Definition
A manufacturing or repair process in which a layer of hard, wear-resistant metal alloy is deposited onto the surface of a softer base metal part, usually by welding. The hard-faced layer protects the part from abrasion, erosion, or impact while allowing the underlying material to retain its toughness.
Plain English
A way of coating a metal part with a tougher, harder layer so its surface stands up to wear without making the whole part brittle.
Context Anchor
Seen in aircraft maintenance and repair discussions, especially for parts that rub, slide, or carry repeated contact loads.
Derivation
Built from 'hard' and 'facing,' where 'facing' means the outer surface of something. The term simply describes putting a hard surface on the face of a part.
Why Pilots Care
Extends service life of high-wear components such as valve seats and blade edges, reducing unscheduled maintenance and improving reliability.
Intuition Check
Hard-facing does not mean the entire part is hardened. It means a hard, wear-resistant surface layer is added where the part needs protection.
Example Sentence 1
The exhaust valve faces are hard-faced with a cobalt-based alloy to resist the heat and wear of repeated seating.
Example Sentence 2
Hard-facing along the propeller leading edges reduces erosion damage from sand and rain.