采用PLC和变频器的电渣炉电控系统改造

The Reformation of Electric Control System of Electro-slag Furnace by Using PLC and Frequency Converters

电渣重熔是冶炼特殊钢的重要手段之一。电渣炉渣池的温度对精炼提纯效果、电极熔化率、铸件成型和结晶具有决定性作用，而温度控制则主要通过对熔炼电流的调节，也即调整电渣炉自熔电极底部与渣池液面的距离来实现，因而电极升降控制就成为了电渣炉生产的关键控制环节。上世纪90年代以前，电极升降控制主要采用晶闸管直流调速装置，存在体积大、故障率高、运行成本高等缺点。随着变频器和PLC的广泛应用，这些先进设备也被用来对以电极升降控带3为主的老式电渣炉电控系统实施改造，使旧电渣炉换上新装备。其良好的稳定性、可靠性、借助程序实现的灵活性以及维护的便捷，使其生产能力和产品质量都得到了大幅提高。

Electro-slag remelting is one of the important approaches for smelting special steel The temperature of slag bath of electro-slag furnace is of decisive role for refining purification effect, electrode melting rate, foundry molding and crystallizing, but the temperature control is achieved mainly by means of regulating smelting current, i.e. regulating the distance between the bottom of self molten electrode and the liquid level of slag bath of the electro-slag furnace, thus the electrode lifting control has become a crucial control link in electro-slag furnace production. Prior to the 1990s, in the electrode lifting control system, the thyristor DC speed regulation device is mainly adopted, but it has the shortcomings of large volume, higher failure rate and higher operating cost, etc. With the widespread applications of frequency converter and PLC, these advanced equipments are also used for implementing the transformation for the outdated electro-slag furnace electric control system which is the electrode lifting control-based; it makes the old electro-slag furnace to be replaced by the up-to-date equipments. The production capacity and product quality of the electro-slag furnace have substantially been enhanced due to its well stability, reliability, flexibility with the help of the programs as well as the convenient and fast maintenance.