Steel boiler plates were first used in 1860, and because of their much greater strength, permitted of steam pressure up to 80 pounds being used. This was a great advance in boiler making. Three years later locomotive boilers were made of steel. But the greatest applica tions by far for steel were for steel rails and steel ships. The first steel rails were made in the year Bessemer steel was first described to the public. They lasted six years in a place where iron rails had to be replaced every three months. From that day to this the great bulk of steel rails has been made by the Bessemer process. In 1863 two small barges were built of steel, and a year later a steel vessel of 1,250 tons was built.
Basic Bessemer.— Many investigators tried to solve the problem of removing phosphorus in the Bessemer blow, but it was not until the early 70's that Mr. Sidney Thomas came to the conclusion that its non-removal was due to the presence of a strongly acid and obviously a basic slag could not be maintained in an acid lined vessel. After many failures Thomas and his cousin, Mr. Gilchrist, discovered that a lin ing of lime or dolomite could be made for the converter, using silicate of soda or clay as a binding material, and that additions of lime during the blow facilitated the removal of phosphorus and that an was necessary.
Open The next great advance in the metallurgy of steel was the development of the open-hearth process. (See STEEL, OPEN HEARTH MANUFACTURE). The prior discovery which led up to the open-hearth process was the invention of the regenerative furnace by Sir W. Siemens. William a German by birth, had both a technical school and university edu cation. His first visit to England was in 1843 for the purpose of introducing a process of electroplating, by means of which silver was deposited with a bright, smooth surface, rather than in the form of a crystalline deposit. The following year 1844, he returned again to Eng land and resided during the 40 more years of his useful life.
Siemens, profoundly impressed by the theory of the conservation of energy and with Joule's determination of the mechanical equiva lent of heat, was ultimately led to the great discovery of the regenerative gas furnace. Then Siemens invented his gas producer, and with economical gas fuel the regenerative gas furnace was a great success. The first furnace on a commercial scale was used for glass melt ink in 1861, and a little later it was used for zinc distillation, heating and puddling furnaces, and for melting crucible steel. In this latter
application it is used exclusively in America, while in England coke fires are still used for melting crucible steel. These are very wasteful of fuel, and possess not one single advantage over the Siemens producer and regenerative gas crucible melting furnace.
Siemens was not very successful in applying his invention to steel melting on the hearth of the furnace itself, and. it was several years be fore any degree of success was attained in Eng land„ but meanwhile Messrs. P. and E. Martin, in France, taking Siemens' own drawings, erected a furnace in France and overcame the obstacles that had almost proved too much for Siemens. Thus originated the Siemens-Martin process, as it is universally known abroad; while in America it is usually merely desig nated as the open-hearth process.
Martin produced his steel from wrought iron scrap dissolved in cast iron on the hearth of Siemens' furnace, with the necessary recar bonization at the end of the process and the addition of manganese. This method is known as the "pig and scrap* method. Siemens mean time was working on a method now known as the "pig and ore* method, in which pig iron is decarbonized by the addition of ore, while scrap may or may not be used. It was not until 1868 that the open-hearth process became an assured success.
As with the case of the Bessemer process, so with the Siemens-Martin, the acid process was the first to be employed. In fact Acid Bessemer and Acid Open-Hearth steel both antedate the basic Bessemer. Thomas and Gilchrist, who perfected the basic Bessemer process, also realized that the essential change necessary to dephosphorize was to substitute a basic lined furnace for the acid lining which had been previously used, and the maintenance of a basic slag during the operation by the use of lime.
Thomas announced the success of his ex periments in 1878 before the Iron and Steel Institute, and although he announced that he had succeeded in removing from 20 to 99.9 per cent of the phosphorus from iron in the con verter, and thus rendered available for steel making mountains of ore the world over, which without dephosphorization were useless, his an nouncement attracted little attention, but before many years England was besieged with Ger man, French, American and other metallurgists, anxious to learn about the epoch-making dis covery,— the basic steel process. Germany profited particularly because of the large quan tities of phosphoric ores which thus became a valuable asset.