Steel is one of the most important materials today. It enables humanity to build massively tall buildings. It enables us to cross great expanses with bridges. It is foundational to our modern infrastructure.
But where did steel come from?
As it turns out, modern steel owes its invention to a man by the name of Henry Bessemer.
Henry Bessemer was born in 1813 in England. His father was an inventor, printer, and typesetter. After growing up, at the age of 17, he moved to London where he really started pursuing building his inventions.
Bessemer's First Inventions
Bessemer demonstrated impressive mechanical and inventive skills during his early life. As he entered his professional career, the first problem he was faced with solving was put forth by the British Government. They had a problem: all of their official documents were marked with stamps that were easily copied by counterfeiters.
Bessemer solved this problem by creating an embossing machine that formed the stamp directly into the fibers of the paper. This made the stamps much harder to copy, and you'll likely still recognize these types of marks on official documents today.
Bessemer's next invention was one that produced bronze powder for gold paints. These paints were used to embellish buildings with gold, which was common during the time.
The inventor visited the factory in Germany where this paint was made, learned about how it worked, and then optimized the entire production technique. By replacing the metal used in the paint with bronze, he was able to cut the price to 1/40th of what the German factory was charging. He was so successful in this endeavor that after receiving a patent for the paint, he used the proceeds from its sale to fund the rest of his inventions.
Bessemer went on to develop sugarcane crushing machinery and other small things for the industry but soon moved on to metallurgy.
The Bessemer Process
In the mid-1800s, the only two iron-based construction materials were cast iron and wrought iron. Cast iron worked well for load-bearing parts like bridges and columns but wasn't great in dynamic tension and compression applications. Wrought iron was better suited for engine parts and girders.
A material known as steel did exist at the time, it was iron with added carbon, but its manufacturing method really only made it useful for things like cutting tools.
During the Crimean War in the early 1850s, Bessemer designed an artillery shell that would be rotated by the powder gases increasing accuracy. The problem was, French engineers told Bessemer that their cast-iron cannons wouldn't be strong enough for these kinds of shells.
Bessemer then set out to create a new kind of cast-iron that would be much stronger. He discovered during testing that excess oxygen in the furnace helped to purify the iron. Expounding upon this, he found that blowing air through melted cast iron accomplished this purification as well as heated the material further. This technique later went on to be known as the Bessemer Process.
Utilizing this process, Bessemer was able to produce large amounts of slag-free bars. After presenting his discovery in 1856 to the British Association for the Advancement of Science, he gained notoriety in the field.
A strange problem soon arose, though. As Bessemer licensed his process to different metal workers, they found that their iron was full of phosphorus and sulfur and that it wasn't being filtered out.
Bessemer was unknowingly working with phosphorus-free iron, so he hadn't run into an issue like this. After realizing his miscalculations, he devised a way to source mass amounts of phosphorus-free iron for his process. In the end, he realized that the steel he was producing was stronger than anything else available on the market, and could be made ten times faster.
In order to further the propagation of new steel, he created a steelworks in Sheffield slowly growing the operation.
Eventually, Bessemer was able to become so effective in his steel production that he was underselling other manufacturers by 10 to 15 British pounds per ton. These numbers were uncatchable by competitors, and the money started to roll in, for the inventor.
After licensing his process and running his own company, Bessemer is believed to have received a sum in excess of a million pounds sterling.
This steel that he created became known as mild steel, which was much less brittle than the hard steel at the time. This type of steel could easily be used in place of wrought iron for shipbuilding, wires, girders, and more.
Bessemer's process revolutionized the steel manufacturing industry and made steel available for a great number of applications. It wasn't until the late 1860s that the Bessemer process fell out of use due to the creation of the open-hearth or Siemens-Martin process.
This process built off of Bessemer's original design and in modern times has yielded oxygen steelmaking, a refinement of the original Bessemer process.
Later on, in Bessemer's life, he developed a solar furnace, an astronomical telescope, and even machines for polishing diamonds that helped restart that trade in London.
In 1877, the Royal Society of London elected Bessemer to their fellowship. In 1879, Bessemer was knighted.
Over the course of his entire life and his career as an inventor, he received more than 129 patents, fully cementing his legacy in the industry he sought to work in.
Living to the age of 85, Henry Bessemer passed away in March of 1898.