AISI D5 High-Chromium Cold-Work Tool Steel
AISI D5 (UNS T30405) — Co + Mo modified D2 for heavy sections >50 mm. Compare with D2, D3, D7 for granulator rotors and rock-crusher blades.
AISI D5 (UNS T30405, DIN 1.2601) is a cobalt- and molybdenum-modified D2 (2.5–3.5 % Co, 0.7–1.2 % Mo added). The cobalt improves through-hardening of heavy sections (>50 mm) while retaining wear resistance similar to D2. Used for heavy-section shear blades, large granulator rotors and rock-crusher blades.
Standard composition: C 1.40–1.60 %, Cr 11.0–13.0 %, Mo 0.70–1.20 %, V 0.40–1.00 %, Co 2.50–3.50 %, Mn ≤ 0.60 %, Si ≤ 0.60 %, balance Fe
Hardness: Annealed HB 220–255; hardened HRC 58–62
Heat treatment: Austenitise 980–1,020 °C, air cool, double temper 510–540 °C
Properties: Slightly better through-hardening than D2 from the Co and Mo additions. Wear resistance similar to D2. Used for heavy-section blades that need full hardness through 50+ mm sections.
Applications: Heavy-section shear blades, large granulator knives, rock-crusher blades, draw dies for thick plate.
Cross-reference: ≈ DIN 1.2601 (close).
See also.
