Alloy 20 is an austenitic nickel-iron-chromium alloy with additions of copper and molybdenum.

The nickel content makes Alloy 20 resistant to chloride-ion stress-corrosion cracking. Copper and molybdenum give resistance to reducing environments. The molybdenum content also provides good resistance to pitting and crevice corrosion. The chromium gives resistance to oxidizing environments such as nitric acid. The addition of niobium reduces the effect of carbide precipitation during welding, thus increasing the alloy’s resistance to intergranular corrosion.

Alloy 20 has exceptional corrosion resistance in sulfuric acid environments, and is used in a range of applications involving this acid. Other uses include the production of gasoline, solvents, explosives, inorganic and organic chemicals, pharmaceuticals, food and synthetic materials. For these and other applications,Alloy 20 is readily fabricated to produce mixing tanks, heat exchangers, process piping, pickling equipment, pumps, valves, fasteners and fittings.

Chemical Analysis of CP Alloy 20

C Ni Mo Co Ir M Cr Si Su Pho
19.00-21.00 32.00-38.00 2.00-3.00 3.00-4.00 Bal. 2.00max 0.07max 1.00max 0.035max 0.045max


 Sheet / Plate  SB- B162 / B160
 Round Bar  SB- B162 / B160
 Pipe  SB- B161 / B725
 Fittings  SB- B366
 Forgings  SB- B564

Mechanical Properties

Form Tensile Min. Yield Min. (.2% offset) Elongation Min. Reduction of Area Min.
Bar (hot or cold finished) 80 ksi 35 ksi 30% 50%
80 ksi
35 ksi