· KAIPU Engineering · materials-encyclopedia · 1 min read
AISI A8 Air-Hardening Cold-Work Tool Steel
Materials encyclopedia entry for A8.
AISI A8 Air-Hardening Cold-Work Tool Steel is a reference entry for industrial cutting tools and blades. The composition, hardness, heat treatment and application guidance are summarised below for engineering reference.
Standard composition: C 0.50–0.60 %, Cr 4.75–5.50 %, Mo 1.15–1.65 %, W 1.00–1.50 %, V 0.30–0.50 %, Mn ≤ 0.50 %, Si 0.75–1.10 %, balance Fe
Hardness: Annealed HB 217–248; hardened HRC 56–60
Heat treatment: Austenitise 980–1,010 °C, air cool, double temper 175–540 °C
Properties: Better hot hardness than A6 from the W addition. Toughness similar to A6. Used for hot-work applications that do not need H13-class hot hardness.
Applications: Cold-header dies, punches for thick plate, shear blades on tough substrate, hot-piercing punches for billet.
Cross-reference: ≈ DIN 1.2343 (similar).
See also: D2 vs SKD11 comparison, Material Grade Converter, The KAIPU 5-Factor Blade Selection Framework.