AISI A2 Air-Hardening Cold-Work Tool Steel
AISI A2 (UNS T30102) — air-hardening medium-alloy cold-work tool steel, HRC 57–62. Compare with A6, A8, D2 and O1 for slitter blades and punches.
AISI A2 (UNS T30102, DIN 1.2363, JIS SKD12) is the standard air-hardening medium-alloy cold-work tool steel — 5 % Cr, 1 % Mo, 0.2 % V. Hardened to HRC 57–62, it is the workhorse grade for slitter blades and punches where D2 wear life is unnecessary but oil-hardening O1 distortion is a problem.
Standard composition: C 0.95–1.05 %, Cr 4.75–5.50 %, Mo 0.90–1.40 %, V 0.15–0.50 %, Mn 0.40–1.00 %, Si 0.20–0.40 %, balance Fe
Hardness: Annealed HB 220–248; hardened HRC 57–62
Heat treatment: Austenitise 940–980 °C, air cool, double temper 175–540 °C
Properties: Good toughness (Charpy 28–40 J, ~2× D2). Air-hardening with low distortion. Lower wear resistance than D2 because of the lower Cr and V. Excellent machinability in the annealed state.
Applications: Slitter blades on tough paper, plastic film and rubber; shear blades on thick mild steel plate; precision blanking and forming dies; gauges and measuring tools.
Cross-reference: ≈ JIS SKD12, DIN 1.2363, GB Cr5Mo1V, BS BA2.
See also.
