Alloy 20

Alloy 20 was designed specifically to withstand sulfuric acid. Its nickel, chromium, molybdenum and copper levels all provide excellent general corrosion resistance. Restricted carbon plus columbium stabilization permits welded fabrications to be used in corrosive environments, normally without post-weld heat treatment. At 33% nickel, Alloy 20 has practical immunity to chloride stress corrosion cracking. This alloy is often chosen to solve SCC problems, which may occur with 316L stainless.


Alloy 20 Plate, Alloy 20 Sheet, Alloy 20 Weld Wire

Common Trade Names

Carpenter® 20, 20CB-3®


  • Excellent resistance to hot sulfuric acid
  • Resistant to intergranular corrosion in the as-welded condition
  • Chloride stress corrosion cracking resistance


  • Sulfuric acid pickling tanks, racks and heating coils
  • Phosphate coating drums and racks
  • Heat exchangers
  • Bubble caps
  • Process piping
  • Mixing tanks
  • Chemical and petroleum process equipment