My Gall, What Just Happened?

You’ve just finished testing a coupon with your new Membrane Test Cell, and are ready to evaluate the performance of a different coupon to compare results. You attempt to disassemble the housing but the fasteners won’t budge. You might be thinking “oh my gall, what just happened? Well, exactly that, it’s a phenomenon known as “galling”. 

What is Galling? 

Galling is a type of adhesive wear that typically occurs between sliding surfaces under compression, and most commonly metals.  Unlike other types of wear, it happens quickly, as opposed to over time, and is characterized by its transfer of material from one surface to the other. 

When Does Galling Occur?

Caused by a combination of friction and adhesion, the two surfaces in contact, bond together, and in severe cases can lead to breakage of the fastener or tool turning it. Materials that are softer in structure and have a face-centered cubic lattice structure, tend to be more likely to allow for material transfer. 

How Do I Prevent Galling?

One of the key ways of preventing galling between susceptible metals is to properly lubricate the contact surfaces. Anti-Sieze products are a widely available option, which can be used over top PTFE tape. Curious how it works? View our newest resource video on the topic of galling.