Galling is a form of metal-to-metal contact that creates a strong adhesion between the surfaces of two different types of materials. It occurs when high amounts of friction force a protrusion into the surface of one material, causing it to adhere to the surface of another material and pull on it. This forms a thick layer of adhesive wear that reduces the performance and durability of fasteners. The good news is, galling is a preventable problem that can be avoided by using the right type of lubrication, by avoiding certain materials, and by installing systems designed to reduce the likelihood of galling.
The most common metals to encounter galling issues are aluminum, stainless steel and titanium. These are corrosion resistant metals that naturally form an oxide film which provides some resistance to abrasion and wear. But when excessive friction is applied, this oxide layer can break down and expose the reactive metals underneath, creating a galvanic interaction.
There are two critical components to galling: friction and ductility. Friction provides the energy for the adhesion, but ductility is necessary for cohesive attraction to form between dissimilar metals. This is why softer metals such as aluminium and stainless steel are more prone to galling than harder metals like martensitic stainless steel or tool steel.
To avoid galling, the first thing to consider is how your fasteners are stored and handled. Poor packaging or haphazardly tossing bolts can damage them and cause threading problems. This can lead to nicks and scratches in the threads which will increase friction. Also, dirt or other debris can easily build up in threaded areas, creating an even greater amount of friction.
Next, it’s important to use the proper lubrication and tools for the job. Using a high-quality lubricant with a thick, low-friction coating can significantly reduce the risk of galling. Additionally, tightening bolts more slowly can prevent the formation of excess heat and friction that can contribute to galling.
Finally, you should consider using premium stainless steel fasteners that are specifically designed to minimize galling. These are often more expensive, but they can greatly extend the life and effectiveness of your hardware. Manufacturing industry executives must understand the serious consequences of galling and do their utmost to ensure that their production equipment is not damaged or downed by galling hardware failures. After all, your hardware is too expensive to gamble with a cheap, galling-prone product. If you’re concerned about galling in your application, contact us today to learn more about our extensive inventory of specialty anti-galling fasteners. We’d be happy to help you find the solution that best fits your needs. We can also custom engineer a solution to suit your specific application. what is galling