Alloy 20 is a highly resistant, nickel-iron-chromium-based alloy with excellent corrosion resistance in acidic and corrosive environments. It is widely used in chemical, petrochemical, pharmaceutical, food, and power generation industries. Alloy 20 Sheet is one of the most popular forms of this alloy, with its excellent resistance to pitting, crevice corrosion, and general corrosion under diverse chemical environments.
This blog post will cover everything about the Alloy 20 sheet, composition, properties, and applications. By the end of this article, you will better understand why the Alloy 20 sheet is an excellent choice for corrosive and acid-resistant applications.
What is Alloy 20 Sheet?
Alloy 20 Sheet is a special nickel-chromium-molybdenum alloy austenitic stainless steel designed specifically for chemical processing. The high chromium content ensures excellent corrosion resistance, while the molybdenum content protects against pitting and crevice corrosion in chloride environments. Low carbon and nitrogen content provides greater intergranular corrosion resistance than Types 303, 310, 316 and 317. It offers superior thermal stability and good fabricability, making it an ideal material for use in various industries such as chemical plant equipment, paper mills, food industry facilities and other industrial applications where acidic solutions are used.
Composition of Alloy 20 Sheet
Alloy 20 is an austenitic alloy with a unique combination of elements that offers excellent corrosion resistance. It comprises nickel, chromium, iron, and molybdenum as the primary alloying elements, with small amounts of copper and silicon. Adding molybdenum and copper enhances the alloy’s resistance to corrosion by sulfuric acid, hydrochloric acid, and other acidic solutions.
Properties of Alloy 20 Sheet
Alloy 20 sheet has excellent mechanical properties, making it resistant to various forms of corrosion, including pitting, crevice, and general corrosion. Its tensile strength ranges from 80 ksi to 100 ksi, yielding 35 ksi to 45 ksi. Alloy 20 sheet is also highly resistant to stress-corrosion cracking and intergranular corrosion.
Applications of Alloy 20 Sheet
Alloy 20 sheet is widely used in the chemical processing industry for its excellent resistance to various corrosive environments. It is used in heat exchangers, tanks, pipe fittings, valves, pumps, and reactors for handling sulfuric acid, phosphoric acid, acetic acid, and other acidic solutions. It is also used in the food processing and pharmaceutical industry for its corrosion resistance and compatibility with food-grade and pharmaceutical-grade requirements.
Fabrication and Welding of Alloy 20 Sheet
Alloy 20 sheet is easy to fabricate and weld using conventional methods, including TIG, MIG, and stick welding. However, the alloy’s high nickel content requires more heat input during fabrication than standard austenitic alloys. Avoiding excessive heat, which can cause distortion and loss of properties, is advisable.
Maintenance and Precautions for Alloy 20 Sheet
Alloy 20 sheet requires routine maintenance and cleaning to retain its corrosion resistance. Harsh cleaning solutions, such as hydrochloric acid or sodium hypochlorite, should be avoided to prevent the alloy’s surface damage. Regular inspection of the equipment that uses the Alloy 20 sheet is essential to identify any signs of damage or corrosion.
Conclusion
In conclusion, the Alloy 20 sheet is an excellent choice for applications that require corrosion resistance under diverse chemical environments. Its unique composition of nickel, chromium, molybdenum, copper, and iron offers excellent mechanical properties, making it resistant to pitting, crevice, and general corrosion. Alloy 20 sheet is widely used in the chemical processing, pharmaceutical, and food processing industries and is easy to fabricate and maintain. However, taking precautions and maintaining the equipment using an Alloy 20 sheet is essential to maintain its excellent corrosion resistance.
