· KAIPU Engineering · materials-encyclopedia · 1 min read
AISI 440B Martensitic Stainless Steel
Materials encyclopedia entry for 440B.
AISI 440B 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 0.75–0.95 %, Cr 16.0–18.0 %, Mo ≤ 0.75 %, Mn ≤ 1.00 %, Si ≤ 1.00 %, Ni ≤ 0.75 %, balance Fe
Hardness: Annealed HB 220–250; hardened HRC 56–59
Heat treatment: Austenitise 1,010–1,050 °C, oil or gas quench, temper 150–200 °C
Properties: The middle member of the 440 family. Slightly higher hardness than 440A, similar corrosion resistance.
Applications: Industrial cutting tools, bearings, valve components, surgical instruments.
Cross-reference: ≈ JIS SUS440B, DIN 1.4112, GB 8Cr17.
See also: D2 vs SKD11 comparison, Material Grade Converter, The KAIPU 5-Factor Blade Selection Framework.