In the beginning, there was iron...

Iron is one of the most common metals in the earth's crust. It can be found almost everywhere, combined with many other elements, in the form of ore. In Europe, iron working dates back to 1700 B.C.

From the time of the Hittites to the end of the Middle Ages, the preparation of iron remained the same: alternating layers of ore and wood (or charcoal) were heated until a mass of molten ore was obtained, which it was then necessary to hammer while hot in order to remove the impurities - and thereby obtain the raw iron, ready to be forged.

The forge was set up a few steps away from the hearth where the metal was prepared. Originally a simple conical hole in the ground, the hearth became a furnace, the "low forge," and was gradually perfected: from a few kilograms at first, the quantity of iron that could be obtained had risen to 50 to 60 kilograms by the Middle Ages.

Moreover, small quantities of steel, i.e., iron enriched with carbon, were manufactured from the beginning. This material proved to be both harder and more resistant.

then came cast iron...

In the 15th century, construction of the first "high forges" (the precursors of the blast furnace) 4 to 6 meters in height resulted in a lucky but major discovery: a ferrous metal in liquid form, cast iron, which was used to manufacture all types of objects (cooking pots, cannon balls, andirons, pipes, etc.).

Cast iron also allowed iron to be produced in quantity, through refining : an ingot of cast iron was heated and air blown over it, causing the carbon in the cast iron to burn and the iron to run off drop by drop, forming a molten mass of raw iron.

...and finally steel!

In 1786 Berthollet, Monge and Vandermonde, three French scientists, precisely defined the nature of the Iron/Cast Iron/Steel relationship and the role of carbon in the preparation and characteristics of these three materials*.

However, it wasn't until the great inventions of the 19th century (the Bessemer, Thomas and Martin furnaces) that steel, up to that point manufactured from iron in small quantities, experienced spectacular growth and quickly became the most important metal of the industrial revolution.

At the beginning of the 20th century, world steel production totaled 28 million tons, i.e., six times more than in 1880.
By the beginning of World War I, it totaled 85 million tons. Within a few decades, steel had powerfully strengthened the equipment used in manufacturing and had replaced iron in most applications.

*The carbon content is less than 0.10% in iron, between 0.10 and 2% in steel and between 2.5 and 6% in cast iron. Today, the term "iron" is no longer used, but has been replaced by "low-carbon steel".

Steel, a metal of many uses

Steel is iron added with carbon with a rate close to 0%, corresponding to very slight traces, up to 2%. Carbon content has an impact on the characteristics of the metal.

There are two major families of steel: alloy steels and non-alloy steels. Alloy refers to chemical elements other than carbon added to the iron in accordance with a minimum variable content for each.

For example: 0.50% for silicon, 0.08% for molybdenum, 10.5% for chrome. Thus an alloy of 17% chrome and 8% nickel is used to create stainless steel. It is for this reason that there is not one but many types of steel.

Currently there are over 3,000 catalogued grades (chemical compositions), not counting those created to meet custom demand, all of them contributing to making steel the most appropriate material for meeting the challenges of the future.

 

STEEL : WHAT IS STEEL USED FOR?

The structure of the Pyramid of the Louvre, canned food, oil platforms, catalytic converters, paper clips, mounts for electronic chips...are all made of steel.

It would of course be impossible to make an exhaustive list of everything that uses steel, since steel is literally everywhere - from commonplace objects to the most sophisticated instruments, from the microscopic (parts for the micro-motors of electronic assemblies, weighing less than one gram) to the gigantic (the hold of a gas tanker, with a volume equal to that of the Arch of Triumph!), steel is the basis for an infinite number of products developed by human industry.

In the construction of bridges or buildings…

Steel may play multiple roles. It is used to strengthen concrete, reinforce foundations, and carry water, gas, and other liquids.

It is also used to form the frameworks of buildings, whether for offices, schools, factories or residences or sports facilities...And to cover them (facades, roofs, etc.).

In short, it is the basic element in the architecture and aesthetics of a structure.

in the automobile sector...

This sector is the second-largest steel market, behind the construction industry.
Chassis and bodies, engine parts, steering, transmissions, exhaust systems, steel belts for tires, etc... Steel represents 55 to 70 percent of the weight of a car.

for everyday uses: cans, pots, containers, etc…

Numerous types of packaging are manufactured using steel plate, coated on both sides with a thin layer of tin to make them stable.

Commonly known today as "tinplate", this type of steel was long referred to as "white steel", because of the whiteness of the tin. Packaging steel is made into cans for food and beverages, as well as spray paint, tubes for lipstick, and pots, cans or containers for paint, grease, solvents and other products requiring any kind of hermetically-sealed preservation.

at the heart of food preservation…

Non-alloy steel (so-called "carbon steel") requires rust protection: a layer of zinc and paint for automobile bodies, a layer of tin and paint for food or drink cans. Stainless steel, nickel and chrome alloy steel can themselves be left uncoated since their mass is stable.

Plates, casseroles, covered pots...stainless steel resists water and detergents indefinitely.
It is perfectly healthy and alters neither the taste nor the color of food.

in communications...

The electronic components used in computer or telecommunications systems, as well as the operating elements of colour television tubes, are sensitive parts, having special requirements: they are therefore manufactured using alloys adapted to each specific situation.

For example: alloys with very low expansion rates for integrated circuit structures or on-board satellite components.

in energy…

The oil and nuclear energy industries require infrastructure, equipment and fluid networks that are very specific.
Steel is a key material in this environment, as it is for the chemical industry, since it meets the critical challenges inherent to uses in very corrosive environments, high temperatures and formidable mechanical constraints.

and in health...

Stable and completely neutral in terms of its interaction with human tissue, stainless steel is ideal for artificial hips and kneecaps, screws, plates, scalpels, etc. Even needles are manufactured using stainless steel wire from 0.15 to 0.45 mm in thickness.

STEEL: HOW IS STEEL MADE?

First, the raw materials -- either iron ore or scrap iron, depending on the process -- are converted into molten steel. The ore-based process uses a blast furnace and the scrap-based process uses an electric arc furnace.

Next, the molten steel is poured and solidified in a continuous caster.
This produces what are known as semi-finished products. These can be either slabs, which have a rectangular cross-section, or blooms or billets, which have a square cross-section. They are the blanks which are used to form the finished product.

Lastly, these semi-finished products are transformed, or "rolled" into finished products. Some of these undergo a heat treatment, known as "hot rolling". More than half the hot-rolled sheet is subsequently rolled again at ambient temperatures (known as "cold rolling"). It can then be coated with an anti-corrosion protective material.

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Semi-finished Products

Finished Products

text and images source: www.steelconstruct.com (ECCS)

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