-the invention and development of modern smelting technology
1After the mid-9th century, European steel production began to develop greatly, and 1856 was the starting point of the great development. In this year, Bessemer invented the converter blowing method, which greatly shortened the steelmaking time, and soon Siemens invented the open hearth smelting method (1867), which not only produced high-quality steel, but also used a lot of scrap steel. These two methods laid the foundation of modern steelmaking and brought mankind into the steel age.
More than 20 years later, Thomas, an Englishman, solved the problem of phosphorus. He studied the behavior of phosphorus from the angle of chemical reaction, and thought that the phosphorus in pig iron was oxidized by air to form phosphorus pentoxide, which was reduced to phosphorus by the silica lining of the blowing furnace and re-entered the steel. So he thought, if we combine it with phosphorus pentoxide with another stove, this problem can be solved. He cooperated with P Gelchrist to carry out a series of experiments on the small furnace of 1877, which proved that dephosphorization can be realized with alkaline lining furnace. Later, he carried out a scale-up experiment in a 1.5-ton furnace, using dolomite as furnace lining and tar as binder, and succeeded in 1879, creating a butyl alkaline converter steelmaking method, also known as Bessemer method.
The inventor of open hearth steelmaking is German Siemens. He and his brother studied the regenerative heat exchanger together, using gas as fuel, which was successfully used in the glass furnace, saving 50% fuel. Later, it was used to melt crucible steel. Subsequently, the method of steelmaking with pig iron and iron ore, namely open hearth steelmaking, was successfully developed, and the patent of 1867 was obtained. Open hearth steelmaking is carried out in the middle reverberatory furnace, and there are two regenerative heat exchangers under the furnace, which alternately use preheated air. This kind of furnace is characterized by high thermal efficiency and high temperature. At the same time, Martin Company of France successfully experimented with the method of smelting pig iron and wrought iron into steel after obtaining Siemens' patent on regenerative furnace, and then used scrap steel to replace wrought iron and pig iron to make steel together. This is the common open hearth steelmaking method, also known as Siemens-Martin method. The lining of open hearth furnace is also acidic and alkaline.