ALLOY 20 FASTENERS Specifications

Also known as Carpenter 20 and 20CB-3, Alloy 20 offers users a combination of nickel, chromium, molybdenum, and copper which provides good general corrosion resistance. Alloy 20 fasteners are best suited for mid-range corrosion use – better than steel alloys but not at the level of high performance nickel based alloys like Hastelloy C276. Alloy 20 is a nickel alloy that was specifically designed to withstand the harsh environment of hot sulfuric acid but also performs well in a variety of other acids.
Inconel 625 ASTM B366 Insert couplet

Alloy 20 fasteners are an ideal choice when you don’t need the corrosion resistance power and price-tag of high performance nickel alloys like Hastelloy C276; but you need something that will give you more protection than 316 stainless steel or even a Super Duplex 2507 stainless steel.

CORROSION RESISTANCE

Alloy 20 fasteners provide good performance in hot sulfuric acid, specifically they offer good resistance to stress-corrosion cracking in boiling sulfuric acid at specific range of 20% to 40% concentration, as well as general sulfuric acid resistance. Alloy 20 fasteners offer solid acid protection and will perform better than Duplex or even Monel, but for high temperature and high concentration acids, you may need to look to Inconel or Hastelloy fasteners. In addition Alloy 20 fasteners also show useful resistance to phosphoric acid and nitric acid.

  • Good sulfuric acid protection at 20% – 40%
  • Decent stress corrosion cracking, pitting and crevice corrosion resistance in chloride
  • Resonable general corrosion protection
  • Good intergranular corrosion resistance in the as-welded condition

ALLOY 20 FASTENERS

Inconel 625 ASTM B366 Insert couplet Grades Marking
Inconel 625 ASTM B366 Insert couplet Pipe Packaging
ALLOY 20 FASTENERS CHEMICAL COMPOSITION
ElementAlloy 20
Ni32 – 38
FeBal
C0.02 max
Mn1 – 2
Si0.7 max
Cu3 – 4
Cr19 – 21
Mo2 – 3
S0.005 max
P0.02 max
Nb0.1 – 0.3

IN WHAT APPLICATIONS IS ALLOY 20 USED?

  • Synthetic rubber manufacturing equipment
  • Processing of pharmaceuticals, plastics and organic and heavy chemicals
  • Tanks, piping, heat exchangers, pumps, valves, and other process equipment
  • Acid cleaning and pickling equipment
  • Chemical process piping, reactor vessels
  • Bubble caps
  • Petrochemical process equipment
  • Food and dye production
ALLOY 20 FASTENERS PHYSICAL & MECHANICAL PROPERTIES
ElementAlloy 20
Density8.1 g/cm3
Melting Point1443 °C (2430 °F)
Tensile StrengthPsi -80,000, MPa -551
Yield Strength (0.2%Offset)Psi – 35,000, MPa – 241
Elongation30 %