AISI D4 Oil-Hardening Cold-Work Tool Steel
AISI D4 (UNS T30404) — tungsten-modified D3, slightly better hot hardness. Compare with D2, D3, D5 for slitter blades at elevated cutting-edge temperatures.
AISI D4 (UNS T30404, DIN 1.2436) is a tungsten-modified D3 (0.5–0.8 % W added). Same basic composition and wear behaviour as D3, with slightly better hot hardness from the W addition. Used where D3 standard is acceptable but slightly elevated temperature at the cutting edge is expected.
Standard composition: C 2.05–2.40 %, Cr 11.0–13.0 %, Mo 0.70–1.20 %, V 0.15–1.00 %, W 0.50–0.80 %, Mn ≤ 0.60 %, Si ≤ 0.60 %, balance Fe
Hardness: Annealed HB 217–248; hardened HRC 58–64
Heat treatment: Austenitise 970–1,010 °C, air or oil cool, double temper 150–200 °C
Properties: Slightly better hot hardness than D3 from the W addition. Wear resistance and toughness similar to D3.
Applications: Slitter blades on highly abrasive substrates; cold-heading dies; blanking and piercing dies for thick stainless plate.
Cross-reference: ≈ DIN 1.2436, GB Cr12W.
See also.
