· KAIPU Engineering · materials-encyclopedia · 1 min read
AISI M2 High-Speed Steel — Materials Encyclopedia Entry
AISI M2 is the workhorse high-speed steel (HSS) of the converting and slitting industry. Molybdenum-tungsten-vanadium tool steel, hardened to HRC 62–65, retains hardness at 500–600 °C.
AISI M2 (UNS T11302) is the most widely used molybdenum-tungsten high-speed steel for industrial cutting tools and blades. It is the default HSS grade for slitting, shearing and converting blades that need to retain hardness at elevated temperatures.
Standard composition: C 0.78–0.88 %, Cr 3.75–4.50 %, Mo 4.50–5.50 %, W 5.50–6.75 %, V 1.75–2.20 %, balance Fe.
Hardness: Annealed HB 248–277; hardened HRC 62–65 (typical), maximum practical HRC 67. Hot hardness HRC 56 at 500 °C, HRC 48 at 600 °C.
Heat treatment: Pre-heat 815–845 °C, austenitise 1,200–1,220 °C, oil or salt-bath quench, triple temper 540–565 °C, 2 h each. Sub-zero (−80 °C) treatment between first and second temper for tightest tolerances.
Properties: Excellent hot hardness; the vanadium-rich MC carbides provide good wear resistance. Toughness sufficient for thin slitter blades down to 1.5 mm thickness.
Applications: Film and foil slitting, food-contact cutting, plastic granulator rotors, paper and tissue sheeting. The default HSS grade for any industrial knife that sees > 200 m/min line speed.
Cross-reference: ≈ JIS SKD51 / SKH51, DIN 1.3343, GB W6Mo5Cr4V2, BS BM2, AFNOR Z85WDCV6-5-4-2. See the Material Grade Converter.
See also: M2 vs M4 HSS, HSS vs Carbide, The KAIPU 5-Factor Blade Selection Framework.