Incoloy refers to a range of

superalloy A superalloy, or high-performance alloy, is an alloy with the ability to operate at a high fraction of its melting point. Key characteristics of a superalloy include mechanical strength, thermal creep deformation resistance, surface stability, ...

s now produced by the Special Metals Corporation (SMC) group of companies and created with a

trademark A trademark (also written trade mark or trade-mark) is a form of intellectual property that consists of a word, phrase, symbol, design, or a combination that identifies a Good (economics and accounting), product or Service (economics), service f ...

by the Inco company in 1952. Originally Inco protected these alloys by patent. In 2000, the SMC published a 61-page document entitled "High-Performance Alloys for Resistance to Aqueous Corrosion" highlighting Incoloy, as well as Monel and Inconel products, and their use in fluid environments such as

sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (English in the Commonwealth of Nations, Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, ...

hydrochloric acid Hydrochloric acid, also known as muriatic acid or spirits of salt, is an aqueous solution of hydrogen chloride (HCl). It is a colorless solution with a distinctive pungency, pungent smell. It is classified as a acid strength, strong acid. It is ...

hydrofluoric acid Hydrofluoric acid is a solution of hydrogen fluoride (HF) in water. Solutions of HF are colorless, acidic and highly corrosive. A common concentration is 49% (48–52%) but there are also stronger solutions (e.g. 70%) and pure HF has a boiling p ...

phosphoric acid Phosphoric acid (orthophosphoric acid, monophosphoric acid or phosphoric(V) acid) is a colorless, odorless phosphorus-containing solid, and inorganic compound with the chemical formula . It is commonly encountered as an 85% aqueous solution, ...

nitric acid Nitric acid is an inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but samples tend to acquire a yellow cast over time due to decomposition into nitrogen oxide, oxides of nitrogen. Most com ...

, other acids as well as freshwater environments. Incoloy products are mostly

chromium Chromium is a chemical element; it has Symbol (chemistry), symbol Cr and atomic number 24. It is the first element in Group 6 element, group 6. It is a steely-grey, Luster (mineralogy), lustrous, hard, and brittle transition metal. Chromium ...

-based and mostly

nickel Nickel is a chemical element; it has symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive, but large pieces are slo ...

-based, and designed for corrosion resistance as well as strength at high temperatures. Incoloy alloys belong to the category of super austenitic stainless steels. One advantage is that Incoloy alloys do not have to be heat treated after welding to restore the corrosion resistance.

Types

There are different alloys to resist particular chemical attacks or under specific circumstances: for example, the DS Incoloy is to be used in heat-treating furnaces with reactive atmospheres and many heat cycles. Incoloy 020 "exhibits excellent corrosion resistance in chemical environments that contain sulfuric acid, chlorides, phosphoric acid and nitric acid." Incoloy 028 "is resistant to both acids and salts. The copper content makes it resistant to sulfuric acid." Incoloy 330 "exhibits good strength at high temperatures and good resistance to oxidation and reduction environments." Incoloy 800 "is capable of remaining stable and maintaining its austenitic structure even after long time exposures to high temperatures". Incoloy 803 is designed for sulfur-rich environments. Incoloy 825 is approved for use in heat exchanger tubes by

ASTM ASTM International, formerly known as American Society for Testing and Materials, is a standards organization that develops and publishes voluntary consensus technical international standards for a wide range of materials, products, systems and s ...

B163, and approved for

pressure vessel A pressure vessel is a container designed to hold gases or liquids at a pressure substantially different from the ambient pressure. Construction methods and materials may be chosen to suit the pressure application, and will depend on the size o ...

operating temperatures up to 525°C or up to 538°C. It "offers exceptional resistance to corrosion by

and

". Incoloy 908 "has high tensile strength, fatigue crack growth resistance, good weldability, metallurgical stability and ductility, high fracture and impact toughness, ndlow coefficient of thermal expansion... tsresistance to oxygen embrittlement... allows hot fabrication without cracking." Incoloy 907 "has high strength and low thermal expansion coefficient at temperatures up to 800°F." Incoloy 945X is designed for chlorine-rich environments. Molybdenum adds crevice corrosion and pitting resistance to Incoloy 945. Incoloy MA956 is made by a mechanical alloying rather than a bulk-melting process; it was studied for space reactor components in the JIMO project. It is difficult to weld and needs to be heated to 200C for forming processes. A special friction welding process has been developed for it.

Compositions (percentages)

{, class="wikitable sortable" , - ! Alloy name !! Fe !! Cr !! Al !! Ti !! C !! !! Cu !! Mn !! Co !! Ni !! P !! Si !! S !! Mo , , Nb , - , 020 , , 35 , , 19-21 , , 0 , , 0 , , 0 , , 0 , , 3-4 , , <2 , , 0 , , 32-38 , , 0 , , <1 , , 0 , , 2-3 , , 0 , - , 028 , , 29-40.4 , , 26-28 , , 0 , , 0 , , 0 , , 0 , , ? , , <2.5 , , 0 , , 30-34 , , 0 , , 0 , , 0 , , 3-4 , , 0 , - , 803 , , 29.435-42.64 , , 25-29 , , 0 , , 0 , , 0 , , 0 , , 0 , , <1.5 , , 0 , , 32-37 , , 0 , , <1 , , 0 , , 0 , , 0 , - , 945 , , balance , , 19.5-23 , , 0.01-0.7 , , 0.5-2.5 , , 0.005-0.04 , , 0 , , 1.5-3 , , 1 , , 0 , , 45-55 , , 0.03 , , 0.5 , , 0.03 , , 3-4 , , 2.5-4.5 , - , 945X , , balance , , 19.5-23 , , 0.01-0.7 , , 0.5-2.5 , , 0.005-0.04 , , 0 , , 1.5-3 , , 1 , , 0 , , 45-55 , , 0.03 , , 0.5 , , 0.03 , , 3-4 , , 2.5-4.5 , - , 330 , , Fe 43 , , 17-20 , , 0 , , 0 , , 0 , , 0 , , 0 , , <2 , , 0 , , 34-37 , , 0 , , * , , 0 , , 0 , , 0 , - , 825 , , Fe >22, ~33 , , 19.5-23.5 , , <0.2 , , 0.6-1.2 , , <0.05 , , 0 , , 1.5-3.0 , , <1.0 , , 0 , , 38-46 , , 0 , , <0.5 , , <0.03 , , 2.5-3.5 , , 0 , - , 907 , , Fe 42 , , 0 , , 0.03 , , 1.5 , , 0 , , 0 , , 0 , , 0 , , 13 , , 38 , , 0 , , 0.15 , , 0 , , 0 , , 4.7 , - , 908 , , 35.588 - 44.6 , , 3.75 - 4.5 , , 0.75 - 1.25 , , 1.2 - 1.8 , , <0.03 , , 0 , , <0.5 , , <1 , , <0.5 , , 47 - 51 , , <0.015 , , <0.5 , , <0.005 , , 0 , , 2.7-3.3 , - , 800 , , Fe >39.5 , , 19-23 , , 0 , , 0 , , 0 , , 0 , , 0 , , <1.5% , , 0 , , 30-35 , , 0 , , 0 , , 0 , , 0 , , 0 , - , 020 , , Fe (~40%) , , 20 , , n/p , , n/p , , <0.07 , , n/p , , 3.5 , , <2.0 , , n/p , , 35 , , <0.045 , , <1.0 , , <0.035 , , 2.5 , , about 1 , - , DS {{cite web , url=http://www.specialmetalswiggin.co.uk/pdfs/products/INCOLOY%20alloy%20DS.pdf , title=Incoloy alloy DS , , Fe (~40%) , , 18 , , n/p , , 0.2 , , 0.1 , , nil , , 0.5 , , 0.8-1.5 , , 18 (Co+Ni 38) , , 18 (Co+Ni 38) , , n/p , , 2.3 , , 0.03 , , , , , - , MA956 , , Fe (~75%) , , 20 , , 4.75 , , 0.4 , , <0.1 , , 0.5 , , <0.15 , , <0.3 , , <0.3 , , <0.5 , , <0.02 , , n/p , , n/p , , , ,

References

Nickel alloys Superalloys

Types

Compositions (percentages)

See also

References