Mild Steel vs Hot Rolled Steel: Key Differences
Steel can seem like an easy material to understand. However, selecting from hot rolled steel or mild steel can vary significantly based on meaning related to impact on project. Each type of steel plate has its advantages, and mechanical properties, as well as method of fabrication must be understood to understand differences in order to make an informed decision on the right steel product. One of the biggest differences is strength and this makes knowing the differences important from a perspective of value in cost and applicability to save you time, effort, and money.
Whether you're creating building structures, machinery parts, and automotive components, understanding the differences between these steels will allow you to make decisions based on strength, finish, price, and use. How do hot roll steel and mild steel differ, and what one is best suited for your application?
Mild and hot rolled steel are two products that have many applications. Both of these products are a form of carbon steel , but there are a few similarities and differences. Knowing these similarities and differences is important before you can choose the proper type of steel plate for your own project. Let's look at hot rolled, and mild steel, their similarities and differences, and which product might be better for you.
Understanding Steel: Hot Rolled vs Mild Steel
Steel is commonly used in construction, manufacturing, and engineering, and it is often regarded as one of the most versatile materials to work with. From the many variations of steel available, hot rolled steel and mild steel make themselves evident in their unique attributes and uses. Understanding the differences between the two steels will help understand how to choose a steel plate for a project, all the while ensuring performance, costs, and working life.
What is Hot Rolled Steel?
Hot rolled steel is produced by placing steel slabs in a furnace and heating them to very high temperatures, usually over 1700°F (927'C) to soften the steel sheet so it can be rolled or shaped into very specific nominal dimensions. At the hot rolling mill, the steel is passed through rollers until the desired thickness and dimensions are achieved. Once the steel is rolled, it is allowed to cool naturally which produces a rough scaly finish due to mill scale. It may seem like hot rolled steel plate would be a straightforward material; however, when deciding to use hot rolled mild steel or mild steel, there can be variations and differences that could impact your project. From the way they are manufactured to their physical properties, both hot rolled and mild steel come in versions that offer their own benefits. Understanding those differences is important to help decide which material is best for your needs. Whether you're deciding on materials for construction, machinery parts, or automotive components, knowing how these two steels differ in strength, finish, cost, and usability can help save you time, money, and effort. So how do hot rolled steel and mild steel compare to each other; and which would be better for your specific application?
Hot rolled steel and mild steel are two varieties of steel products used for a large number of applications. Both are forms of carbon steel , but there is a difference between them. It’s a good idea to understand the differences before selecting your steel plate.
Hot rolled steel is made to be highly ductile and workable, typically having a tensile strength of 67,000 psi and a yield strength of 45,000 psi. Hot Rolled Steel is not as strong as cold rolled steel ; however, hot rolled steel is more ductile making it easier to work with, especially for applications where bending and shaping is required.
Hot rolled steel is frequently utilized in construction for things like beams and columns, in automotive manufacturing for parts and in vehicle frames, in rail tracks for strength, and in heavy machinery due its toughness.
Hot rolled steel is seen as cost efficient due to its production process, which is a simple but efficient process. This makes hot rolled steel very versatile to use, in addition to being easy to work with because of its high ductility .
What is Mild Steel?
Mild steel is a type of carbon steel that is relatively low in carbon content - in fact it is sometimes called "low carbon steel ." While ranges can vary depending on the reference, mild steel typically has a specified carbon content in the range of 0.05% to 0.25% by weight, while higher carbon steels are typically defined by their carbon content ranging from 0.30% up to 2.0%. If any more carbon is added it would be classified as cast iron.
Mild steel is not an alloy steel, so it doesn't have large amounts of other elements apart from iron, meaning it does not have large amounts of chromium or molybdenum as an example. Since the carbon and alloying element amounts are fairly low, there are several properties it has that differentiate it from higher carbon and alloy steels.
Low carbon means that mild steel is usually more ductile, machinable, and weldable than high carbon and other steels, but it also means it is nearly impossible to harden and strengthen by heating and quenching . The low carbon content means it has almost no carbon and other alloying elements to resist dislocation in its crystal structure, which generally leads to lower tensile strength than high carbon and alloy steels. Mild steel has a relatively high amount of iron and ferrite, making it magnetic.
The lack of alloying elements, as found in stainless steels, means that iron in mild steel is prone to oxidation (rust) if not painted/ coated when exposed to moisture. But the almost nonexistent amount of alloying elements does allow mild steel to be more affordable in contrast to other steels. It is affordability, weldability , machinability that make it such a common usable steel product for consumers.
Again, mild steel pipe is a versatile commodity and is used widely in plumbing, construction, and fabrication.
Difference Between Hot Rolled Steel and Mild Steel
Hot rolled steel and mild steel share similarities in composition, but differ greatly in their properties. Hot rolled steel has greater malleability , due to its processing at elevated temperatures. This makes it easier to shape into specific shapes or components without heat treatment or another preparation step. By way of contrast, mild steel has much less malleability , and is not suitable in applications where bending or shaping is required.
Aside from the improved yield strength over mild steel, another advantage hot rolled steel has for many applications such as car frames, bridges, etc., is its more industrial-style rough finish than cold rolled steel sheet. Some people like the rough aesthetic appeal hot rolled steel has, while cold rolled steel has a very nice even and smooth finish that some people may prefer, but which is again, good if you expect any degree of blemishing from movement or construction on site. Finally, a hot rolled steel sheet is appropriate for being painted or powder-coated as a means to color it or to provide corrosion resistance from the environment. Mild steel must be treated properly and with a rust-resistant coating for well-done finishes to last.
Naturally, there are many applications that mild steel is far superior to hot rolled steel. Mild steel is more resilient than hot rolled steel since the lower carbon content it has yields it less brittle, making it less prone to wear and tear. An advantage that mild steel again has over hot rolled steel is that it is more weldable, making mild steel the optimal choice for crafting multiple parts that need the correct fine detail work for either furniture frame work or art sculptures. Mild steel is also cheaper than hot rolled steel as mild steel only takes less steps after its cooled down while hot rolled steel needs further shaping with heat to be condensed into specific parts.
Hot Rolled Steel vs Mild Steel: A Comparative Analysis
Process and Properties
Hot rolled steel is produced when steel is heated above 1700F, and rolled into the desired shape. Due to the heat treatment there during the hot rolling process, steel becomes ductile so it is more easily worked into the desired shape. After the steel is hot rolled, it will shrink as it cools slightly, which leaves a rougher surface finish. Hot rolled steel also has mill scale on the surface. Hot rolled steel ends up having a lower tensile strength because it is subject to heating, due to the hot rolling process it is also cheaper than cold rolled steel as it is a simpler processing technique.
Mild Steel
Mild steel (also called low-carbon steel ) has a carbon content of between 0.06% and 0.24%. Mild steel can be processed through hot or cold rolling . The properties of mild steel vary depending on the form of rolling . Overall, mild steel is a low-cost product, with great variability based on many applications.
Hot Rolled Steel
Hot rolled steel has a rougher surface texture due to mill scale, which can removed with sanding. The dimensions are less precise than cold rolled steel - this is because hot rolled steel cools at room temperature, leading to slightly warped steel and variations in thickness.
Cold Rolled Mild Steel
Cold rolling is another processing step that is completed on mild steel at room temperature or near room temperature. This is another operation that has little to no strain hardening. Cold rolled steel has a better surface finish and no scale, as well as tighter tolerances and better surface quality.
Hardness and Strength
Hot rolled steel is softer and more flexible, which allows it to be shaped more easily. However, its yield strength and tensile strength are lower than those of cold rolled steel , which helps to resist deformation.
Cold Rolled Mild Steel
Cold rolled mild steel hardens due to work hardening associated with a rolling process. It provides an increase in yield and tensile strength making it more resistant to deformation and better suited for high durability applications.
Applications and Cost
Hot rolled steel is useful for large structural applications where cost and ease of forming are critical. Applications include beams, columns and frames in construction, as well as automotive and heavy machinery components.
Mild Steel
Mild steel is widely adaptable and can be used in many forms de
Choosing the Right Steel for Your Project
Choosing the Right Steel for Your Project
Factors to Consider When Selecting Steel
Identify the needs and goals of your project to be sure the selected steel meets all of the planned functions and structural considerations. For example, a construction project may need to focus on strength and durability while a manufacturing application may need materials of exact dimensions and smooth finishes.
Application Type
Knowing what the intended use is is key. Structural components like beams or columns often need a material that is both strong and inexpensive making hot rolled steel a reasonable option. On the other hand, parts like automotive body panels or machinery pieces benefit from a more refined surface and accuracy of cold rolled steel .
Budget
Hot rolled steel is the more economical option due to a simpler manufacturing process which is best for projects that require lower cost. If your application requires precision and a more finished product, then cold rolled mild steel, although a more costly option, would be warranted.
Performance Needs
Consider the physical properties your project requires, including strength, flexibility, and durability. Hot rolled steel's ductility and ease of forming allow it to used well in flexible applications, such as curving or molding a structural shape. Conversely, cold rolled mild steel is typically used for projects with precise sizes and smooth finishes as it provides more strength and hardness than hot rolled steel.
Hot Rolled Steel
Advantages: Hot rolled steel is a low-cost material and is easy to shape, making it appropriate for a wide range of structural uses. It is very malleable, making it simple to fabricate. This is quite useful when a certain shape is requested for a project.
Disadvantages: The ugly surface texture and lack of careful dimensions may limit uses in applications when look or precise dimensions are key.
Mild Steel
Advantages: Mild steel is very versatile, it is highly malleable, and it welds easily. When cold rolled, it has better tolerance and smooth surfaces which is an advantage when aesthetics or tolerances are of importance in an application.
Conclusion
