Engineering Reference

Galling

Severe adhesive wear in which material transfers between two sliding surfaces and tears them up.

Definition

Galling happens when two metals slide under pressure, weld at microscopic contact points, and then tear apart, pulling material from one surface to the other. It is not gradual wear — it can seize a joint on first assembly.

Stainless steel is notorious for it, particularly 304 and 316, because the passive oxide layer reforms instantly and prevents the surfaces from bedding in. The remedies are dissimilar materials, a lubricant, or a gall-resistant alloy such as Nitronic 60.

Common misuse

Assuming galling is a lubrication problem. It is a materials problem — adding grease to stainless threads helps but does not solve it.

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