INCONEL 625

Industries and Applications

Inconel 625 is utilized in a variety of industries, including automotive, aerospace, oil and gas, chemical processing, marine engineering, and nuclear reactors, offering high strength and longevity in demanding applications.

In the automotive industry, Inconel 625 is utilized for heat exchangers, exhaust systems, and quick connect fittings that require high resistance to corrosive environments. In aerospace, it is commonly used in bellows, expansion joints, fasteners, and other components that require strength and durability at high temperatures.

The oil and gas industry values Inconel 625 for its exceptional resistance to pitting and crevice corrosion, making it a reliable material for use in harsh offshore environments. In chemical processing, it offers excellent resistance to corrosion, even in the presence of acidic media, making it an ideal choice for pollution-control equipment.

Marine engineering applications also benefit from Inconel 625’s resistance to corrosion, as it performs exceptionally well in seawater and other corrosive marine environments. In the nuclear industry, it is commonly used in reactors and nuclear power plants, where high-temperature stability and resistance to corrosion is critical.

Inconel 625 can be formed using various cold and hot working processes, and offers resistance to deformation at hot working temperatures. It has three heat treatments to choose from, including solution annealing, annealing, and stress relieving.

Resistance to Corrosion

The unique combination of elements in Alloy 625 provides excellent resistance to various forms of corrosion. This alloy is almost impervious to attack in mild environments such as fresh and seawater, neutral pH environments, and alkaline media. The high chromium content in Alloy 625 gives it superior resistance to oxidizing environments, while the high molybdenum content makes it highly resistant to pitting and crevice corrosion.

Fabrication and Heat Treatment 

Alloy 625 can be formed using various cold and hot working processes. Although it resists deformation at high temperatures, higher loads are required to form the material. Hot forming should be performed within a temperature range of 1700°F to 2150°F, while during cold working, the material work hardens more rapidly than traditional austenitic stainless steels. This alloy has three heat treatment options, including solution annealing, annealing, and stress relieving. Solution-annealed (grade 2) material is commonly used for applications above 1500°F where resistance to creep is important, while soft-annealed material (grade 1) is commonly used for lower temperatures and has the optimum combination of tensile and rupture properties.

Inconel 625 – Applicable Specifications

Common Trade Names

Alloy 625 is commonly known by its trade name, INCONEL®. This is a registered trademark of the Special Metals Corporation group of companies.