Analysis of Structure and Service Life of Electric Arc Furnace Cover

The furnace cover of an electric arc furnace consists of two parts: the furnace top and the furnace body, which play a key role in insulation, reducing heat loss, and preventing chemical gases and dust from leaking and polluting the environment. The central area of the furnace cover usually has holes for the insertion of electrodes and the addition of metallurgical auxiliary materials. Although the furnace cover does not directly come into contact with the molten steel, it is subjected to strong thermal shock stress, high temperature, and dust erosion due to frequent opening of the furnace cover. Especially during the operation of the electric arc furnace, the interaction between iron oxide dust and the refractory material of the furnace cover forms a liquid phase, which promotes the sintering of the surface material of the furnace cover. Due to temperature fluctuations and thermal stress, the interface between the sintered layer and the unsintered layer is prone to crack enlargement or material peeling, which in turn affects the structural integrity of the furnace cover.

Especially when the temperature exceeds 2000 ℃, the light radiation of the arc, the insertion and removal of electrodes, and other processes can cause significant thermal stress and corrosion in the triangular area of the furnace cover, resulting in surface peeling and cracking of the furnace cover, shortening its service life. This is the main reason for the damage of the electric arc furnace cover.

To solve this problem, the furnace cover of electric arc furnaces generally adopts a tube type water-cooled dense tube structure. The furnace cover mainly includes the furnace cover body and the receiving hopper device. The main frame is made of seamless steel pipes, forming a circular structure that not only meets the requirements of structural strength, but also serves as the main inlet and outlet pipelines, connecting various cooling water pipes through these pipelines. The other parts are composed of slightly smaller dense tubes, and the water-cooled plate is easy to replace and maintain, with a service life of usually over 3000 heats. The lower part of the receiving hopper adopts a water-cooled material tube design.

The main inlet and outlet water cooling pipes of the furnace cover are made of flanged stainless steel metal hoses and equipped with rotary joints, while other water cooling pipes use handle type stainless steel metal hoses. The central part of the furnace cover is a small central furnace cover with three electrode holes, made of refractory pouring material.

The structural design of Water-cooled Furnace Cover further optimizes the heat dissipation effect. The water-cooled cover is located at the lower part of the Water-cooled Furnace Cover frame, and the lifting ring is welded on the main beam of the furnace cover frame. The water-cooled plate is set on the flat section of the water-cooled furnace cover frame, with the central small furnace cover seat placed on the inner ring of the water-cooled plate and equipped with electrode holes. The distance between the water-cooled cover plate and the electrode is 400mm to 450mm, the height of the flat section table of the furnace cover water-cooled frame is 1050mm to 1150mm, the diameter of the flat section table is 2500mm to 2580mm, the inner diameter of the water-cooled cover plate is 2720mm to 2780mm, and the diameter of the water-cooled plate is 2650mm to 2750mm.

This water-cooled structure greatly enhances the durability of the furnace cover, effectively extends its service life, and reduces the risk of damage caused by high temperature and thermal shock stress.