Stainless Steel 440c

E Steel Sdn Bhd are Asia Metal traders, exporters, manufacturers agent, providing high-performing stainless steel and nickel alloy & titanium material. As : 300 Series stainless steel , 400 series stainless steel , 253ma, sus301, sus304, sus304l, sus309,  sus310, sus310s, sus316, sus316l, sus316ti, sus317, sus321, sus347, sus403 , sus409, sus410 , sus416, sus420 , sus420j2, sus430,sus430f, sus431 , sus440c , sus630 , 15-5ph, 17-4ph,  sus904L, s31803 , s32750 , s32760, s31254, s329j4l, Nitronic30, Nitronic50 , Nitronic60, F6nm, Ferralium 255.



Martensitic Stainless Steel 440A, 440B, 440C

WHAT IS 440C material?

Stainless Steel 440C ( 1.4125 ) is capable of attaining, after heat treatment, the highest strength, hardness and wear resistance of all the stainless alloys. Its very high carbon content is responsible for these characteristics, which make SS440C particularly suited to such applications as ball bearings and valve parts.

  • Hardenable high-carbon chromium steels designed to provide stainless properties with maximum hardness
  • Have maximum hardness together with high strength and corrosion resistance in the hardened and stress relieved condition
  • Always used in the hardened or hardened and stress relieved conditions
  • None of the alloys has its full corrosion resistance either in the annealed or in the hardened and tempered condition
  • Wide applications where good corrosion resistance along with high hardness or abrasion resistance is required


 440C stainless steel equivalent 

Country USA BS & DIN Japan
Standard ASTM A276 EN 10088 JIS G4303
Grades S44004/440C X105CrMo17/1.4125 SUS440C


ASTM 440C Stainless Steel Properties

Tempering Temperature (°C) Tensile Strength (MPa) Yield Strength 0.2% Proof (MPa) Elongation (% in 50mm) Hardness Rockwell (HRC) Impact Charpy V (J)
Annealed* 758 448 14 269HB max#
204 2030 1900 4 59 9
260 1960 1830 4 57 9
316 1860 1740 4 56 9
371 1790 1660 4 56 9

Applications of stainless Steel 440C

  • Used in numerous applications in areas where a very hard and abrasion resistant stainless is called for
  • Applications include pivot pins, dental and surgical instruments, cutlery valve parts, ball bearings, nozzles, hardened steel balls and seats for oil well pumps, plus valve parts

Will 440C stainless steel rust?

These stainless steels have good corrosion resistance in the hardened and stress relieved conditions.  Hence, they should, usually, be used only in that condition. These steels are resistant to such conditions as fresh water, steam, crude oil, gasoline, perspiration, and alcohol.

Property SS 440A          SS 440B    SS 440C
Carbon .60 – .75 .75 – .95 .95 – 1.2
Manganese 1.00 max 1.00 max 1.25 max
Silicon 1.00 max 1.00 max 1.00 max
Phosphorus .04 max .04 max .04 max
Sulfur .03 max .03 max .04 max
Chromium 16.0 – 18.0 16.0 – 18.0 16.5 – 18.0
Molybdenum .75 max .75 max .75 max
Nickel .50 max NA NA

Hardening of 440C Steel

Stainless steel 440C grade can be hardened by heating at 760°C (1400°F). Temperature can be increased up to 1010°C (1850°F) followed by quenching in warm oil or cool in air. However, don’t overheat, because when overheated, full hardness cannot be obtained.

440c stainless steel Heat Treatment

PROCESS ANNEAL:  Heat at 1350-1450° F then cool very slowly in the furnace.
FULL ANNEAL: Heat uniformly at 1550-1600° F soak and cool slowly in furnace to 1000-1250° F at a rate of 20-50° F per hour, then cool in air, oil, or water.
HARDENING: Preheat slowly to 1450° F and soak, then raise temperature to 1850-1950° F, quench in warm oil or air. Products hardness of C55-58 Rockwell.
STRESS RELIEVE:  Heat to 300-800° F for 1 to 3 hours, air cool.

What hardness is 440C stainless steel?
440C (UNS designation S44004) is a martensitic 400 series stainless steel, and is the highest carbon content from 400 stainless steel series. It is usually heat treated to reach hardness of 58–60 HRC. It is a bearing steel, and used in rolling contact stainless bearings, e.g. ball bearings and roller bearings.