Fact Checked

What is Mild Steel?

Lori Kilchermann
Lori Kilchermann

Mild steel is the least expensive of all steel and the most common steel used. Used in nearly every type of product created from steel, it is weldable, very hard and, although it easily rusts, very durable. Containing a maximum of 0.29% carbon, this type of steel is able to be magnetized and used in almost any project that requires a vast amount of metal. Its structural strength prevents it from being used to create load-bearing girders and structural beams.

Many of the everyday objects that are created of steel are made using mild steel, including automobile chassis, motorcycle frames, and most cookware. Due to its poor corrosion-resistance, it must be painted or otherwise protected and sealed in order to prevent rust from damaging it. A light coat of oil or grease is able to seal this steel and aid in rust control.

Pipeline is often constructed of mild steel.
Pipeline is often constructed of mild steel.

Unlike high-carbon steel, mild steel is easily welded. The properties of the steel allow the electrical current to travel through the metal without distorting the makeup of the material. Some types of high-carbon steel, such as stainless steel, require special techniques in order to properly weld the material. Being less brittle than high-carbon steels, the mild variant is able to flex and give in construction projects where a higher-carbon version could simply break.

Mild steel has many applications, such as motorcycle frames.
Mild steel has many applications, such as motorcycle frames.

Most of the pipeline in the world is created using mild steel. This allows the pipe to not only be easily welded into place, but also lets the pipeline flex and avoid cracking and breaking under pressure. The corrosive properties of the steel pipeline mean that it must be properly sealed through painting or a process often used on pipelines that involves wrapping the pipe with a corrosive-resistant material.

Mild steel has applications in construction.
Mild steel has applications in construction.

Often in very cold climates, a warming type of insulating material is wrapped around the pipeline. This material helps keep the cold inside the pipe running smoothly. The wrap also prevents the soft mild pipe steel from becoming brittle and cracking. The constant expansion and shrinkage due to cold and warmth cycling in the pipe could create structural integrity problems, but these are held in check by the insulating wrap. On a much smaller scale, household pipes can be prevented from becoming cold and breaking by the use of electrical heating tape.

You might also Like

Discussion Comments


Car bodies are made of mild steel. How are they protected from corrosion?


Is it possible to use mild steel to heat water for the purpose of home pasteurization process, probably a mild steel drum cut in half.


@parklinkz – Mild steel will probably work fine for a model car. I’ve done some artwork in the past using thin mild steel sheets. I pounded the sheets into different shapes with a small hammer because I wanted an uneven, bumpy texture on the finished piece.

Mild steel’s very malleable and can be bent and twisted if you have the right tools. You’ll have to use a cutting torch in order to cut the steel, though. Cut it before bending it.

I’m going to assume you’re working with small sheets. If that’s the case, I think bending your cut steel pieces over the side of a work table will achieve the results you want. Bend all the pieces so they look the way you want, then you can weld them together to make the finished shell of your model car.


How easy is it to mold a mild steel sheet? I want to make a model car from scratch, so I wonder it mild steel would be a good material for the body.


@kangaBurg – There’s no need to worry. I’ve been laying pipe for three years, and we use mild steel pipes in almost every project. The chlorine that water treatment plants put into drinking water inhibits the rusting process inside the pipes. The company I work for always buys pipes that are coated with copper on the inside and outside, just to make sure the pipes won’t rust.

It’s a common practice for the interior of mild steel pipes to be treated in some way if they’re going to be transporting stuff like drinking water or natural gas.


Since mild steel rusts easily, is it really okay to use mild steel pipes? Won’t the insides of the pipes rust and leech rust into your drinking water? Or, is the inside usually treated to prevent corrosion?

Post your comments
Forgot password?
    • Pipeline is often constructed of mild steel.
      By: fottoo
      Pipeline is often constructed of mild steel.
    • Mild steel has many applications, such as motorcycle frames.
      By: Akhilesh Sharma
      Mild steel has many applications, such as motorcycle frames.
    • Mild steel has applications in construction.
      By: Vibe Images
      Mild steel has applications in construction.