ASTM B425 Incoloy 825 (Alloy 825, UNS N08825) Bar/Rod

Incoloy 825 Characteristics

Incoloy alloy is a range of superalloys produced by JN Alloy. They are nickel-iron-chromium alloys that are used for applications that require high corrosion-resistant and high-temperature strength. Incoloy 825 is a Nickel-iron-chromium alloy with additions of molybdenum, copper, and titanium. The alloy's chemical composition provides exceptional resistance to many corrosive environments. The Nickel content is sufficient for resistance to Chloride-ion stress corrosion cracking. The nickel, combined with molybdenum and copper, also gives outstanding resistance to reducing environments such as those containing sulfuric and phosphoric acid. The molybdenum also aids resistance to pitting and crevice corrosion. The alloy Chromium content confers resistance to a variety of oxidizing substances such as nitric acid, nitrates, and oxidizing salts. The titanium addition, with appropriate heat treatment, will stabilize the alloy against sensitization to intergranular corrosion.

Nickel Alloy 825 bar, rod, and wire is a nickel-iron-chromium alloy with additions of molybdenum, copper, and titanium. The alloys chemical composition is designed to provide exceptional resistance to many corrosive environments. The nickel content is sufficient for resistance to chloride-ion stress-corrosion cracking. The nickel, in conjunction with the molybdenum and copper, also provides outstanding resistance to reducing environments, such as those containing sulfuric and phosphoric acids. The molybdenum also aids resistance to pitting and crevice corrosion. And the titanium addition serves to stabilize the alloy – following appropriate heat treatment – against sensitization to inter-granular corrosion.

JN Alloy carries a significant stock of Alloy 825 solid bar, from ¾” up to 10” in a large number of incremental sizes. In addition, we also carry some bespoke sizes of hollow bar or tube for specific customer applications, as well as using our in-house deep hole borer to offer one-offs and specific sizes of bored bar. Popular applications currently served by our customers includes valve components, thermowells and sensors, fasteners and also some downhole tooling which make use of its non-magnetic properties.

Chemical Composition of Incoloy 825

Incoloy 825 was brought to the market in 1952, building upon Incoloy 800 in order to better resist sulphuric acid. Copper additions are well-known to improve resistance to reducing environments, such as sulphuric acid. This property is also exploited in Ferralium 255 (containing 2% copper additions) and the much more highly alloyed Alloy 20 (3-4% copper) to great effect. The nickel content of Incoloy 825 makes it resistant to chloride stress corrosion cracking. The composition of molybdenum and copper improves the corrosion resistance in reducing environments of Incoloy 825 when compared to other austenitic stainless steels. The chromium and molybdenum make it more resistant to chloride pitting and oxidizing atmospheres. The titanium can stable the alloy against sensitization in the as-welded condition. These compositions make Incoloy825 have excellent resistance to stress corrosion cracking and great pitting resistance in most environments except strongly oxidizing chloride solutions.

The high nickel content ensures resistance to stress corrosion cracking, combined with molybdenum and copper to strongly resist reducing environments such as sulphuric and phosphoric acids, chromium to resist oxidising environments such as nitric acid, titanium to inhibit intergranular corrosion, and overall resistance to pitting and crevice corrosion. The superior resistance ability to corrosion environments makes Incoloy 825 has been applied in many industrials such as chemical processing, pollution control, oil and gas recovery, and nuclear fuel reprocessing. Incoloy 825 Round Bar Specification:

Incoloy 825 Bar Characteristics Properties

Alloy 825 bar is a compound metal alloy with a high nickel content product. Due to various metal inclusions, UNS N08825 possesses high corrosion resistance and favorable mechanical properties. Demonstrating broad usefulness with optimum machining characteristics and good weldability, Incoloy 825 is an ideal metal alloy for strenuous applications and corrosive environments.

Corrosion Resistance

Providing resistance to stress corrosion, the high nickel content prevents cracking and works with copper and molybdenum contents for chemical resistance to phosphoric and sulfuric acids. Including molybdenum compounds also reduces pitting and crevice corrosion from surface layer oxidization. Additionally, the chromium content provides additional resistance to other oxidizing substances, like nitric acid, nitrates, and salt. To protect against intergranular corrosion, Incoloy alloy 825 rod also features titanium for increased stability.

Mechanical

UNS N08825 bar can withstand exposure to cryogenic temperatures and moderately high temperatures. However, microstructural changes can occur when exposed to temperatures above 1000 degrees Fahrenheit. With exceptional tensile and compressive yield strength properties, Incoloy alloy 825 bar has a maximum tensile strength of 104,000 psi. It has good impact strength at room temperature and can retain its strength at subzero temperatures.

Fabrication

Incoloy 825 rod can be readily hot or cold worked. Hot working should be in the range 870 – 1180°C, finishing at 870 – 980°C. For maximum corrosion resistance hot worked parts should be stabilise annealed before use. The alloy is easier to cold form than stainless steels.

Heat Treatment

Incoloy 825 bar is stabilise annealed at 940°C. The softest structure is obtained at 980°C. Sections heavier than sheet, strip and wire should be quenched to avoid sensitisation.

Applications of Incoloy 825 bars

Typical Applications of Incoloy 825 bars include:

Sulphuric acid piping and vessels

Phosphoric acid evaporators

Pickling tank heaters, pickling tanks and equipment

Chemical process equipment

Propellor shafts

Tank trucks

Calorifiers

Electrostatic precipitator electrodes

Hot vessels for food, water and seawater,

Ammonium sulphate vessels

Expansion bellows

Marine exhaust systems

Power station ash hoppers