A2 vs D2
The classic tool-steel matchup: two air-hardening cold-work steels separated by carbide volume. A2 is the tough, fine-edged, easy-finishing one; D2 is the wear-resistant, semi-stain-resistant, stubborn one. Which belongs in your blade depends on whether it will chop or slice for a living.
Quick Verdict
Pick A2 for hard use: it is clearly tougher, grinds and finishes far more easily, and takes a finer edge. Pick D2 when slicing wear resistance rules and chipping risk is low - and accept the coarser edge and harder finishing. Both need a kiln (or a heat treat service) and rust care, though D2 resists stains noticeably better.
Toughness
A2 wins decisively - its restrained carbide volume absorbs impact D2 cannot. This is the core reason choppers and hard-use blades run A2 while D2 stays in slicers.
Edge Retention
D2 wins on wear - roughly 12% chromium forms abundant carbides that out-slice A2 meaningfully. A2 holds a good working edge but resharpens sooner.
Corrosion Resistance
D2 (~12% Cr, "semi-stainless") shrugs off stains A2 (~5% Cr) will take. Neither is stainless; A2 demands honest carbon-steel care.
Heat Treat
Nearly identical workflow: foil pouch, high soak (A2 1750-1800F, D2 ~1850F), air or plate quench, double temper. Both are kiln steels - and both love a plate quench for flatness.
Grinding
A2 by a wide margin: it grinds, files, and hand-sands like a cooperative tool steel. D2 fights belts and hand-sanding alike, and its big carbides limit how fine an edge polish is worth chasing.
Best-Use Scenarios
A2: camp knives, choppers, bushcraft blades, tough kitchen workhorses, plane irons. D2: EDC slicers, hunting knives, and abrasive-material work where the edge rubs more than it impacts.