Test on the suspended crown of a large-tonnage steel-smelting arc furnace

Abstract

During the operation of large-tonnage steel-smelting furnaces, stresses arise in the refractory lining of the crown; these are caused by the weight of the crown and the variable temperatures of the subcrown space [i]. The cyclic nature of the change in stress is responsible for the fatigue-type fracture of the components of the crown, which, in addition to the physicochemical processes of wear in the refractories, is a factor determining the durability (resistance) of the crown lining [2].In order to improve the durability of the refractory linings a design of crown has been developed for an arc furnace which ensures that the stresses in the lining are reduced as a result of the partial off-loading of the load on the crown due to its weight and the localization of the stresses arising in the peripheral and central regions of the lining [3].The suspended design of crown includes making the linings of the peripheral and central region from shaped, periclase--chromite crown refractories, grades PKhSE-3 and PKhSE-5 (Tech. Spec. (TU) 14-8-271-7:8).The peripheral region is made up of round tiers of items on their "edge,"and the central region by using a sector-arc method in a water-cooled central ring. The ring lining of the peripheral section is suspended from suspension beams by means of pins and metal plates. The load is off-loaded from the crown lining using the adjusting equipment.

Operational features and development of a combined design for the roof of a 100-ton electric arc furnace

“…The data obtained and also observations during operations confirm the more uniform distribution of stresses in the structure of the annular roof compared with the sector-arch [3]. In order to arrange further improvements in the annular construction of the roof and boost its resistance we developed a combined design for a roof made of periclase--chromite and high-alumina refractories.…”