440C STEEL (X105CRMO17)

440C is a martensitic stainless steel with relatively high carbon content resulting in good hardness and wear resistance. With correct heat treating, it can reach 58-60 HRC, and is typically used in bearings, ball screws, and other rolling contact applications. The high hardness and moderate corrosion resistance make 440c suitable for knife blades, medical instruments, food service, and valves as well.

Sullivan stocks only domestic melted 440C, both VAR and Air Melt.



FOR REQUIREMENTS: Stainless Bearing Steel
CORROSION RESISTANCE: Superior to 52100 / Worse than XD Alloys
SPECIFICATIONS: AMS5630 / AMS5880 – Air Melt
AMS5618 – VAR

Typical Applications

  • Cutting Instruments
  • Ball Bearings and Ball Screws
  • Knife Blades, Chisels, and Swords
  • Surgical Instruments

Chemical Composition

  C Si Mn Cr Mo S P
min. 0.95 16.00
max. 1.20 1.00 1.00 18.00 0.75 0.030 Air-melt
0.010 VAR
0.040 Air-melt
0.020 VAR

Corrosion Resistance

While considered a “stainless steel”, 440C will corrode in certain environments. In these cases, XD15NW and XD16N should be considered for superior corrosion resistance and mechanical properties.

Stocking Sizes

AMS 5618 VAR: Bar – 0.125″ø – 6.000″ø; Wire – 0.135” – 0.218” ø

AMS 5630 / AMS 5880 Air Melt Bar: 0.25″ – 6.50″

Additional Small Diameter Bar and Wire sizes available upon request.

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