Metallurgical machinery including: metallurgical equipment (sinterer, circular cooler, cooler, hot-ore Screen, hot-ore crusher, iron-casting machine, converter, electric arc furnace, continuous caster, rolling mill, ladle trolleys, etc.), metallurgical furnaces (rotary kiln, vertical kiln, heat treatment furnace, etc.), deep-processing equipment, transmission equipment, transportation equipment, reclaimer mixing machinery, cooling equipment, coking equipment, foundry equipment, etc. Most metallurgical machinery are design to operate in the high-temperature, high-load and high-pollution enviroment, thus putting higher requirements on bearings and other components. Only special bearings that can withstand high temperature, high load, highly corrosion can be used to ensure the normal and effective operation of shaft and the smooth production in the whole process, so that qualified steel can be finally produced after ores are processed through the blast furnace and converter. About 2,000 different kinds of alloy steel can be produced by means of steelmaking, and then casted into ingots and slabs by means of a continuous casting equipment.
Converter: pig iron is changed into steel in a converter. For that purpose, the reduction in carbon content, removal of harmful substances and adding of required alloy composition are also required. This large container shall be provided with special bearings and housings. Converter trunnion bearings are designed to bear high loads, and the speed is very low. Effective sealing and proper lubrication system can prevent rolling bearings from environmental pollution. Converter trunnion bearings are designed with high static load rating and over 10 years’ service life. Large-size bearings with diameters ranging from 620 mm to 1720 mm and matched housings are usually adopted.
NTN bearings are designed for applications in harsh operating environment required by the iron and steel industry. Effective sealing and proper lubrication system can prevent rolling bearings from environmental pollution. Converter drive gear box bearings are designed fwith high static load carrying capacity and over 10 years’ service life. Large-size bearings with outside diameter greater than 600 mm are commonly used.
Ladle turret is a very important part in the continuous casting process, which bears pouring ladle with the maximum weight of 300 tons. With ladle turret, the pouring ladle alternately enter the pouring and loading positions. This feature ensures the uninterrupted operation of the continuous casting. When a ladle is empty, the ladle turret will provide another ladle filled with molten steel to the other side. Though it is required to bear very large load and some overturning moment, the ladle turret bearing can still realize a service life of more than 10 years. Cylindrical roller bearing, spherical roller thrust bearings and spherical plain bearings with inner diameter of more than 1000mm are recommended.
Guide roller: in the process of continuous casting, the guide roller is used to support the continuous casting equipment, and provide vertical plane guide from the horizontal plane. To avoid deformation, the guide roller is usually supported by using a plurality of rolling bearings that must meet the requirements on high load, low speed, water splashing and high temperature. Spherical roller bearings or cylindrical roller bearings of different designs (open, non-split or split type) can be used for the guide roller. Needle roller bearings shall be used in the 0/1 segment at the top. Depanding on the use position and maintenance condition, the service life of an import bearing used in a continuous casting equipment can be one year or several years, which is also closely related to the type and quality of the seal.
Applications of Bearings in Rolling Mill and Steel Rolling
The steel billet, ingot and slabs produced through the casting process can be maded into products of the desired shape, size and characteristics through the rolling process. The rolling mill (hot-rolling mill, section mill, straightener, cold rolling mill, multi-roll cold rolling mill, drive shaft, hot rolling mill) is the very equipment to complete this process. In a hot strip mill, slabs are rolled into hot-rolled steel strips. The work roll is usually supported by four-row tapered roller bearings.
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