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440C Stainless Steel Plate - UNS S44004

Type 440C is a martensitic stainless steel with high carbon and chromium content.  After heat treatment, it is capable of attaining the highest strength, hardness and wear resistance of all stainless alloys.  Compared to austenitic grades, 440C has moderate corrosion resistance, comparable to 304.  This grade of stainless steel plate can be hardened through heat treatment, but machining is preferable in the annealed condition and becomes extremely difficult once hardened.

Highest resistance can be achieved through hardening and polishing, and the properties of 440C steel make it ideal for knife blades and cutting instruments like surgical blades.  This grade, once hardened, hold a sharp edge and resists corrosion, and can be polished to a near mirror finish.  Its toughness and ability to resist wear makes 440C stainless steel a good choice for tools like chisels and ball bearings.

  • T-440-C
    Type 440C Stainless Steel Plate

440C Plate

Standard Inventory Specifications

  • UNS S44004
  • AMS 5630 Chem Only
  • ASTM: A480
  • SAE AMS 5630


  • Hardenable chromium steel
  • High strength
  • High wear resistance

Inventory Size Range

  • Plate : 0.1875" - 2.500"

Please contact us for more details.

The technical data provided is for information only and not for design purposes. It is not warranted or guaranteed.

440C Chemical Composition

Element Percent By Weight
C Carbon 1.20
Cr Chromium 18.0
Mn Manganese 1.00
Mo Molybdenum 0.75
P Phosphorous 0.04 
Si Silicon 1.00
S Sulfur 0.30

Percent maximum unless a range is specified

Common Applications of 440C Stainless Steel Plate include:

  • Cutting Instruments
  • Knife Blades
  • Surgical Instruments
  • Chisels
  • Measuring instruments
  • Ball Bearings and Valves



Density kg/mᶟ


Thermal Conductivity at 212°F (100°C)


Thermal Conductivity at 932°F (500°C)


Electrical Resistivity


Elastic Modulus (Gpa)




Yield Strength 0.2% Proof (Mpa)


Tensile Strength (Mpa)


Elongation (% in 50mm)


Hardness (HB)

269 max

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