An eye for an i #408 Children

Bessemer lays the foundation for steel

Sir Henry Bessemer   | Photo Credit: Wellcome Library, London

One of the most important materials in today’s world is steel. It has become an integral building block in humanity’s ever-expanding domain on Earth and lets us build everything from towering skyscrapers to huge bridges. The man who gave us this steel that lies at the foundation of modern-day infrastructure is English inventor and engineer Henry Bessemer.

Born in Charlton, England in 1813, Bessemer was the son of an engineer, printer and typesetter. Even though he was largely self-educated, Bessemer showed an aptitude for inventing from an early age and had a natural flair for mechanical skills.

While still a teenager, Bessemer came up with the idea of movable stamps for dating title deeds and other government documents. He improvised the idea and it saved a lot of money for those in the business, but Bessemer hardly gained monetarily for his methods.

Becomes secretive

After having learnt it the hard way, Bessemer decided that he probably had to be more secretive with his ideas. So when he came up with a method that allowed him to manufacture a powder using brass as a paint additive, he kept it to himself. He invented machines to mimic his mixing, set up a factory where the process remained top-secret and produced this powder, which could be used as a gold substitute for décor. As the floral decorations of the time required large quantities of such material, Bessemer was able to gain great wealth in the process.

The Bessemer converter at Kelham Island Museum is one of the few converters left in the world. It was used until 1975 and was brought to the museum to serve as an example of the revolutionary steel-making process.

The Bessemer converter at Kelham Island Museum is one of the few converters left in the world. It was used until 1975 and was brought to the museum to serve as an example of the revolutionary steel-making process.   | Photo Credit: Dave Pickersgill/ Wikimdia Commons

 

During the Crimean War (1853-56), Bessemer came up with an artillery shell that was heavier than the typically used canon balls. While the French authorities were interested, they pointed out to him that their cast-iron cannon wouldn’t be strong enough for these shells. That put him on the path to produce stronger cast iron, leading him to a cheap way of mass-producing steel.

Air and heat

While experimenting, Bessemer observed that oxygen in the furnace removed excess carbon and impurities from pig iron being preheated, leaving pure iron. He then realised that blowing air through melted iron purified the iron and heated it more, allowing it to be poured more easily.

These techniques, which came to be known as the Bessemer process, were patented by him in October 1855. He also came up with the Bessemer converter, a huge egg-shaped contraption into which molten pig iron could be poured and then air could be blown from below after it is tilted. Using this, Bessemer was able to cheaply produce large quantities of steel.

Urban infrastructure

Even though Bessemer hadn’t perfected the technology, he was able to benefit from it largely. Everything from railroads to the early skyscrapers lapped up steel as defence and construction industries put the material to good use.

The Bessemer process did not remove phosphorus and sulphur, two elements that could harm iron. Other processes that came in later were able to address these issues, but modern steel is still made using technology that is based on the Bessemer process.

As for Bessemer himself, he spent a lifetime inventing and innovating. He built a solar furnace, designed and built an astronomical telescope for his own use, produced a machine of advanced design that could crush sugarcane and extract its juice, and even built a vessel – the Bessemer Saloon Ship – to combat seasickness. Not all his attempts were successes (the SS Bessemer crashed into a pier on its first and only public voyage), but by the time Bessemer died in 1898, he had been knighted for his contributions to science, awarded the Fellowship of the Royal Society and notched up over a 100 patents.

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Printable version | Oct 28, 2020 5:57:42 AM | https://www.thehindu.com/children/bessemer-lays-the-foundation-for-steel/article32813325.ece

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