· KAIPU Engineering · materials-encyclopedia · 1 min read
AISI O1 Oil-Hardening Cold-Work Tool Steel
Materials encyclopedia entry for O1.
AISI O1 Oil-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 0.85–1.00 %, Cr 0.40–0.70 %, Mn 1.00–1.40 %, W 0.40–0.70 %, V ≤ 0.30 %, Si 0.20–0.40 %, balance Fe
Hardness: Annealed HB 183–212; hardened HRC 58–64
Heat treatment: Austenitise 780–820 °C, oil quench, double temper 175–200 °C
Properties: Excellent dimensional stability on oil quenching. Hardness up to HRC 64 achievable. Lower wear resistance than D2 (low Cr and V). Used for precision parts where dimensional control matters more than wear.
Applications: Precision gauges, dies for short-run blanking, master tools, low-volume slitter blades, draw dies for sheet metal.
Cross-reference: ≈ JIS SKS3, DIN 1.2510, GB 9Mn2V, BS BO1.
See also: D2 vs SKD11 comparison, Material Grade Converter, The KAIPU 5-Factor Blade Selection Framework.