CN109719146B - Efficient descaling method for high-surface-quality medium plate product - Google Patents
Efficient descaling method for high-surface-quality medium plate product Download PDFInfo
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Abstract
According to the efficient descaling method for the high-surface-quality medium plate product, the scale on the surface of the steel plate is completely removed in the heating and rolling processes of the medium plate production line by arranging the corresponding device and combining a composite descaling mode of 'aerosol spraying and high-pressure water descaling'. The method is based on the FeO high-temperature mechanical property change rule and a laboratory simulation descaling test, relevant parameters of an aerosol spray device are adjusted according to the thickness of scale at each stage and the temperature interval of the scale on the surface of the steel plate at each descaling position, the temperature of the scale on the surface of the steel plate is quickly reduced under the condition of not reducing the temperature of a steel plate matrix, the steel plate is converted from a plastic material into a brittle material and generates a large amount of thermal stress cracks, and then the cracked scale is removed by adopting high-pressure water. The descaling technology is applied to a medium plate production line, so that the descaling effect of the steel plate is greatly improved, the surface defects of the steel plate are eliminated, and the state of iron scales on the surface of the steel plate is improved.
Description
Technical Field
The invention belongs to the technical field of hot rolled steel production, and particularly relates to a high-efficiency descaling method for a high-surface-quality medium plate product.
Background
In the production process of the hot-rolled medium plate, the defects of pockmarks, mottling and the like on the surface of a steel plate caused by the pressing-in of the iron scale are one of the surface quality defects which are difficult to completely solve. The surface defects with shallow pressing-in can be polished and removed, but in the heating and rolling processes, because the process control is unreasonable, large-area oxidized iron sheets on the surface of the steel plate are pressed in, the surface quality of a finished product is seriously influenced, the steel plate is degraded, the production efficiency is influenced, and the production cost is increased.
At present, the scale removing mode in the hot rolling process of domestic and foreign iron and steel enterprises mainly comprises high-pressure water descaling and mechanical descaling. The Chinese patent with application number 201510141638.1 discloses a method for improving the descaling quality of low-alloy primary scale, and compared with the conventional heating process, the method proposes that a low-temperature heating section is additionally arranged in front of a first heating section, the heating temperature of the low-temperature heating section is controlled to be 600-900 ℃, and the tapping temperature of steel billets is 1220-1240 ℃. The invention has the advantages that the surface quality of the low-alloy series steel plates is improved, and the practical production application result shows that the thickness of the billet steel scale is reduced by 0.2mm through the optimization of the heating process. However, the method only increases the preheating section and reduces the heating time, thereby reducing the thickness of the iron scale and having little effect on improving the surface quality of the steel plate.
In addition, the related patents carry out surface quality control at angles such as iron scale removal, but the problems of large surface roughness, poor plasticity and the like exist, the product performance is influenced, surface cracks appear, and the surface quality control in the subsequent production process is not facilitated.
In conclusion, the key to improving the surface quality of the steel is to improve the descaling effect of the iron scale on the surface of the hot rolled steel. Therefore, the key for improving the surface quality of the medium plate product is how to improve the scale removal performance of furnace-generated iron scale and the iron scale generated in the rolling process aiming at the characteristics of the iron scale of the steel plate in the heating and rolling processes of the hot rolling medium plate production line, and the reduction of the incidence rate of the press-in defects of the iron scale on the surface of the steel plate.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a high-efficiency descaling method for high-surface-quality medium and heavy plate products. The descaling efficiency of the hot rolling production flow can be effectively improved, so that the residue of scale after descaling is reduced, and the generation of scale pressing defects is prevented.
In order to achieve the purpose, the invention adopts the following technical scheme:
a high-efficiency descaling method for high-surface-quality medium and heavy plate products is completed by adopting a medium and heavy plate production line, the rolling mill is a single-rack reversible rolling mill, in the medium and heavy plate production line, an aerosol spray device is arranged between a heating furnace and a descaling box, the position, close to the descaling water beam at the odd-number pass rolling inlet, between the descaling box and the descaling water beam at the odd-number pass rolling inlet of the rolling mill is provided with the aerosol spray device at the odd-number pass rolling inlet, the aerosol spray device at the even-number pass rolling inlet of the rolling mill is provided with the aerosol spray device at the even-number pass before the descaling water beam at the even-number pass rolling inlet:
step (1), heating a heating furnace heating-descaling box section:
heating the steel billet in a heating furnace at 1100-1350 ℃ for 120-300 min, growing the steel billet into furnace-grown iron scales after the steel billet passes through the heating furnace, and descaling the steel billet in a descaling box after the steel billet passes through an aerosol spray device;
step (2), an odd-number pass inlet section of the rolling mill:
the temperature of the steel billet passing through an odd-number pass inlet of a rolling mill is 950-1250 ℃, new scale is rapidly grown on the surface of the steel billet, and aiming at the regenerated scale, the steel billet passes through an odd-number pass aerosol spray device, is descaled through a descaling water beam at an odd-number pass rolling inlet of the rolling mill, and is then rolled in odd-number passes;
step (3), an even number of passes of the inlet section of the rolling mill:
the surface temperature of the steel billet passing through an even-number pass inlet of the rolling mill is 800-1150 ℃, new iron scale can also rapidly grow on the surface of the steel billet, the steel billet passes through an even-number pass aerosol spray device, then passes through an even-number pass rolling inlet of the rolling mill to remove a scale water beam, then passes through an even-number pass rolling inlet of the rolling mill to perform even-number pass rolling, and the steps are repeated in this way to finish rolling, obtain a hot-rolled steel plate, and the hot-rolled medium plate.
In the method, the billet moves forwards from the heating furnace to the descaling box.
In the method, the rolling mill is a single-stand reversible rolling mill, an odd-number pass rolling descaling water beam is arranged in front of an odd-number pass rolling inlet, and an even-number pass rolling descaling water beam is arranged in front of an even-number pass rolling inlet.
In the method, two groups of aerosol spray devices, an odd number of times of aerosol spray devices and an even number of times of aerosol spray devices are arranged between the heating furnace and the descaling box, and specifically, one group of aerosol spray devices is respectively arranged on the upper side and the lower side of a roller way at the corresponding position of a medium plate production line so as to ensure that the billet is completely sprayed.
In the method, an aerosol spray device, an odd-number-pass aerosol spray device and an even-number-pass aerosol spray device between the heating furnace and the descaling box are all a group of spray beams, and the number of spray heads is 50-80.
In the method, the angle of the spray head of the aerosol spray device can be adjusted, and the angle range is 0-30 degrees.
In the method, the installation height of a spray head of the aerial fog spraying device in front of the descaling box is 150-400 mm away from the surface of the steel billet, the installation height of the spray head of the aerial fog spraying device in front of the hot rolling odd-numbered and even-numbered gate inlets is 100-300 mm away from the surface of the steel plate, and the position of the spray head of the aerial fog spraying device is obtained by adjusting according to the thickness of the iron scale and the temperature interval.
According to the method, the horizontal distance between the installation of the aerial fog spraying device in front of the descaling box and the descaling box is 1.5-3 m, the installation of the aerial fog spraying device in front of the hot rolling odd-number pass inlet and the descaling water beam at the odd-number pass rolling inlet is 0.5-2 m, the installation of the aerial fog spraying device in front of the hot rolling even-number pass inlet and the descaling water beam at the even-number pass rolling inlet are 0.5-2 m, and the method is obtained according to the thickness of the scale and the temperature interval.
In the method, the gas/water ratio in the aerosol spray device is adjusted according to the thickness of the iron scale, and the gas is air or other non-combustible gas.
In the method, when the steel billet is sprayed by the gas mist spraying device, the odd-number-pass gas mist spraying device and the even-number-pass gas mist spraying device which are arranged between the heating furnace and the descaling box, the temperature reduction range of the scale on the surface of the steel billet is controlled to be 300-700 ℃.
In the method, the water pressure and the gas flow in the aerosol spray device are adjusted, and a pressure-stabilizing energy storage device is designed among the water pump, the air pump and the aerosol spray device to ensure that the water pressure, the water spray quantity and the gas pressure are stable, the water pressure is 0.6-1.2 MPa, and the water flow is 80-200 m3The flow rate of the gas in the nozzle is 50-350L/min.
In the step (1), the steel billet comprises the following components in percentage by weight: 0.04% -0.1%, Si: 0.05% -0.2%, Mn: 1.20% -1.80%, S: less than or equal to 0.01 percent, P: less than or equal to 0.018%, Als: 0.015% -0.045%, Ti: 0.01% -0.03%, Nb: 0.025% -0.070%, Cr: 0.22% -0.38%, Ni: 0.1% -0.2%, Mo: 0.22% -0.28%, B: 0.001-0.002%, and the balance of Fe and inevitable impurities during smelting.
In the step (3), the product degradation rate of the prepared hot-rolled medium plate caused by the press-in defect of the scale is as low as below 0.4%.
The scale formed by the steel at high temperature generally has a typical three-layer structure, with the outermost layer being Fe2O3Fe of the intermediate layer3O4And the innermost FeO in a ratio of about 1:4: 95. Therefore, it is essential to ensure the surface quality of the steel sheet to remove FeO during descaling. Since the mechanical properties of iron oxide at different temperatures are greatly changed, fig. 1 shows the tensile curve of FeO at high temperature, and it can be seen that, below 600 ℃, FeO is brittle and fractured when the strain is 1.5%. Therefore, FeO at a temperature lower than this temperature is a brittle material and does not have deformability. When the temperature is higher than 700 ℃, FeO can bearThe steel is subjected to certain deformation to generate ductile fracture, at the moment, FeO can generate certain plastic deformation, the plasticity of FeO is continuously enhanced along with the increase of the temperature, when the temperature exceeds 1000 ℃, the elongation of FeO is more than 120%, and in addition, the strength of FeO is continuously reduced along with the increase of the temperature. Therefore, when the alloy is subjected to external stress under high-temperature conditions, FeO shows good high-temperature plasticity. Therefore, mastering the high-temperature mechanical property change behavior of FeO is the basis for developing the efficient descaling technology.
The invention has the beneficial effects that:
in order to remove the scale on the surface of the hot rolled steel as much as possible, the iron and steel companies tend to increase the pressure of the descaling high pressure water as much as possible, but the obtained effect is not ideal. The patent provides an efficient descaling method for high-surface-quality medium plate products by researching the high-temperature mechanical property change rule of FeO, and the principle is as follows: firstly, spraying is adopted to quickly reduce the temperature of surface oxide skin, so that the surface oxide skin is converted from a plastic material into a brittle material and generates thermal stress cracks, and then ordinary high-pressure water is adopted to remove the cracked oxide skin. The application of the technology greatly improves the descaling effect of the steel plate, thereby eliminating the surface defects of the steel plate and improving the oxide scale state of the surface of the steel plate.
Drawings
FIG. 1 is a high temperature mechanical property diagram of FeO;
FIG. 2 is a macroscopic view of the surface of a medium plate prepared in example 1;
FIG. 3 is a macroscopic view of the surface of the medium plate prepared in comparative example 1;
FIG. 4 is a macroscopic view of the surface of the medium plate prepared in example 2;
FIG. 5 is a macroscopic view of the surface of the medium plate prepared in comparative example 2;
FIG. 6 is a macroscopic view of the surface of the medium plate prepared in example 3;
fig. 7 is a macroscopic view of the surface of the medium plate prepared in comparative example 3.
Detailed Description
The present invention will be described in further detail with reference to examples.
Example 1
The high-efficiency descaling method for the high-surface-quality medium plate products is completed by adopting a medium plate production line, wherein an aerosol spray device is arranged between a heating furnace and a descaling box in the medium plate production line, an odd-number pass aerosol spray device is arranged between the descaling box and a descaling water beam at an odd-number pass rolling inlet of a rolling mill and close to the descaling water beam at the odd-number pass rolling inlet, an even-number pass aerosol spray device is arranged in front of the descaling water beam at an even-number pass rolling inlet of the rolling mill, and the steel comprises the following components in percentage by weight: 0.04%, Si: 0.2%, Mn: 1.80%, S: 0.01%, P: 0.018%, Als: 0.045%, Ti: 0.01%, Nb: 0.025%, Cr: 0.22%, Ni: 0.1%, Mo: 0.22%, B: 0.001 percent, and the balance of Fe and inevitable impurities during smelting, and the descaling method is specifically carried out according to the following steps:
conveying a steel billet through a roller way to heat in a stepping heating furnace, wherein the heating temperature is 1180 ℃, the heating time is 300min, then continuously conveying the steel billet through the roller way, aiming at furnace-grown iron scale growing in the stepping heating furnace, a group of aerosol spray devices are respectively arranged at the upper side and the lower side of the roller way between a descaling box and the heating furnace, the number of spray heads is 50, the angle of the aerosol spray heads is 0 degree, the height of the aerosol spray heads is 150 mm away from the surface of a steel plate and 3m away from a water beam of the descaling box, the air/water ratio in the device is 0:1, the water pressure is 0.6 MPa, and the water flow is 80 m3Controlling the temperature reduction range of the scale on the surface of the billet to be 700 ℃, performing odd-number pass descaling water beam descaling through a rolling mill after passing through an odd-number pass aerosol spray device, and then performing odd-number pass rolling;
at the inlet section of the rolling mill with odd number of passes, the temperature of the plate blank is 1050 ℃, new iron oxide scales can grow on the surface rapidly, aiming at the regenerated iron oxide scales, a group of odd number pass aerosol spray devices are respectively arranged between the descaling water beam and the descaling box, the position close to the descaling water beam and the upper side and the lower side of the roller way, the number of spray heads is 50, the angle of the air spray head is 0 degree, the height of the spray head of the device is 300mm away from the surface of the steel plate and 2m away from the descaling box water beam, the air/water ratio in the device is 1:1, the water pressure is 0.6 MPa, and the water flow is 803The flow rate of gas in the nozzle is 350L/min, and the temperature of the iron scale on the surface of the steel is controlled to be reducedThe amplitude is 450 ℃, and after passing through an odd-number pass aerial fog spraying device, odd-number pass descaling water beam descaling is carried out through a rolling mill, and then odd-number pass rolling is carried out;
at the inlet section of an even number of passes of the rolling mill, the temperature of a plate blank is 1030 ℃, new iron oxide scales can grow on the surface of the plate blank rapidly, aiming at the regenerated iron oxide scales, a group of even number of pass aerosol spray devices are arranged in front of a descaling water beam and on the upper side and the lower side of a roller way, the number of spray heads is 50, the angle of an air spray head is 0 degree, the height of the spray head of the device is 300mm away from the surface of a steel plate and 2m away from the descaling box water beam, the air/water ratio in the device is 1:1, the water pressure is 0.6 MPa, and3and h, controlling the flow rate of gas in a nozzle to be 350L/min, controlling the temperature reduction amplitude of the iron scale on the surface of the steel to be 450 ℃, enabling the steel billet to pass through an even number of times of gas spray devices, then passing through a descaling water beam, then carrying out even number of times of rolling, repeating the steps in the above steps to finish the rolling, and obtaining the hot rolled steel plate after carrying out shot blasting, wherein the surface quality of the hot rolled medium plate is shown in figure 2, the surface quality of the steel plate is greatly improved after the gas spray devices are additionally arranged, and the product degradation rate of the hot rolled medium plate in the batch is 0.4% due to the pressing defect of the iron scale.
Comparative example 1
After hot-rolled steel sheets were prepared by removing the three sets of spray devices according to the technical parameters used in example 1, hot-rolled steel sheets were obtained, and hot-rolled medium plates were obtained by shot blasting, the surface quality of which is shown in fig. 3.
Example 2
The high-efficiency descaling method for the high-surface-quality medium plate products is completed by adopting a medium plate production line, wherein an aerosol spray device is arranged between a heating furnace and a descaling box in the medium plate production line, an odd-number pass aerosol spray device is arranged between the descaling box and a descaling water beam at an odd-number pass rolling inlet of a rolling mill and close to the descaling water beam at the odd-number pass rolling inlet, an even-number pass aerosol spray device is arranged in front of the descaling water beam at an even-number pass rolling inlet of the rolling mill, and the steel comprises the following components in percentage by weight: 0.1%, Si: 0.05%, Mn: 1.20%, S: 0.007%, P: 0.008%, Als: 0.015%, Ti: 0.03%, Nb: 0.070%, Cr: 0.38%, Ni: 0.2%, Mo: 0.28%, B: 0.002%, and the balance of Fe and inevitable impurities during smelting, and the descaling method is specifically carried out according to the following steps:
conveying a steel billet through a roller way to heat in a stepping heating furnace, wherein the heating temperature is 1350 ℃, the heating time is 250 min, then continuously conveying the steel billet through the roller way, aiming at furnace-grown iron scale growing in the stepping heating furnace, a group of aerosol spray devices are respectively arranged on the upper side and the lower side of the roller way in front of a descaling box, the number of spray heads is 80, the angle of the air spray heads is 30 degrees, the height of the spray heads of the device is 400mm away from the surface of a steel plate and 1.5 m away from a water beam of the descaling box, the air/water ratio in the device is 0:1, the water pressure is 1.2MPa, and the water flow is 200m3Controlling the temperature reduction range of the iron scale on the surface of the steel to be 700 ℃, performing odd-number pass descaling water beam descaling through a rolling mill after passing through an odd-number pass aerosol spray device, and then performing odd-number pass rolling;
at the inlet section of the rolling mill with odd number of passes, the temperature of the plate blank is 1250 ℃, new iron scale can grow on the surface rapidly, aiming at the regenerated iron scale, a group of odd number pass aerosol spray devices are respectively arranged between the descaling water beam and the descaling box, the position close to the descaling water beam and the upper side and the lower side of the roller way, the number of spray heads is 50, the angle of the air spray head is 30 degrees, the height of the spray head of the device is 100 mm away from the surface of the steel plate and 0.5 m away from the descaling box water beam, the air/water ratio in the device is 1:3, the water pressure is 1.2MPa, and the water flow is 200m3The flow rate of gas in the nozzle is 50L/min, and the temperature reduction range of the iron scale on the surface of the steel is controlled to be 600 ℃.
At the even-number pass inlet section of the rolling mill, the temperature of a plate blank is 1150 ℃, new iron oxide scales can grow on the surface of the plate blank rapidly, aiming at the regenerated iron oxide scales, a group of even-number pass aerosol spray devices are arranged in front of a descaling water beam and on the upper side and the lower side of a roller way, the number of spray heads is 50, the angle of each air spray head is 30 degrees, the height of each spray head of the device is 100 mm away from the surface of a steel plate and 0.5 m away from the descaling box water beam, the air/water ratio in the device is 1:3, the water pressure is 1.2MPa, and the water3The gas flow rate of the nozzle is 200L/min, the temperature reduction range of the iron scale on the surface of the steel is controlled to be 600 ℃, the steel billet passes through the even number of times of gas mist spraying devices, then passes through the descaling water beam and then is rolled by the even number of times, and the likeAnd then, after the rolling is finished, the hot rolled steel plate is shot-blasted to obtain a hot rolled medium plate, the surface quality of the hot rolled medium plate is shown in figure 4, so that the surface quality of the steel plate is greatly improved after the air spray spraying device is additionally arranged, and the product degradation rate of the batch of hot rolled medium plates caused by the press-in defect of the iron scale is 0.37%.
Comparative example 2
After hot-rolled steel sheets were prepared by removing the three sets of spray devices according to the technical parameters used in example 2, hot-rolled steel sheets were obtained, and hot-rolled medium plates were obtained by shot blasting, the surface quality of which is shown in fig. 5.
Example 3
The high-efficiency descaling method for the high-surface-quality medium plate products is completed by adopting a medium plate production line, wherein an aerosol spray device is arranged between a heating furnace and a descaling box in the medium plate production line, an odd-number pass aerosol spray device is arranged between the descaling box and a descaling water beam at an odd-number pass rolling inlet of a rolling mill and close to the descaling water beam at the odd-number pass rolling inlet, an even-number pass aerosol spray device is arranged in front of the descaling water beam at an even-number pass rolling inlet of the rolling mill, and the steel comprises the following components in percentage by weight: 0.07%, Si: 0.12%, Mn: 1.50%, S: 0.006%, P: 0.010%, Als: 0.025%, Ti: 0.02%, Nb: 0.025%, Cr: 0.25%, Ni: 0.1%, Mo: 0.24%, B: 0.0015 percent, and the balance of Fe and inevitable impurities during smelting, and the descaling method is specifically carried out according to the following steps:
conveying a steel billet through a roller way to heat in a stepping heating furnace, wherein the heating temperature is 1100 ℃, the heating time is 120 min, then continuously conveying the steel billet through the roller way, aiming at furnace-grown iron scale growing in the stepping heating furnace, a group of aerial fog spraying devices are respectively arranged on the upper side and the lower side of the roller way in front of a descaling box, the number of spray heads is 65, the angle of the aerial fog spray heads is 0 degree, the height of the aerial fog spray heads of the aerial fog spray devices is 250 mm away from the surface of a steel plate and 2m away from a water beam of the descaling box, the air/water ratio in the aerial fog spray devices is 1:1, the water pressure is 1.3The flow rate of gas in the nozzle is 350L/min, and the temperature reduction range of the iron scale on the surface of the steel is controlled to be 450 ℃.
In the odd-number pass inlet section of the rolling mill, the temperature of a plate blank is 950 ℃, new iron oxide scales can rapidly grow on the surface of the plate blank, aiming at the regenerated iron oxide scales, a group of odd-number pass aerosol spray devices are respectively arranged between a descaling water beam and a descaling box, the position close to the descaling water beam and the upper side and the lower side of a roller way, the number of spray heads is 65, the angle of the air spray heads is 30 degrees, the height of the spray heads of the device is 100 mm away from the surface of the steel plate and 1 m away from the descaling box water beam, the device adopts full air spraying, the gas flow rate of a nozzle is 350L/min, the temperature reduction amplitude of the iron oxide scales on the surface of the steel is controlled to be 300 ℃, after passing through the odd-number pass aerosol spray;
in the even number pass entrance section of the rolling mill, the plate blank temperature is 800 ℃, new iron oxide scales can rapidly grow on the surface, aiming at the regenerated iron oxide scales, a group of even number pass aerosol spray devices are respectively arranged in front of the descaling water beam and on the upper side and the lower side of the roller way, the number of spray heads is 65, the angle of the air spray heads is 30 degrees, the height of the spray heads of the device is 100 mm away from the surface of the steel plate and 1 m away from the descaling box water beam, the device adopts full-gas spraying, the gas flow rate of the spray nozzles is 350L/min, the temperature reduction amplitude of the iron oxide scales on the surface of the steel is controlled to be 300 ℃, the steel billet passes through the even number pass aerosol spray devices and then passes through the descaling water beam, the even number rolling is carried out in a reciprocating way, the rolling is completed, the hot rolled steel plate is obtained, the hot rolled medium plate is obtained after the shot blasting, the surface quality, the product degradation rate of the hot-rolled medium plate of the batch caused by the press-in defect of the scale is 0.23%.
Comparative example 3
After hot-rolled steel sheets were prepared by removing the three sets of spray devices according to the technical parameters used in example 3, hot-rolled steel sheets were obtained, and hot-rolled medium plates were obtained by shot blasting, the surface quality of which is shown in fig. 7.
Claims (3)
1. An efficient descaling method for medium and heavy plate products is characterized in that a medium and heavy plate production line is adopted, a rolling mill is a single-rack reversible rolling mill, an aerosol spray device is arranged between a heating furnace and a descaling box in the medium and heavy plate production line, an odd-number-pass aerosol spray device is arranged between the descaling box and a descaling water beam at an odd-number-pass rolling inlet of the rolling mill and close to the descaling water beam at the odd-number-pass rolling inlet, and an even-number-pass aerosol spray device is arranged in front of the descaling water beam at an even-number-pass rolling inlet of the rolling mill;
two groups of aerial fog spraying devices, an odd-number-pass aerial fog spraying device and an even-number-pass aerial fog spraying device are arranged between the heating furnace and the descaling box, and specifically, one group of aerial fog spraying devices is arranged on the upper side and the lower side of the roller way at the corresponding position of the medium plate production line so as to ensure that the billet is completely sprayed;
the installation height of a spray head of the aerial fog spraying device in front of the descaling box is 150-400 mm away from the surface of a steel billet, the installation height of the spray head of the aerial fog spraying device in front of hot rolling odd-number and even-number pass inlets is 100-300 mm away from the surface of the steel plate, the horizontal distance between the installation height of the aerial fog spraying device in front of the descaling box and the descaling box is 1.5-3 m, the installation height of the aerial fog spraying device in front of the hot rolling odd-number pass inlet is 0.5-2 m away from the descaling water beam at the odd-number pass rolling inlet, and the installation height of the aerial fog spraying device in front of the hot rolling even;
when the steel billet is sprayed by an aerosol spray device, an odd-number-pass aerosol spray device and an even-number-pass aerosol spray device between the heating furnace and the descaling box, controlling the temperature reduction range of the scale on the surface of the steel billet to be 300-700 ℃;
the spraying water pressure in the gas spray spraying device is 0.6-1.2 MPa, and the water flow is 80-200 m3The flow rate of gas in the nozzle is 50-350L/min, and the gas/water ratio in the gas fog spraying device is adjusted according to the thickness of the iron scale;
the descaling method is specifically carried out according to the following steps:
step (1), heating a heating furnace heating-descaling box section:
heating a steel billet in a heating furnace, wherein the heating temperature is 1100-1350 ℃, the heating time is 120-300 min, the steel billet grows to form furnace-grown iron scale after passing through the heating furnace, and the steel billet enters a descaling box for descaling after passing through an air mist spraying device, wherein the steel billet comprises the following components in percentage by weight: 0.04-0.1%, Si: 0.05-0.2%, Mn: 1.20% -1.80%, S: less than or equal to 0.01 percent, P: less than or equal to 0.018%, Als: 0.015% -0.045%, Ti: 0.01 to 0.03 percent, Nb: 0.025-0.070%, Cr: 0.22-0.38%, Ni: 0.1% -0.2%, Mo: 0.22-0.28%, B: 0.001 to 0.002 percent of the total weight of the alloy, and the balance of Fe and inevitable impurities during smelting;
step (2), an odd-number pass inlet section of the rolling mill:
the temperature of the steel billet passing through an odd-number pass inlet of a rolling mill is 950-1250 ℃, new scale is rapidly grown on the surface of the steel billet, and aiming at the regenerated scale, the steel billet passes through an odd-number pass aerosol spray device, is descaled through a descaling water beam at an odd-number pass rolling inlet of the rolling mill, and is then rolled in odd-number passes;
step (3), an even number of passes of the inlet section of the rolling mill:
the surface temperature of a steel billet passing through an even-number pass inlet of a rolling mill is 800-1150 ℃, new iron oxide scales can also rapidly grow on the surface of the steel billet, the steel billet passes through an even-number pass aerosol spray device, then passes through an even-number pass rolling inlet of the rolling mill to remove scale water beams, then passes through even-number pass rolling, the rolling is finished in such a reciprocating way, a hot-rolled steel plate is obtained, and a hot-rolled medium plate is prepared by shot blasting, wherein the product degradation rate of the hot-rolled medium plate caused by the iron oxide scale pressing defect is as low as below 0.4%.
2. The method for efficiently descaling medium and thick plate products according to claim 1, wherein the aerosol spray devices, the odd-numbered pass aerosol spray devices and the even-numbered pass aerosol spray devices between the heating furnace and the descaling box are all a group of spray beams, and the number of spray heads is 50-80.
3. The method for efficiently descaling a medium plate product according to claim 2, wherein the angle of the nozzle of the gas spray device is adjustable, and the angle is 0-30 °.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910017644.4A CN109719146B (en) | 2019-01-07 | 2019-01-07 | Efficient descaling method for high-surface-quality medium plate product |
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| CN201910017644.4A CN109719146B (en) | 2019-01-07 | 2019-01-07 | Efficient descaling method for high-surface-quality medium plate product |
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| CN105964710A (en) * | 2016-06-21 | 2016-09-28 | 广西梧州市金海不锈钢有限公司 | High pressure water descaling device and descaling method |
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| JPS5950903A (en) * | 1982-09-14 | 1984-03-24 | Nippon Steel Corp | Continuous hot rolling device for steel plate |
| JPH08206724A (en) * | 1995-02-06 | 1996-08-13 | Mitsubishi Heavy Ind Ltd | Scale stripping device |
| CN203409000U (en) * | 2013-08-20 | 2014-01-29 | 首钢总公司 | Device for removing oxide scales on surface of small size hot billet |
| CN103433310A (en) * | 2013-09-18 | 2013-12-11 | 河南理工大学 | Scale removal method of hot-rolled metal |
| CN103952643A (en) * | 2014-05-13 | 2014-07-30 | 莱芜钢铁集团有限公司 | Low-yield ratio steel plate with yield strength of 690MPa and preparation method of steel plate |
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