Tuesday, 1 May 2012

Article - Stainless Steel, 100 years old but who invented it? (Sheffield)

A common answer to the question of who invented stainless steel is usually “Harry Brearley” from Sheffield , in reality the answer to this question regarding stainless steel may not be so clear cut, even though its now officially 100 years old.

Firstly when we discuss this it is important to note that the term “inventor” is very loose, what is it we define as an “inventor”? Is it the person who first thought of the idea, the person who first documented the idea, the person who got the patent for the idea or even the person who produced the idea?

Secondly the actual name “stainless steel” wasn’t actually defined until 1911 and prior to this there was chromium-iron alloys which didn’t meet the minimum requirement of 10.5% chromium but they still held some level of corrosion resistance and so this is hard to just simply push to one side.

There have been many of people from various of countries who have claimed to be the inventor of stainless steel however; the argument was set into motion when Stoddard and Farraday who were two Englishmen and then Pierre Berthier noticed in 1821 that iron-chromium alloys were more resistant to attack.

Tests were then carried out on low chromium alloys and then higher chromium alloys were attempted to be produced but at this initial stage the importance of low carbon content wasn’t understand and thus production failed.

In 1872 when Woods and Clark filed for a patent of an acid and weather resistant allow which contained 30-35% chromium and 2% tungsten. This would be the first ever patent on what is now considered stainless steel.

It was 1875 when Frenchman, Brustlein detailed the importance of low carbon content being a key factor in the successful creation of stainless steel. He said that in order to create an alloy with a high percentage of chromium the carbon content needs to remain below 0.15%.

Twenty years later as scientists attempted to develop stainless steel and they tried creating low carbon stainless steel but no attempts were successful. But it was in 1895 when Hans Goldschmidt of Germany then developed the aluminothermic reduction process which would produce carbon-free chromium and it was at this point when stainless steel became a reality.

In 1904 Leon Guillet carried out extensive research on iron-chromium allows and thus he came up with compositions of what is now known as 410, 420, 442, 446 and 440-c. following this in 1906 he then analysed iron-nickel-chrome alloys which provided the basis for the properties 300 series stainless steels which we have today. He never documented the potential corrosion of the above materials.

In 1911, the importance of minimum chromium content was discovered by Monnartz and Borchers. They noted the correlation and relationship between chromium content and corrosion resistance and thus produced detailed works on this.

In 1871 this was when Harry Brearley was introduced; in 1912 he was given the task of prolonging the life of gun barrels which were eroding too quickly. He was on a mission to find erosion resistant steel and not a corrosion resistant one; he experimented with steel alloys containing chromium.

On the 13th August 1913 Harry created a steel with 12.8% chromium and 0.24% carbon it is this which has been argued to be the first ever stainless steel. There are a number of myths which have since arisen concerning Harry’s tests against corrosion however in reality he had to etch his steels with nitric acid and then examine them using a microscope.

Their resistance to corrosion was noted as were the resistance to attacks from acid and he recognized the potential for this steel; he noted that it would be ideal within the cutlery industry. His current employer at this stage wouldn’t support him and thus he went to produce his new steel at a local cutler.

Within three weeks he perfected a hardening process for knifes and named the invention “rustless steel” however his friend Stuart named it “stainless steel” and since the name has stuck. It isn’t all that simple though because during the five year period between 1908 and the discovery in 1913 other scientists had potential claims to his title.

At a similar time Professor Dr Benno Strauss and his co worker Dr Eduard Maurer created a formula for non rusting steels which are insensitive to water and humidity , then on October 18th 1912, a patent was granted for the production of articles requiring high resistance to corrosion. This was a quantum leap in material research, and it was followed two months later by a patent for the production of articles requiring high resistance to corrosion through acids and extreme strength.

In Malmo in Sweden in 1914, products of stainless steel were presented to the public for the first time. In 1919 a further patent was granted in the medical field for the “production of artificial internal parts for human and animal bodies made of stainless steel”. The stainless steel material also became popular with architects. The Chrysler Building in New York (built 1928-1930) was the first to feature stainless steel roof cladding. Stainless steel was also used in the facade of the world’s tallest building, the Burj Kalifa in Dubai which was opened in 2010, this was recently seen in the film Mission Impossible staring Tom Cruise. Today we see stainless steel exhausts, stainless steel sinks and stainless steel screws.

This year it is widely celebrated 100 years of stainless steel by the Institute of Stainless Steel forum (ISSF) and other country forums like the British Stainless Steel Association (BSSA).

It was certainly a combined effort by all scientists and metallurgists which has created such a rich and versatile metal, it is safe to say we will never solve the speculation behind who invented stainless steel

From: http://www.stainlesssteel.me/stainless-steel-news/stainless-steel-100-years-invented-1307

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