· KAIPU Engineering · materials-encyclopedia · 1 min read
AISI 440A Martensitic Stainless Steel
Materials encyclopedia entry for 440A.
AISI 440A Martensitic Stainless 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 0.60–0.75 %, Cr 16.0–18.0 %, Mo ≤ 0.75 %, Mn ≤ 1.00 %, Si ≤ 1.00 %, Ni ≤ 0.75 %, balance Fe
Hardness: Annealed HB 215–240; hardened HRC 54–58
Heat treatment: Austenitise 1,010–1,050 °C, oil or gas quench, temper 150–200 °C
Properties: The lower-carbon member of the 440 family. Less hardenable than 440C but tougher. Better corrosion resistance than 420.
Applications: Food slicer blades, meat processing, medical instruments where impact resistance matters.
Cross-reference: ≈ JIS SUS440A, DIN 1.4110, GB 7Cr17.
See also: D2 vs SKD11 comparison, Material Grade Converter, The KAIPU 5-Factor Blade Selection Framework.