The converter furnace is a high temperature metallurgical equipment and must be stacked with refractory materials. In particular, the inner lining of the converter is subject to the chemical corrosion of high temperature molten steel and slag, as well as the scouring effect of molten steel, slag, furnace gas and the mechanical resistance of waste indium. which is more demanding on refractory materials. The function of the refractory material is not only related to the life of the lining, but also affects the quality of the steel.
The converter refractory brick lining consists of a working layer, a filling layer and a permanent layer. The working layer is directly touched by molten steel, slag and furnace gas, which is constantly subjected to physical, mechanical and chemical corrosion effects, the filling layer is interposed between the working layer and the permanent layer, generally using tar magnesia or tar dolomite. The effect is to reduce the extrusion of the furnace shell when the refractory brick lining expands to prevent damage to the permanent layer, and to remove the residual bricks in the working layer, the permanent layer is used to maintain the furnace shell, which can be used to burn magnesia brick, tar combined with magnesium, refers to the construction of refractory bricks. Generally do not replace when repairing the furnace.
The damage mechanism of the converter lining is very complicated. In general, the oxygen converter lining under the effect of physical, chemical and thermal stress, the phenomenon of mechanical wear, erosion and heat loss occurs, which eventually leads to the damage of the lining. Because the working conditions of the various parts of the converter lining are very different, the damage of the various parts of the converter lining is different, so the function of the refractory bricks for each part of the converter lining is very demanding.
The mouth of the furnace and the part of the furnace hat: firstly, it is washed by the high the attachment is finished, it is mechanically hit, the two furnaces are subjected to intense exercise during the exercise. The influence of thermal shock requires that the refractory material of the masonry has high thermal shock resistance and slag resistance, slag resistance and high temperature furnace gas scouring, which is not easy to stick steel, even if the steel is easy to be finished. Therefore, the high strength magnesium charcoal fire bricks are often used in this part.
The charging side of the lining: in addition to the corrosion of molten steel and slag, it is also subjected to the intense impact of scrap steel and the intense erosion of molten iron during charging, this effect is very severe. Therefore, the refractory material required for masonry on the converter charging side has high temperature strength, good thermal shock resistance, high slag resistance. Therefore, most of the areas used are high corrosion resistant and high thermal resistant magnesia carbon bricks.
The tapping side of the lining: less affected by thermal shock, but due to the hot scouring effect of the molten steel, the same grade of refractory material as the charging side can be used, and the thickness can be slightly thinner.
The trunnion parts on both sides: in addition to the corrosion of molten steel and slag during the blowing process, and also subjected to the erosion and oxidation of the airflow, the surface of the lining is not covered by the slag layer, so the carbon in the lining refractory brick is easily oxidized, and further damaged, It is not very good to repair, so the erosion is severe. The masonry brick with high oxidation resistance and slightly higher carbon content should be used for masonry.
Slag line: Long term contact with slag is a severe part of corrosion caused by slag. The tapping side slag line changes with the time of tapping, and the damage is not significant; but the slag side, because of the intense slag corrosion effect, plus other effects suffered by the converter belly during the blowing process, the corrosion is more severe. Therefore, high corrosion resistant magnesium carbon bricks should be used.
The molten pool part: although it is affected by the erosion effect of molten steel in the blowing process, compared with other parts, the damage is lighter, and the operation of the slag splashing protection of the converter tends to increase the bottom of the converter, so the molten pool part of the converter can be used. General magnesium charcoal bricks.
The tapping part: the tapping port is affected by the corrosion and erosion of high temperature molten steel and slag, the sudden change of temperature, the damage is more severe, so the masonry fire brick with good erosion resistance and high oxidation resistance should be built. Use all the magnesia carbon bricks, or combination of magnesia carbon bricks, and repair or replace them after using them for a certain number of times.
Refractory Brick for Converter Furnace Construction
1.Shake the converter to zero position, find the center line of the bottom of the furnace, check the air holes on the gas supply casing and the steel structure, and ensure that all the pipes and air holes are unblocked, the three layers of magnesia bricks are laid on the bottom of the furnace floor and are laid to the ventilation place. The hole is close to the furnace shell and is required to be flush with the refractory brick. The third layer of magnesia fire brick is placed on the lower edge of the flange, the gap between the fire brick and the flange is filled with refractory material.
2.The working layer of the bottom of the furnace is set up with magnesia carbon bricks. Firstly, find the center of the bottom of the furnace, and pre-assemble the masonry center firebricks. The degree of partial pain should meet the requirements. The surrounding bricks should be built according to the planned bricks, and the wrong teeth should be handled. When laying permeable bricks, the thickness of the fire bricks around the ventilated bricks is not more than 1mm. The venting pipes should be twisted according to the orientation of the venting ducts. After the venting bricks are positioned, the materials are used to cut the holes under the venting firebricks.
1) When laying the briquetting bricks, use the ramming refractory material to control the height of the briquetting bricks to ensure the flatness of the outer side of the briquetting bricks, use the alcohol resin to select the air hammer between the briquetting brick and the permanent layer.
2) The permanent layer of the furnace body is built, the cone part of the converter pool, the straight part of the furnace body, the permanent layer of the cone part of the furnace cap are made of magnesia refractory brick, with the furnace shell as the guide surface, close to the furnace shell, and the conditioning fire brick door, control the level of each ring, fill the firebrick joint with fine magnesia powder.
3).The cone part of the converter pool, the straight part of the furnace body, the cone part of the furnace cap are made of magnesia carbon brick, with the furnace shell as the guide surface, the working layer is close to the permanent layer, the expansion layer is pressed as required, and the working layer brick. The gap between the fire bricks and the permanent layer bricks is filled with materials to ensure the level of each ring; each door is closed at a door, the orientation of the door bricks is arranged between 15℃ and 30℃ of the center line of the interval tapholes. The door bricks should be staggered by at least 2~3 bricks, the processing of the door bricks should not exceed two-thirds of the original brick width.
1) When the tapping hole is built, the orientation and viewpoint of the tapping port should meet the planning requirements. The center line of the tapping port should be consistent with the center line of the furnace. Use the brine magma mud to wet the firebrick, between the refractory brick and the pipe. The lining and the furnace shell are filled with refractory materials, and the seam is not clamped within 1m of the tapping area. The fire brick joint is not more than 1mm.
2) Reserve about 100mm between the topmost brick of the furnace hat and the furnace door, weld the anchor on the furnace shell, and beat it with the ramming material.
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