Lightning Bolt is capable of manufacturing a wide range of Carpenter-20 fasteners.  Known by many as “Alloy 20 studs” and “20CB-3 studs, CARPENTER-20 Studs are 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 carpenter-20 studs 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.

Carpenter 20 studs / stud bolts are composed of what some consider 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.  Carpenter-20 stud bolts are 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.

Carpenter 20 stud bolts 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)

Being an ISO 9001:2008 certified company, we are capable of manufacturing any type of fastener.  Specials are our “specialty”, however standard items also within our capabilities include:

Click here for more information about Carpenter-20 Fasteners and contact Lightning Bolt today at 225-272-6200

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