A record indicator for the resilience of the refractory lining of the main arch of the two-hearth furnace (THF) was achieved at the electric steel smelting shop at Magnitogorsk Iron and Steel Works (MMK).
Periclase carbonaceous refractories within the lining of THF No. 32 withstood three full months and 1,265 melts. The previous highest indicator of lining stability for this unit was 1,259 melts, achieved in 2005. An increase in the numbers of melts per lining allows for an increase in the output of products, reduces the operational costs of the enterprise and increases the efficiency of production by saving refractories and reducing the costs of repair work.
The achievement of this record became possible as a result of coordinated efforts and involvement by the staff at the THF site, as well as from all other associated parts of the company. MMK’s steelmakers are continuously improving steel smelting technology and providing necessary maintenance to linings. In order to increase the resilience of refractories, steelmakers must ensure that liquid metal remains within the units for an optimal period of time, avoid temperature changes and carry out necessary preventive measures. The quality of the refractories is of great importance and is requested from suppliers. Additional factors that affect resilience include: the quality of the lining implementation, which is carried out by repair specialists of the metallurgical furnaces from the OSK company, and the gunning of the main roof – the application of a special shotcrete made from refractory powder to working refractory lining increases its strength and improves resilience.
A system of motivation and material incentives contributes to the involvement of the technological personnel of the enterprise in increasing lining resilience: for each additional melting that exceeds the number prescribed by guidelines, funds are allocated to be distributed among the site workers.
Currently, THF No. 32 is completing preparations, including relining and scheduled cold repair, to commission a unit. The unit is capable of producing up to eight melts per shift. In 2017, the unit smelted over 1 million tons of steel. (MMK/Ukrainian metal)