Corrosion is a major concern to manufacturers of chemical process equipment and other products that contain metals and alloys. Corrosion resistant alloys are designed to protect structures and products from corrosive agents such as salt, water, acids, and alkalis. These alloys are usually composed of iron, chromium, molybdenum, nickel, and other elements.
One common corrosion resistant alloy is stainless steel. This alloy contains at least 10-30 percent chromium, which helps form a protective layer of chromium oxide. Other alloys that are resistant to corrosion include tungsten, hastelloy, titanium, and zirconium. Each alloy has its own set of characteristics that make it suitable for different applications.
Tungsten is a sturdy and highly corrosion resistant alloy that is often used in marine environments. It is also used in applications where it is exposed to water or strong acid solutions. The advantages of tungsten are its toughness and high melting point.
Hastelloy is a corrosion resistant alloy made up of nickel, chromium, cobalt and other elements. It has excellent resistance to most oxidation and corrosive environments, making it suitable for use in a variety of applications. Its high nickel content also makes it resistant to chloride attack.
Titanium is a non-ferrous metal that is well known for its corrosion resistance and its strength-to-weight ratio. Titanium corrosion resistant alloys are composed of titanium, along with other metals such as aluminum, vanadium, iron, and molybdenum. They can be used in applications like process vessels, offshore structures, and piping systems.
Zirconium is a lightweight, corrosion resistant alloy that is highly resistant to both salt water and seawater. It is also used in nuclear energy applications because it is extremely resistant to radiation. Because of its light weight, zirconium is also used in the aerospace and automotive industries.
These are just a few of the many corrosion resistant alloys that are available on the market. Different alloys are suitable for different applications, so it is important to know the characteristics and limitations of each alloy before purchasing.
Corrosion resistant alloys are designated by numbers known as trade or brand names. These trade names typically include the alloying elements, and the percentage of each that is present in the alloy. For example, the trade name for a tungsten or hastelloy alloy would likely include the letters “M” for molybdenum and “C” for chromium. Those alloys containing titanium would include the letters “T” for titanium, and alloys containing zirconium would include the letters “Z” for zirconium.
In addition to the trade name, the corrosion resistant alloys are also classified by the composition and acid resistance (pH) of the metal. The composition of the alloy is determined by the amount of chromium, nickel, molybdenum and other elements included in the metal, while the acid resistance is determined through laboratory testing.
When selecting a corrosion resistant alloy, it is important to know the environment in which it will be exposed and the particular requirements, as each alloy will have different properties and capabilities. The best option is to consult with a corrosion specialist to ensure the correct selection and specification of the correct alloy.
