There are many industries where the use of steel fasteners such as the 316 stainless steel carriage bolts is practiced heavily. In such cases, the performance of such fasteners is often affected by many things, including how you decide to use them. For instance, if you intend to use 316 stainless steel hex head cap screws or carriage bolts, one of the decisions you will need to make is whether to have them lubricated or not. This is a process that many people take for granted, but which will ultimately affect the performance of the fasteners.
The logic behind this
In order to understand why this is important, you only need to think about the mechanics of fastening such a device. When you fasten a screw or bolt, the forces acting on the threads increase as you keep tightening it. After some time, the stresses that the threads are subjected to might be so great that they end up losing the protective oxide layer that they have.
When this happens, the stainless steel underneath the protective layer will be exposed. It will then be subjected to a number of chemical reactions such as oxidation, which in turn means that the threads might stick together and freeze. This means that if you decided to try and undo the fastener later on, it would be very difficult and you would need to use specialized means to do it. Even then, there is not guarantee that the fastener will be removed easily.
The role of using lubrication
The process of having the threads between the fastener and the item you are fastening it to sticking together is called galling. When you use some lubrication on the fastener before putting it in place, the risk of this happening is reduced. It is important to note that in order to reduce the risk of galling, the lubricant has to be put on the fastener before using it, rather than afterwards.
What lubricants should you use?
Not all lubricants are good enough for this application. Generally speaking, the lubricants that are most ideal to prevent galling are the ones that are based on graphite. They should therefore be your first choice, rather than using more traditional solutions such as grease.
There are some special circumstances where you will need to adhere to even stricter standards. For instance, if you are going to use the fasteners in a device used in the food industry, you would need to use a lubricant that would not cause damage to the food, and which is also not toxic. You might need to refer to the regulations in your country to find out which lubricants to use in such settings.
In summary, if you are going to use device such as screws and bolts on a large scale, you should always remember to use a lubricant before doing so. This will not only protect the fasteners from corrosion, but it will also reduce the risk of galling and ensure that in case you ever need to undo the fasteners, you will not have such a hard time.
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.