Carpenter 20 is a highly resistant alloy prized for its exceptional durability and strength, especially in investment castings. This metal is composed of nickel, chromium, molybdenum, and copper, which make it highly resistant to corrosion and acidic environments.  
Also known as Alloy 20, it is often used in industries requiring extreme corrosion resistance, including chemical, food processing, and pharmaceutical industries.  

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Carpenter 20: The Resilient Alloy You Need to Know About

History  

Carpenter 20 was first developed in the 1950s by the Carpenter Technology Corporation based in Reading, Pennsylvania. At the time, Carpenter 20 was used to produce tanks to transport concentrated sulfuric acid. Since then, it has become a staple material in various industries that require corrosion-resistant alloys.  

Properties

Carpenter 20 has a unique combination of properties, making it highly desirable in various industrial applications. It has excellent resistance to stress corrosion cracking, which is a type of corrosion that occurs under tensile stress. Such alloy is also highly resistant to pitting, crevice, and intergranular corrosion. Additionally, it has good mechanical properties, including high strength and flexibility.  

Corrosion Resistance

It is highly resistant to corrosive environments, including sulfuric acid, phosphoric acid, and nitric acid. It is also resistant to chlorides, which can cause pitting and crevice corrosion in other alloys.  

Stress Corrosion Cracking Resistance

Carpenter 20 has excellent resistance to stress corrosion cracking, which is a type of corrosion that occurs under tensile stress. This makes it an ideal material for applications where the metal is subjected to high stress and corrosive environments.  

Weldability

This alloy is easy to weld using conventional welding methods. However, it is important to use welding techniques that minimize the amount of heat input to avoid the formation of intermetallic phases, which can reduce the alloy’s corrosion resistance.  

Mechanical Properties

Carpenter 20 has good mechanical properties, high strength, and ductility. It has a yield strength of 35 ksi (240 MPa) and a tensile strength of 80 ksi (550 MPa). It also has good impact resistance at both room temperature and low temperatures.  

Thermal Expansion

It has a low thermal expansion coefficient, making it a good choice for applications where dimensional stability is important.  

Fabrication

Carpenter 20 is easy to fabricate using standard methods, including machining, forging, and cold working. It can be formed into a variety of shapes and sizes to meet the needs of different applications.  

Overall, the properties of Carpenter 20 make it a highly desirable material for a variety of industrial applications. Its resistance to corrosion and stress corrosion cracking, good mechanical properties, and ease of fabrication make it a popular choice for a wide range of industries, including chemical processing, food and beverage, and pharmaceuticals.  

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Applications

It is used in a variety of applications where corrosion resistance is essential. It is commonly used in the chemical industry, where it is used to manufacture tanks, heat exchangers, and pipes.  

Carpenter 20 is also used in the food processing industry, where it is used to manufacture equipment that comes into contact with acidic foods and beverages. Additionally, it is used in the pharmaceutical industry, where it is used to manufacture equipment that comes into contact with highly acidic solutions.  

Chemical Processing

Carpenter 20 is commonly used in chemical processing to manufacture tanks, heat exchangers, and piping systems exposed to highly corrosive chemicals. It often produces sulfuric acid, phosphoric acid, and other acids.  

Food and Beverage Processing

It is also used in the food and beverage processing industry to manufacture equipment that comes into contact with acidic foods and beverages. This includes tanks, piping systems, and other equipment for juices, soft drinks, and other acidic food products.  

Pharmaceutical Processing

Carpenter 20 is also used in the pharmaceutical processing industry to manufacture equipment that comes into contact with highly acidic solutions. This includes tanks, piping systems, and other equipment used to produce pharmaceuticals.  

Petrochemical Industry

This alloy is used in the petrochemical industry to manufacture equipment exposed to highly corrosive environments. This includes heat exchangers, tanks, and piping systems used in producing petroleum products.  

Water Treatment

Carpenter 20 is also used in the water treatment industry to manufacture equipment exposed to highly corrosive water. This includes tanks, piping systems, and other equipment for treating municipal and industrial wastewater.  

Marine Applications

It is also used where corrosion resistance is essential. This includes the manufacturing of boats, ships, and offshore oil rigs.  

Overall, Carpenter 20 is a versatile material used in various applications where resistance to corrosion and acidic environments is essential. Its properties make it an ideal material for a wide range of industries, and its use has helped advance various fields.  

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Learn More About the Alloys Used in Investment Castings

Carpenter 20 is a highly resistant alloy prized for its exceptional durability and strength. It has a unique combination of properties that make it highly desirable in a variety of industrial applications where corrosion resistance is essential. Its use has helped advance various industries and will continue to be a valuable material.  Call us for more information.