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Alloy 20 Knowledge

Views: 2     Author: Wang     Publish Time: 2024-04-16      Origin: Site

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Alloy 20 Features

Alloy 20 is a type of stainless steel with superior corrosion resistance. This alloy is composed of nickel, chromium, molybdenum, and copper to provide excellent resistance against sulfuric acid, phosphoric acid, nitric acid, and alkaline solutions. Additionally, it has good weldability and machinability properties for those who are looking for an alloy that is easy to work with. Let’s take a look at the composition of alloy 20 and its various properties. Austenitic alloy – Alloy 20 is based on nickel, iron, and chromium and has high corrosion resistance in settings including sulfuric acid and other hostile fluids. This alloy is stabilized with niobium to stop intergranular corrosion. When carefully compared to higher nickel-based alloys, Alloy 20 may offer possible cost savings while outperforming regular stainless steels.

Alloy 20 provides remarkable resistance against acid attack for corrosion prevention. Excellent resistance in stress-cracking conditions. Better mechanical properties. Excellent Fabric ability. It gives you minimum carbide precipitation. Due to the high nickel content, the characteristics are at the border between stainless steel and nickel. Therefore, the alloy is referred to as either stainless steel or nickel. The material, which has excellent mechanical properties at ambient and elevated temperatures of up to 930°F (500°C), is readily fabricated using common industrial techniques.

Alloy 20 are common in use because of its wide range of properties and advantages they offer. This nickel iron chromium-based alloy is considered as a super alloy because of its amazing properties. the alloy 20 provide resistance to crevice corrosion, pitting and even hostile environments because of the chromium and molybdenum added to it. Welding alloy 20 is easy due to the minimum carbide precipitation which is offered by columbium added to it. Moreover, it has characteristics of both nickel and stainless categories.

UNS N08020 offers maximum resistance to environments where stress corrosion cracking appears due to the use of sulfuric acid in the 20-40% range. It is less affected with such acid attacks and shows resistance to general corrosion as well. Moreover, it does not get affected by chloride stress corrosion cracking. its impressive mechanical properties make it good for both elevated and ambient temperatures. It can be used up to a range of 500C or 930 F.

Chemical composition of Alloy 20

Alloy 20 contains nickel-iron-chromium as the base metal. It also contains copper, which increases its corrosion resistance and improves its stress corrosion cracking resistance. Molybdenum helps increase the strength of this alloy, while chromium provides extra corrosion resistance to resist pitting and crevice corrosion in chloride environments. The most common chemical composition of alloy 20 is as follows:


Content (%)

Iron, Fe


Nickel, Ni


Chromium, Cr


Copper, Cu


Manganese, Mn


Molybdenum, Mo


Niobium, Nb


Silicon, Si


Carbon, C


Phosphorous, P


Sulfur, S


Alloy 20 physical properties

Resistance to Corrosion:

One of Alloy 20 most remarkable features is its unparalleled resistance to corrosion. Delving into the alloy’s molecular structure, we uncover the mechanisms that empower Alloy 20 to withstand the harsh environments of chemical compounds, particularly those containing sulfuric acid. Through real-world examples and scientific insights, we illustrate how Alloy 20 stands as a stalwart guardian against the corrosive forces that can compromise other materials.

Fabrication and Heat Treatment:

The journey from raw materials to the final Alloy 20 product involves intricate fabrication techniques and carefully orchestrated heat treatments. We dissect the fabrication process, highlighting the steps that shape Alloy 20 into its final form.Furthermore, we investigate the impact of heat treatment in improving the mechanical characteristics of the alloy and ensuring that it fits the requirements of diverse applications.

It is possible to cold-work or hot-work alloy 20 using conventional techniques. Prior to forging, hot forged material should be heated to a temperature between 2100°F and 2250°F with rigorous temperature management to ensure that the material does not drop below 1800°F. After hot working, anneal the material by raising its temperature to between 1725°F and 1850°F for at least 30 minutes per inch of thickness, and then quench it in water.

When stress relief is sought, heat to a temperature below 1000°F and then quench with water once the appropriate time has passed at the temperature. Alloy 20 should be annealed at a temperature of 1725°F to 1850°F for 30 minutes per inch of thickness. By heating to 2100°F, a reduced hardness can be achieved, although this may not be good for the alloy’s ability to stabilize.

Alloy 20 is often welded using TIG, MIG, and submerged arc welding (SAW), with the appropriate filler metal (ER320LR for TIG, MIG, and SAW, and E320LR for SAW). When welding to higher-grade alloys like C276 and Alloy 22, or to dissimilar alloys like 316, AWS ERNiCrMo-3 may be used for TIG and MIG, whereas ENiCrMo-3 can be used for SAW.

Welding & Machinability

Alloy 20 can be welded using conventional methods such as gas tungsten arc welding or gas metal arc welding with appropriate precautions taken for preventing intergranular attack or sensitization during welding. When it comes to machining this alloy, machinists should use tools with sharp edges since it tends to work hard quickly due to its higher carbon content than other stainless alloys like 304 stainless steel or 316 stainless steel. It also requires slower cutting speeds than other alloys since the material tends to be tougher than usual due to its higher nickel content making it difficult to machine at normal speeds without breaking the tool edge or stalling the machine spindle motors.

Alloy 20 Applications

Chemical Processing:

Chemical plants rely heavily on Alloy 20 for chemical processing. Alloy 20 Pipe is used in the chemical industry for its excellent corrosion resistance to caustic solutions and strong acids, including sulfuric, hydrochloric, and phosphoric acids. This is because of the alloy’s strong resistance to highly acidic chemicals. It can handle environments with sulfuric acid, acetic acid, and hydrochloric acid. Furthermore, Alloy 20 pipes can withstand high temperatures that occur during the chemical reaction process, making them ideal for processing applications. Alloy 20 has a wide range of applications in the chemical and petrochemical industries due to its excellent corrosion resistance and strength.

Heat Exchangers:

Alloy 20 is an excellent choice for heat exchangers in the chemical and petrochemical industry due to its high corrosion resistance, especially to sulfuric acid. The chemical and petrochemical industry uses heat exchangers as they are essential for producing chemicals and petroleum products. Alloy 20 corrosion-resistant make it an ideal material for heat exchangers. They are used in oil refineries, desalination plants and even pharmaceuticals. Thus, Alloy 20 is an appropriate and cost-effective investment when selecting a heat exchanger. This durability results in a longer lifetime for these products when compared with other alloys or metals used in heat exchanger applications. Using Nickel-Iron-Chromium (NiFeCr) based alloys such as Alloy 20 ensures both safe operation and superior performance for this equipment which are integral components of many chemical/petrochemical industrial processes.

Pollution Control:

Alloy 20 is an ideal choice for Pollution Control applications in the Chemical and Petrochemical industries. In petrochemical and chemical industries, pollution is a major concern as it can cause severe damage to the environment. However, Alloy 20 is vital in producing pollution control equipment as they can withstand highly corrosive pollutants. Experts recommend using Alloy 20 for manufacturing air pollution control equipment, which can withstand strong acidic compounds and protect the environment. The alloy resists stress-corrosion cracking due to its higher chromium content (20%), increasing resistance to oxidizing agents such as nitric and chromic acids while providing excellent pitting resistance in most neutral pH solutions. Its molybdenum content (4%) enhances the overall creep strength of the alloy at elevated temperatures, making it suitable for use in high-temperature applications such as those found within power plant configurations. Furthermore, its nickel (2–3%) makes it resistant to chloride stress corrosion cracking while ensuring maximum ductility when welded or fabricated into components.

Gas and Liquid Transfer:

Alloy 20 is resistant to various types of corrosive elements, making it an ideal material for pipes and pipeline systems. As such, they are ideal for transporting gas and liquid in the chemical and petrochemical industries. Alloy 20 is also essential in transferring hazardous materials like gasoline, oil, and other chemicals.

Water Treatment:

Water treatment involves the use of chemicals to purify water. During this process, various corrosive chemicals are used. Alloy 20 pipe is commonly used in chemical and petrochemical applications due to its corrosion resistance against many acids, alkalis, and salts. Alloy 20 has been used in water treatment systems to transport chlorine dioxide, hydrochloric acid, sodium hydroxide and other solutions within the system for neutralizing polluted water. Alloy 20 are ideal for water treatments as they resist highly corrosive substances.

Furthermore, they can withstand harsh environments without losing their structural integrity, making them reliable in ensuring access to clean water. Due to its high strength-to-weight ratio and excellent stress rupture properties at elevated temperatures, Alloy 20 is particularly good for these types of applications. It also provides superior mechanical properties when exposed to both acid and chloride environments.

JN Alloy is a distributor and product manufacturer of stainless steel, duplex steel, and nickel.
Tel: +86 19339900211
Add: Stainless steel Market 289, Xinwu District , Wuxi, China
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