Steel

Steel as an alloy of iron and carbon

Steel is one of the most widely used materials in the modern world. It is found in buildings as well as in tools and machinery. This widespread use can be explained by a combination of rare qualities. Steel is strong, resistant, adaptable, durable and relatively easy to produce.
Steel is an alloy, meaning it is a combination of several elements. The two most important components are iron and carbon. Iron is very abundant in the Earth’s crust, but it is found in the form of oxides and must be purified to become usable. Carbon, on the other hand, can be added in different forms in order to modify the properties of the metal.
When these two elements are combined, even in very small proportions, they profoundly change the internal structure of iron.

Carbon at the heart of the metal

What are the different types of iron according to carbon content?

The amount of carbon contained in iron entirely determines its nature and its behaviour.
If iron contains almost no carbon, it is referred to as pure iron.
If the carbon content ranges approximately between 0.1 percent and 2 percent, the material is steel.
Above 2 percent, the metal becomes cast iron, which is more brittle and less deformable.
This simple classification helps explain why each type of metal is used differently. Pure iron is malleable but not very strong. Steel offers an ideal balance between hardness and elasticity. Cast iron is valued for its resistance to compression but remains fragile when subjected to impact.

What is non alloy steel?

Non alloy steels contain only iron and carbon, with no deliberate addition of other elements. This family of steels is very broad, as even a very small variation in carbon content is enough to create a new material.
Extra mild steels, which are very low in carbon, are easy to work, weld and shape. They are commonly used for sheet metal, bent parts and decorative elements.
Steels with a higher carbon content become harder and more resistant. They can be hardened through quenching, which consists of heating the metal and then cooling it rapidly to further increase its hardness.
These steels form the basis of many trades, including blacksmithing, construction, simple toolmaking, general mechanics and traditional crafts.

What is alloy steel?

In some cases, steel is deliberately enriched with other elements. Even in very small quantities, these additions significantly change its properties.
Chromium allows the production of stainless steels that resist oxidation.
Nickel improves toughness and the ability to withstand low temperatures.
Molybdenum, vanadium, tungsten or cobalt increase strength, hardness or resistance to high temperatures.
Thanks to these additional elements, there exists a wide range of specialised steels adapted to very specific uses, from aeronautics to cutlery, including springs, cutting tools and engine components.

What are the uses and advantages of steel?

Steel is used in countless fields. It can be found in building frames, bridges, railway tracks, mechanical parts, knives, springs, gears, kitchen utensils, sculptures and scientific instruments.
Its advantages are numerous.
It can be adjusted to be very hard or more elastic depending on its composition.
It offers excellent resistance to tension, compression and bending.
It can be forged, rolled, drawn, heated or shaped cold.
It retains its shape and can return to its original position even under significant stress.
It is infinitely recyclable with no significant loss of quality, making it an essential material in an environmentally responsible approach.

Steel commercial steels

What are commercial steels?

Commercial steels refer to steels produced industrially in large quantities in steelworks or rolling mills. They are standardised materials designed to meet the most common needs of modern manufacturing.
Their chemical composition and shapes are standardised, which makes them easy to use in industry.
In demanding sectors such as the automotive industry, aeronautics or mechanical engineering, this composition plays a crucial role, as it determines strength, ductility and the ability to undergo heat treatment.
For craftsmanship, however, composition is often less critical. For example, an XC48 steel contains about 0.48 percent carbon, a few natural impurities and the rest is iron. This is more than sufficient for making simple tools or common mechanical parts.

Why can the same steel have several designations?

The same steel can have different names depending on the standard system used. For instance, a steel known as C45 may also be designated C45U or 1045, depending on whether French, European, German or American standards are applied.
Suppliers therefore have to deal with these different conventions, which explains why the same material may appear to have several identities.

What are the main characteristics of commercial steels?

The steels offered by suppliers mainly differ in several aspects.
They are available in different shapes, such as plates, round bars and rectangular bars, and more rarely octagonal or special sections.
They come in a wide range of dimensions, with bars available in many diameters or sections, sold either cut to length or in standard industrial lengths of around six metres.
Their surface condition also varies. Some steels are delivered with a light, intentional oxidation to protect against corrosion. Others are supplied as rolled but cleaned, while some are coated with a protective layer such as zinc or tin.
Although, in theory, millions of compositions and shapes could exist, suppliers mainly offer the most common products used by the majority of technical sectors.

What are miniature commercial steels?

When working at a small scale, the situation becomes more complex. For miniature dimensions, it becomes very difficult to find exactly what is needed. Very small diameters, extremely thin sections or very thin plates are often not available as standard products.
Even industrial manufacturers sometimes have to order special production runs to obtain certain small dimensions. This clearly shows how much suppliers focus on the most profitable formats, to the detriment of atypical sizes.

What is the artisanal solution to the limits of commercial supply?

In a workshop dedicated to miniature objects, the most reliable solution is to make one’s own bars and plates from standard materials. We therefore transform readily available steel bars into pieces perfectly suited to our needs.
This approach makes it possible to adjust thickness, width, length and even surface quality according to the requirements of each project. For example, it is common for us to create a miniature bar before even starting the fabrication of steel objects. This prepares a homogeneous raw material that can then be machined or forged with precision.

Why do commercial steels cause problems at a miniature scale?

Producing miniature bars often requires starting from very small pieces of metal, proportioned to the objects being made. One of the simplest and most controllable methods is to forge them oneself.
By hammering a piece of steel, copper or another suitable metal, it is possible to progressively reduce its cross section, elongate the material, correct the shape and adjust the dimensions to within a tenth of a millimetre if necessary.
This approach offers great creative freedom and makes it possible to obtain materials that are unavailable commercially, perfectly suited to the manufacture of miniature parts or complex mechanisms.