Stainless steel, or inox, is becoming more and more popular for kitchen utensils, for your water bottle or for the straw of your Mojito.
In the previous article, we discovered 5 reasons why you should use stainless steel utensils. Today, we will discover how stainless steel is made.
CONTENTS
What is stainless steel?
What are the different types of stainless steel ?
What is the manufacturing process of stainless steel ?
Is there stainless steel made in Europe ?
1. What is stainless steel?
Stainless steel, or inox, is an alloy of Iron and Carbon. An alloy is simply the combination of several metallic elements by fusion.
It also contains Chromium which gives it a resistance to corrosion, hence its name "stainless".
Other elements can also be found in stainless steel such as Nickel, which improves its mechanical properties, or Titanium or Molybdenum.
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2. What are the different kind of stainless steel ?
There are different types of stainless steels [2,3,4,5]. Here are 4 main categories of stainless steel:
Austenitic : this is the most used type of stainless steel in the world (about 65% of the world production). It is often presented as 18% Chrome and 8% Nickel (called 18/8 or 18/10 when there is 10% Nickel). It is therefore a combination of iron, chromium, nickel, carbon (< 0.1%). This type of steel has a wide range of applications: metallurgy, automobiles, hospitals, breweries, mechanics, architecture, food and pharmaceutical industries, ...
Ferritic : this type of steel represents about 30% of the current world production. It is a combination of iron, chromium and carbon (<0.1%). This type is used in the automotive industry, as knives, sinks, household items, railroads, silos, etc.
Martensitic : it is a combination of iron, chromium and carbon (>0.1%). This kind of steel is mainly used in cutlery but also in mechanical engineering, pumps, turbines, etc.
Duplex : it is a kind that combines the austenitic and ferritic ones (it combines iron, chromium and nickel). They have better mechanical characteristics and superior corrosion resistance. That's why they are used in petrochemicals, paper industry and in the desalination of sea water, for example.
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3. What is the manufacturing process of stainless steel ?
As we have already seen, stainless steel is compounded of several elements :
Iron
Chrome
Nickel
Carbon
Sometimes Titanium or Molybdenum.
These elements must first be extracted. For iron, for example, this is done via iron ores. These iron ores come mainly from China, India and Russia.
Chromium comes mainly from South Africa. Nickel comes mainly from Russia or Australia.
However, as we saw in the previous article, stainless steel is 100% recyclable and therefore, much of the raw material is recycled stainless steel.
Today, 60% of the stainless steel manufactured is made from recycled stainless steel. Not too bad, eh?
The raw materials are put into large tanks in precise quantities according to the type of stainless steel.
Then, these tanks are heated up to 1650 degrees so that the steel reaches its melting point. The liquid steel is then purified and certain elements such as nickel are added.
Afterwards, a laboratory analysis is performed to adjust the alloy if necessary. Once the mixture is ready, the steel is cast to be cooled and thus to solidify.
Finally, the stainless steel cut into plates will be flattened and then rolled into coils. The coils can then be transported to be processed in their final use [6].
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4. Is there stainless steel made in Europe ?
Currently, China produces 80% of the world's stainless steel. It has a big monopoly on the raw material, especially on the chromium which comes from South Africa.
In Europe, 14,5 % of the steel is produced and the production is mainly industrial. Therefore, it is very difficult (if not impossible) to get a stainless steel bottle or stainless steel cutlery made in Europe.
So, yes, it takes a long time to get stainless steel to us. However, it can be recycled, it has a long life span and it is very resistant. These qualities make it a material of choice against other more polluting materials like plastic.
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See you soon !
Titi the Wapiti
Take care of yourself and your planet