Overlays and underlays are protective layers added to surfaces of buckets, blades, or other high-wear areas. Overlays typically involve welding wear-resistant material onto the equipment, while underlays may involve adding a sacrificial layer beneath the surface. Both methods help shield the base metal from direct abrasion.

 Common overlay materials include chromium carbide or tungsten carbide, which offer excellent hardness and durability. Underlays can be simpler plates of hardened steel that absorb impact and wear. By reinforcing equipment in this way, operators can significantly extend component life.

 These protective layers are particularly beneficial in extreme applications, such as mining or quarrying, where constant contact with abrasive materials is inevitable. Properly installed overlays and underlays can reduce repair costs and downtime. Regular inspection ensures any worn sections are re-applied or replaced as needed.