AISI 440A Martensitic Stainless Steel
AISI 440A (UNS S44002) — lowest-carbon 440 grade, HRC 54–56, optimised for corrosion over hardness. Compare with 440B/C for food-contact blades.
AISI 440A (UNS S44002, DIN 1.4109) is the lowest-carbon member of the 440 family, optimised for corrosion resistance over hardness — typical achievable HRC 54–56. It is used where 440B/440C hardness is unnecessary but the corrosion resistance of the 440 family is required: food-contact slitter blades, pump shafts, lower-end cutlery.
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.
