Alloy 20 Fasteners Bolts Nuts and Socket Head Cap Screws

Alloy 20 Fasteners

Alloy 20, which is also known as “carpenter 20” and “20CB-3, is a nickel-chromium-molybdenum stainless steel alloy designed for applications with sulfuric acid. Its corrosion resistance also gives it many other uses within the chemical, food, pharmaceutical, and plastics industries. A main reason why Alloy 20 fasteners are so common is because they resists pitting and chloride ion corrosion and its copper content protects it from sulfuric acid. Cast versions are designated CN7M. Alloy 20 hex bolts, nuts washers, and stud bolts can be fabricated to meet your projects exact requirements. Lightning Bolt specializes in hard to find alloy fasteners, including alloy20 bolts.

Alloy-20 is one of the “Super” stainless steels that was engineered for superior resistance to acid attack. It’s nickel, chromium, molybdenum and copper content contribute to its overall resistance to chlorideon stress corrosion cracking and general pitting attack.  It is practically immune to chloride stress corrosion cracking.  Alloy-20 is stabilized with columbium to minimize carbide precipitation during welding. It has great mechanical properties and can be fabricated with relative ease. Though the alloy was designed for use in sulfuric acid related industries, it finds wide usage throughout the chemical industry throughout the world. It also is used for processing pharmaceuticals, food, gasoline, solvents, plastics, explosives, synthetic fibers and many other products.

It has been known to have superior resistance to stress-corrosion
cracking in boiling 20 to 40% sulfuric acid. Also, it has excellent general corrosion resistance to
sulfuric acid. In addition, it has excellent resistance to chloride stress
corrosion cracking. In general this makes alloy 20 an excellent alloy of fastener to use in the
chemical industry, Food and dye production industry, 
SO 2 scrubbers and other severe environments.


Specials alloy fasteners are our “specialty”, however standard items also within our capabilities include:

To learn more about our products, or to place an order, please call (225) 272-6200 or send an email to  For calls placed from outside of the United States, please call 001-225-272-6200.


Alloy 20 tensile Strength (KSI) 80

Other Names for alloy 20 include UNS N08020, DIN 2.4660,CN7M,Carpenter 20 CB 3TM,AL 20TM,Carlson Alloy C20TM,Nickelvac 23TM, Nicrofer 3620 NbTM.


  • Nickel, 32.5-35%

  • Chromium, 19-21%

  • Carbon, 0.06% maximum

  • Copper, 3-4%

  • Molybdenum, 2-3%

  • Manganese, 2% maximum

  • Silicon, 1% maximum

  • Columbium, 1% maximum

  • Iron, 31-44% (balance)

Physical Properties

Density: 0.278 lb/in3 annealed

Melting Point: 2525-2630°F

Electrical Resistivity: 651 Ohm-circ mil/ft

Temperature, °F70212392572752842932
Coefficient* of Thermal Expansion, in/in°F x 10-68.168.378.628.628.848.91
Thermal Conductivity
Btu • ft/ft2 • hr • °F
Modulus of Elasticity, Dynamic psi x 10628

* 70°F to indicated temperature.

Mechanical Properties

Minimum Specified Properties, Asme Sb-688 Plate

Ultimate tensile strength, ksi80
0.2% yield strength, ksi35
Elongation, %30
Hardness MAX, Brinell217

Typical Tensile Properties, Bar

Temperature, °F70
Ultimate Tensile Strength, ksi91
0.2% Yield Strength, ksi48
Elongation, %45
Charpy Impact V-notch, ft-lbs200


For More Information or to Place Orders

To learn more about our products, or to place an order, please call (225) 272-6200 or send an email to  For calls placed from outside of the United States, please call 001-225-272-6200.

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