Alloy 686 (UNS N06686) is a single-phase, nickel-chromium-molybdenum, tungsten alloy designed for outstanding corrosion resistance in a wide range of environments. This alloy is used in the most severe environments encountered in chemical processing, pollution control, pulp and paper production, marine (seawater) and treatment of industrial and municipal wastes. Chemical processing uses include heat exchangers, reaction vessels, evaporators and transfer piping. Air pollution control applications are stack liners, ducts, dampers, scrubbers, stack-gas re-heaters, fans and housings.
Development for Navy Applications:
Alloy 686 has been tested and qualified for manufacture of fasteners for service in aggressive marine environments. By cold working, fasteners with yield strength levels up to 150 ksi can be made. The resulting products exhibit excellent resistance to corrosion by seawater and hydrogen embrittlement. Alloy 686 fasteners are galvanically compatible with the common materials of marine construction. The high strength fasteners exhibit good ductility and fracture toughness. Thus, alloy 686 fasteners are expected to solve many of the problems encountered with existing grades of corrosion-resistant marine fasteners.
Fasteners of three grades of alloy 686 can be specified by ASTM F467 (nuts) and ASTM F468 (bolts). Each grade offers differing mechanical properties but maintains the same chemistry.