Metallurgist whose additive made the process practical
Plate 066
1856
England and United States
No photograph is shown for this exhibition. The museum displays an image only where it can show the object honestly.
About this date
Henry Bessemer announced the process in 1856. William Kelly in the United States and Robert Mushet in Britain also contributed.
About credit
Kelly claimed prior discovery and the US patent was granted to him. Mushet’s spiegeleisen addition fixed problems in Bessemer’s method.
Chapter II
The world before
Life before Cheap Steel (the Bessemer Process)
Steel was costly and made in small batches. Most structures used cast or wrought iron.
II
The human achievement
How it came about
A pear-shaped converter was filled with molten pig iron. Air blasts removed carbon and impurities in about twenty minutes, producing tons of steel at a time. The Siemens-Martin open hearth process followed in the 1860s.
III
Understanding the invention
How it works
Cheap Steel (the Bessemer Process), explained in two steps.
01
Step 01 of 02
Burning off carbon
Oxygen from the air reacts with carbon and silicon in the iron, releasing heat that keeps the metal molten.
Burning off carbon
Controlling the mix
IV
The transformation
What changed for humanity
Railways and bridges
Steel rails lasted much longer.
Buildings
Steel frames supported skyscrapers.
Cheap steel made rails, bridges, ships, tools and, later, skyscrapers stronger and lighter than iron.
V
Before and after
Life before and after Cheap Steel (the Bessemer Process)
Before
Hours of labour, high cost.
After
Minutes in a converter, at a fraction of the price.
On larger screens, drag the divider (or use the arrow keys) to give more room to the world before or after.
VI
Its legacy
What came after
MHI 066
Cheap Steel (the Bessemer Process)
Beyond the collection
Skyscrapers
Steel frames and the safety elevator.
Beyond the collection
Modern steelmaking
Oxygen furnaces replaced Bessemer’s converters.
VII
Human stories
The people and the moments
Mushet’s forgotten fix
Robert Mushet solved Bessemer’s quality problem but was not well rewarded. Bessemer was knighted in 1879.
Where accounts differ, this museum follows the documented record and says so.