Bessemer process in the context of "Ironworks"

The Second Industrial Revolution, also known as the Technological Revolution, was a phase of rapid scientific discovery, standardisation, mass production and industrialisation from the late 19th century into the early 20th century. The First Industrial Revolution, which ended in the middle of the 19th century, was punctuated by a slowdown in important inventions before the Second Industrial Revolution in 1870. Though a number of its events can be traced to earlier innovations in manufacturing, such as the establishment of a machine tool industry, the development of methods for manufacturing interchangeable parts, as well as the invention of the Bessemer process and open hearth furnace to produce steel, later developments heralded the Second Industrial Revolution, which is generally dated between 1870 and 1914 when World War I commenced.

Advancements in manufacturing and production technology enabled the widespread adoption of technological systems such as telegraph and railroad networks, gas and water supply, and sewage systems, which had earlier been limited to a few select cities. The enormous expansion of rail and telegraph lines after 1870 allowed unprecedented movement of people and ideas, which culminated in a new wave of colonialism and globalization. In the same time period, new technological systems were introduced, most significantly electrical power and telephones. The Second Industrial Revolution continued into the 20th century with early factory electrification and the production line; it ended at the beginning of World War I.

An open-hearth furnace or open hearth furnace is any of several kinds of industrial furnace in which excess carbon and other impurities are burnt out of pig iron to produce steel. Because steel is difficult to manufacture owing to its high melting point, normal fuels and furnaces were insufficient for mass production of steel, and the open-hearth type of furnace was one of several technologies developed in the nineteenth century to overcome this difficulty. Compared with the Bessemer process, which it displaced, its main advantages were that it did not embrittle the steel from excessive nitrogen exposure, was easier to control, and permitted the melting and refining of large amounts of scrap iron and steel.

The open-hearth furnace was first developed by German/British engineer Carl Wilhelm Siemens. In 1865, the French engineer Pierre-Émile Martin took out a licence from Siemens and first applied his regenerative furnace for making steel. Their process was known as the Siemens–Martin process or Martin–Siemens process, and the furnace as an "open-hearth" furnace. Most open hearth furnaces were closed by the early 1990s, not least because of their slow operation, being replaced by the basic oxygen furnace or electric arc furnace.

Steelmaking is the process of producing steel from iron ore and/or scrap. Steel has been made for millennia, and was commercialized on a massive scale in the 1850s and 1860s, using the Bessemer and Siemens-Martin processes.

Currently, two major commercial processes are used. Basic oxygen steelmaking (BOS) uses liquid pig-iron from a blast furnace and scrap steel as the main feed materials. Electric arc furnace (EAF) steelmaking uses scrap steel or direct reduced iron (DRI). Oxygen steelmaking has become more popular over time.

The technological development of the US iron and steel industry has closely mirrored that of other countries. In the 1800s, the US switched from charcoal to coal in ore smelting, adopted the Bessemer process, and saw the rise of very large integrated steel mills. In the 20th century, the US industry transitioned from the open hearth furnace to the basic oxygen steelmaking process. After peaking in the 1940s and 1950s, the US iron and steel industry shifted toward smaller mini-mills and specialty mills that use iron and steel scrap instead of iron ore.

Sir Henry Bessemer FRS (19 January 1813 – 15 March 1898) was an English inventor, whose steel-making process was the most important technique for making steel in the nineteenth century for almost one hundred years. He played a significant role in establishing the town of Sheffield, nicknamed ‘Steel City’, as a major industrial centre.

Bessemer had been trying to reduce the cost of steel-making for military ordnance, and developed his system for blowing air through molten pig iron to remove the impurities. This made steel easier, quicker and cheaper to manufacture, and revolutionised structural engineering. One of the most significant inventors of the Second Industrial Revolution, Bessemer made at least 128 inventions in the fields of iron, steel and glass. Unlike many inventors, he brought his own projects to fruition and profited financially from their success. In 1879, he was knighted for his contribution to science and was elected a fellow of the Royal Society.