Haynes International, Inc., headquartered in Kokomo, Indiana, is one of the world’s largest producers of high‑performance nickel‑ and cobalt-based alloys in flat product form such as sheet, coil and plate forms; it also manufactures alloys in seamless and welded tubulars, and in slab, bar, billet and wire forms. The company specializes in corrosion-resistant and high-temperature alloys for the aerospace, chemical processing and industrial gas turbine industries.

The company was founded by Elwood Haynes in 1912 in Kokomo, Indiana, as Haynes Stellite Works. Haynes had recently received a patent for a metal he created, which he named Stellite.

In 1920, the company was purchased by Union Carbide.

In 1922, the company invented its first alloy under the Hastelloy brand, derived from the first letters of the words Haynes Stellite Alloy.

In 1927, Charles Lindberg's aircraft, the Spirit of St. Louis, which included hard-surfaced engine valves manufactured by Haynes, crossed the Atlantic Ocean.

In 1970, Cabot Corporation purchased the company.

In 1989, the investment banking firm of Morgan, Lewis, Githens, and Ahn purchased the company.

In 1997, the Blackstone Group purchased the company. The debt incurred ultimately forced Haynes into bankruptcy in March 2004, from which it emerged 5 months later in August 2004.

In 1999, the company opened an office in Singapore, its first sales office in Asia.

In 2004, the company acquired Branford Wire & Manufacturing of Mountain Home, North Carolina.

In March 2007, Haynes completed a public equity offering.

In addition to Kokomo, Haynes has manufacturing facilities in Arcadia, Louisiana, and Mountain Home, North Carolina. The Kokomo facility specializes in flat products, the Arcadia facility in tubular products, and the Mountain Home facility in wire products.

The space shuttle’s engines have a total of 47 parts made from Haynes 188 alloy and 7 from Haynes' Hastelloy B alloy. Hastelloy C-22 alloy is used for the fuel line bellows that assist in achieving takeoff.

The company's revenues in fiscal year 2016 were derived from the following industries:

The company produces 12 corrosion-resistant alloys that it markets under the Hastelloy brand. These alloys are based on nickel and can survive in high-temperature, high-stress situations such as chemical reactors.