Iron and steel in metalworking

Iron and steel in metalworking are the raw material. Without these elements it would be impossible to supply parts and components to the other industries that metalworking serves, such as the automotive, aerospace and manufacturing industries, among others. What are the metals we work with like? What shape must they have before they can be sent to other industries?

Iron, the most important metal

When we talk about iron and steel in metalworking, iron is undoubtedly the main element. Not only as iron itself, but all of its derivatives and alloys. This metal has very particular characteristics: for example, it rusts easily and is harder than copper. You may be surprised to learn that iron is the most widely used metal in the machining industry: 90% of all metal is iron.

After aluminium, iron (abbreviated as Fe) is the second most abundant metal on Earth. Iron is the most abundantly produced metal, because oxides can be smelted with the iron at high temperatures in special furnaces that use a carbon residue. Iron is turned into steel in the same furnace in which pure iron is smelted. 98% of iron is transformed into steel; the rest is used as cast iron and wrought iron. How are iron and steel made in metalworking?

How iron is made

Iron is extracted from the Earth's crust from minerals and oxides such as magnetite. The first step is to extract these minerals and then separate the iron from them (by magnetism or by density). Next a sinter is formed and passed through a furnace at high temperatures, where the metal is transformed into pig iron and then into steel. Steel is nothing more than an alloy of iron with carbon.

Iron with between 2 and 4% carbon is used as cast iron. Its mix contains silicon, manganese, phosphorus and sulphur, and it rusts easily. In this state, iron can be found in everyday items such as hinges, grilles and some furniture.

Iron and its alloys

As we mentioned earlier, the main alloy of iron is steel which, when mixed with other elements, forms further alloys. Nowadays steel is the most widely used metal. We can find it, for example, protecting building structures, as it provides great strength; it is also used in railway tracks and roads, as well as in vehicles and other household objects.

When iron is alloyed with carbon to form steel, the hardness and strength of the material improve. There is a rust-resistant version, which is none other than stainless steel. Stainless steel is the alloy of iron with carbon and 11% chromium. You will easily find stainless steel in machine tools, generally in the food industry, because, as its name indicates, it does not rust. For example, factories that produce food use machines such as sausage stuffers made of stainless steel. And canned food? Salted fish requires machines that do not rust easily because of the brine. Stainless steel is designated by three digits: AISI 304 and 316. One is more resistant than the other.

In addition, steel can be mixed with other elements to form different alloys. These are:

• Manganese
• Chromium
• Molybdenum
• Nickel
• Tungsten
• Vanadium

Iron and steel in metalworking: how are they machined?

Iron and steel in metalworking come in different forms and shapes. To obtain these shapes, raw metals have to undergo different machining processes.

Sheet metal

Sheet metal consists of metal plates, of different sizes and thicknesses, that are fundamental to industry. We find these sheets as covers for machine tools, to make car and aircraft parts, or to make furniture and doors. Sheets are worked on press brakes through forming and deforming processes.

The most widely used are stainless steel and carbon steel sheets.

Sections

Other parts obtained from iron and steel are flat bars, angles and sections. These are metal pieces with specific shapes that can be worked on press brakes and on other machines such as cutting machines.

Tubes

Tubes are sheets that are deformed in such a way that they are bent right round. This requires machines such as the bending machine. Tubes are hollow; solid pieces are bars, and the thinnest ones are called rods. The shapes are varied: round, square, hexagonal, etc.

Fasteners

Yes, screws and nuts are also made from steel and iron. Screws, for example, are machined by metal cutting with the help of machine tools. The workpiece is placed in a die while the cutting tools approach its surface to cut away the swarf and generate the thread grooves typical of screws.

The same applies to the nuts that hold the screws.