2: These fasteners are made with standard hardware grade steel. They are mainly used in light industry operations and do-it-yourself home projects.
- Grade 5: This group of fasteners is subjected to multiple treatments to harden it. They are mainly used in the automotive industry.
- Grade 8: These fasteners are stronger compared to grade five steel fasteners. They are mainly used in demanding applications like vehicle suspensions.
- Alloy steel: This category of fasteners is made with alloy steel that has been hardened through heat treatment. It is prudent to note that though these fasteners are strong, they can also be very brittle.
If you need super strong fasteners, it is important to go for superalloys that have strength exceeding 250,000 psi. Note that metals that surpass 180,000 psi are rarely used in industries today. Indeed, they are mainly created for extreme applications like rocket building and space exploration machines.
3. Corrosion resistance
Corrosion is the natural wearing of metal when it interacts with chemicals in the environment. The most common method of corrosion is oxidation. In this case, the metal reacts with oxygen to create rust. Therefore, you need to look for fasteners that are resistant to corrosion.
To make metal fasteners resistant to corrosion, a protective coating is applied on their surface. Here some of the coating materials used on metallic fasteners:
- Chrome: Though expensive, chrome is preferred for its strong anti-corrosion properties and attractive appearance.
- Zinc: In this case, fasteners are electro-plated using zinc to prevent the metal from getting into contact with water and air. Such fasteners are preferred for outdoor applications.
- Hot dip galvanizing: Though the fasteners are made of metal, the treatment through hot-dip galvanization makes them more resilient. This means that they can also be used even in coastal environments.
4. The Operational Temperatures
Before you can place that order for the preferred fasteners, it is also important to determine the level of temperatures they will be operating in. Well, it is obvious that fasteners made of plastic and non-ferrous alloys should not be used on applications that have temperatures exceeding 450° F such as auto engines.
Although the first option for high-temperature applications is stainless steel and steel alloys, they easily lose ductility in temperatures around 1,200° F. Besides, they also become brittle when temperatures fall below -100° F. Therefore, if your operations will run in very low temperatures, it is better to use titanium, brass, Teflon or copper fasteners.
If you want to get more from your application, it is prudent to ensure that only the right fasteners are used. This article provides a comprehensive outlook of the fasteners to help you pick the best.