incoloy-alloy-825-oil-gas-extractionWhile Incoloy Alloy 825 was introduced to the market over fifty years ago, questions still abound about the proper methods for fabricating, welding and heat treating the alloy.

Despite the fact that Incoloy Alloy 825 is a conventional iron-nickel-chromium-molybdenum alloy, it requires special attention to detail during processing to ensure that the product develops the optimum metallurgical structure, mechanical properties and corrosion resistance for the given application. For optimum properties the alloy should enter service in a stabilized condition. Proper mechanical processing and heat treatment are required to produce the microstructure required for optimum corrosion resistance.


Nickel-chromium-molybdenum alloys such as Alloy 825 are often solution annealed at a high temperature prior to service. However, stabilized alloys offer optimum corrosion resistance after annealing at a lower temperature. This process is commonly referred to as stabilization anneal. This is the standard condition of supply for Incoloy Alloy 825 products and is the key to successful fabrication of the alloy. However carefully the material is formed and welded, if the material has not been correctly stabilized it will not give maximum performance.  


Incoloy Alloy 825 is stabilized by the carbon content being limited to 0.05% max. The alloy is further stabilized by its content of 0.6 to 1.2% titanium. Finally the stabilizing anneal heat treatment used for Incoloy Alloy 825 results in the optimum performance when unstabilized Incoloy Alloy 825 is exposed to intergranular grain boundary attack.

Topics: Incoloy Alloy 825

Sign up for our blog