ASTM B564 UNS N08020 Flange

Alloy 20 seems to fall in-between both the stainless and nickel categories, as it does contain characteristics of both; however, the unified numbering system (UNS) does ultimately recognize it as a nickel based alloy, hence the UNS N08020 number.

Alloy 20 is an austenitic nickel-iron-chromium based alloy with additions of copper and molybdenum. Its nickel content aids in its chloride ion stress and corrosion resistance. The addition of copper and molybdenum provides resistance to hostile environments, pitting and crevice corrosion. Chromium adds to its resistance of oxidizing environments, such as nitric acid, and columbium (or niobium) reduces the effects of carbide precipitation. Most welding methods can be used when working with Alloy 20, except for oxyacetylene welding. It can also be hot formed using the same forces required to hot work austenitic stainless steels. In terms of machineability, outstanding finishes are possible using the same set-up and process speeds used for austenitic stainless steels, such as Stainless Steels 316 or 317. 

UNS N08020 Alloy 20 Flange Design features

 Exceptional stress-corrosion resistance in boiling 20% to 40% sulfuric acid

 Sulfuric acid general corrosion resistance

 Ideal fabricability and mechanical characteristics

 Welding produces minimal carbide precipitation

UNS N08020 Alloy 20 Flange Applications

 Chemical and allied industries

 Pharmaceutical processing

 Food and dye

 Sulfur dioxide (SO2) scrubbers

 Pickling racks

 Tanks

Alloy 20 Chemical Composition %