1.2 Minor maintenance
Based on the peeling off of the carbon-free corundum cladding at the part that touches the upper slag line, special smearing materials with a thickness of 30 mm and a height of 300-400 mm were applied during minor repairs to slow down the gap between carbon-containing bricks and carbon-free bricks. reaction speed. After applying the repair material for 45 times, there is still some remaining.
1.3 Maintenance of slag line during medium repair
The above measures in the working layer of the ladle wall can only slow down the erosion and peeling speed of the corundum brick at the contact part with the slag line, but the erosion rate is still faster than other wall positions. Most of the refining ladle turnover is to match multiple sets of slag line bricks with one set of wall bricks. According to the erosion of the wall reinforcement layer, when replacing the slag line, it is necessary to replace 2 to 3 layers of corundum bricks to achieve simultaneous erosion and damage of the slag line and the wall . However, in use, a 10-20 mm thick sintered layer will be formed at the hot end of the corundum brick. This sintered layer has high strength and hangs slag, and the masonry plane is difficult to handle. When operating on site, use an angle grinder to grind the corundum brick surface Grind and smooth, and then use special fire clay to build the slag line.
2 Partial repair or lining
On the premise that the overall condition of the refractory materials is good, the weak parts can be repaired or replaced by partial excavation and repair. Due to the thick sintered layer of carbon-free corundum bricks, it is difficult to level the masonry plane, and the strength of the brick body is high, and the operation of digging and replacing bricks is not easy to realize. It has good sinterability and forms a good penetrating bond with the lining material after sintering. It has good resistance to molten steel erosion and steel slag erosion. A new type of ladle smearing repair material is used for the inner lining. This smearing repair material has the advantages of simple operation and good use effect. It can fully guarantee the safe operation and improve the overall service life. Apply the repairing material to the wall of the ladle in a cold state, locally or as a whole, with a thickness of about 20 mm, and the ladle is used for more than 20 times, and the effect is good.
Applying repairing materials plays a huge role in local repairing or in small steel factories on site, but the operation method is not in place during construction, and the use effect is greatly affected. At the same time, manual application is labor-intensive. The method of spraying and repairing lining [8] can solve the above problems very well. This method uses equipment to spray directly on the working layer. It has the advantages of good construction quality, fast solidification, less dust, low rebound rate, high degree of mechanical automation, and easy construction. Significant advantages such as short construction period. Among the three spraying construction methods of dry method, semi-dry method and wet method, wet spraying construction is widely used because of its advantages of eliminating dust, improving construction efficiency and reducing rebound loss during construction, convenience, speed, labor saving and high efficiency. application. In the construction of wet spraying paint, since the sprayed material is fully stirred after adding water, compared with dry spraying and semi-dry spraying construction methods, the working environment conditions during wet spraying construction are good, and there is no hazard of dust. Moreover, the adhesion performance of the material is also very superior, and the loss of spray rebound is small, which realizes frameless construction. The cladding wall is sprayed with a thickness of 50 mm, and it is operated more than 60 times to achieve the purpose of gunning and lining. The problem that needs to be solved in use is that after each spraying operation is completed, the equipment and pipelines must be cleaned, and how to deal with the sewage from cleaning equipment and pipelines.
3 Lower slag line maintenance
The slag line is one of the weak links. If the control of the tapping point of the converter is not in place, it is easy to impact the slag line on the slag pouring surface, and the molten steel will flow back, together with the slag pouring surface and other parts of the slag line. It will also impact the slag line, resulting in damage to the slag line Faster than other parts; at the same time, the steel pouring is completed, and the slag liquid level drops to the lower slag line. During the hot repair process of ladle turnover, the slag liquid level stays at the lower slag line for a certain period of time, which has a certain erosion and penetration effect on the lower slag line. It also causes the lower slag line to erode faster than other parts. At present, methods such as lengthening the brick type and improving the material to strengthen the slag line can only alleviate the erosion of the slag line. Combined with the site conditions, a special tire membrane for the slag line was produced [9]. The tire membrane is composed of two semicircles. Semi-circular shape, two semi-circular membranes are combined into a casting membrane when used, the membrane can be moved to change the diameter, suitable for different diameters of the slag line. Place the tire membrane at the inner slag line, and leave a gap of 50-80 mm wide between the brick and the brick of the lower slag line. It can also be adjusted according to the use requirements. The castable is formed in the gap, and the mold is removed after the castable is solidified. , In this way, the castable and the slag line brick are combined into one, and this method is used to enhance the erosion resistance of the slag line, improve the weak link, increase the package life, and reduce the ton consumption of refractory materials.
4 Conclusion
(1) According to the on-site use of the carbon-free lining, the comprehensive masonry method of lengthening the cladding reinforcement layer, the lower slag line and the cladding impact area is adopted to promote the synchronous erosion of the lining.
(2) By adding different carbon sources into the carbon-free ladle corundum bricks to conduct water-cooled thermal shock tests and combining with field use, it is concluded that carbon-containing bricks and carbon-free bricks contact the corundum brick layer, and carbon elements diffuse into the carbon-free bricks. Promote the spalling of carbon-free corundum bricks, and use special fireclay to wet the contact layer during construction to slow down the diffusion of carbon and increase the service life of the reinforcement layer.
(3) Partial repair of carbon-free ladle bricks or the overall use of smear material for lining. The smear repair material is applied to the wall of the wall in a cold state, and the thickness of the smear is about 20 mm. The turnover is used more than 20 times, and the use effect is good.
(4) The environmental conditions of the wet spraying construction are good, there is no dust hazard, and the adhesion performance of the material is also very good, the loss of the spray rebound is small, and the frameless construction is realized. The cladding wall is sprayed with a thickness of 50 mm, and it is operated more than 60 times to achieve the purpose of gunning and lining.
(5) The slag line uses a proprietary tire film, and casts a corundum castable with a thickness of 50-80 mm. The castable and the slag line brick are integrated to enhance the erosion resistance of the slag line and improve the weak link.