The System Concept of Technology and Control of VIM and VAR of Superalloys and Steels
Abstract
The bulk analysis of superalloys and special steels vacuum induction melting (VIM) and vacuum arc remelting (VAR) at Chelyabinsk metallurgical works is presented. Measures of processes modernization for quality warrant and decreasing of products cost is proposed. The system of automatic control of VIM and new control system of VAR are founded of the measures. There are VIM control system functions: calculation of charge, computation of melt temperature and chemistry during melting, computation in on-line mode of optimal melting project, fixing of all melting parameters, melting report generation, and accumulation of database for technological analyzing. The main goals of VIM control system are decreasing of dispersion of REM concentration in VIM ingots and real fixing of all events during melt. The principle deference of the new VAR control system from the other known controllers is effective stabilization of mass melt rate in shot periods of arc disturbances. Application of the achievements to production allows to implement the new “VIM + 2 VAR” technology with low level of scrap. The technology “VIM + 2 VAR” guarantees full absence of exogenous defects in VAR ingots (coarse oxides, crown, and white spots) which can take place in ordinary VAR ingots, made from cast consumable electrode. Complex application of new controllers and “VIM + 2 VAR” technology enables to stabilize ingots chemistry and micro-composition; increases purity of metal, improves of VAR ingots workability and therefore increases yield production. [Rus.]
Key words: VIM, VAR, superalloys, innovation, process control, VIM + 2 VAR technology, VAR ingot defects, purity of metals.
