Magnets have been around for thousands of years, helping ships navigate oceans. Today, magnets are used for a wide variety of purposes, including microwaves, televisions, generators, motors, speaker systems and much more. There is some misunderstanding about what types of materials are magnetic – particularly steel. Is steel magnetic, can it be magnetized, or neither?
Nearly all steel you find or see is not a magnet. However, steel could be manufactured to be made into a magnet. Steel is a magnetic material, in the sense that it can be pulled by magnets, because it is mostly made up of ferromagnetic materials. To understand this important difference of being a magnet and being a ferromagnetic material, it is good to understand the difference between the different types of magnets.
Permanent Magnets
When most people think of magnets, they are thinking of permanent magnets. They are the types that can attach to some metallic objects like refrigerators and other magnets without the need of an electrical current.
A variety of materials can be used to create permanent magnets, but iron, cobalt, nickel and other alloy metals are most commonly used.
Electromagnets
Electromagnets are created by creating an electromagnetic field around a material. A copper wire coil is wound around a core typically made out of iron, cobalt or nickel. When electricity flows through the copper wire, a magnetic field is generated. The big advantage of electromagnets is that the magnetic field can be managed easily by turning on or off the electrical current.
Michael Faraday, possibly the most important person that you have never heard of, was a pioneer electrical experiments and magnetism and was the first to figure out that they were two sides of the same coin. He discovered that moving electrical currents generate magnetic fields, and also magnetic fields generate electrical currents. He is credited with creating the first motor, which was a critical invention that kickstarted the industrial revolution.
Steel is a Ferromagnetic Material
Technically steel is composed mostly of iron, which is a ferromagnetic material. For example: 1018 steel, a very common grade of steel, is composed of 98.81-99.26% iron. Other ferromagnetic materials include nickel cobalt.
Why are some materials magnetic and others not?
It all has to do with the elements contained in the material. You may have learned about the orbital shells of elements in your chemistry class and how electrons congregate around shells in the nucleus of an atom. Some elements like helium, radon and neon have filled electron shells with electrons that zoom around equally in all directions. The currents they generate will cancel out and produce no magnetic field. Elements with full outer electron shells or nearly full shells will have no attraction to a magnetic field, or a very weak one that can only be detected by instruments.
Other elements with half-filled shells will have unpaired electrons in their outer shell. In a permanent magnet, these electrons will all point in one direction and their magnetic fields will add up to form a magnetic field. For elements that are not permanent magnets but are magnetic like iron, their electrons will point in all directions, but will all point in a single direction when introduced to a magnetic field.
To learn more about the physics behind magnetism and why watch this great video produced by Minute Physics:
Is stainless steel magnetic?
It depends. Some stainless steel is magnetic while some is not. There are many different types of stainless steel, as alloy steel with at least 10.5% chromium is considered stainless steel. Ferritic stainless steel will be magnetic as a result of its high concentration of iron and molecular structure that enables magnetism. The molecular structure of austenitic stainless steel is different as a result of a higher chromium and nickel concentration added. The result is that austenitic steel does not behave in a ferromagnetic way, despite high concentrations of ferromagnetic materials.
Is galvanized steel magnetic?
Generally yes, galvanized steel will be magnetic. Galvanized steel has a protective coating of zinc, which will not affect the magnetic properties of the steel, iron or other metal type that it is protecting. The zinc coating will not enhance the magnetic properties of the steel, but as long as the underlying metal is magnetic, the galvanized steel as a whole will have magnetic properties.
Are steel cans magnetic?
Yes, because steel cans are made up of ferromagnetic elements like iron, steel cans are attracted to magnets like permanent magnets and electromagnets. Even if a material is not made up entirely of ferromagnetic elements, it can still have magnetic properties and be influenced by magnets.
Is all metal magnetic?
No. In fact most metallic elements such as silver, titanium and copper are not magnetic. There are only three elements from the periodic table that are magnetic: nickel, cobalt and iron, and this is due to their partially filled outer electron shells in the d-orbitals.
