The high alloy content of Alloy 625 enables it to withstand a wide variety of corrosive environments. The alloy is almost completely resistant to mild environments such as the atmosphere, fresh water and seawater, neutral salts, and alkaline media. In more severe environments, the combination of nickel and chromium provides resistance to reducing conditions. The molybdenum content also makes Alloy 625 highly resistant to pitting and crevice corrosion. The high nickel content provides freedom from chloride stress-corrosion cracking.
Nickel and nickel based alloys are used for a wide variety of applications in the aerospace, chemical processing, marine and automotive industries.
Alloy 625 was introduced in the 1960's, developed for aircraft engines, but has found wide use in other applications requiring high-temperature strength and corrosion resistance. It contains a nominal 20% Cr, 9% Mo and 2.5% Fe, and is stabilised with approximately 3.5% Nb.
Alloy 625 belongs to the Nickel-chromium-molybdenum alloy family. They are among the most versatile of the nickel base alloys and are used in a broad range of environments, both oxidising and reducing. Alloy 625 which contains 9% Mo, serves effectively as both a corrosion resistant and heat resistant material. The combination of high temperature strength and carbonation has made alloy 625 a popular choice for hostile environments.
Nickel Alloy, Corrosion and Heat-Resistant, Seamless or Welded Tubing - Annealed
Standard Specification for Welded Nickel Alloy Tubes
Standard Specification for Nickel-Chromium-Molybdenum-Columbium Alloys (UNS N06625 and UNS N06852) and Nickel-Chromium-Molybdenum-Silicon Alloy (UNS N06219) Pipe and Tube
Nickel Alloy, Corrosion and Heat-Resistant, Bars, Forgings, Extrusions, and Rings - Annealed
Nickel Alloy, Corrosion and Heat-Resistant, Sheet, Strip, and Plate
Nickel Alloy, Corrosion and Heat-Resistant, Sheet, Strip, and Plate - Solution Heat Treated
Nickel Alloy, Corrosion and Heat-Resistant, Welding Wire
In an attempt to try and unify the designations used, a system called the Unified Numbering System was developed by the American Society for Testing and Materials (ASTM) and Society of Automotive Engineers (SAE) in 1972.