China from the 5th century BCE; Europe from the 12th–15th century
◐Approximate date
China, then Europe
Associated with
Chinese ironworkers
Anonymous; developed cast iron
European ironmasters
Developed larger blast furnaces in the late Middle Ages
Plate 040
China from the 5th century BCE
China, then Europe
No photograph is shown for this exhibition. The museum displays an image only where it can show the object honestly.
About this date
Chinese cast iron dates from the 5th century BCE. Blast furnaces appear in Europe from around the 12th century, with large-scale use in the 15th.
About credit
Whether European blast furnaces were independent inventions or derived from Chinese practice is debated.
Chapter II
The world before
Life before Cast Iron and the Blast Furnace
Iron was forged from a spongy lump, the bloom, which was hammered into shape. The process was slow and the pieces were small.
II
The human achievement
How it came about
A blast furnace is loaded with ore, charcoal and limestone. Bellows drive in air to raise the temperature so iron melts and runs out. In England in 1709, Abraham Darby used coke instead of charcoal at Coalbrookdale, helping make iron cheaper.
III
Understanding the invention
How it works
Cast Iron and the Blast Furnace, explained in two steps.
01
Step 01 of 02
Heat plus carbon
Charcoal burns to give heat and also carbon monoxide, which strips oxygen from the ore.
Heat plus carbon
Limestone cleans
IV
The transformation
What changed for humanity
Industry
Iron became cheap enough for machines, rails and bridges.
Warfare
Cast iron cannon became available at scale.
Cast iron could be made in large amounts and cast into pots, cannon, pipes and later bridges and machine parts.
V
Before and after
Life before and after Cast Iron and the Blast Furnace
Before
Hammered from small blooms.
After
Poured in one piece from a mould.
On larger screens, drag the divider (or use the arrow keys) to give more room to the world before or after.
