Grade 440 Stainless Steel – High-Hardness Martensitic Alloy For Wear-Resistant Applications

Overview

Grade 440 is a family of high-carbon martensitic stainless steels known for their exceptional hardness, wear resistance, and moderate corrosion resistance. It contains 16.0-18.0% chromium and varying carbon contents (depending on the sub-grade), which enable heat treatment to achieve ultra-high hardness (up to 60 HRC). Unlike lower-carbon martensitic grades (410, 420), Grade 440 offers superior edge retention and wear resistance, making it ideal for cutting tools, bearings, and precision components. It is magnetic and has good machinability when annealed, though its high carbon content requires careful heat treatment to avoid brittleness.

Chemical Composition (wt%)

C: 0.60-1.20, Cr: 16.00-18.00, Mn ≤ 1.00, Si ≤ 1.00, P ≤ 0.045, S ≤ 0.030, Mo: 0.75-1.25, Ni ≤ 0.75

Typical Mechanical Properties (Annealed Condition)

Tensile Strength (Rm): ≥ 700 MPa; Yield Strength (Rp0.2): ≥ 450 MPa; Elongation (A): ≥ 12%; Brinell Hardness (HB): ≤ 255

Core Advantages

Ultra-high hardness and wear resistance after heat treatment; excellent edge retention for cutting tools; moderate corrosion resistance in mild environments; magnetic; good machinability in annealed state; suitable for precision, wear-intensive applications.

Applications

High-quality knives, bearings, gears, valves, surgical instruments, and precision components requiring extreme wear resistance and edge retention.

Equivalent Grades

EN 1.4125 (440A/B/C), UNS S44000 Series, GB 9Cr18, SUS440 Series

 

Stainless Steel Suppliers

If you have project requirements for stainless steel, we welcome your order. GNEE has a large inventory of popular products for you to choose from. It can be processed into various practical product forms, including plates, coils, tubes, bars, wires, etc. For detailed chemical composition information and free samples, please contact our factory immediately. We offer competitive prices and excellent service.Email: info@gneestainless.com

 

Testing and Documentation: Factory test certificate, EN 10204 3.1, chemical report, mechanical report, destructive testing report, non-destructive testing report, PMI test report, visual inspection report, third-party inspection report, NABL certified laboratory report.
Packaging: Wooden crate packaging, bubble wrap packaging, steel strapping, or packaging according to customer requirements.