Reading wear: crazing, washout, abrasion, adhesive pickup, plastic deformation

Visual: directional scratches and grooves in regions where the billet slides across the die. Distinct from washout because abrasion is scratched, not eroded smooth. Under 10-30x the scratches show parallel orientation aligned with the sliding direction, and at higher magnification embedded particles of scale or oxide are visible in the scratch floor. Each scratch has a defined start, a defined end, and a defined direction.

Cause: hard particles between the die and the workpiece under sliding load. The particles are usually scale, oxide, or foreign matter carried into the die with the billet. The 2022 Materials paper on white-layer formation in pre-form forging tools documented coexisting abrasive and adhesive wear with embedded oxide particles in the scratch path, exactly the pattern that shows up at the bench when the billet was not descaled cleanly.

On the shop floor: abrasion and washout share a root cause (scale on the billet) but show different visual signatures. Washout is smooth and erosive, abrasion is scratched and grooved. Both are addressed first by billet cleanliness, which means descaling discipline at the furnace and shielding the billet path from contamination between the furnace and the die. A die that shows abrasion scratches on a clean billet is running with a lube film that is thinner than the particle size of whatever debris is making it into the die. Increase lube film thickness in the affected region, or check whether the lube tank itself is the source of the particles (settled graphite agglomerates, contamination at the fill point).