| 摘要 |
The invention is a method for cleaning bearing steel that primarily consists of carbon, silicon, manganese, phosphorus, sulphur, chrome, aluminium, oxygen, nitrogen and titanium, with the remainder being iron together with impurities. The bearing steel is smelted in a smelting furnace in order to clean the steel through oxidation. The smelted steel is then poured into a separate container, phosphorus is removed from the smelted steel and oxide-containing slag that flows on top of the smelted steel is absorbed and removed with a vacuum slag cleaner. Reducing cleaning of the steel is then carried out through forceful stirring of the smelted steel in the presence of a high degree of basic slag, which has a basicity of at least 3, while at the same time the temperature of the steel bath is adjusted. Said cleaning is carried out in an indifferent atmosphere which is under a pressure greater than normal pressure. Vacuum extraction of the steel is carried out by means of a vacuum extraction circulation device that generates powerful circulation for 2/3 of the processing time and weak circulation for 1/3 of the processing time. Finally, there is a reduction cleaning of the steel through gentle stirring of the smelted steel in a reducing atmosphere at normal pressure. Said process reduces the amount of phosphorus, sulphur, aluminium, oxygen, nitrogen and titanium to no more than 0.01 percent, 0.002 percent, 0.015 percent, 0.0006 percent, 0.005 percent and 0.0015 percent, respectively (all calculated in percent by weight). |
