A method for maintaining a blow-through part of a converter vessel

Abstract

The present application provides a kind of converter body leakage burning-through site maintenance method, according to the different of converter body leakage burning-through site, corresponding molten steel and slag emptying stop operation is used, effectively avoid converter body leakage burning-through site damage aggravation.Laser thickness gauge is used to measure the residual thickness of converter body leakage burning-through site lining brick, to determine the amount of maintenance magnesium carbon brick and specific maintenance location.According to the converter body leakage burning-through site, corresponding maintenance means is taken, namely, internal " patching magnesium carbon brick + magnesium calcium shotcrete material wet method shotcrete " mode, external " spray into chrome corundum slurry + furnace shell welding repair " mode, internal and external combination is used to maintain the converter body leakage burning-through site, which can effectively improve the maintenance quality of the place.Compared with the traditional maintenance method, the probability of converter body leakage burning-through site leakage burning-through again is reduced to zero.The method is convenient to operate, time-saving and labor-saving, and has popularization and application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of converter steelmaking furnace condition maintenance technology, and in particular relates to a method for maintaining a steel leakage burn-through portion of a converter furnace body. Background Art

[0002] The converter body is generally composed of a steel structure shell and a lining of refractory materials. The converter shell is welded from ordinary boiler steel plates or low-alloy steel plates. It can be divided into three parts: the furnace cap, the furnace body and the furnace bottom according to different parts. Its function is to bear the entire weight of the refractory materials, molten steel and slag liquid, maintain the furnace in a fixed shape, and withstand torsional torque when tilting; the converter lining refractory materials mainly consist of an insulating layer, a permanent layer and a working layer.

[0003] During the actual smelting process, the extremely complex and intense physical and chemical reactions and mechanical movements within the converter make the converter lining susceptible to erosion and damage during use. In particular, the combined effects of high-temperature overoxidation can further erode the lining. In severe cases, this can even lead to converter body breakouts and burnouts, posing a significant threat to converter safety. Therefore, the service life of the converter lining is crucial for improving production efficiency, increasing furnace life, enhancing molten steel quality, improving product mix, reducing refractory consumption, and increasing economic benefits. Due to the installation method of the furnace body and support rings, as well as their heavy weight, disassembly is extremely difficult. Therefore, in the event of a converter body breakout and burnout, minimizing converter downtime and resuming production is crucial.

[0004] The patent with publication number CN 110653450 A published on January 7, 2020, discloses an online repair method for perforation of a converter body. The repair steps are: first, a working platform needs to be built on one side of the perforation of the furnace body; then, magnesia carbon bricks for furnace building are inserted into the perforation position of the converter shell, and the perforation position of the converter shell is filled with magnesia carbon bricks. The edge gaps of the magnesia carbon bricks are filled, compacted and fixed with mixed fire mud; then, repair welding is carried out; finally, after the welding process is completed, the furnace is shaken to a position suitable for repairing the furnace, and the erosion pits of the furnace lining at the perforation position of the furnace shell are treated again, and the furnace lining pits are filled by sticking magnesia carbon bricks and laying hand-throwing furnace charges. This method has played a certain positive effect in repairing perforations in the converter body, but this method requires the construction of a working platform. The operator on the working platform must first fill the perforation position with magnesia carbon bricks and fill the edge gaps of the magnesia carbon bricks with fire mud, but it cannot ensure that the gaps between the magnesia carbon bricks are full, affecting the repair effect; in addition, when this method is used to treat the lining erosion pits at the perforation position of the furnace shell, due to the influence of the perforation position of the converter body, the method of pasting magnesia carbon bricks and laying hand-throwing furnace charges cannot ensure that the hand-throwing can accurately cover the perforation position, and as the furnace temperature drops, the sintering quality of the refractory material also decreases, which also affects the repair effect to a certain extent. Summary of the Invention

[0005] The present invention aims to provide a method for maintaining burnout areas in a converter body. This method effectively maintains these burnout areas, prolongs the service life of the converter lining, and reduces the labor intensity of operators. The method addresses the technical issues of difficulty, time consumption, and poor maintenance results associated with burnout areas in converter bodies.

[0006] The specific technical solutions of the present invention are as follows:

[0007] A method for maintaining a burnout portion of a converter body comprising the following steps:

[0008] 1) When a steel leak or burn-through accident occurs in the converter body, empty the molten steel and slag in the converter and shut down the furnace;

[0009] 2) Measure the residual thickness and damaged location of the lining bricks at the burnout site of the converter body to determine the amount of maintenance materials and the specific maintenance location;

[0010] 3) First, perform maintenance and sintering on the damaged lining of the converter body where steel leaks and burns through;

[0011] 4) Mix the chrome corundum castable with water to make chrome corundum slurry, and spray the chrome corundum slurry into the burnout area of ​​the converter body from the external furnace shell to fill and compact the gap between the furnace shell steel plate and the furnace lining, and then sinter;

[0012] 5) Finally, the furnace shell of the converter body where steel leaks and burns through is repaired by welding.

[0013] In step 1), when the converter body steel leakage and burn-through accident occurs, according to the different locations of the converter body steel leakage and burn-through, select the corresponding treatment method to promptly empty the molten steel and slag in the converter to prevent the accident from expanding and create conditions for the next step of the furnace body steel leakage and burn-through maintenance, as follows:

[0014] 1-1) When the accident of steel leakage and burning through of the furnace body on the slag pouring side of the converter occurs, the converter is tilted toward the steel tapping side, and the molten steel and slag in the furnace are poured into the ladle from the furnace mouth and emptied, so as to prevent the steel structure of the furnace shell from being burned through at the slag pouring side of the converter from being further burned.

[0015] 1-2) When the accident of steel leakage and burning through of the furnace body on the steel-tapping side of the converter occurs, the converter is tilted toward the slag-discharging side, and the molten steel and slag in the furnace are poured into the ladle from the furnace mouth and emptied, so as to prevent the steel structure of the furnace shell on the steel-tapping side from being further burned.

[0016] 1-3) When the accident of steel leakage and burning through of the furnace body in the converter ear shaft area occurs, the converter is tilted to the slag discharge side or the steel tapping side, and the molten steel and slag in the furnace are poured into the ladle from the furnace mouth and emptied to prevent the steel structure of the furnace shell from being burned through in the converter ear shaft area.

[0017] 1-4) When a steel leakage and burn-through accident occurs in the cap area on the slag-dumping side of the converter, the converter is tilted toward the steel-discharging side, and the molten steel and slag in the furnace are poured into the ladle from the furnace mouth and then emptied to prevent the steel structure of the furnace shell from being burned through in the cap area on the slag-dumping side of the converter.

[0018] 1-5) When a steel leakage and burn-through accident occurs in the cap area on the steel-tapping side of the converter, the converter is tilted toward the slag-dumping side, and the molten steel and slag in the furnace are poured into the ladle from the furnace mouth and emptied, so as to prevent the steel structure of the furnace shell from being burned through in the cap area on the steel-tapping side of the converter.

[0019] 1-6) When a steel leakage and burn-through accident occurs in the converter bottom area, the converter is tilted toward the slag discharge side or the steel tapping side, and the molten steel and slag in the furnace are poured into the ladle from the furnace mouth and emptied to prevent the steel structure of the furnace shell from being burned through in the converter bottom area.

[0020] In step 2), after the molten steel and slag in the converter are emptied, a laser thickness gauge is used to measure the residual thickness and damaged position of the lining bricks at the steel leakage and burn-through parts of the converter body to determine the amount of magnesia carbon bricks used for maintenance and the specific maintenance location.

[0021] Preferably, when using magnesia carbon bricks, the reference amount of magnesia carbon bricks is appropriate to fill the depressions in the damaged lining in the furnace, and is determined by the empirical formula:

[0022]

[0023] In formula (1), m is the amount of magnesia carbon bricks, the calculated result needs to be rounded and is a multiple of the weight of a single magnesia carbon brick, kg; M is the standard value of the thickness of the new furnace lining, which is 650 mm, mm; N is the residual thickness of the furnace lining bricks at the furnace body leaking and burning-through part, mm; 50 is the thickness of the magnesia carbon bricks, mm; 20 is the weight of a single magnesia carbon brick, kg.

[0024] Furthermore, in step 2), the maintenance materials include magnesia carbon bricks, converter sand, magnesia calcium gunning material and chrome corundum castable;

[0025] The magnesia carbon brick is a 200mm×100mm×50mm rectangular block, with a single block weight of 20kg, w(MgO)≥72.00%, w(C 固 )≥18.00%;

[0026] The converter sand is in granular shape, with a particle size of ≤20 mm, w(MgO)≥78.00%, w(C 固 )≥2.50%;

[0027] The magnesium-calcium gunning material is in the form of particles, with a particle size of ≤3.00 mm, w(MgO) ≥80.00%, w(CaO) ≥7.00%, w(SiO2) ≤5.00%, and w(H2O) ≤0.50%;

[0028] The chrome corundum castable is in the form of fine-grained powder with a particle size of ≤0.20 mm, w(Al2O3)≥85.00%, w(Cr2O3)≥5.00%, and w(Fe2O3≤1.50%.

[0029] The technical indicators of magnesia carbon bricks are: volume density ≥ 2.90g / cm 3 , compressive strength ≥ 35.00MPa, apparent porosity ≤ 3.00%, high temperature flexural strength ≥ 10.00MPa in reducing atmosphere 1400℃×0.5h;

[0030] The technical indicators of magnesium-calcium gunning materials are: refractoriness ≥1760℃; under the condition of 110℃×24h: bulk density ≥2.20g / cm 3 , compressive strength ≥7.00MPa; under the conditions of 1500℃×3h: compressive strength ≥15.00MPa, flexural strength ≥5.00MPa, linear change rate -2.5~0%;

[0031] The technical indicators of chrome corundum castables are: refractoriness ≥1780℃; under the conditions of 110℃×24h: bulk density ≥3.00g / cm 3 , compressive strength ≥ 50.00MPa, flexural strength ≥ 10.00MPa; under the conditions of 1500℃×3h: compressive strength ≥ 80.00, flexural strength ≥ 25.00MPa, linear change rate -0.30~0%;

[0032] In step 3), the damaged lining of the converter body where steel leaks and burns through is first maintained from the inside, specifically:

[0033] When leakage and burn-through occur in the converter body on the slag-dumping side, the furnace body on the steel-tapping side, the furnace body in the converter trunnion area, the furnace cap area on the slag-dumping side, and the furnace cap area on the steel-tapping side, first use magnesia-carbon bricks to maintain the damaged lining in the furnace, then use magnesia-calcium gunning material mixed with water to gunpowder and fill the gaps between the patched magnesia-carbon bricks, and then sinter. The sintering temperature is ≥1620℃, and the sintering time is 20-25min. The weight ratio of the magnesia-calcium gunning material to water is 1:1.0-1:1.3.

[0034] In step 3), the gunning pressure is controlled at 0.3-0.5 MPa;

[0035] When steel leakage and burn-through occur in the bottom area of ​​the converter, use converter sand to add it into the furnace from the converter mouth, and then shake the converter to an angle of 30°~40° towards the back and front of the furnace based on the zero position (vertical state), and shake the furnace repeatedly 2~3 times to ensure that the converter sand is completely spread and covers the damaged lining of the converter bottom where steel leakage and burn-through occur, and then sintering is carried out. The sintering temperature should be ≥1620℃, and the sintering time should be controlled within 50~60min.

[0036] In step 4), the mass ratio of chrome corundum castable to water is 1:0.30 to 1:0.35;

[0037] In step 4), the sintering temperature is 280-400° C. and the sintering time is 30-40 min;

[0038] In step 4), the pressure of the chrome corundum slurry injection is controlled at 0.2-0.4 MPa.

[0039] In step 5), the furnace shell of the converter where the steel leaks and burns through is repaired by welding using a steel plate made of the same material as the furnace shell.

[0040] Compared with existing technologies, this invention utilizes appropriate shutdown procedures to empty the furnace and slag according to the location of the breakout, effectively preventing further damage to the burnout area. A laser thickness gauge is used to measure the residual thickness of the lining bricks at the breakout site to determine the required amount of magnesia-carbon bricks for maintenance and the specific location for maintenance. This provides a scientific basis for precise maintenance at that location, avoiding waste of refractory materials and reducing maintenance costs. Targeted maintenance measures are implemented based on the location of the breakout in the converter. Specifically, internal maintenance measures employ a "magnesia-carbon brick patching and magnesia-calcium gunning material" method, while external measures employ "chrome corundum slurry spraying and furnace shell welding." This combined internal and external maintenance approach effectively improves the quality of maintenance at the breakout site. Furthermore, the fluidity of the chrome corundum slurry spraying facilitates filling and compacting the gap between the furnace shell and the lining bricks. Compared with traditional maintenance methods, the probability of a recurring breakout in the breakout area is reduced to zero. The method of the present invention is easy to operate, saves time and labor, and has good promotion and application prospects in the maintenance of steel leakage and burn-through parts of converter furnace bodies in similar steel enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a schematic diagram of the operating process for maintaining the steel leakage and burn-through parts of the converter furnace body. DETAILED DESCRIPTION

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0043] The present invention provides a method for maintaining a burn-through portion of a converter body, comprising the following steps:

[0044] 1) Turn over and stop the furnace:

[0045] When a converter body leak and burn-through accident occurs, according to the different locations of the converter body leak and burn-through, select the appropriate treatment method to empty the molten steel and slag in the converter in time to prevent the accident from expanding and create conditions for the next step of maintenance of the furnace body leak and burn-through location. The details are as follows:

[0046] 1-1) When the accident of steel leakage and burning through of the furnace body on the slag pouring side of the converter occurs, the converter is tilted toward the steel tapping side, and the molten steel and slag in the furnace are poured into the ladle from the furnace mouth and emptied, so as to prevent the steel structure of the furnace shell from being burned through at the slag pouring side of the converter from being further burned.

[0047] 1-2) When the accident of steel leakage and burning through of the furnace body on the steel-tapping side of the converter occurs, the converter is tilted toward the slag-discharging side, and the molten steel and slag in the furnace are poured into the ladle from the furnace mouth and emptied, so as to prevent the steel structure of the furnace shell on the steel-tapping side from being further burned.

[0048] 1-3) When the accident of steel leakage and burning through of the furnace body in the converter ear shaft area occurs, the converter is tilted to the slag discharge side or the steel tapping side, and the molten steel and slag in the furnace are poured into the ladle from the furnace mouth and emptied to prevent the steel structure of the furnace shell from being burned through in the converter ear shaft area.

[0049] 1-4) When a steel leakage and burn-through accident occurs in the cap area on the slag-dumping side of the converter, the converter is tilted toward the steel-discharging side, and the molten steel and slag in the furnace are poured into the ladle from the furnace mouth and then emptied to prevent the steel structure of the furnace shell from being burned through in the cap area on the slag-dumping side of the converter.

[0050] 1-5) When a steel leakage and burn-through accident occurs in the cap area on the steel-tapping side of the converter, the converter is tilted toward the slag-dumping side, and the molten steel and slag in the furnace are poured into the ladle from the furnace mouth and emptied, so as to prevent the steel structure of the furnace shell from being burned through in the cap area on the steel-tapping side of the converter.

[0051] 1-6) When a steel leakage and burn-through accident occurs in the converter bottom area, the converter is tilted toward the slag discharge side or the steel tapping side, and the molten steel and slag in the furnace are poured into the ladle from the furnace mouth and emptied to prevent the steel structure of the furnace shell from being burned through in the converter bottom area.

[0052] 2) Maintenance refractory material preparation:

[0053] The refractory materials used for the maintenance of the burnout parts of the converter body mainly include magnesia carbon bricks, converter sand, magnesia calcium gunning materials and chrome corundum castables. Among them, the magnesia carbon bricks are 200mm×100mm×50mm rectangular blocks, with a single block weight of 20kg, w(MgO)≥72.00%, w(C 固 )≥18.00%; converter sand is in granular form, with a particle size of ≤20mm, w(MgO)≥78.00%, w(C 固) ≥ 2.50%; magnesium-calcium gunning material is in granular form with a particle size of ≤ 3.00mm, with w(MgO) ≥ 80.00%, w(CaO) ≥ 7.00%, w(SiO2) ≤ 5.00%, and w(H2O) ≤ 0.50%; chrome-corundum castable is in fine-grained powder form with a particle size of ≤ 0.20mm, with w(Al2O3) ≥ 85.00%, w(Cr2O3) ≥ 5.00%, and w(Fe2O3) ≤ 1.50%. The technical specifications of magnesium-carbon bricks, magnesium-calcium gunning material, and chrome-corundum castable are shown in Tables 1, 2, and 3, respectively.

[0054] Table 1 Technical indicators of magnesia carbon bricks

[0055]

[0056] Table 2 Technical indicators of magnesium calcium gunning material

[0057]

[0058] Table 3 Technical indicators of chrome corundum castables

[0059]

[0060] 3) Thickness measurement and positioning

[0061] After the molten steel and slag in the converter are emptied, the Lacam M3 laser thickness gauge is used to measure the residual thickness and damaged location of the lining bricks at the burnout site of the converter body to determine the amount of magnesia carbon bricks used for maintenance and the specific maintenance location. Among them, the reference amount of magnesia carbon bricks is suitable for filling the concave parts of the damaged lining in the furnace, and is determined by the empirical formula:

[0062]

[0063] In formula (1), m is the amount of magnesia carbon bricks, the calculated result needs to be rounded and is a multiple of the weight of a single magnesia carbon brick, kg; M is the standard value of the thickness of the new furnace lining (this value is 650mm), mm; N is the residual thickness of the furnace lining bricks at the furnace body leaking and burning through part, mm; 50 is the thickness of the magnesia carbon bricks, mm; 20 is the weight of a single magnesia carbon brick, kg.

[0064] 4) Maintenance operation process

[0065] According to the measurement results of the Lacam M3 laser thickness gauge, the converter body leaking steel burn-through parts are maintained in accordance with the order of "internal repair first and external repair later" and the principle of "high-temperature hot repair". That is, first, taking advantage of the high temperature conditions in the furnace that are conducive to the sintering of refractory materials, the "patching magnesia carbon bricks + magnesia-calcium gunning material wet gunning" method is adopted to maintain the damaged lining of the converter body leaking steel burn-through parts from the inside, and wait until sintering is completed; then, a concrete spraying machine is used to mix chrome corundum castables with water to form a slurry, and the chrome corundum slurry is sprayed into the converter body leaking steel burn-through parts from the external furnace shell to fill and compact the gap between the furnace shell steel plate and the furnace lining, and wait until sintering is completed; finally, the furnace shell of the converter body leaking steel burn-through parts is welded with steel plates of the same material as the furnace shell. The specific operation procedures for different leaking steel burn-through parts are as follows:

[0066] 4-1) Maintenance of the steel leakage and burn-through parts of the converter slag pouring side:

[0067] 4-1-1) The converter is tilted to -90°~-100° toward the platform in front of the furnace. The magnesia carbon bricks are delivered from the furnace mouth to the damaged lining position in the furnace using a furnace repair shovel for brick laying maintenance. The aforementioned brick laying maintenance operation is repeated until the damaged lining at the furnace body on the slag pouring side of the converter is filled and leveled.

[0068] 4-1-2) After the tile maintenance work is completed, a wet gunning process is used. The compressed air pressure of the PB-II gunning tank is controlled at 0.3-0.5MPa. The magnesium-calcium gunning material and water are mixed at a weight ratio of 1:1.0-1:1.3. After mixing through the gunning gun, the magnesium-calcium gunning material is evenly and completely covered with the magnesium-carbon bricks. The purpose is to fill the gaps between the magnesium-carbon bricks after the gunning, and improve the density and thermal shock resistance of the magnesium-carbon sintered bricks. After the gunning operation is completed, the sintering temperature is ≥1620℃, and the sintering time is controlled at 20-25min.

[0069] 4-1-3) After the magnesium-calcium gunning material is fully sintered, the converter is tilted to 140°~150° toward the rear working platform. The compressed air pressure of the Xuda brand PZ-3 refractory material spraying machine is controlled at 0.2~0.4MPa. The chrome corundum castable and water are mixed at a weight ratio of 1:0.30~1:0.35. The mixture is mixed through a spray gun to obtain chrome corundum mud. The chrome corundum mud is sprayed from the outside of the furnace shell into the steel leakage and burn-through parts of the furnace body on the slag pouring side of the converter to fill and compact the gap between the furnace shell steel plate and the furnace lining. The sintering temperature is 280~400℃ and the sintering time is controlled at 30~40min.

[0070] 4-1-4) After the chrome corundum slurry is fully sintered, the converter is tilted to 140°~150° toward the platform behind the furnace, and a maintenance work platform is built. The furnace shell on the slag pouring side of the converter where steel is leaking and burned through is repaired by welding using steel plates of the same material as the furnace shell.

[0071] 4-2) Maintenance of the steel leakage and burn-through parts of the converter body on the steel tapping side

[0072] 4-2-1) The converter is tilted to 90°~100° toward the rear platform. The magnesia carbon bricks are delivered from the furnace mouth to the damaged lining position in the furnace using a furnace repair shovel for brick laying maintenance. The aforementioned brick laying maintenance operation is repeated until the damaged lining at the furnace body on the tapping side of the converter is filled and leveled.

[0073] 4-2-2) After the tile maintenance work is completed, a wet gunning process is used. The compressed air pressure of the PB-II gunning tank is controlled at 0.3-0.5MPa. The magnesium-calcium gunning material and water are mixed at a weight ratio of 1:1.0-1:1.3 through the gunning gun. The magnesium-calcium gunning material is then evenly and completely covered with the magnesium-carbon bricks. The purpose is to fill the gaps between the magnesium-carbon bricks after the gunning, and improve the density and thermal shock resistance of the magnesium-carbon sintered bricks. After the gunning operation is completed, the sintering temperature is ≥1620℃, and the sintering time is controlled at 20-25min.

[0074] 4-2-3) After the magnesium-calcium gunning material is fully sintered, the converter is shaken to the front platform at -140°~-150°, and the compressed air pressure of the Xuda brand PZ-3 refractory material spraying machine is controlled at 0.2~0.4MPa. The chrome corundum castable and water are mixed in a weight ratio of 1:0.30~1:0.35 through a spray gun. The resulting chrome corundum slurry is sprayed from the outside of the furnace shell into the steel-tapping side of the converter furnace body where steel is leaking and burned through, filling and compacting the gap between the furnace shell steel plate and the furnace lining. The sintering temperature is 280~400℃, and the sintering time is controlled at 30~40min.

[0075] 4-2-4) After the chrome corundum slurry is fully sintered, the converter is moved to the platform in front of the furnace to -140°~-150°, and a maintenance work platform is built. The furnace shell of the converter on the steel-out side where the steel is leaking and burned through is welded using steel plates of the same material as the furnace shell.

[0076] 4-3) Maintenance of the burnout area of ​​the converter body in the trunnion area

[0077] 4-3-1) Swing the converter to 90°~100° toward the rear platform or -90°~-100° toward the front platform, and use a furnace repair shovel to deliver magnesia carbon bricks from the furnace mouth to the damaged lining position in the furnace for brick laying maintenance. Repeat the above-mentioned brick laying maintenance operation until the damaged lining at the converter ear shaft area where the furnace body has leaked steel and burned through is filled.

[0078] 4-3-2) After the tile maintenance work is completed, a wet gunning process is used. The compressed air pressure of the PB-II gunning tank is controlled at 0.3-0.5MPa. The magnesium-calcium gunning material and water are mixed at a weight ratio of 1:1.0-1:1.3 through the gunning gun. After mixing, the magnesium-calcium gunning material is evenly and completely covered with the magnesium-carbon bricks. The purpose is to fill the gaps between the magnesium-carbon bricks after the gunning, and improve the density and thermal shock resistance of the magnesium-carbon sintered bricks. After the gunning operation is completed, the sintering temperature is ≥1620℃, and the sintering time is controlled at 20-25 minutes.

[0079] 4-3-3) After the magnesium-calcium gunning material is fully sintered, the converter is shaken to 90°~100° toward the rear of the furnace or to -90°~-100° toward the platform in front of the furnace. The compressed air pressure of the Xuda brand PZ-3 refractory material spraying machine is controlled at 0.2~0.4MPa. The chrome corundum castable and water are mixed in a weight ratio of 1:0.30~1:0.35 through a spray gun. The obtained chrome corundum slurry is sprayed from the outside of the furnace shell into the steel leakage and burnt-through parts of the furnace body in the trunnion area of ​​the converter to fill and compact the gap between the furnace shell steel plate and the furnace lining. The sintering temperature is 280~400℃ and the sintering time is controlled at 30~40min.

[0080] 4-3-4) After the chrome corundum slurry is fully sintered, the converter is tilted to 90°~100° on the rear platform or -90°~-100° on the front platform. A maintenance work platform is built and the furnace shell is welded to the burnt-through parts of the converter body in the trunnion area using steel plates of the same material as the furnace shell.

[0081] 4-4) Maintenance of steel leakage and burn-through parts in the converter cap area:

[0082] 4-4-1) If the steel is leaking and burning through in the furnace cap area on the slag pouring side, swing the converter toward the furnace front platform to -90°~-100°; if the steel is leaking and burning through in the furnace cap area on the steel tapping side, swing the converter toward the furnace rear platform to 90°~100°, use a furnace repair shovel to send magnesia carbon bricks from the furnace mouth to the damaged lining position in the furnace for brick laying maintenance, and repeat the above-mentioned brick laying maintenance operation until the damaged lining in the converter cap area is filled and leveled.

[0083] 4-4-2) After the tile maintenance work is completed, a wet gunning process is used. The compressed air pressure of the PB-II gunning tank is controlled at 0.3-0.5MPa. The magnesium-calcium gunning material and water are mixed at a weight ratio of 1:1.0-1:1.3 through a dedicated gunning gun. The magnesium-calcium gunning material is then evenly and completely covered with the magnesium-carbon bricks. The purpose is to fill the gaps between the magnesium-carbon bricks after the gunning, and improve the density and thermal shock resistance of the magnesium-carbon sintered bricks. After the gunning operation is completed, the sintering temperature is ≥1620℃, and the sintering time is controlled at 20-25 minutes.

[0084] 4-4-3) After the magnesium-calcium gunning material is fully sintered, if the steel is leaking and burning through in the furnace cap area on the slag pouring side, shake the converter to 90°~100° on the rear platform; if the steel is leaking and burning through in the furnace cap area on the steel tapping side, shake the converter to -90°~-100° on the front platform, control the compressed air pressure of the Xuda brand PZ-3 refractory material spraying machine to 0.2~0.4MPa, mix the chrome corundum castable and water in a weight ratio of 1:0.30~1:0.35 through a special spraying gun, and spray the chrome corundum slurry from the outside of the furnace shell into the steel leaking and burning through part of the furnace body in the furnace cap area to fill and compact the gap between the furnace shell steel plate and the furnace lining. The sintering temperature is 280~400℃, and the sintering time is controlled at 30~40min.

[0085] 4-4-4) After the chrome corundum slurry is fully sintered, if the steel is leaking and burning through in the furnace cap area on the slag pouring side, swing the converter toward the rear platform to 140°~150°; if the steel is leaking and burning through in the furnace cap area on the steel tapping side, swing the converter toward the front platform to -140°~-150°, build a maintenance work platform, and use steel plates of the same material as the furnace shell to weld and repair the furnace shell at the leaking and burning through part of the converter cap area.

[0086] 4-5) Maintenance of steel leakage and burn-through parts in the bottom area of ​​the converter

[0087] 4-5-1) Shake the converter to -50°~-60° toward the platform in front of the furnace, and use a scrap steel bucket to add converter sand from the converter mouth into the furnace. The reference amount of converter sand is 1000~1200kg. Then, with the converter at zero position (vertical state) as the reference, shake it to -30° toward the front of the furnace and to 30° toward the back of the furnace. Shake the furnace repeatedly 2~3 times to ensure that the converter sand is completely spread and covers the damaged lining at the leaking and burnt-through parts of the converter bottom. The sintering temperature is ≥1620℃ and the sintering time is controlled at 50~60min.

[0088] 4-5-2) After the converter sand is fully sintered, the converter is tilted towards the rear platform to 90°~100° or the front platform to -90°~-100°. The compressed air pressure of the Xuda PZ-3 refractory material spraying machine is controlled at 0.2~0.4MPa. The chrome corundum castable and water are mixed at a weight ratio of 1:0.30~1:0.35 through a spray gun. The chrome corundum slurry is then sprayed from the outside of the furnace shell into the steel leakage and burn-through areas in the bottom area of ​​the converter to fill and compact the gaps between the furnace shell steel plate and the furnace lining. The sintering temperature is 280~400℃ and the sintering time is controlled at 30~40min.

[0089] 4-5-3) After the chrome corundum slurry is fully sintered, the converter is tilted to 90°~100° on the rear platform or -90°~-100° on the front platform, and a maintenance work platform is built. The converter shell with the same material as the furnace shell is welded to the leaked and burned-through parts of the converter bottom area.

[0090] 5) Converter resumes production:

[0091] After the furnace shell welding repair of the steel leakage and burnt-through parts of the converter body was completed, the converter resumed normal production.

[0092] 6) Confirm the maintenance effect:

[0093] After the converter smelts one batch of steel normally and operates normally with slag splashing and furnace protection, the slag in the furnace is emptied and the thickness of the lining bricks at the steel leakage part of the converter body is measured again using a LacamM3 laser thickness gauge to evaluate the maintenance effect and provide a reference for subsequent maintenance of the lining at the steel leakage and burn-through part of the converter body.

[0094] Several specific embodiments of the present invention are as follows:

[0095] Example 1

[0096] A method for maintaining a steel leaking burn-through portion of a converter body is provided, which is for maintaining a steel leaking burn-through portion of the converter body on the slag pouring side, comprising the following steps:

[0097] 1) When the accident of steel leakage and burning through the furnace body on the slag pouring side of the converter occurs, the converter tilts to the steel tapping side and cooperates with the ladle car under the furnace to turn the molten steel and slag in the furnace into the ladle from the furnace mouth. The converter is shaken at an angle of 180° to empty the molten steel and slag in the furnace.

[0098] 2) After the molten steel and slag in the converter were emptied, a Lacam M3 laser thickness gauge was used to measure the residual thickness of the furnace lining bricks at the steel leakage part of the converter body on the slag pouring side and the steel leakage burn-through position. The measured residual thickness of the steel leakage part of the converter body was 20mm, located in the middle of the molten pool on the slag pouring side of the converter. The amount of magnesia carbon bricks used for maintenance was determined to be 260kg.

[0099] 3) The leaking and burning parts of the furnace body on the slag pouring side of the converter are maintained in accordance with the order of "internal repair first and external repair later" and the principle of "high-temperature hot repair". The internal part adopts the method of "patching magnesia-carbon bricks + magnesia-calcium gunning material wet gunning repair", and the external part adopts the method of "spraying chrome corundum slurry + furnace shell welding repair". The two methods are combined to maintain the leaking and burning parts of the furnace body on the slag pouring side of the converter. The specific steps include:

[0100] 3-1) Swing the converter to -90° toward the front platform, and use a furnace repair shovel to deliver magnesia carbon bricks from the furnace mouth to the damaged lining position in the middle of the molten pool on the slag pouring surface of the furnace for brick maintenance. Repeat the above-mentioned brick maintenance operation until the damaged lining at the leaky and burned-through part is filled.

[0101] 3-2) After the tile maintenance work is completed, the wet gunning process is adopted. The compressed air pressure of the PB-II type gunning tank is controlled at 0.3MPa. The magnesium calcium gunning material and water are mixed in a weight ratio of 1:1.2 through the gunning gun. The magnesium calcium gunning material is evenly and completely covered with the magnesium carbon bricks, filling the gaps between the magnesium carbon bricks after the patching. The sintering temperature is 1630℃ and the sintering time is 20min.

[0102] 3-3) After the magnesium-calcium gunning material is fully sintered, the converter is tilted to 150° toward the rear platform. The compressed air pressure of the Xuda PZ-3 refractory concrete spraying machine is controlled at 0.3 MPa. The chrome corundum castable and water are mixed at a weight ratio of 1:0.30 through a concrete spraying gun. The chrome corundum slurry is then sprayed from the outside of the furnace shell into the center of the molten pool on the slag pouring side of the converter, where the steel is leaking and the burn-through part of the furnace body is located. The gap between the furnace shell steel plate and the furnace lining is filled and compacted. The sintering temperature is 300°C and the sintering time is controlled at 30 minutes.

[0103] 3-4) After the chrome corundum slurry is fully sintered, the converter is tilted to 150 degrees toward the rear platform, and a maintenance work platform is built. The furnace shell is welded to the center of the molten pool on the slag pouring side of the converter where the steel is leaking and burning through.

[0104] 4) After the furnace shell welding repair of the steel leakage and burn-through part of the furnace body in the middle of the molten pool on the slag pouring side of the converter was completed, the converter resumed normal production.

[0105] 5) After the converter smelted one batch of steel normally, no red-hot furnace shell or steel leaks were observed at this location during the smelting process. After the converter operated normally with slag splashing and protection, the slag in the furnace was emptied and remeasured using a Lacam M3 laser thickness gauge. The measured thickness of the furnace lining brick at the location of steel leaking through the center of the molten pool on the slag pouring side of the converter was 600 mm, indicating a satisfactory maintenance effect. The maintenance work was completed.

[0106] Example 2

[0107] A method for maintaining a burnout portion of a converter body having steel leakage, specifically comprising the following steps:

[0108] 1) When the converter body leaks and burns through on the steel-tapping side, the converter tilts toward the slag-dumping side and cooperates with the ladle car under the furnace to turn the molten steel and slag in the furnace into the ladle from the furnace mouth. The converter is shaken at a reference angle of -180° to empty the molten steel and slag in the furnace.

[0109] 2) After the molten steel and slag in the converter were emptied, a Lacam M3 laser thickness gauge was used to measure the residual thickness of the lining bricks at the leaking part of the converter body and the location of the leaking burn-through. The measured residual thickness of the lining bricks at the leaking part of the converter body was 50 mm, located in the lower right corner of the converter tapping side. The amount of magnesia carbon bricks used for maintenance was determined to be 240 kg.

[0110] 3) Maintain the steel leakage and burn-through parts of the converter body on the steel tapping side in accordance with the order of "internal repair first and external repair later" and the principle of "high-temperature hot repair". The internal part adopts the method of "patching magnesia carbon bricks + magnesia calcium gunning material wet gunning", and the external part adopts the method of "spraying chrome corundum slurry + furnace shell welding repair". The two methods are combined to maintain the steel leakage and burn-through parts of the converter body. The specific process is as follows:

[0111] 3-1) The converter is tilted to 100° toward the rear platform. A magnesia carbon brick is delivered from the furnace mouth to the damaged lining at the lower right corner of the steel-outlet side of the furnace using a furnace repair shovel for brick laying maintenance. Repeat the aforementioned brick laying maintenance operation until the damaged lining at the lower right corner of the furnace body on the steel-outlet side of the converter is filled.

[0112] 3-2) After the tile maintenance work is completed, the wet gunning process is adopted. The compressed air pressure of the PB-II type gunning tank is controlled at 0.4MPa. The magnesium calcium gunning material and water are mixed in a weight ratio of 1:1.2 through the gunning gun. The magnesium calcium gunning material is evenly and completely covered with the magnesium carbon bricks, filling the gaps between the magnesium carbon bricks after the patching. The sintering temperature is 1620℃ and the sintering time is 20min.

[0113] 3-3) After the magnesium-calcium gunning material is fully sintered, the converter is tilted toward the front platform to -150°. The compressed air pressure of the Xuda PZ-3 refractory concrete spraying machine is controlled at 0.3MPa. The chrome corundum castable and water are mixed at a weight ratio of 1:0.32 through a concrete spraying gun. The chrome corundum slurry is then sprayed from the outside of the furnace shell into the steel leakage and burn-through area of ​​the furnace body at the lower right corner on the steel tapping side of the converter to fill and compact the gap between the furnace shell steel plate and the furnace lining. The sintering temperature is 320℃ and the sintering time is controlled at 30min.

[0114] 3-4) After the chrome corundum slurry is fully sintered, the converter is tilted to -150° toward the platform in front of the furnace, and a maintenance work platform is built. The furnace shell at the lower right corner of the converter on the steel-outlet side where the steel is leaking and burned through is repaired by welding using steel plates of the same material as the furnace shell.

[0115] 4) After the furnace shell welding repair of the steel leakage and burnt-through part of the furnace body in the lower right corner of the steel-outgoing side of the converter was completed, the converter resumed normal production.

[0116] 5) After the converter smelted one batch of steel normally, no red-hot furnace shell or steel leaks were observed at this location during the smelting process. After the converter operated normally with slag splashing and protection, the slag inside the furnace was emptied and remeasured using a Lacam M3 laser thickness gauge. The measured thickness of the furnace lining brick at the location of steel leaking and burn-through in the lower right corner of the converter's tapping side after maintenance was 620 mm, indicating a satisfactory maintenance effect. The maintenance work was completed.

[0117] Example 3

[0118] A method for maintaining the steel leakage and burn-through part of the converter body, which is aimed at maintaining the steel leakage and burn-through part of the converter body in the right trunnion area. The specific method is as follows:

[0119] 1) When the steel leakage and burn-through accident occurs in the right ear shaft area of ​​the converter, the converter is tilted to the slag discharge side, and cooperates with the ladle car under the furnace to turn the molten steel and slag in the furnace into the ladle from the furnace mouth. The converter is shaken at a reference angle of -180° to empty the molten steel and slag in the furnace.

[0120] 2) After the molten steel and slag in the converter were emptied, a Lacam M3 laser thickness gauge was used to measure the residual thickness and location of the lining bricks at the converter trunnion area where the steel leaked through. The measured residual thickness of the lining bricks at the converter trunnion area was 40 mm, located at the slag line on the right side of the converter trunnion. The amount of magnesia carbon bricks used for maintenance was determined to be 260 kg.

[0121] 3) The burnout area of ​​the converter body at the slag line on the right side of the trunnion was maintained in the order of "internal repair first and external repair later" and the principle of "high-temperature hot repair". The internal part was repaired by "wet gunning with magnesia-carbon bricks + magnesia-calcium gunning materials" and the external part was repaired by "spraying chrome corundum slurry + furnace shell welding". The two methods were combined to repair the burnout area of ​​the converter body. The specific process is as follows:

[0122] 3-1) The converter is tilted to -90° toward the platform in front of the furnace, and the magnesia carbon bricks are delivered from the furnace mouth to the damaged lining position in the furnace using a furnace repair shovel for brick laying maintenance. The aforementioned brick laying maintenance operation is repeated until the damaged lining at the slag line of the right ear shaft of the converter is filled and leveled.

[0123] 3-2) After the tile maintenance work is completed, a wet gunning process is used. The compressed air pressure of the PB-II gunning tank is controlled at 0.4MPa. The magnesium-calcium gunning compound and water are mixed at a weight ratio of 1:1.2 through the gunning gun. The magnesium-calcium gunning compound is then evenly and completely covered with the magnesium-carbon bricks. The purpose is to fill the gaps between the magnesium-carbon bricks after the gunning, and improve the density and thermal shock resistance of the magnesium-carbon sintered bricks. After the gunning operation is completed, the temperature is 1640℃ and the sintering time is controlled at 25 minutes.

[0124] 3-3) After the magnesium-calcium gunning material is fully sintered, the converter is tilted to 90 degrees toward the rear platform. The compressed air pressure of the Xuda PZ-3 refractory material spraying machine is controlled at 0.4 MPa. The chrome corundum castable and water are mixed at a weight ratio of 1:0.33 through a spray gun. The chrome corundum slurry is then sprayed from the outside of the furnace shell into the steel leakage and burn-through area of ​​the slag line on the right side of the converter to fill and compact the gap between the furnace shell steel plate and the furnace lining. The sintering temperature is 380°C and the sintering time is controlled at 30 minutes.

[0125] 3-4) After the chrome corundum slurry is fully sintered, the converter is rotated to 90 degrees toward the platform behind the furnace, and a maintenance work platform is built. The furnace shell of the right ear shaft area of ​​the converter where steel leakage and burn-through are located is welded using steel plates of the same material as the furnace shell.

[0126] 4) After the furnace shell welding repair of the steel leakage and burn-through area in the right ear shaft area of ​​the converter was completed, the converter resumed normal production.

[0127] 5) After the converter smelted one batch of steel normally, no red-hot furnace shell or steel leaks were observed in this area during the smelting process. After the converter operated normally with slag splashing and protection, the slag inside the furnace was emptied and remeasured using a Lacam M3 laser thickness gauge. The measured thickness of the furnace lining bricks at the location of steel leaking and burn-through in the right trunnion area of ​​the converter after maintenance was 640 mm, indicating a satisfactory maintenance effect. The maintenance work was completed.

[0128] Example 4

[0129] A method for maintaining a burnout site of a converter body, specifically comprising the following steps:

[0130] 1) When the accident of steel leakage and burning through of the furnace body occurs in the furnace cap area on the slag pouring side of the converter, the converter is tilted to the steel tapping side, and cooperates with the ladle car under the furnace to turn the molten steel and slag in the furnace into the ladle from the furnace mouth. The converter is shaken at a reference angle of 180° to empty the molten steel and slag in the furnace.

[0131] 2) After the molten steel and slag in the converter were emptied, a Lacam M3 laser thickness gauge was used to measure the residual thickness and location of the lining bricks at the furnace body where the steel leaked and burned through. The measured residual thickness of the lining bricks at the furnace body where the steel leaked and burned through was 20 mm, located in the center of the converter cap on the slag dumping side. The amount of magnesia carbon bricks used for maintenance was determined to be 260 kg.

[0132] 3) According to the order of "internal repair first and external repair later" and the principle of "high temperature hot repair", the steel leakage and burn-through part of the furnace body in the middle of the furnace cap on the slag pouring side of the converter is maintained. The internal part adopts the method of "patching magnesia carbon bricks + magnesia calcium gunning material wet gunning", and the external part adopts the method of "spraying chrome corundum slurry + furnace shell welding repair". The two methods are combined to maintain the steel leakage and burn-through part of the converter body. The specific process is as follows:

[0133] 3-1) The converter is tilted to -90° toward the platform in front of the furnace, and the magnesia carbon bricks are delivered from the furnace mouth to the damaged lining position in the furnace using a furnace repair shovel for brick laying maintenance. The aforementioned brick laying maintenance operation is repeated until the damaged lining at the center of the furnace cap on the slag pouring side of the converter is filled.

[0134] 3-2) After the tile maintenance work is completed, a wet gunning process is used. The compressed air pressure of the PB-II gunning tank is controlled at 0.4MPa. The magnesium-calcium gunning compound and water are mixed at a weight ratio of 1:1.3 through the gunning gun. The magnesium-calcium gunning compound is then evenly and completely covered with the magnesium-carbon bricks. The purpose is to fill the gaps between the magnesium-carbon bricks after the gunning, and improve the density and thermal shock resistance of the magnesium-carbon sintered bricks. After the gunning operation is completed, the temperature is 1640℃ and the sintering time is controlled at 20 minutes.

[0135] 3-3) After the magnesium-calcium gunning material is fully sintered, the converter is tilted to 100° toward the rear platform. The compressed air pressure of the Xuda PZ-3 refractory material spraying machine is controlled at 0.4 MPa. The chrome corundum castable and water are mixed at a weight ratio of 1:0.32 through a spray gun. The chrome corundum slurry is then sprayed from the outside of the furnace shell into the center of the furnace cap area on the slag discharge side of the converter, where the steel leaks and burns through. The gap between the furnace shell steel plate and the furnace lining is filled and compacted. The temperature is 400°C and the sintering time is controlled at 30 minutes.

[0136] 3-4) After the chrome corundum slurry is fully sintered, the converter is tilted to 150 degrees toward the rear platform, and a maintenance work platform is built. The furnace shell is welded to the center of the furnace cap area on the slag pouring side of the converter, where the steel is leaking and burned through. Steel plates of the same material as the furnace shell are used.

[0137] 4) After the furnace shell welding repair of the steel leakage and burn-through area in the middle of the furnace cap area on the slag pouring side of the converter was completed, the converter resumed normal production.

[0138] 5) After the converter smelted one batch of steel normally, no red-hot furnace shell or steel leaks were observed at this location during the smelting process. After the converter operated normally with slag splashing and protection, the slag inside the furnace was emptied and remeasured using a Lacam M3 laser thickness gauge. The measured thickness of the furnace lining brick at the location of steel leaking and burning through, located in the center of the cap area on the slag pouring side of the converter, was 650 mm after maintenance. This indicates a satisfactory maintenance outcome, and the work is complete.

[0139] Example 5

[0140] A method for maintaining a burnout site in a converter body, targeting at a burnout site in the converter bottom area, comprises the following steps:

[0141] 1) When the converter bottom leaks and burns through accident occurs, the converter tilts to the slag discharge side, and cooperates with the ladle car under the furnace to turn the molten steel and slag in the furnace into the ladle from the furnace mouth. The converter is shaken at a reference angle of -180° to empty the molten steel and slag in the furnace.

[0142] 2) Maintain the steel leakage and burn-through parts of the converter bottom area in accordance with the order of "internal repair first, then external repair" and the principle of "high-temperature hot repair". The internal part adopts the "converter sand hot repair" method, and the external part adopts the "chrome corundum slurry injection + furnace shell welding repair" method. The two methods are combined to maintain the steel leakage and burn-through parts of the converter bottom area. The specific process is as follows:

[0143] 2-1) Shake the converter to -60° toward the platform in front of the furnace, use a scrap steel bucket to add converter sand into the converter, the amount of converter sand is 1200kg, and then shake the converter to -30° toward the front of the furnace and 30° toward the back of the furnace based on the zero position (vertical state). Shake the furnace twice to ensure that the converter sand is completely spread and covers the damaged lining at the bottom of the converter where the steel leaks and burns through. The sintering temperature is 1638℃ and the sintering time is controlled at 60min.

[0144] 2-2) After the converter sand is fully sintered, the converter is tilted to 90° toward the rear. The compressed air pressure of the Xuda PZ-3 refractory concrete spraying machine is controlled at 0.3 MPa. The chrome corundum castable and water are mixed at a weight ratio of 1:0.33 through a concrete spraying gun. The chrome corundum slurry is then sprayed from the outside of the furnace shell into the steel leaking and burnt-through areas in the converter bottom area to fill and compact the gaps between the furnace shell steel plate and the furnace lining. The sintering temperature is 400°C and the sintering time is controlled at 40 minutes.

[0145] 2-3) After the chrome corundum slurry is fully sintered, the converter is tilted to 90 degrees to the rear of the furnace, and a maintenance work platform is built. The furnace shell of the converter bottom area where steel leakage and burn-through are located is welded and repaired using steel plates of the same material as the furnace shell.

[0146] 3) After the furnace shell welding repair of the steel leakage and burnt-through parts in the bottom area of ​​the converter was completed, the converter resumed normal production.

[0147] 4) After the converter smelted one batch of steel normally, no reddening of the furnace shell or steel leaking was observed at this location during the smelting process. After the converter operated normally with slag splashing and protection, the slag inside the furnace was emptied and remeasured using a Lacam M3 laser thickness gauge. The measured thickness of the furnace lining bricks at the location of the steel leaking and burn-through at the bottom of the converter after maintenance was 610 mm, indicating a satisfactory maintenance effect. The maintenance work was completed.

[0148] The present invention aims to solve the technical problems of difficult maintenance, long maintenance time and poor maintenance effect in the maintenance process of the steel leakage and burn-through parts of the converter body, and adopts a highly targeted maintenance operation method: (1) according to the different steel leakage and burn-through parts of the furnace body, the corresponding molten steel and slag emptying and furnace shutdown operation is adopted to avoid the aggravation of the damage of the steel leakage and burn-through parts of the furnace body; (2) the LacamM3 laser thickness gauge is used to measure the residual thickness of the furnace lining bricks and the steel leakage position of the furnace body steel leakage and burn-through parts, so as to determine the amount of magnesia carbon bricks used for maintenance and the specific maintenance position, and provide a reference for the maintenance of the steel leakage and burn-through parts of the converter body; (3) the magnesia carbon bricks used for maintenance inside the converter are made of the same material as the original converter lining bricks, which effectively avoids the influence of thermal expansion degree difference on maintenance effect; the external chrome corundum castable with high compressive strength and refractoriness is selected, and the chrome corundum slurry is sprayed into the steel leakage and burn-through parts of the furnace body by a concrete spraying machine The parts are conducive to filling and compacting the gap between the furnace shell and the furnace lining bricks. The outermost part is welded with steel plates of the same material as the original furnace shell to play a role in supporting and protecting and preventing the chromium corundum castable material from being powdered and falling off after being sprayed and sintered; (4) According to the difficulty of maintaining the steel-burning parts of the converter body, the steel-burning parts of the converter body are maintained in the order of "internal repair first and then external repair" and the principle of "high-temperature hot repair". The internal part adopts the method of "wet spraying of magnesium carbon bricks + magnesium calcium spraying materials" and "hot repair of converter sand", and the external part adopts the method of "spraying chromium corundum mud + furnace shell welding". The two are combined to maintain the steel-burning parts of the converter body. In the process, the sintering temperature and sintering time of the refractory materials after different maintenance are reasonably limited, which effectively improves the maintenance quality of the steel-burning parts of the converter body; (5) After the converter smelts one batch of steel normally, Lacam is used. The M3 laser thickness gauge was used to measure the thickness of the lining bricks at the leaking part of the converter body again to evaluate the maintenance effect and provide a reference for the subsequent maintenance of the lining at the leaking and burn-through part of the converter body.

[0149] Comparative Example 1

[0150] A method for maintaining a burnout site of a converter body, specifically comprising the following steps:

[0151] 1) When the accident of steel leakage and burning through of the furnace body occurs in the furnace cap area on the slag pouring side of the converter, the converter is tilted to the steel tapping side, and cooperates with the ladle car under the furnace to turn the molten steel and slag in the furnace into the ladle from the furnace mouth. The converter is shaken at a reference angle of 180° to empty the molten steel and slag in the furnace.

[0152] 2) After the molten steel and slag in the converter were emptied, a Lacam M3 laser thickness gauge was used to measure the residual thickness and location of the lining bricks at the furnace body leaking and burning-through locations in the converter cap area. The measured residual thickness of the lining bricks at the furnace body leaking location was 50 mm, located in the center of the converter cap on the slag dumping side. The amount of magnesia carbon bricks used for maintenance was determined to be 240 kg.

[0153] 3) The internal method of "patching magnesia carbon bricks + magnesia calcium gunning material wet gunning" was adopted, and the external method of "spraying chrome corundum slurry" was not adopted to maintain the steel leakage and burn-through parts of the converter body. The specific process is as follows:

[0154] 3-1) The converter is tilted to -90° toward the platform in front of the furnace, and the magnesia carbon bricks are delivered from the furnace mouth to the damaged lining position in the furnace using a furnace repair shovel for brick laying maintenance. The aforementioned brick laying maintenance operation is repeated until the damaged lining at the center of the furnace cap on the slag pouring side of the converter is filled.

[0155] 3-2) After the tile maintenance work is completed, a wet gunning process is used. The compressed air pressure of the PB-II gunning tank is controlled at 0.4MPa. The magnesium-calcium gunning compound and water are mixed at a weight ratio of 1:1.3 through the gunning gun. The magnesium-calcium gunning compound is then evenly and completely covered with the magnesium-carbon bricks. The purpose is to fill the gaps between the magnesium-carbon bricks after the gunning, and improve the density and thermal shock resistance of the magnesium-carbon sintered bricks. After the gunning operation is completed, the sintering temperature is 1620℃ and the sintering time is controlled at 20 minutes.

[0156] 3-3) After the magnesium-calcium gunning material is fully sintered, the converter is tilted to 150 degrees toward the rear platform, and a maintenance work platform is built. The furnace shell is welded to the center of the furnace cap area on the slag pouring side of the converter, where the steel is leaking and burned through. Steel plates of the same material as the furnace shell are used.

[0157] 4) After the furnace shell welding repair of the steel leakage and burn-through parts in the furnace cap area on the slag pouring side of the converter was completed, the converter resumed normal production.

[0158] 5) Because the "chrome corundum slurry injection + furnace shell welding repair" method was not adopted on the outside of the converter body, the gap between the furnace shell and the furnace lining could not be filled and there was no supporting and protective function. During the normal smelting of one batch of steel in the converter, the furnace shell burned red and steel leaked again.

[0159] The above embodiments are described to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for maintaining the burn-through part of a converter body, characterized in that: The method for maintaining the burnout portion of the converter body comprises the following steps: 1) When a steel leak or burn-through accident occurs in the converter body, empty the molten steel and slag in the converter and shut down the furnace; 2) Measure the residual thickness and damaged location of the lining bricks at the burnout site of the converter body to determine the amount of maintenance materials and the specific maintenance location; 3) First, perform maintenance and sintering on the damaged lining of the converter body where steel leaks and burns through; 4) Mix the chrome corundum castable with water to make chrome corundum slurry, and spray the chrome corundum slurry into the burnout area of ​​the converter body from the external furnace shell to fill and compact the gap between the furnace shell steel plate and the furnace lining, and then sinter; 5) Finally, the furnace shell of the converter body where steel leaked and burned through was repaired by welding; In step 3), the damaged lining of the converter body where steel leaks and burns through is first maintained from the inside, specifically: When steel leakage and burn-through occur in the converter slag pouring side body, converter steel-tapping side body, converter ear shaft area, converter slag pouring side cap area and converter steel-tapping side cap area, first use magnesia carbon bricks to maintain the damaged lining position in the furnace, and then use magnesia calcium gunning material mixed with water to gunpowder to fill the gaps between the patched magnesia carbon bricks, and then sinter. The sintering temperature is ≥1620℃ and the sintering time is 20~25min.

2. The method for maintaining the burn-through portion of the converter body according to claim 1, characterized in that: In step 1), when a steel leakage and burn-through accident occurs on the slag discharge side of the converter, the converter is tilted toward the tapping side, and the molten steel and slag in the furnace are turned into the ladle from the furnace mouth and emptied; Or, when the converter body leaks and burns through on the tapping side, the converter tilts toward the slag dumping side, pouring the molten steel and slag from the furnace mouth into the ladle and emptying it; Or, when the converter trunnion area steel leakage and burn-through accident occurs, the converter tilts toward the slag discharge side or the steel tapping side, and the molten steel and slag in the furnace are poured into the ladle from the furnace mouth and emptied; Or, when a steel leak and burn-through accident occurs in the cap area on the slag-dumping side of the converter, the converter tilts toward the tapping side, pouring the molten steel and slag from the furnace mouth into the ladle and emptying it; Or, when a steel leak and burn-through accident occurs in the cap area on the tapping side of the converter, the converter tilts toward the slag discharge side, pouring the molten steel and slag from the furnace mouth into the ladle and emptying it; Or, when a steel leakage and burn-through accident occurs in the bottom area of ​​the converter, the converter tilts toward the slag pouring side or the steel tapping side, and the molten steel and slag in the furnace are poured into the ladle from the furnace mouth and emptied.

3. The method for maintaining the burn-through portion of the converter body according to claim 1, characterized in that: In step 2), the maintenance materials include magnesia-carbon bricks, converter sand, magnesia-calcium gunning material and chrome corundum castable.

4. The method for maintaining the burn-through portion of the converter body according to claim 1, characterized in that: In step 3), the weight ratio of the magnesium-calcium gunning material to water is 1:1.0 to 1:1.3, and the gunning pressure is controlled at 0.3 to 0.5 MPa.

5. The method for maintaining the burn-through portion of the converter body according to claim 1, characterized in that: When steel leakage and burn-through occur in the bottom area of ​​the converter, use converter sand to add it into the furnace from the converter mouth, and then shake the converter to an angle of -30° to 30° towards the front and back of the furnace based on the zero position. Shake the furnace repeatedly 2 to 3 times to ensure that the converter sand is completely spread and covers the damaged lining of the converter bottom where steel leakage and burn-through occur. Then sintering is carried out. The sintering temperature is ≥1620℃ and the sintering time is 50 to 60 minutes.

6. The method for maintaining the burn-through portion of the converter body according to claim 1, characterized in that: In step 4), the mass ratio of the chrome corundum castable to water is 1:0.30 to 1:0.

35.

7. The method for maintaining the burn-through portion of the converter body according to claim 1 or 6, characterized in that: In step 4), the pressure of the chrome corundum slurry injection is controlled at 0.2-0.4 MPa.

8. The method for maintaining the burn-through portion of the converter body according to claim 1 or 6, characterized in that: In step 4), the sintering temperature is 280-400° C., and the sintering time is 30-40 minutes.

9. The method for maintaining a blowout burn-through portion of a converter body according to claim 1, wherein in step 5), the converter shell at the blowout burn-through portion is welded with a steel plate made of the same material as the shell.

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