ThePipingMart Blog Grades 440C Stainless Steel (UNS S44004) – Composition, Properties and Uses

440C Stainless Steel (UNS S44004) – Composition, Properties and Uses

440C Stainless Steel

If you’ve been browsing for stainless steel products, chances are you’ve come across the term “440C stainless steel.” But do you know what it is? What makes it different from other types of stainless steel? Let’s take a closer look at this popular alloy and break down its composition, mechanical properties, physical properties, and uses.

440C Stainless Steel Composition

UNS S44004 is an alloy made up of iron, chromium, carbon, and trace amounts of manganese and silicon. The addition of chromium gives this alloy excellent corrosion resistance and a high hardness level (58 HRC on the Rockwell scale). It also contains 0.95-1.20% carbon which allows it to be heat-treated to achieve a range of mechanical properties.

Element Content (%)
Iron, Fe 79.15
Chromium, Cr 17
Carbon, C 1.1
Manganese, Mn 1
Silicon, Si 1
Molybdenum, Mo 0.75

440C Stainless Steel Mechanical Properties

The mechanical properties of 440C stainless steel are very impressive due to its unique composition and heat treatment process. This alloy can achieve a tensile strength of up to 980 MPa (144 ksi) and an ultimate yield strength of 885 MPa (129 ksi). It also has excellent fatigue strength when compared to other alloys in its class. Additionally, it has good wear resistance thanks to its high hardness level.

Properties Metric Imperial
Tensile strength 760-1970 MPa 110000-286000 psi
Yield strength (@ strain 0.200%) 450-1900 MPa 65300-276000 psi
Bulk modulus 166 GPa 24100 ksi
Shear modulus 83.9 GPa 12200 ksi
Elastic modulus 200 GPa 29008 ksi
Poisson’s ratio 0.27-0.30 0.27-0.30
Elongation at break 2-14 % 2-14 %
Hardness, Rockwell B (converted from Brinell hardness) 97 97

440C Stainless Steel Physical Properties

In addition to providing superior mechanical properties, 440C stainless steel also offers excellent physical properties, such as low thermal expansion coefficients and high thermal conductivity. It is non-magnetic in nature and provides good electrical conductivity compared to other steels in its class. Lastly, it can withstand temperatures up to 1000°F without experiencing any degradation or loss in performance.

Properties Metric Imperial
Density 7.80 cm³ 0.282 lb/in³
Melting point 1483°C 2700°F

440C Stainless Steel Thermal Properties

Properties Metric Imperial
Thermal expansion co-efficient 10.2 µm/m°C 5.67 µin/in°F
Thermal conductivity 24.2 W/mK 168 BTU in/hr.ft².°F

440C Stainless Steel Equivalent

  • AMS 5618
  • AMS 5630
  • AMS 5880
  • ASTM A276
  • ASTM A314
  • ASTM A473
  • ASTM A493
  • ASTM A580
  • DIN 1.4125
  • QQ S763
  • MIL-S-862
  • SAE 51440C
  • SAE J405 (51440C)

440C Stainless Steel Uses

Due to its superior combination of physical and mechanical properties, 440c stainless steel is used in a variety of applications, including cutlery (knives), surgical instruments, aerospace components (shafts & valves), bearings & roller components, pump components & valves, ball screws & lead screws, petrochemical industry parts (valves), etc. This type of stainless steel is also commonly used for making moulds such as plastic injection moulds due to its superior corrosion resistance and ability to withstand high temperatures without losing performance or degrading over time.


For those looking for an alloy that offers superior physical and mechanical properties with excellent corrosion resistance, then look no further than 440C stainless steel! This type of stainless steel is perfect for applications where superior strength and corrosion resistance are needed, such as cutlery, aerospace components or petrochemical industry parts . Its nonmagnetic nature also makes it ideal for use in moulds where magnetic fields could cause interference with the moulding process or damage the part itself. If your application requires superior strength or corrosion resistance , 440C may be the right fit!

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