Views: 31 Author: Site Editor Publish Time: 2022-01-19 Origin: Site
When the electric furnace is tapped, the furnace body is inclined to the tapping direction at a certain angle (usually 45s), and the molten steel flows through the tapping trough and enters the ladle. In addition to diversion of the molten steel, the tapping trough also prevents the molten steel from dispersing and protects the molten steel from secondary oxidation. If the geometric design or the improper use of refractory materials, it will cause large heat loss, high refractory material consumption, and even increase non-metallic inclusions in molten steel.
The structure of the trough tapping is that the tapping port is located above the copper water surface. In the past, the tapping method of the tapping channel was to tap the steel in the state where the steel slag covered the molten steel. The main purpose was to prevent the temperature drop of the molten steel, improve the desulfurization capacity, and prevent the molten steel from oxidizing. . Now the tapping opening starts from close to the bottom of the furnace and communicates with the large tapping trough that is inclined upward at the outer flat wall.
The tapping trough is connected to the furnace shell, and its masonry methods include ramming, pouring, brickwork or comprehensive masonry, etc. The taphole construction method is relatively consistent. Generally, taphole bricks of various shapes are used to smash or a steel pipe in the center, with high-quality magnesia castable around it, and ceramic pipes with a wall thickness of 25mm and 23 pieces of high-grade It is made of fused magnesia bricks. Usually after using the 5070 furnace, it is necessary to replace the new tapping hole. When the tapping trough is used for tilting tapping, the main damaged parts are the steel line, slag line, and the bell mouth at the front end of the trough. The refractory material is required to have good wear resistance, slag corrosion resistance, and thermal shock resistance, and is used in the tapping trough. Prevent cracks and minimize wear.
The material of the tapping trough of foreign electric furnaces is generally high-aluminum, magnesia-aluminum, zirconium, magnesia-carbon, waxstone, etc., or adding SiC, Si3N4 and C and oxidizers, and the service life can reach more than 100 after maintenance. Up to 300 times.
Brick-built steel channel
Japan uses high-durability CFC-ZRN-15X zirconium bricks. The bricks are made of pure zircon as the main raw material, supplemented by silicon nitride that is resistant to the erosion of molten steel, so that it has good adhesion to molten steel, erosion and erosion of molten slag. It has anti-corrosion effect, but the price is more expensive. This brick is built in a 50t electric furnace with a 1.95m long tapping trough. The life of ordinary steel smelting can reach 300 furnaces. It is used in a 100t electric furnace and a 2.8m long tapping trough. The life of special steel is smelted. 200 furnaces.
In addition, CFC-ZRN-5X semi-zirconium brick is also used. This brick uses pure zircon as the main raw material and uses some high-silica raw materials to make it have the properties of a semi-zircon brick, and the price is higher than that of pure zircon and silicon nitride. The bricks are much lower. Used in 40t electric furnace, 0.9m long tapping trough, smelting ordinary steel life can reach 300 furnaces.
Prefabricated block tapping channel
The use of prefabricated large blocks to build the tapping channel has the smallest brick gap, which is beneficial to prolong the life of the tapping channel and at the same time reduce the construction time. It can be mechanically hoisted and can be used after installation. In the 1980s, Ben widely used high-aluminum and low-cement castable precast block steel troughs. The castable uses alumina as the aggregate, silicon carbide and flake graphite as the main raw materials, plus special ultra-fine powder and dispersant. The 80t electric furnace uses low-cement castables and aluminum-carbon prefabricated blocks to build steel tanks, with a service life of 118 furnaces. The original use of resin combined with ramming to form the steel tank has a service life of only 2040 times.
Overall tapping channel
The tapping channel is generally made of unshaped refractory material, which has good integrity, long life and low cost. The materials used are ramming material using phenolic resin as the bonding agent or vibrating castable using non-cement system as the bonding agent. Generally, it can be prepared and constructed on site.
Comprehensively build the steel channel
A French company uses pre-casting high-aluminum lining for electric furnace tapping. The tapping trough is opened as low as possible in the furnace. During tapping, the slag surface is kept above the tapping port for easy tilting. The slag will not flow out. The properties of RERCAST10 high-aluminum castable are as follows: chemical composition (%) is Al2O376.3, SiO26.5, SiR4.8, C6.8; bulk density is 3.05g/cm3; normal temperature compressive strength (MPa) 110℃75 , 1200℃60; permanent linear change rate (1200℃) is -0.3%. A 100t electric furnace of a company in West Germany used magnesia-carbon bricks to build the tapping channel with a life of 100,150 times.