Stirring of metal melts for improving the efficiency of the «ladle – furnace» units. Message 1. Methods and systems for stirring of liquid alloys in metallurgical aggregates (review)

Abstract

Based on the global trends in the metallurgy, the features of the further development of technologies for the cast metal productions are predicted. At the same time, there is considered the constant tightening of requirements for energy and resource saving, environmental and work safety, with the simultaneous need to improve the quality of casting, widening the range of obtained alloys and products from them. Also, ensuring reliable operation and expanding the functional capabilities of “ladle – furnace” units has particular importance, since they provide the complex out-of-furnace processing of melts, including averaging on temperature and chemical composition (at alloying and modifying too), removal gases and non-metallic inclusions, etc. It is noted that for the successful implementation of the listed technological operations, “ladle – furnace” units are equipped with additional devices and systems for heating the melt, vacuuming, blowing with inert gas (argon) and electromagnetic stirring. A comparative analysis of different methods of liquid metal stirring (by gas blowing and under the action of an external alternating electromagnetic field) showed that electromagnetic stirring is more effective and appropriate, especially at manufacturing relatively small batches of high-quality and special alloys on metallurgical mini- mills. At that, the most common at metallurgical enterprises and among research developments are electromagnetic stirrers of travelling magnetic field.There are indicated that applications of such stirrers have certain limitations due to physical characteristics. It relates to the need (in most cases) to supply them with a low frequency, making changes to the design of operating metallurgical aggregates for installation of the stirrer, as well as with not always rational hydrodynamic modes of melt stirring.The requirements concerning the development and application of electromagnetic stirrers for “ladle – furnace” units were formulated. Such devices should be simpler in design and operation, ensuring their long-term reliable working at obtaining a wide range of high-quality alloys. Keywords: “ladle – furnace” unit, metallic melt, gas blowing, electromagnetic stirring.