Mild steel is a type of steel alloy, which contains a high percentage of carbon as a major alloying agent. Alloys are simply a mixture of one or more metals with non-metals, designed to give specific improved properties over the parent base metal. Mild steel is the type of steel, which is used in the majority of all steel internal and external applications in the UK.
Steel is a range of alloys principally of iron, with 0.2% to 2.1% of carbon, acting as a hardening agent. As well as the carbon, there are many metal elements that are a part of steel alloys and have a great affect on their properties. The elements other than iron and carbon used in steel can be a mixture of some or all of these; chromium, manganese, tungsten and vanadium. These elements in addition to carbon, act as hardening agents. By hardening agents we mean they create points within the iron crystal lattice layers preventing the layers from sliding past each other. They do this by attaching themselves to the interstitial sites within the crystal structure and act as a block on lattice movement. This is simply why steel is harder than iron, the addition of alloying agents. When the alloying agents are varied different grades of steel are produced with different practical industrial uses. The higher the percentage of carbon and other hardening agents within the steel the harder the steel will become but with a consequent reduction in ductility.
Mild steel may also be thought of as steel which is not stainless. Mild steel and low carbon steels mainly differ from stainless steels in having a much lower percentage of chromium. Stainless steels do contain a much higher percentage of chromium than standard mild steels giving them a better resistance to corrosion but at a higher financial cost.