AISI 1020 Carbon Steel: Equivalents, Compositions, Properties and Applications

AISI 1020 carbon steel is a widely used low carbon steel. Its low carbon content means it is soft and easy to shape. It also welds well. While it is soft, it can be strengthened on the surface by a process called case hardening. This process gives the surface a hard layer while the core stays tough. The balance of properties makes it a useful material for many different applications, from parts for machines to pieces used in construction.

AISI 1020 carbon steel components can be produced via casting processes such as investment casting, sand casting and shell mold casting, each process has its own advantages and limitations and is used for different purposes.

This article looks at AISI 1020 steel, its international equivalents, its chemical and mechanical properties, and the ways it is treated and used.

Common 1020 Carbon Steel International Equivalents

Different countries and engineering groups have their own systems for naming steel grades. This means that a single type of steel, like 1020 carbon steel, might have several different names depending on where it is made or sold.

These different names show that the steel has a chemical makeup and properties that are similar to AISI 1020. This is important for companies and engineers who need to find and use the right material from different places in the world.

The table below shows some of the different names for 1020 carbon steel in other countries.

Standard	Designation
AISI	1020
ASTM/UNS	G10200
EN	C22E / 1.0402
JIS	S20C
DIN	Ck 22 / C22
BS	080A20
GB	20

Chemical Composition of 1020 Carbon Steel

The properties of 1020 carbon steel are due to its chemical makeup. It is a low carbon steel, which means it has a low amount of carbon percentage. Carbon is the main element that gives steel its hardness and strength. Manganese is also in the steel, which helps with strength and makes it easier to work with. There are also small amounts of phosphorus and sulfur. These two elements can affect how the steel is processed, and they are kept at low levels. The different percentages of these elements give the steel its specific qualities, like being easy to shape and weld.

The table below shows the typical chemical composition of 1020 carbon steel.

Element	Composition (Weight %)
Carbon (C)	0.18−0.23%
Manganese (Mn)	0.30−0.60%
Phosphorus (P)	≤0.040%
Sulfur (S)	≤0.050%
Iron (Fe)	99.08 – 99.53 %

1020 Carbon Steel Mechanical Properties

The mechanical properties of aisi 1020 carbon steel describe how it behaves under different forces. These properties are important for figuring out where this steel can be used. The values listed below are typical for this steel when it is in a normalized condition, which is a common state after it has been heat treated to relieve internal stress.

Tensile strength is the maximum pulling force the steel can handle before it breaks. It is a measure of the steel’s overall strength. Yield strength is the point at which the steel starts to change shape permanently. Once the force reaches this point, the material will not return to its original shape. Elongation shows how much the steel can stretch before it breaks. A higher elongation means the steel is more ductile, or less brittle. Hardness measures how well the steel resists scratches or indentations.

Another property is impact strength. This measures the steel’s ability to absorb energy when a sudden, heavy force is applied to it. 1020 carbon steel has good impact strength, which means it can handle sudden blows without breaking. This quality is useful for parts that might see shocks or impacts during their use.

The table below gives the typical mechanical property values for 1020 carbon steel.

Property	Value
Tensile Strength	420 MPa (60,900 psi)
Yield Strength	205 MPa (29,700 psi)
Elongation	15%
Hardness	121 HB / 68 HRB
Impact Strength	17−48 J (Charpy, L-T)

1020 Carbon Steel Physical Properties

The physical properties of aisi 1020 carbon steel describe its characteristics that do not involve a force or chemical reaction. These properties are about how the material exists at different temperatures and its basic makeup.

Density is the mass of the steel per unit of volume. This value is consistent for all forms of the steel and is used for calculating the weight of parts. The melting point is the temperature range where the steel changes from a solid state to a liquid state. This is a very high temperature for steel. Thermal conductivity measures how well the steel can transfer heat. Because 1020 carbon steel has a high thermal conductivity, it is good at moving heat away from a hot area.

The table below shows the typical physical properties of 1020 carbon steel.

Property	Value
Density	7.87 g/cm3 (0.284 lb/in3)
Melting Point	1460−1505∘C (2660−2740∘F)
Thermal Conductivity	51.9 W/m\cdotpK

Manufacturing Properties of 1020 Carbon Steel

The way aisi 1020 carbon steel is made into a finished part depends on its manufacturing properties. These properties describe how the steel responds to common shaping and joining processes like machining, welding, and casting.

Machinability

Machinability is a measure of how easily a material can be cut and shaped with tools. Because of its low carbon content, 1020 carbon steel is soft, which makes it easy to machine. It is a material that cuts smoothly, but it can create long, stringy chips during the process.

Weldability

Weldability is about how well the steel can be joined to other pieces by welding. The low carbon content of this steel means that it welds very well using many common methods. The risk of cracking is low, and preheating is not often needed before welding.

Castability

Castability is the ability of the liquid steel to flow into a mold and fill it completely. 1020 steel has good castability. When it is melted, it flows smoothly, which helps in making parts with complex forms. This allows it to be used in various casting methods.

The table below shows a summary of these manufacturing properties.

Property	Summary
Machinability	Good due to low carbon content; creates long chips.
Weldability	Excellent, with many methods; low risk of cracking.
Castability	Good fluidity, flows well into molds to make complex shapes.

Heat Treatment of AISI 1020 Carbon Steel

Heat treatment changes the properties of aisi 1020 carbon steel by heating and cooling it in specific ways. These processes can make the steel harder, softer, or stronger. The low carbon content of this steel means it does not respond well to some heat treatments like simple hardening. However, it is a very good material for surface hardening processes.

Annealing

Annealing is a heat treatment that makes the steel softer. It involves heating the steel to a high temperature and then letting it cool slowly. This process helps to remove internal stresses from the material and improves its ability to be shaped.

Carburizing

Carburizing, also known as case hardening, is a common process for 1020 steel. This is done to make the surface of a part hard while keeping the inside soft and tough. In this process, the steel is heated in a carbon-rich setting. Carbon atoms move into the surface of the steel. After this, the steel is quenched (cooled fast). The outer layer becomes very hard because of the added carbon, but the inner part stays ductile and able to absorb impacts.

Normalizing

Normalizing is another heat treatment. The steel is heated to a high temperature and then allowed to cool in the air. This process makes the internal structure of the steel more uniform and can improve its strength and ability to be machined.

AISI 1020 Carbon Steel Manufacturing Processes

Manufacturing processes for 1020 carbon steel shape the raw material into finished parts. The choice of process depends on the part’s shape, size, and how many units are needed. The low carbon content of this steel makes it useful for both casting and machining.

Investment Casting

Investment casting is used for small, detailed parts. A wax pattern is made, coated with a ceramic material, and then melted out. Liquid steel is poured into the hollow space. This process can produce 1020 carbon steel casting parts with a smooth surface and a high level of detail. It helps reduce the need for further shaping or finishing.

Sand Casting

Sand casting is a simple and cost-effective method for producing aisi 1020 carbon steel castings. It uses a mold made from a mixture of sand, clay, and water. This method is good for creating large and heavy parts. It is a flexible process that can handle many different sizes and forms. The surface finish is rougher than with other casting methods.

Shell Mold Casting

Shell mold casting uses a mold made from a special resin-coated sand. The sand forms a hard shell around a pattern. This process is more expensive than sand casting but gives parts with better dimensional accuracy and a smoother surface. It is a useful middle ground between sand and investment casting.

Lost Foam Casting

Lost foam casting uses a pattern made of foam. The foam is placed in a flask and surrounded by sand. When the liquid steel is poured into the mold, the foam turns into gas and is pushed out. The steel then fills the space. This process can create relatively complex 1020 casting parts without a need for mold parting lines. It is good for making complicated parts or large parts.

Machining

Machining involves removing material from a piece of steel to get a desired shape. This is done with cutting tools. Because of its low carbon content, 1020 carbon steel is soft and easy to cut. It has a high machinability rating. This makes it a popular material for parts that need to be made with a lathe or a milling machine.

The table below compares the different casting processes and machining for 1020 carbon steel.

Process	Typical Part Size	Surface Finish	Cost Per Part
Investment Casting	Small, detailed	Good to very good	High
Sand Casting	Medium to very large	Rough	Low
Shell Mold Casting	Small to medium	Good	Medium
Lost Foam Casting	Medium to large	Good	Medium
Machining	Small to medium	Good to very good	High

Surface Treatments for 1020 Carbon Steel Castings

Surface treatments give 1020 carbon steel castings a better surface or appearance. These treatments are often used to make the parts last longer by protecting them from rust or wear, or to give them a specific finish.

Plating

Plating is the process of applying a thin layer of another metal to the surface of a casting. This is often done to protect against corrosion. For 1020 steel castings, common types of plating include nickel and chrome. The plated layer creates a barrier that helps prevent the underlying steel from rusting. Plating also gives the part a smoother, more finished look.

Coating

Coatings, like paints and powder coatings, are non-metallic layers applied to the surface. These are used to give the casting a specific color or finish. Coatings also act as a simple way to protect the surface from rust. Powder coating uses a dry powder that is heated to form a hard layer, giving a durable finish. Paint is a liquid that dries to form a protective layer. Both methods are used to improve the appearance and life of the parts.

Galvanizing

Galvanizing is a process where a protective layer of zinc is put onto the steel. This is usually done by dipping the steel part into a bath of hot, melted zinc. The zinc forms a barrier that keeps air and moisture from the steel, helping to stop rust from forming. Zinc also provides a type of protection called cathodic protection. Even if the coating gets scratched, the zinc will corrode before the steel.

Black Oxidation

Black oxidation, also known as blackening, creates a thin black layer on the steel’s surface. This is done through a chemical reaction that changes the top layer of the steel. This black layer gives the 1020 steel castings a more finished look and helps with rust protection, but it is not as strong as a plated layer. It is often used for a matte finish and is common for tools and small parts.

Phosphating

Phosphating puts a thin phosphate coating on the steel’s surface. This layer is not for looks but for function. It helps with lubrication, makes paint stick better, and gives some protection from rust. This is a good base for a final coating like paint or oil. The process involves dipping the part into a phosphoric acid solution.

E-coating

E-coating, or electrocoating, uses an electric current to coat the part. The steel part is dipped into a paint bath, and a current is applied. This makes the paint particles stick evenly to the part’s surface. E-coating creates a very uniform layer, even on complex shapes. It gives a good base for other paint layers and provides a high level of corrosion protection.

Advantages and Limitations of AISI 1020 Carbon Steel

Every material has its own benefits and drawbacks. Knowing these helps in deciding if aisi 1020 carbon steel is the right material for a specific job. As a low carbon steel, aisi 1020 provides a balance of low cost and good forming ability. These characteristics indeed make this grade of steel a popular choice for general use.

Advantages

AISI 1020 carbon steel has many benefits that make it a common choice. One of its main benefits is its low cost. Because it has a simple chemical makeup with a low amount of expensive alloying elements, it is cheap to produce and buy. This makes it a good option for projects where a large amount of material is needed.

The steel is also very easy to machine. Its softness and low carbon content mean that tools can cut and shape it with less effort. This helps speed up production processes and can reduce tool wear.

Another benefit is its excellent weldability. The low carbon content helps to prevent the steel from cracking when it is welded. This means it can be joined using many different welding methods without needing special heat treatments before or after welding.

While 1020 steel itself is soft, it is very good for surface hardening processes like carburizing. This allows a part to have a hard, wear-resistant surface that can stand up to friction. At the same time, the inside core of the part stays soft and tough, which helps it absorb impacts without breaking.

Limitations

Despite its many advantages, aisi 1020 carbon steel also has some limitations. The low carbon content means it is not a good choice for applications that need high strength. It has a low tensile and yield strength compared to other types of steel. This means it is not used for parts that have to handle heavy loads or a lot of stress.

Because it is a carbon steel with no special elements to fight corrosion, it rusts easily. Parts made from this steel must have a surface treatment like galvanizing, plating, or painting if they are going to be used in wet or outdoor settings. This extra step adds to the overall cost of the finished part.

The low carbon content also means the steel cannot be hardened all the way through. A simple heat treatment process will not make the entire piece hard. This is why surface treatments like carburizing are used for parts that need a hard surface. It is not a good material for applications that need the entire part to be hard and strong.

Typical Applications of AISI 1020 Carbon Steel

AISI 1020 carbon steel is used in many different areas because of its balance of low cost, good formability, and easy machinability. While it is not a high-strength steel, its ability to be surface hardened makes it useful for parts that need a hard surface to resist wear.

Machine Parts and Gears

Many parts for machines are made from 1020 carbon steel. Things like shafts, levers, and gears are often made from this material. For parts like gears that need a hard surface to stand up to use, the steel is surface hardened with a process like carburizing. The inside of the part stays soft, which helps it handle impacts.

Pumps and Valves

Because of its good castability and machinability, 1020 carbon steel is a good choice for making parts for pumps and valves. These components are often made using investment casting or sand casting. The steel’s ability to be shaped into complex forms helps with making the bodies and internal parts of pumps and valves.

Automotive Industry

This steel is used for various parts in cars and other vehicles. It can be found in non-critical engine parts and body panels. Its good formability allows it to be shaped into different body parts. For parts that need to be strong, it is used for items like brackets and fittings that do not have to carry heavy loads.

Structural Components and Fasteners

AISI 1020 is used for some structural components where high strength is not needed. This includes things like brackets and simple frames. It is also a popular choice for fasteners like bolts, studs, and rivets. Its good formability and low cost make it a good material for these items, especially when they are made using cold forming.

General Engineering

In general engineering, 1020 carbon steel is used for many different parts and fittings. It is often used for rods, simple shafts, and general-purpose components where there is not much stress. Because it is so easy to work with, it is a good material for small parts in tools or jigs where wear is not a big concern or where the surface can be hardened. Its simple properties and low cost make it a reliable material for everyday jobs.

Conclusion

In summary, AISI 1020 carbon steel is a material that balances low cost with good performance for a range of uses. The steel’s low carbon content makes it soft and easy to work with, allowing it to be shaped and machined easily. While it has low strength on its own and will rust without a surface treatment, its ability to be case hardened makes it useful for parts that need a hard surface with a soft core. Its good formability, weldability, and low cost make it a popular and reliable material in many industries.

Taiyuan SIMIS Investment Casting Co., Ltd is a Chinese manufacturer of high quality metal castings. We have experienced engineers and operators, equipped with advanced equipment and facilities, dedicated to providing both high-end OEM and custom carbon steel casting services. Contact us now for more information.