Although AL 20 alloy was developed for improved resistance to corrosion by sulfuric acid, it fins wide use throughout the chemical industry. It is used extensively in the manufacture of solvents, explosives, plastics, synthetic fibers, organic chemicals, pharmaceuticals, and food-processing equipment. Containment of acid mixtures and chloride stress corrosion resistance are examples of successful applications for AL 20 alloy. Where purity must be maintained in the processing of products such as foodstuffs or dyes, AL 20 alloy is used to protect end products from the danger of contamination by metallic ions through corrosion.

AL 20 alloy has been applied economically in many areas where other materials my provide the necessary corrosion resistance, but are either higher in initial cost or more expensive to install and maintain. Important advantages of AL 20 alloy are its excellent mechanical properties and comparative ease of fabrication. The presence of columbium in the alloy minimizes the precipitation of carbides in heat-affected zones during welding so that assemblies can usually be placed in service in the as-welded condition. Welds with matching filler metal will be slightly less corrosion resistant than the base alloy.

The N08020 alloy is readily available in a wide range of product forms, and is covered by a wide variety of ASTM and ASME specifications having assigned maximum working stresses to 540 °C. The alloy is familiar to many fabricators and the weldability of this alloy contributes to its use in many engineered applications. Weld filler metal is readily available and welding procedures are well established.

Information provided by Allegheny Ludlum