The Ultimate Guide to Alloy 20: Chemical Composition, Properties, Applications, and Fabrication

The high volume of non-metals and austenite in the chemical composition of Alloy 20 makes it non-metallic and easy to fabricate. Whether you are an engineer or work in an industry that requires easy fabricability and ductility, understanding the chemistry and other key properties of Alloy 20 is crucial. Keep reading!

What is Alloy 20?

Alloy 20 stainless steel is highly resistant to sulfuric acid-induced corrosion, and chloride-induced stress cracking. Chromium in Alloy 20 helps maintain its passivity, preventing it from corroding when exposed to oxygen. Alloy 20 austenitic can withstand extremely high and low temperatures, making it suitable for various operating conditions. 

The Main Characteristics of Alloy 20

The characteristics of Alloy 20 stainless steel include：

• Corrosion Resistance: Alloy 20 material demonstrates remarkable resilience against a diverse range of rust-inducing substances, including harsh acids like sulfuric acid, phosphoric acid, nitric acid, and chloride solutions. 
• Versatility: Alloy 20’s weldability and formability allow easy fabrication and customization according to specific requirements, including dimensions, sizes, shapes, and designs.
• Resistance to Intergranular Corrosion: Certain stainless steel materials are vulnerable to Intergranular corrosion, but not Alloy 20. It has low susceptibility to sensitization, a process that can lead to the precipitation of chromium carbides along grain boundaries, causing intergranular corrosion. 
• High Nickel Content: Nickel provides Alloy 20 with excellent toughness and durability, and resistance to chloride-induced stress cracking, making it capable of withstanding challenging conditions over an extended period.

Chemical Composition of Alloy 20

Alloy 20 chemistry comprises various chemical elements and the chart below showcases the chemical components of Alloy 20 and their ensuing values.

Physical Properties of Alloy 20

This stainless steel has a high heat resistance rate, good thermal conductivity, and other features (highlighted in the table below), making it ideal for use in sulfur-rich environments, such as heat exchangers, acid cleaning and pickling equipment, reactor vessels, and dye production. 

Alloy 20 Mechanical Properties

Its mechanical properties (showcased in the table below) retain the material’s structural and profile integrity under various temperature conditions.

Alloy 20 Corrosion Resistance

Corrosion resistance is among Alloy 20’s best-selling characteristics. It is recognized for its exceptional rust resistance, particularly in aggressive and corrosive environments. The high nickel content in Alloy 20 imparts superior deformation resistance, especially in sulfuric acid environments. 

Alloy 2 exhibits minimal susceptibility to sensitization and subsequent grain boundary precipitation of chromium carbides, which can cause intergranular corrosion in some other stainless steels. This makes it suitable for applications where exposure to high temperatures can lead to intergranular corrosion.

Alloy 20 Machinability

This refers to the ease with which a material can be cut, shaped, and finished using machining processes like drilling, turning, milling, and threading. Alloy 20 can be easily worked with standard machining techniques due to its low carbon content than other stainless steel materials.

When machining Alloy 20, using sharp tools and adequate cutting speeds is advisable to minimize heat buildup. Lubricants or coolants must be utilized to dissipate heat and reduce tool wear. While Alloy 20 has good machinability, it is important to note that its toughness can cause some challenges during machining operations. 

Common Forms of Alloy 20 (UNS N08020)

Since Alloy is one of the most versatile stainless steels, and manufacturers use it to make various products in different shapes, dimensions, and sizes for different purposes. Below is a description of some of the most common products from this stainless steel material.

1. Alloy 20 Ball Valves

Alloy 20 ball valves are resistant to rust, durable, and strong. Alloy 20 ensures these valves can prevent leakage and extend their lifespan, making them suitable for applications in chemical processing plants and pharmaceutical industries. Alloy 20 valves consist of a hollow ball with a hole (bore) through its center. 

The ball and the valve seats are designed so that when the valve is closed, the sealing surfaces come into contact, creating a tight seal. This ensures minimal leakage and enhances the efficiency of the valve. They can be manually operated or equipped with an actuator for automated control. The actuator allows for remote valve operation, making it suitable for integration into automated systems.

2. Alloy 20 Sheets/Plates

Alloy 20 sheets and plates possess the same characteristics as their parent metal, making them suitable for chemical processing plants, pharmaceutical industries, food processing equipment, and other environments with corrosive substances.

These sheets and plates can withstand extreme temperatures and pressures, making them suitable for heat exchangers, pressure vessels, and other equipment operating in demanding conditions. Alloy 20 sheets and plates are available in various sizes, thicknesses, and finishes to meet specific requirements. 

They can be hot-rolled, cold-rolled, or annealed to achieve the desired properties. Alloy 20 sheets and plates are commonly used in the chemical processing industry to construct tanks, pipes, and fittings for handling sulfuric acid, phosphoric acid, and other aggressive chemicals. 

Alloy 20 sheets and plates are used in the pharmaceutical industry to manufacture equipment like reactors, storage vessels, and piping systems. Other Alloy 20 sheets and plates applications include desalination plants, marine environments, and pollution control equipment. 

3. Alloy 20 Pipe

Alloy 20 pipes are used in various industrial workspaces, including chemical processing sectors, for transporting corrosive chemicals such as sulfuric acid, phosphoric acid, and nitric acid. These pipes provide reliable and leak-free performance, ensuring the integrity of the chemical handling systems. 

They are also used in the pharmaceutical industry, transporting corrosive fluids and chemicals. They are used in manufacturing pharmaceutical processing equipment, including reactors, storage tanks, and piping systems, ensuring the purity and safety of pharmaceutical products.

In the oil and gas industry, Alloy 20 austenitic pipes find application in offshore platforms, refineries, and pipelines. They are suitable for handling corrosive fluids, including sour gas and oil, where the presence of hydrogen sulfide and other corrosive agents necessitates high corrosion resistance.

Alloy 20 pipes are also used in food processing to transport acidic liquids and corrosive food products. They can be seamless or welded, depending on the application and the specific conditions they will be exposed to.

4. 20 Alloy Rims

Rims, or wheels, provide structural support and serve as the mounting point for automotive tires. Rims are circular metal components that form the wheel’s outer edge and are attached to a vehicle’s axle. 20 Alloy rims are lightweight, improving fuel efficiency and overall vehicle performance. 

The reduced weight of alloy 20 rims reduces the vehicle’s unsprung mass, resulting in better handling, acceleration, and braking. 20 Alloy wheels also have enhanced heat dissipation than other stainless steel rims. 

This heat dissipation is especially important in high-performance vehicles or vehicles that frequently encounter heavy braking to prevent overheating of the brakes, reducing the risk of brake fade and maintaining optimal braking performance. They are commonly used in passenger, sports, and luxury vehicles. 20 Alloy rims have a natural oxide layer that forms on the surface, providing a protective barrier against corrosion.

5. Alloy 20 Bar

Alloy 20 round bars are used to construct various chemical processing components, such as pumps, valves, flanges, and fittings, which come into contact with corrosive chemicals. These bars are used to build reactors, storage tanks, agitators, and other critical pharmaceutical components. 

In the food processing industry, Alloy 20 austenitic bars find application in constructing equipment that comes into contact with acidic food products or cleaning agents. They are used in producing dairy processing equipment, brewing tanks, and other food processing machinery. The corrosion resistance of Alloy 20 bars ensures good hygiene, purity, longevity, and safety of pharmaceutical and food products.

In addition, they are also used in marine environments, desalination plants, and pollution control equipment, such as heat exchangers, condensers, scrubbers, and other components that require resistance to corrosion and excellent mechanical properties. Alloy 20 bars are available in various diameters, lengths, and finishes to meet specific requirements. 

6. Alloy 20 Bolts

The high strength of Alloy 20 bolts makes them suitable for demanding applications. These bolts exhibit excellent mechanical properties, enabling them to withstand heavy loads and offer reliable performance even under extreme conditions. This strength is essential in industries where the bolts are subjected to high pressures or harsh environments.

Alloy 20 bolts can be easily installed using common bolt fastening tools. They are also readily formed into various shapes and sizes, allowing for versatility in their application. Whether for securing pipelines, assembling machinery, or constructing infrastructure, Alloy 20 bolts offer flexibility and ease of use.

To maintain the longevity of Alloy 20 bolts and maximize their corrosion resistance, it is important to follow proper handling and maintenance practices, such as proper storage and keeping them away from highly corrosive media. Regular inspections, cleaning, and lubrication can also help prevent corrosion and ensure optimal performance over time.

7. Alloy 20 Fasteners

20 Alloy fasteners include bolts, screws, nuts, washers, and studs. They exhibit excellent resistance to various corrosive environments, such as acids, alkaline solutions, and chloride-containing media. 

Like bolts, they are flexible and exhibit excellent mechanical properties,  allowing them to withstand heavy loads and harsh conditions. Applications such as securing pipelines, assembling machinery, or constructing infrastructure rely on Alloy 20 fasteners to ensure structural integrity and safety.

Alloy 20 fasteners are compatible with common tools. They can be easily installed or removed, making them convenient for maintenance and repairs. They are also available in the market, with different sizes, types, and configurations to meet specific requirements. 

8. Alloy 20 Fittings

Alloy 20 fittings are components used in piping systems and other applications to connect, control, or redirect the flow of fluids. They exhibit excellent performance in various corrosive environments while ensuring the integrity and longevity of piping systems, equipment, and structures in these demanding environments.

Alloy 20 fittings are available in types, including elbows, tees, reducers, couplings, and flanges, to accommodate different piping configurations and requirements. Maintain and clean the Alloy 20 fitting often to ensure longevity and optimal performance 

9. Alloy 20 Flanges

These are critical components in piping systems to connect pipes, valves, and other equipment. They create a strong, secure, leak-proof joint by providing a connection point for bolting or welding. Alloy 20 flanges are designed and manufactured with corrosion resistance and high strength in mind.

Alloy 20 flanges are durable and reliable, with excellent mechanical properties, good tensile strength, and impact resistance. Power generation and other sectors rely on Alloy 20 flanges to ensure the secure and leak-free connection of pipes and equipment in critical applications.

Each type of flange has specific characteristics and uses, allowing for flexibility in design and installation. They can be bolted or welded to the adjoining pipes or equipment, providing a secure and tight connection. 

10. 20 Alloy Strip

Alloy 20 strips, or metal strips, are thin, flat pieces of metal used in various industries for various applications. Alloy 20 strips are suitable for industries such as chemical processing, pharmaceutical, food and beverage, and petrochemical, where exposure to corrosive substances is common. These strips help ensure the longevity and reliability of structures and equipment in demanding environments.

Alloy 20 strips are versatile and can be employed as raw materials for fabrication, or they can be utilized as components in machinery, equipment, or structural elements. The thin and flat nature of strips allows for easy shaping, cutting, bending, and welding, enabling customization and adaptation to specific project requirements.

11. 20 Alloy Wires

Alloy 20 wires are thin, flexible strands with similar chemical composition and mechanical properties as other Alloy 20 materials. Despite their thin and flexible nature, these wires are used in automotive, aerospace, electrical, and manufacturing for various applications, including wiring harnesses, electrical components, and structural supports.

Alloy 20 wires are good conductors of electricity and are commonly used in electrical and electronic industries for wiring, grounding, and connecting electrical components, ensuring a reliable and efficient flow of electricity and contributing to the optimal performance of electrical systems.

Alloy 20 ASTM Specifications

The ASTM International—enforces industry standard requires that all Alloy 20 products must attain specification for various Alloy 20 materials are highlighted in the chart below:

Alloy 20 Fabrication Process

The process begins with selecting high-quality Alloy 20 material according to the chemical composition. Followed by:

• Cutting and Shaping: The Alloy 20 steel is cut into the desired shapes and sizes using saws, shears, or laser cutting machines. This step helps in preparing the material for further processing and forming.
• Forming and Shaping: You can use various tech noiques to form or shapes Alloy 20. These processes may include forging, rolling, bending, or stamping, depending on the specific requirements of the fabrication project.
• Machining: If necessary, machining operations such as drilling, milling, turning, or threading may be performed to achieve precise dimensions, smooth surfaces, or specific features on the Alloy 20 components. Ensure that your machining techniques are carefully selected to achieve minimal stress or deformation to the material.
• Welding and Joining: Alloy 20 can be welded using various welding methods, including Tungsten Inert Gas, Metal Inert Gas, or SMAW (Shielded Metal Arc Welding). Welding is often used to join different Alloy 20 components together or to attach fittings and connectors.
• Heat Treatment: Heat treatment processes, such as annealing or solution annealing, enhance the mechanical properties and remove residual stresses from the fabricated Alloy 20 components. They are used because they improve the material’s toughness, strength, and corrosion resistance.
• Surface Finishing: Depending on the application and desired aesthetics, the fabricated Alloy 20 austenitic components may undergo surface finishing processes like grinding, polishing, or coating. These processes enhance the final product’s appearance, smoothness, and corrosion resistance.

Once the Alloy 20 material is set, it is neatly packaged with strong cartons to reduce possible shipping incidents.

Applications of Alloy 20

Aside from the general characteristics of metal Alloys, Alloy 20 has many applications due to the decay resistivity and other characteristics that make it unique. Such applications include;

• Food Processing Equipment: Rust can threaten food items passed through processing equipment. Due to their high resistance to decay, Alloy 20 produces valves, pumps, and pipes for passing foods and liquids without contaminating them.

• Dye Production: Alloy 20 austenitic steel can withstand exposure to acids, alkalis, and reactive dye solutions commonly used in dyeing operations. This corrosion resistance ensures the longevity and reliability of equipment used in the dye processing industry. Some other uses of Alloy 20 in dye production include;

• Dye Vessels and Piping Systems: It is used in constructing dye vessels, tanks, piping systems, and other components directly interacting with contact with corrosive dye solutions.

• Heat Exchangers: Heat exchangers are crucial in dye processing to control and maintain the temperature of dye solutions during various process stages. 

• Dye Bath Agitation Equipment: Alloy 20 is also used to fabricate equipment used in dye bath agitation, such as impellers and stirrers. These components must withstand the corrosive nature of dye solutions while providing efficient and effective agitation for uniform dye distribution.

• Dye Mixing and Dispensing Equipment: Alloy 20 austenitic materials finds application in dye mixing and dispensing equipment, including pumps and valves. 

• Dye Waste Treatment: The dyeing process generates waste streams that require treatment before disposal. Alloy 20 is suitable for constructing equipment and piping systems used in dye waste treatment facilities. 

• Chemical Processing Equipment: Most industrial processes use concentrated or hazardous chemicals. If certain materials are used to transport them, they will become weak, rusty, and eventually lose their mechanical and structural integrity. Alloy 20 materials are ideal for these processes due to their resistance to decay backed by their composition.

• Refineries: Alloy 20 is found in the petrochemical industry, specifically in oil refining and gas processing plants. It is used for heat exchangers, pipes, and valves that withstand highly corrosive environments, including sulfuric acid and chloride solutions.

• Pharmaceutical Industry: It is used in pharmaceutical manufacturing facilities for equipment and vessels that handle aggressive chemicals, acids, and sanitizing agents. Its corrosion resistance and ease of fabrication make it suitable for pharmaceutical processes requiring high purity and hygiene.

• Desalination Plants: Alloy 20 is also used in desalination plants to construct equipment that encounters saline water and corrosive brine. It ensures the durability and reliability of components in these demanding environments.

• Power Generation: This stainless steel is utilized in power plants, particularly in flue gas desulfurization (FGD) systems, where it is resistant to sulfuric acid and acidic gases produced during the combustion of fossil fuels. It is also used in heat exchangers and condensers that handle corrosive cooling water.

• Paper and Pulp Industry: Alloy 20 austenitic material is found in the paper and pulp industry for equipment exposed to chemicals, acids, and bleaching agents during production. 

• Water Treatment: To ensure the longevity and reliability of water treatment components in the presence of corrosive chemicals and water conditions, Alloy 20 is employed in water treatment facilities for the equipment involved in the treatment and purification of water, including pumps, valves, and tanks. 

• Mining and Ore Processing: Alloy 20 is used in mining and ore processing operations for equipment that encounters corrosive substances like sulfuric acid, hydrochloric acid, and acidic leaching solutions. It offers excellent rust resistance and durability in these harsh environments.

• Marine and Offshore Applications: The sea is one of the main beneficiaries of the many advantages of various stainless steel and alloy metals. Alloy 20 is found in marine and offshore industries for seawater cooling systems, piping, and valves. Its resistance to chloride-induced corrosion makes it suitable for these demanding applications where exposure to seawater is prevalent.

• Fertilizer Industry: Alloy 20 austenitic steel is used in the fertilizer industry for the equipment involved in producing fertilizers, such as ammonia reactors, storage tanks, and piping systems. Its resistance to sulfuric acid and other corrosive substances in fertilizer production makes it suitable for these applications.

Advantages of Alloy 20

If you are in the market for cost-effective, strong, and highly durable stainless steel material, the Alloy 20 stainless steel can help you achieve the desired result for your project. This Alloy material offers many mouthwatering benefits, including;

• Cost-effectiveness: Although Alloy 20 has a higher initial cost than some other stainless steel materials, its long-term durability and resistance to corrosion reduce frequent maintenance and replacements, resulting in significant cost savings over the lifespan of equipment and structures.
• Corrosion Resistance: This stainless steel exhibits exceptional resistance to various decay-inciting substances, including acids, alkalis, and chloride solutions. This makes it highly suitable for applications in aggressive and corrosive environments.
• Excellent Weldability: Alloy 20 has good weldability, allowing for efficient and reliable joining of components through various welding techniques. This facilitates the manufacturing process and enables the construction of complex structures.
• Ease of Fabrication: Alloy 20 can be easily fabricated using standard techniques such as cutting, shaping, machining, casting, and welding. This allows for efficient and cost-effective production of components and equipment.
• Long-term Durability: Durability determines how long a material can withstand load or various stresses before losing its properties. Alloy 20’s resistance to corrosion and other forms of degradation ensures its long-term durability and reliability, reducing the need for frequent maintenance and replacement.

Limitations of Alloy 20

Here are some limitations of Alloy 20 stainless steel.

• Sensitization: Alloy 20 is susceptible to sensitization—the formation of chromium carbides along grain boundaries during high-temperature exposure. Sensitization can reduce the corrosion resistance of the material in certain environments. 
• Limited Temperature Range: Alloy 20 has a limited temperature range compared to other alloys. It is not recommended for continuous use in temperatures above 1000°F (537°C). 
• Embritllement: The stainless steel alloy becomes brittle when exposed to low temperatures due to its chromium composition. This can cause the steel to lose its crystal structure, toughness, and mechanical integrity.

Comparison Between Alloy 20 Vs Hastelloy

Their temperature resistance is an important factor to consider in this debate. When it comes to temperature resistance, Hastelloy alloys have better high-temperature capabilities, with some grades capable of withstanding temperatures up to 1,900°F (1,037°C). On the other hand, Alloy 20 is limited to temperatures below 1,000°F (537°C). 

Difference Between Alloy 20 and Stainless Steel

Alloy 20 has nickel, iron, and chromium as its main alloying element. What differentiates it from stainless steel is its chromium content which is higher than that of stainless steel. The chart below further breaks down more differences between the two.

Alloy 20 Vs Hastelloy C276

With decay resistance as one of its top qualities, Alloy 20—a non-metallic alloy containing austenite also has good mechanical properties and weldability, but its temperature resistance is limited than Hastelloy C276. 

On the other hand, Hastelloy C276 is a nickel-molybdenum-chromium alloy with superior rust resistance to various corrosive chemicals, including strong acids, alkalis, and oxidizing agents. It exhibits excellent high-temperature resistance up to 1,900°F (1,037°C).

Conclusion

The Alloy 20 stainless steel materials have one of the most outstanding characteristics; they combine all their properties to offer high-quality, durable, and rust-resistant steel while retaining longevity. Visit Tuolian Metal and explore their high-grade Alloy 20 steel collection, all manufactured with mechanical integrity and decay resistance in mind.

FAQ

1. What are Alloy 20 Common Trade Names?

Different manufacturers and suppliers prefer a certain name over another when naming Alloy 20 materials. This doesn’t mean anyone can just name the alloy. The generally accepted common trade names for Alloy 20 stainless steel include;

• UNS N08020
• DIN 2.4660
• CN7M
• Carlson Alloy C20
• Carpenter 20 CB-3
• AL 20
• Nickelvac 23
• Nicrofer 3620 Nb.

2. Alloy 20 Vs Super Duplex

Alloy 20 and Super Duplex are two different types of materials that have different compositions, properties, and even use cases. Their chemical compositions vary, with Alloy 20 containing nickel, iron, and chromium, while Super Duplex alloys combine chromium, molybdenum, and nitrogen. While both materials resist decay, Alloy 20 has an advantage in sulfuric acid environments. On the other hand, Super Duplex alloys excel in chloride-rich environments.