Xylan Coated Bolts Prevent Galling
Galling isn’t an issue that may happen. It’s a predictable one. Considered a form of adhesive wear, it’s a type of material transfer that occurs when two metal surfaces slide against each other under pressure.
Instead of moving smoothly, the metals weld together microscopically, then tear apart. This results in seized fasteners, damaged threads, inconsistent torque readings, and permanent component failure. Most galling problems don’t show up until it’s too late - and too expensive - to fix.
Galling occurs most often with stainless steel, aluminum, and titanium. These materials form protective oxide layers. But these layers break down under pressure and friction, exposing the raw metal that bonds.
Special applications
When talking about purpose-built fastener solutions designed for demanding conditions such as high friction, high load, or corrosive environments, these applications focus on one goal: reducing friction and preventing metal-to-metal adhesion.
Coated fasteners are one way to reduce the risk of galling.
Anti-galling coatings create a barrier layer between the two surfaces. They work by preventing metal contact, reducing friction during tightening, or by maintaining more consistent torque.
Common anti-galling coatings include PTFE (Teflon), which creates extremely low friction, zinc plating, which adds lubricity and corrosion resistance, and dry film lubricants, often used in aerospace and industrial settings.
Xylan is a coating in a class by itself.
Xylan falls into the category of fluoropolymer-based, dry film lubricants in the same family as PTFE. But Xylan isn’t an entry-level coating - it’s used when standard solutions aren’t reliable enough. It combines the best of two worlds: the ultra-low friction of PTFE and the adhesion and durability of resin binders. It also creates strong adhesion to the fastener surface, and its thin coating doesn’t gum up threads.
When you look at the three factors that result in galling - similar metals, pressure, plus friction, Xylan addresses two of the three, primarily friction
How Xylan works
Xylan works in three ways: by creating a permanent barrier, preventing metal-to-metal contact, reducing friction, and enabling smoother installation.
It’s also more reliable than zinc coatings in high-load or repeated assemblies. It’s pre-applied and controlled at the factory, versus anti-seize, which is messy and inconsistent. Lastly, it’s more durable and better bonded than standard PTFE coatings with less risk of wear-off during installation.
Xylan isn’t a fit for every assembly, however. It’s best suited for stainless steel assemblies - especially in food processing, marine, and construction applications. It’s ideal for high-volume production environments, corrosive environments such as oil and gas, marine and chemical processing, and in hard-to-access installation, where you don’t get a second chance.
More than just a coating upgrade, Xylan is a process upgrade. It removes the guesswork from installation, reduces reliance on field lubrication, and prevents one of the most common and costly fastener failures.
Everything old is new again
Xylan isn’t new. It’s been around since the 1960s and 1970s. But its use in fasteners and anti-galling applications has expanded as modern industries rely more heavily on stainless steel than they did decades ago.
The need for low-friction coatings and anti-galling creates a perfect niche for Xylan to fill. It’s a proven technology that’s become more relevant as demands evolve and grow.
So while it’s not new, Xylan is solving today’s assembly problems better than ever.
Want to find out more about Xylan? Call or email one of our Melfast experts for information.
