Materials · 1865
Open-hearth steel
A regenerative furnace makes large, controllable steel batches.
Pierre-Emile Martin used the Siemens regenerative furnace to make steel in 1865. Open hearth became the dominant steel process for most of the 20th century.
What it built on 1
Related measurements
The dashed line marks when it first worked.
US railway network length Latest: 231k km (1993) Source: Our World in Data