What is the difference between Stainless Steel and Mild Steel?

When choosing the right type of steel for a project, understanding the difference between stainless steel and mild steel is essential. While both are widely used in construction, fabrication, and manufacturing, they have distinct properties that make them suitable for different applications. From corrosion resistance and strength to cost and appearance, this blog post breaks down the key differences between the two to help you make an informed decision for your next project.

What is Mild Steel?

Mild steel is a low-carbon steel, typically between 0.05% and 0.25%. This low carbon content makes it easier to work with than other steels with a higher carbon content. Mild steel is one of the most common and widely used steels in the construction and manufacturing industries, among others.

What is Stainless Steel?

Stainless Steel is a corrosion-resistant alloy made primarily of iron and chromium, and must contain a minimum of 10.5% chromium. This chromium content creates the protective chromium oxide layer, which makes stainless steel corrosion-resistant. It is used across various industries, including food manufacturing, construction, architecture and automotive.

What are the differences between mild steel and stainless steel?

Chemical Composition

The primary difference between stainless steel and mild steel is the chemical composition, which changes the attributes of the metal, changing the strength, ductility, and hardness of the material. For mild steel and stainless steel, the key difference is that mild steel contains primarily iron and carbon, whereas stainless steel contains a combination of iron, carbon, and chromium, among other alloys, such as nickel. The chromium makes it corrosion resistant and a more formable and weldable metal.

Corrosion Resistance

Stainless steel is corrosion-resistant due to its chromium content; however, the same cannot be said for mild steel, which is not corrosion-resistant. The iron content in mild steel reacts with the oxygen in the atmosphere, causing it to corrode quickly.  To protect the mild steel, it must undergo processes such as galvanising or painting to stop it from corroding.

Stainless steel is not completely corrosion-proof, but it is highly corrosion-resistant. The added chromium bonds with the oxygen in the atmosphere, preventing the iron from being able to oxidise.

Malleability

Mild steel is more malleable than stainless steel due to its lower carbon content. This makes it far easier to produce and shape into the desired products. Typically, stainless steel is not very malleable and is more prone to cracking due to its higher chromium content. However, austenitic stainless steels like grades 304 and 316 are the most malleable and are commonly used.

Strength

Mild steel is ideally suited for use in commercial buildings and infrastructures such as bridges due to its high tensile and yield strength. This means that when pulled on by forces, it is less likely to break or become deformed. Stainless steel, however, has a lower carbon content and is softer than mild steel, making it more susceptible to breakages and damage.

Industry Applications

Mild Steel

Mild steel is a versatile metal that can be used in various industries, including construction, manufacturing, transportation and household appliances.

Construction: Mild steel is commonly used to construct buildings, bridges, and other infrastructure, creating structures such as beams and frames. It is also used in reinforced concrete to strengthen structures.

Manufacturing: Mild steel is used for manufacturing in elements such as fluid transportation, fixtures and jigs. It is also used for tools and fixtures due to its affordability and strength.

Transportation: It is used in car body panels, chassis and vehicle frames due to its strength. It is also used in brackets and supports. Not only is it used in the automotive industry, but it is also used in the rail industry to create train body components and undercarriage structures.

Household Appliances: Many items found around the home, such as refrigerators and microwaves, contain mild steel components. Mild steel can also be used to make bed frames or chairs.

Stainless Steel

Stainless steel is a highly corrosion-resistant metal that is popular in sectors that require good hygiene or for more aesthetic appeal due to its shiny, smooth finish. It can be used in a variety of industries.

Food and Beverage: Stainless steel is widely used in the food processing sector due to its hygienic properties and corrosion resistance. It is used to make sinks, countertops, and utensils, as well as for cutting and storing food items.

Medical and Healthcare: Stainless steel is primarily used to make surgical instruments and medical devices. It can also be used in implants and dental equipment.

Transportation: Stainless steel is used in many different components in the transportation sector, from vehicle components such as exhaust systems and fuel tanks to ship construction and road tankers.

Energy Sector: Stainless steel is used in the renewable energy sector to make wind turbines and solar panels. It is also used in power plants for various components, including heat exchangers. It is also used in the oil and gas sector to make pipelines and storage tanks.

Which should I choose?

Mild steel and stainless steel are very different, and their uses vary. If you’re not sure what you need, speak to one of our experts, and they will be more than happy to discuss your needs. Call us on 01765 522 222 or email sales@dmdesignfabrication.co.uk.

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