Siemens Process
An open-hearth technique for steel making.
1861 William Siemens took out a patent on his design for a regenerative furnace; the patent stated that the furnace was applicable to the melting of steel on the open hearth.
1862 The initial successful application of the regenerative furnace was at Chance Brothers and Co's glass works near Birmingham, which was quickly followed by several other furnaces. Michael Faraday spent two days in Birmingham with Siemens viewing the works and made the furnace the subject of his final lecture to the Royal Institution, on 20th June 1862. Siemens designed furnaces for a number of iron makers, with limited success due to the new metallurgy and impurities in the steel produced[1].
1865 William rented a small factory in Birmingham, and set up the Sample Steelworks to develop the process[2].
1865 the French engineer Pierre-Émile Martin took out a licence from Siemens and first applied the regenerative furnace for making steel, which became known as the Siemens-Martin process.
By 1867 William had succeeded in developing the furnace for steel making, converting old iron rails into steel which was rolled into rails at John Brown and Co in Sheffield. These rails so impressed the directors of the Great Western Railway that the Landore Siemens Steel Co was immediately formed in Swansea to apply the furnace. By 1869 these works were making 75 tons a week [3].
1867 The furnace was awarded a Grand Prize at the Paris Exhibition of 1867.
c.1872 Sir Charles Tennant led the formation of the Steel Company of Scotland, intending to make use of the iron found in pyrites mined by another of his ventures. William Siemens conducted some experiments to see if his new open-hearth furnace could deal with the iron by-product of the pyrites. On the strength of Siemens's encouragement, Charles Tennant and his friends decided to embark on a full-scale steelworks at Hallside and commissioned Siemens to design it, the idea being to use conventional materials to start with. In the event, the metallurgical techniques proved inadequate to deal with the iron from pyrites but the Siemens plant was so successful with conventional materials that it launched Scotland as a steel-producing nation.
1872 The Steel Company of Scotland was registered on 9 February [4]. Colonel J Roper Wright supervised the works; Wright had worked at the Sample Steelworks at Birmingham[5]
The shipbuilders on the Clyde were quick to adopt open-hearth steel. Although it was up to 50% more expensive than malleable iron it had better properties and was a more reliable product than Bessemer Steel. Once it was approved by the Chief Naval Architect of the Royal Navy in 1876 the market was created. This was also an advantage to Scotland as the Bessemer Process had not been very successful with the local Scottish iron ores whilst the Siemens process gave Hallside an advantage in quality.
The Steel Company of Scotland at Hallside had an initial monopoly over the market for open hearth steel. However, because of the demand from the shipyards, other steelworks were started and some malleable ironworks changed to steel production.
By the early 1880s, almost all ships built on the Clyde were built of steel - no other British shipbuilding area made the switch from iron to steel so rapidly and Hallside was equipped to meet the demand [6].
1880 the Steel Company took over and converted the Blochairn Iron Works to production of Siemens open-hearth steel. 8 furnaces were erected.