When you are in the market looking for fasteners such as Inconel socket head cap screws and nitronic 50 hex head cap screws, one of the challenges you might face is deciding which corrosion resistant polymers they should be coated in. This is an important decision to make, particularly if you are interested in ensuring […]

When you are in the market looking for fasteners such as Inconel socket head cap screws and nitronic 50 hex head cap screws, one of the challenges you might face is deciding which corrosion resistant polymers they should be coated in. This is an important decision to make, particularly if you are interested in ensuring that you get the most out of such bolts. In such cases, choosing the wrong polymer coating could result in a number of problems, including finding that the whole project is far too expensive. You may also not benefit from the full effects of the corrosion resistance if you get a polymer that is not suited to the application you want to put them in.

Over the recent past, there has been an increase in the number of products designed for this use. On the surface, this means that you have more options as far as polymer choices are concerned. However, it also means that if you are not sure about exactly what you want, you have a higher chance of picking the wrong polymer for bolt design. To avoid this, it may be necessary to understand a few of the practical aspects about different types of polymers
Chemical property of PTFE

PTFE

PTFE is one of the most common corrosion resistant polymers available. Due to its ubiquity, it is also considered to be one of the most affordable as well. However, one of the major downsides of using PTFE is the fact that it’s a relatively weak material. It may therefore not be suitable for use in applications where mechanical strength is required. However, when you need the fasteners to be resistant to most types of chemical damage, this is the best polymer you can use.

 

PEEK

PEEK is a polymer that does not have the same corrosion resistant qualities as PTFE. However, it’s still very impressive as far as this type of resistance is concerned, being able to withstand damage by chemicals such as hydrochloric acid and sulfuric acid. The advantage that it has over PTFE and most other polymers is the fact that it’s very strong. This makes it the most suitable polymer for use in environments where the fasteners are likely to be subjected to high amounts of force, such as in mechanical applications.

PVDF

PVDF is another new polymer. It is considered a compromise between the pros and cons of PTFE and PEEK. In terms of chemical corrosion resistance, it is not as resistant as PTFE and PEEK, though it still has an acceptable degree of resistance to most common chemicals. When it comes to strength, PVDF sits somewhere between PEEK and PTFE. This makes it an ideal compromise when you want an averagely strong polymer that will not be too expensive.
Of course, there are many more technical details that you need to consider when comparing these and other polymers. When you are interested in buying fasteners made out of or coated using any of the polymers, it would be wise to get the help you need from a reliable source.

About the Author

Larry Melone
By Larry Melone
President

Started my career in the fastener world in 1969 at, Parker Kalon Corp. a NJ based screw manufacturer located in Clifton, NJ working in inventory control, scheduling secondary production and concluding there in purchasing. In 1971 I accepted a sales position at Star Stainless Screw Co., Totowa, NJ working in inside sales and later as an outside salesman, having a successful career at Star I had the desire with a friend to start our own fastener distribution company in 1980 named: Divspec, Kenilworth, NJ. This was a successful adventure but ended in 1985 with me starting Melfast in August 1985 and have stayed competitive and successful to date. Melfast serves the OEM market with approximately 400 accounts nationally.

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