Bessemer Process: The Age of Iron to the Age of Steel
The Industrial Revolution in the United States advanced with technological advancement and invention known as the Bessemer Process. This enabled movement from the Age of Iron to the Age of Steel making new inventions and innovations possible in the Second Industrial Revolution.
Steel Making and the Bessemer Process
The Bessemer Process was created in England by Henry Bessemer in 1855 and brought into production by Henry Bessemer in 1860. To create the Bessemer Process he invented a large, pear-shaped receptacle called a converter and utilized a blast of air in a de-carbonization process to create the steel from iron.
Summary and Definition of the Bessemer Process
Summary and Definition: The Bessemer Process is the method for making steel by blasting compressed air through molten iron to burn out excess carbon and impurities. The Bessemer Process lowered the cost of production steel, leading to steel being widely substituted for cast iron. It was the creation of modern steel.
Steel Making and the Bessemer Process
Bessemer Process for kids: Brief History of Iron and Steel
Steel is an alloy of iron, with carbon. Steel was known in antiquity and used in weapons by the Roman Army. Steel had been produced in blast furnaces for thousands of years and new production methods were devised in the 17th century for blister steel and then crucible steel. Up to 3 tons of expensive coke was burnt for each ton of blister steel that was produced.
Wrought iron has a little carbon (.02% to .08%), just enough to make it hard without losing its malleability.
Cast iron has a lot of carbon (3% to 4.5%), which makes it hard but brittle and non-malleable
In between wrought and cast iron is steel (with .2% to 1.5% carbon) making it harder than wrought iron, yet malleable and flexible, unlike cast iron.
These properties make steel far more useful than either wrought or cast iron but there was no simple way to control the carbon level in iron so that steel could be manufactured cheaply and efficiently in large quantities. In 1856 the Bessemer Process made this possible and moved the United States into the Age of Steel.
Background History of the Bessemer Process for kids: William Kelly
In 1847 an American named William Kelly (1811 - 1888), the owner of an iron-works at Eddyville, Kentucky started to experiment in processes for converting iron into steel. William Kelly had the idea that, in the refining process, fuel would be unnecessary after the iron was melted if powerful blasts of air were forced into the fluid metal. Theory behind the conversion from iron to steel was that the heat generated by the union of the oxygen of the air with the carbon of the metal, would accomplish the refining (burning off the impurities). This would become known as the Bessemer Process - the procedure to refine fluid iron by passing a stream of air through it, which created the type of steel material used for the making of structures.
Bessemer Process for kids: Henry Bessemer
The Bessemer Process is named after the British metallurgist, engineer and inventor Sir Henry Bessemer (1813-1898). During his career, he registered more than 110 patents, the most famous being the converter for what would be called the Bessemer Process. In 1877 the Royal Society of London elected Henry Bessemer into fellowship and two years later, in 1879, he was knighted. His involvement in steel began during the Crimean War (1853 - 1856) when Henry Bessemer was working on the problem of how to create more durable cannons for the British navy. Cannons were traditionally made of cast iron but these were proving unsuitable against new weapons which caused the cannons to explode. Steel was the obvious choice of metal to replace cast iron but it was expensive to produce - until he developed the Bessemer Process.
The Bessemer Process: The Converter
|Bessemer Process: The Converter|
In 1856 Henry Bessemer designed what he called a converter:
- The converter was a large, pear-shaped receptacle
- There were holes at the bottom of the converter to allow the injection of compressed air
- The Bessemer converter was filled with molten pig iron
- Compressed air was blown through the molten metal
- The pig iron was emptied of carbon and silicon in just a few minutes
- The metal became even hotter and so remained molten
Bessemer Process: The Phosphorus Problem
One problem with the early Bessemer process was that it did not remove phosphorus from the pig iron which makes steel excessively brittle and the initial Bessemer process could only be used on pig iron made from phosphorus-free ores. The phosphorus-free ores were relatively scarce and therefore expensive.