There are more than 3500 steel grades available globally. Each grade is suited for a different application because of varying compositions.
One specific type of steel class includes low-carbon steel. These steels contain very small amounts of carbon compared to other classes like high and medium-carbon steels. The low carbon content improves the mechanical properties of steel, like welding and working capabilities.
In this article, we’ll discuss all about steels that fall under the ASTM A36 specification.
What Is the Composition of ASTM A36 Steel?
ASTM A36 deals with mild to low-carbon steel; these are mild and hot-rolled materials. Generally, low-carbon steels contain less than 0.25% carbon, but this grade has up to 0.29% carbon. It also contains up to 1.2% manganese, 0.15-0.40% silicon, and very small amounts of phosphorus and sulfur. In the case of copper steels, a minimum of 0.20% of copper is also present.
1.Effect of Carbon.
This of steel has high formability and can be easily worked on and welded because of its low carbon content. The low carbon content also improves ASTM A36 steel’s toughness and bending ability, helping it resist cracking.
2.Effect of Manganese and Silicon.
The addition of manganese improves ASTM A36 steel’s wear resistance, strength, and hardening ability. It also prevents the cracking of the steel while improving its formability and welding capabilities. Adding manganese makes it easier for us to work on ASTM A36 and create desired shapes out of the steel.
Silicon improves the corrosion resistance, strength, and toughness of the steel. It also acts as a deoxidizer and removes oxygen from the steel.
Removal of oxygen from steel is important as it can create porosities and other defects, especially when the steel is being cast. Silicon also improves the steel’s ability to withstand thermal shock, making it suitable for high-temperature applications.
3.Effect of Sulfur and Phosphorus
Normally, sulfur is an impurity in steel. We try to limit steel’s sulfur and phosphorus content to prevent undesired effects on properties. High amounts of sulfur in ASTM A36 steel can decrease the steel’s flexibility. The machinability of the steel grade also decreases with sulfur content increases, making it difficult to shape or cut.
Phosphorus is an alloying addition to improve the strength and toughness of the steel grade. The addition of phosphorus is limited, and only a maximum of 0.04% of phosphorus is added to prevent brittleness and low ductility of our steel.
Mechanical Properties of ASTM A36 Steel.
ASTM A36 has various desirable mechanical properties. These include having a yield strength of 250 MPa and an ultimate tensile strength ranging from 400 to 550 MPa. Additionally, this steel grade has excellent welding capabilities and can be heat treated to obtain improved properties.
The Heat Treatment of ASTM A36 Steel.
You can subject this steel grade to different heat treatments for improved properties. These include:
1.Normalizing.
In this method, you heat your steel above a critical temperature of about 900 to 950 degrees Celsius and hold it at that temperature for an established time. After this, you air-cool your steel sample.
Normalizing your steel helps to improve its strength and toughness as the grain structure gets refined.
2.Quenching and Tempering.
In this process, you heat your steel to a temperature above the critical value of around 500 degrees Celsius and then rapidly cool the sample in an oil or water bath which causes the steel to harden.
You then heat your steel sample to a lower temperature and hold it for a specific duration. This process is called tempering and improves the steel’s toughness without compromising strength.
Manufacturing ASTM A36.
You are required to use a combination of steps for manufacturing ASTM A36 Steel. These steps include:
- The raw materials, including iron ore, limestone, and coke, are smelted in a blast furnace to produce molten steel.
- This molten steel is then collected and cast into billets or ingots.
- You can then hot-roll the steel to form plates or sheets of ASTM A36 steel. Hot rolling uses a series of rollers to reduce the thickness of the steel.
- You can also cold work your steel to improve its surface finish or perform heat treatment on your sample to improve the steel’s mechanical properties.
- Since ASTM A36 has excellent machinability, you can cut the steel into different shapes using saws or other cutting tools.
- You can also paint or galvanize the steel surface to protect it from different forms of corrosion.
Properties of ASTM A36 Steel
This steel grade has various properties, making it suitable for use in different industries, particularly for structural applications. These include:
1.High Strength.
ASTM A36 has a high tensile strength of 58 to 80,000 PSI, making it suitable for load-bearing structural comparison. The tensile strength of this steel grade is much higher than 306, 304, and 430 stainless steels that are commonly used in the industry.
2.Good Weldability and Formability.
You can weld this steel grade easily compared to other steels, which aids your manufacturing process. You can also easily shape ASTM A36 steel because of its low carbon content.
3.High Durability.
You can use this steel grade in applications where high amounts of loads are experienced. ASTM A36 steel can withstand high stresses and impact loads without breaking, making it ideal for structural applications.
4.Good Surface Finish.
You can apply various surface treatments to this steel grade to obtain a good surface finish. Some treatments include galvanization and painting, which also help improve the steel’s corrosion resistance.
5.Low-Cost.
ASTM A36 is less costly than other stainless steel grades as it contains lower amounts of alloying additions. It can also be easily manufactured.
Applications of ASTM A36 Steel.
This steel grade has a variety of applications, including:
1.Structural Applications.
ASTM A36 is primarily used for making structures like bridges and buildings. This is because it has a high-strength-to-weight ratio and can be worked easily to create different shapes.
2.Automotive Parts.
This steel grade is used in making car frames and other structural components because it is easily welded and has high strength and toughness.
3.Manufacturing.
ASTM A36 is also used for making different machine and equipment parts because it has excellent machinability and can be welded easily to assemble different parts.
4.Construction.
Apart from structural uses, you can use this steel grade for construction purposes like roofing and flooring because it is highly durable but cheap.
5.Ship Parts
ASTM A36 is used for manufacturing decks, hulls, and other parts of ships because of its high strength and toughness.
Limitations of ASTM A36 Steel
There are some limitations associated with using ASTM A36 steel. These include
1.Susceptible to Cracking.
Since this steel grade has low carbon content, it can crack easily when you weld it. This usually happens when you do not use proper welding procedures.
2.Low Corrosion Resistance.
This steel grade has low corrosion resistance compared to 306, 304, and 430 stainless steels, as it does not contain chromium or nickel. So, Using ASTM A36 for applications where the steel part will be exposed to highly corrosive environments is not preferable.
3.Limited Hardness.
This steel grade has a limited hardness and cannot be improved using heat treatment. You cannot use ASTM A36 for applications where high hardness is required.
4.Limited Temperature Range.
ASTM A36 becomes brittle at higher temperatures and can crack, making it unsuitable for high-temperature applications.
The Environmental Impact of ASTM A36 Stainless Steel Production.
This steel grade is manufactured using a blast furnace, which is a highly energy-intensive process. Greenhouse gases are released during manufacturing. Some environmental concerns associated with this steel grade’s production include:
1.Carbon Emissions.
Coal is primarily used as a fuel source to produce heat and electricity to run the blast furnace. Burning it releases carbon dioxide in large amounts, increasing the global carbon footprint.
2.Waste Generation.
Slag and other waste materials are generated during the melting process. If these waste materials are not properly disposed of, they can create negative environmental impacts.
3.Air Pollution.
Harmful sulfur and nitrogen oxides are released during steel production. This disrupts the air quality and can lead to a rise in respiratory diseases.
4.Land Use
Large amounts of land are used for steel production. Large amounts of land are acquired by cutting down forests or other plants in the vicinity, which are natural habitats for wildlife.
Endnote
ASTM A36 is a low-carbon steel grade. It is primarily used for structural and other load-bearing applications because it has a high-strength-to-weight ratio, excellent formability, and weldability.
ASTM A36 is used for different applications like constructing bridges and buildings, making vehicle frames, and different ship parts. This steel has some drawbacks, like the possibility of experiencing cracking during welding and low corrosion resistance compared to other steel grades like 304, 303, and 430. However, ASTM A36 is less costly than these steel grades.
You should consider ASTM A36 if you require high strength and the ability to wear high-impact loads. This steel is also a good choice if you want to create parts that require heavy machining or welding.
Finding a manufacturer to meet your industrial steel needs is difficult. If that’s the case, don’t worry! Contact us if you require a particular steel grade for your manufacturing needs.
Frequently Asked Questions.
1.How do you maintain and care for ASTM A36 stainless steel?
You should use mild soap or detergent to clean steel surfaces. Use lubricants to prevent wear and tear of ASTM A36 steel in machinery. You can also apply protective coatings like paint on the steel surface to prevent rust accumulation.
2.How much does ASTM A36 stainless steel cost?
ASTM A36 stainless steel costs around $500-$600 per metric ton.
3.What is the availability of ASTM A36 stainless steel?
ASTM A36 is a widely available steel grade and is easy to source.
