CN210816745U - Cooling equipment capable of adapting to extremely short post-rolling cooling line of hot-rolled wide steel strip - Google Patents
Cooling equipment capable of adapting to extremely short post-rolling cooling line of hot-rolled wide steel strip Download PDFInfo
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Abstract
The utility model belongs to the technical field of ferrous metallurgy, and relates to a cooling device which can adapt to a cooling line after extremely short rolling of a hot-rolled wide steel strip, wherein a transport roller is arranged along the transport direction of a steel rolling steel plate, a cooling line is arranged on the plane of the transport roller, the cooling line sequentially comprises a fast cooling section, a laminar cooling section and a fine adjustment section from front to back, the upper parts of the fast cooling section, the laminar cooling section and the fine adjustment section are respectively provided with a fixed beam, and the fixed beams are used for fixing a cooling collecting pipe; 2-4 groups of cooling headers are arranged in the quick cooling section, 5-7 groups of cooling headers are arranged in the laminar flow cooling section, and 1-3 groups of cooling headers are arranged in the fine adjustment section; each set of cooling headers includes an upper cooling header and a lower cooling header. Use the utility model discloses an equipment carries out suitable configuration to the length parameter, the cooling water flow parameter of fast cold section, laminar flow cooling section, fine tuning section, can control to roll the material tissue and be ferrite + pearlite to reduce the structure difference of rolling material surface and core.
Description
Technical Field
The invention belongs to the technical field of ferrous metallurgy, and particularly relates to cooling equipment suitable for a cooling line after extremely short rolling of a hot-rolled wide steel strip, in particular to equipment suitable for producing a hot-rolled Q355B hot-rolled wide steel strip of the cooling line after extremely short rolling.
Background
The Q355B-grade low-alloy structural steel is widely applied to the fields of bridges, vehicles, ships, buildings, pressure vessels and the like, has good comprehensive mechanical properties, is the steel grade with the largest domestic consumption at present, is the main product variety of most steel plants, and steel enterprises are dedicated to research the stable, efficient and low-cost production method of the Q355B-grade low-alloy structural steel.
When some domestic hot-rolled wide steel strip production lines are constructed, due to the fact that site construction area is limited, products are positioned to be thin wide steel strips and the like, the constructed cooling line after finish rolling is extremely short, and the length of the cooling line after finish rolling is about 40-70 meters. Because the finish rolling speed of the hot rolling width line is high, the finish rolling speed reaches 2.5-8 m/s, calculated by the effective cooling length of 50m, the steel needs to be cooled from the finish rolling temperature (870 ℃) to the coiling temperature (about 640 ℃) within 6-20 seconds, the cooling speed is high, a large amount of cooling water needs to be sprayed on the surface of the rolled material within unit time, and the cooling water takes away a large amount of heat from the surface of the rolled material.
According to the Fourier equation, Q is K × A × delta T/d, (Q is heat, K is thermal conductivity, A is contact area, d is heat transfer distance), the heat transferred to the surface of the rolled product at the thickness of the rolled product core is in proportion to the thickness of the rolled product, namely the thicker the rolled product is, the slower the heat transfer speed from the inside of the rolled product to the surface of the rolled product is, so the thick-gauge rolled product is easy to generate the problem of uneven cooling of the surface and the core of the rolled product in the cooling process, the different structures of the surface and the core of the rolled product can be caused, in the case of rapid cooling, bainite and even martensite phase transformation often occurs on the surface of the rolled product, but the pearlite transformation occurs in the core of the rolled product, the different structures of the surface and the core of the rolled product are caused, and the obvious difference of the mechanical properties of the rolled product is caused.
The simple method for solving the problem is to adopt a longer cooling line after finish rolling to prolong the cooling time after rolling of the thick-specification rolled steel, so that the cooling strength can be reduced, and the temperature difference between the core part and the surface of the rolled steel can be reduced.
With the deep understanding of 'water alloy', the cooling process after rolling increasingly draws more attention of steel enterprises, various cooling processes such as ultra-fast cooling, intensive cooling and laminar cooling are widely applied in steel rolling mills, but most of the prior art aims at long cooling lines, and the prior art disclosed at present has no specific introduction on how to properly configure length parameters and cooling water flow parameters of a fast cooling section, a laminar cooling section and a fine adjustment section to homogenize rolled material tissues as much as possible under the working condition of an extremely short cooling line, and has some technical difficulties in stably, efficiently and low-cost production of Q355B hot-rolled wide steel strips under the working condition of the extremely short cooling line.
As shown in fig. 1 of the present invention, laminar cooling is mostly performed by water spray cooling using gooseneck nozzles, a certain distance exists between every two gooseneck tubes in the transverse direction of a rolled product, the gooseneck tubes can perform high-intensity cooling on a position of the rolled product right below the position of the gooseneck tubes, but the cooling intensity of the position between every two gooseneck tubes is weak, and the gooseneck tubes on a next cooling header are still designed, the gooseneck nozzles are arranged in order like a soldier, so that the rolled product position which is cooled by high intensity in the previous cooling header is still cooled by high intensity in the next cooling header, the rolled product position which is cooled by low intensity in the previous cooling header is still cooled by low intensity in the next cooling header, and finally the rolled product is cooled unevenly in the width direction, and red marks (weak cooling intensity) and black marks (high cooling intensity) appear after the rolled product is subjected to laminar cooling in the width direction The displacement phenomenon causes the difference of mechanical properties of the rolled stock in the width direction.
Disclosure of Invention
In order to solve the problem of uneven cooling of rolled materials, the application provides equipment and a method for producing hot-rolled wide steel strips which can adapt to an extremely short cooling line after rolling, in particular to equipment and a method for producing hot-rolled Q355B wide steel strips which can adapt to an extremely short cooling line after rolling.
The application provides a cooling device capable of adapting to a cooling line after extremely short rolling of a hot-rolled wide steel strip, wherein a transport roller is arranged along the transport direction of a steel rolling steel plate, the cooling line is arranged on the plane of the transport roller, the cooling line sequentially comprises a fast cooling section, a laminar cooling section and a fine adjustment section from front to back, and fixed beams are arranged at the upper parts of the fast cooling section, the laminar cooling section and the fine adjustment section and used for fixing a cooling collecting pipe; 2-4 groups of cooling headers are arranged in the quick cooling section, 5-7 groups of cooling headers are arranged in the laminar flow cooling section, and 1-3 groups of cooling headers are arranged in the fine adjustment section; each set of cooling headers includes an upper cooling header and a lower cooling header. A group of upper cooling collecting pipes are formed by a plurality of gooseneck pipes, the upper cooling collecting pipes are arranged right above the conveying rollers and are parallel to the conveying rollers, and the upper cooling collecting pipes are arranged on the fixed beams. By using the equipment provided by the invention, the length parameters and the cooling water flow parameters of the rapid cooling section, the laminar cooling section and the fine adjustment section are properly configured, the structure of the rolled material can be controlled to be ferrite and pearlite, and the structure difference between the surface and the core of the rolled material is reduced as much as possible.
The cooling line is arranged in front of one end close to the rolling mill and behind one end close to the coiling machine. In the present invention, the directions or positional relationships indicated by the directional terms such as "upper", "lower", "front", "rear", and the like are all based on the directions and positional relationships shown in the drawings, and are only for convenience of describing the structures and positional relationships of the present invention, but do not indicate or imply that the parts referred to have specific directions or operate according to specific directions, and are not to be construed as limitations of the present invention.
Preferably, a pyrometer is arranged at the outlet of the fast cooling section, the laminar cooling section and/or the fine adjustment section. The surface temperature of the rolled stock is detected by a pyrometer. Pyrometers may also be provided at the entry locations of the fast cooling section, laminar cooling section, and/or fine conditioning section, the take-up apparatus entry location. The number of pyrometers, which can be selected by the person skilled in the art according to the actual requirements, can be one or more.
Preferably, the fast cooling section is provided with 2-4 groups of cooling headers, each group of cooling headers is 2-3m long, and each group of cooling headers comprises 3-5 upper cooling headers and 6-10 lower cooling headers.
More preferably, the fast cooling section is provided with 3 groups of cooling headers, each group of cooling headers is 2-3m long, and each group of cooling headers comprises 4 upper cooling headers and 8 lower cooling headers.
More preferably, the length of the fast cooling section is about 8-12 m, and the temperature of the rolled stock in the fast cooling section is reduced by about 150 ℃. And a lower cooling header is arranged in the middle of the gap between every two conveying rollers of the quick cooling section, an upper cooling header is arranged in the middle of every two lower cooling headers, and every two lower cooling headers correspond to one upper cooling header.
The temperature difference between the surface of the rolled stock and the core is large due to the fact that the rolled stock is rapidly cooled in the rapid cooling section, and according to production experience, the temperature gradient between the surface and the core reaches 50-100 ℃ when the rolled stock enters the laminar cooling section, so that the surface temperature of the rolled stock is 650-730 ℃ when the rolled stock exits the rapid cooling section, but the average temperature of the rolled stock is above 700 ℃.
Preferably, the laminar flow cooling section is provided with 5-7 groups of cooling headers, each group of cooling headers is 3-4m long, and each group of cooling headers comprises 5-7 upper cooling headers and 10-14 lower cooling headers. And a lower cooling header is arranged in the gap between every two conveying rollers of the laminar flow cooling section, the upper cooling header is arranged in the middle of every two lower cooling headers, and each two lower cooling headers correspond to one upper cooling header.
More preferably, the laminar flow cooling section is provided with 6 groups of cooling headers, each group of cooling headers is 3-4m long, and each group of cooling headers comprises 6 upper cooling headers and 12 lower cooling headers.
The laminar flow section cooling line is longer, the length is 18-22m, the cooling strength is weaker, the rolled stock is subjected to weak cooling in the laminar flow cooling section, the average temperature of the rolled stock is reduced by about 50 ℃, and the temperature gradient of the surface and the core of the rolled stock is reduced to 10-20 ℃.
Preferably, the fine adjustment section is provided with 1-3 groups of cooling headers, each group of cooling headers is 4-6m long, and each group of cooling headers comprises 2-6 upper cooling headers and 4-12 lower cooling headers. The lower cooling headers are arranged in the gap between the two transport rollers, and every two lower cooling headers are separated by one transport roller, and the upper cooling headers are arranged in the middle of every two lower cooling headers, and every two lower cooling headers correspond to one upper cooling header.
More preferably, the fine adjustment section is provided with 2 groups of cooling headers, each group of cooling headers is 4-6m long, and each group of cooling headers comprises 4 upper cooling headers and 8 lower cooling headers.
Preferably, the lower cooling header has a radial inclination angle A of 2-8 degrees. Preferably, A is 3 to 5 degrees.
Preferably, the cooling headers in post-rolling cooling are arranged in a staggered manner in the width direction of the rolled stock. More preferably, the staggered arrangement mode is as follows: every two spray pipes in the cooling headers are spaced by a distance b in the width direction of the rolled stock, and of 3 adjacent groups of cooling headers, the second group of cooling headers is shifted by b/2 in the width direction of the rolled stock on the basis of the position of the first group of cooling headers, and the third group of cooling headers is shifted by-b/2 in the width direction of the rolled stock on the basis of the position of the second group of cooling headers, so that the cooling headers are cyclically staggered in this order.
The invention also provides a production method of the hot-rolled wide steel strip which can adapt to the cooling line after the extremely short rolling, and is characterized in that steel passes through a fast cooling section, a laminar cooling section and a fine adjustment section in sequence; the length of the fast cooling section is 8-12 m, and the surface temperature of the rolled material exiting the fast cooling section reaches 650-730 ℃; the length of the laminar cooling section is 18-22m, the surface temperature of a rolled material at the outlet of the laminar cooling section is 630-650 ℃, and the temperature gradient of the surface and the core of the rolled material is reduced to 10-20 ℃; the temperature of the rolled material is reduced by 10-20 ℃ in the fine adjustment section, and the coiling temperature is controlled to be 620-650 ℃.
The method for producing the hot-rolled wide steel strip which can adapt to the cooling line after the extremely short rolling comprises the following steps:
1. the titanium content in the components of the Q355B hot-rolled wide steel strip is properly increased, and the strength of the steel is improved by using a cheap titanium element, so that the strength of the steel improved by the water alloy after rolling can be reduced, the water cooling and spraying amount after rolling can be reduced, and the problem of uneven cooling of the surface and the core of the rolled steel under the working condition of an extremely short cooling line can be solved.
Q355B uses the molten steel composition as follows:
table 1: Q355B composition
At present, the price of 30 percent ferrotitanium is about 9000 yuan/ton, and through calculation, the increased alloy cost is 3.3 yuan/ton steel when 0.01 percent of titanium in molten steel is increased, and the cost is not increased much; according to production experience, the yield strength can be improved by about 25MPa and the tensile strength can be improved by 20MPa for every 0.01 percent of titanium in the steel, and the titanium in the steel has no obvious side effect on the toughness and the plasticity of the steel when the content of the titanium is less than 0.045 percent. The method controls Ti at the middle upper limit of a component interval without influencing toughness and plasticity, and effectively improves the yield strength and the tensile strength of the steel under the condition of not increasing much cost.
Although other domestic steel mills have reports of setting the Ti content in the steel to be 0.035-0.050%, all the reports set the Ti content to be 0.035-0.050% for the purpose of reducing the alloy cost. The Ti content in the steel is set to be within the range of 0.035-0.050% for the purposes of reducing the water cooling and spraying amount after rolling, reducing the strength of the steel improved by water alloy after rolling and improving the cooling uniformity of the rolled material, and the technical purposes of the method are different from the technical purposes of the patent technology disclosed and reported in the application.
Therefore, the yield strength can be improved by 25Mpa and the tensile strength can be improved by 20Mpa for each 0.01 percent of titanium in the steel, the strength improved for each 0.01 percent of titanium is approximately equal to the strength reduced by improving the coiling temperature by 20 ℃, the water spraying amount after rolling can be reduced by about 10 percent, the Ti content in the molten steel is set at the upper limit of the component interval which does not influence the toughness and the plasticity of the steel obviously, the strength of the steel can be improved by using cheap Ti very possibly, and the toughness and the plasticity of the steel can not be reduced obviously.
2. The method is characterized in that the length parameters and the cooling water flow parameters of a quick cooling section, a laminar cooling section and a fine adjustment section are configured properly, the structure of a rolled material is controlled to be ferrite plus pearlite, the structure difference between the surface of the rolled material and the core part is reduced as much as possible, and the method mainly comprises the following steps:
(1) the front section of the cooling line is a fast cooling section, 2-4 groups of cooling collecting pipes are arranged in the fast cooling section, each group of cooling collecting pipes is 2-3m long, each group of cooling collecting pipes comprises 3-5 upper cooling collecting pipes and 6-10 lower cooling collecting pipes, the upper cooling collecting pipes are arranged right above the conveying rollers and are arranged in parallel to the conveying rollers, and the flow range of the single upper cooling collecting pipe is as follows: 140-200m3Flow range of single lower cooling header: 85-150m3And h, taking the distance a between two adjacent rollers of the conveying rollers as a unit, taking the distance a between two adjacent lower cooling headers of the quick cooling section as a, arranging one lower cooling header in the middle of the gap between every two conveying rollers of the quick cooling section, arranging 2a between two adjacent upper cooling headers of the quick cooling section, arranging the upper cooling header in the middle of every two lower cooling headers, and enabling every two lower cooling headers to correspond to one upper cooling header.
The method comprises the steps of arranging pyrometers at the positions of the quick cooling outlets, detecting the surface temperature of rolled stock by using the pyrometers, numbering the cooling headers of the quick cooling sections, wherein each numbering corresponds to one upper cooling header and two lower cooling headers, and setting the priority of opening the cooling headers, wherein the priority of opening the cooling headers is in such a way that the cooling headers opened in the cooling sections are distributed uniformly in the cooling sections as much as possible, and assuming that the total number of the numbers of the cooling headers of the sections is M and the distance between every two adjacent cooling headers corresponding to the numbers is L, the cooling header opened preferentially at the first stage is the cooling header numbered (1+ M)/2, wherein if the calculated value of (1+ M)/2 is not an integer, the integer closest to the calculated value is taken as the value of (1+ M)/2, the cooling header opened preferentially at the second stage is the cooling header opened preferentially at the interval from the cooling header opened at the previous stage is × L }/2, the calculated value of (M-1) at the interval from the cooling header opened preferentially at the previous stage is M-1, wherein the interval from the cooling header opened preferentially at the third stage is equal to the interval of M-1, the cooling header n, and the calculated value of opening preferentially n is taken as the integer from the interval between the cooling header n-1, wherein the interval between the cooling header opened preferentially n + n/(M-1, the calculated value of the cooling headers n-1, the interval of the cooling headers opened preferentially-361 is decreased sequentially from the interval of the cooling headers opened preferentially-n, and the interval of the cooling headers n-1, wherein the interval of the cooling headers opened preferentially-n, the cooling headers at the interval of the cooling headers opened preferentially-n, the interval of the.
If the headers from the inlet to the outlet of the quick cooling section are numbered 1 respectively#、2#、3#、4#、5#、6#、7#、 8#、9#、10#、11#、12#And the priority is 6 from high to low#→1#→12#→3#→9#→2#→11#→4#→7#→10#→5#→8#。
The number of cooling headers which need to be opened is calculated and the number of cooling headers with the highest priority is opened, i.e. if only 5 numbered cooling headers need to be opened, then 6 is opened#、1#、12#、3#、9#Cooling manifold, if 10 cooling manifolds corresponding to the number of the cooling manifolds need to be opened, then 6 are opened#、1#、12#、3#、9#、2#、11#、 4#、7#、10#The corresponding cooling manifold is numbered.
The aim of uniformly distributing cooling water in the quick cooling section as much as possible is achieved by controlling the preferential opening sequence of the cooling header. The surface temperature of the rolled material at the position of the quick cooling outlet is controlled to be 650-730 ℃ by controlling the opening group number of the cooling collecting pipes of the quick cooling section and matching with a high-temperature detector at the outlet of the quick cooling section. Because the temperature at which the transformation from austenite to bainite occurs in the rolled steel at a relatively high cooling rate is generally 600 ℃ or lower, the absence of bainite is an ideal target structure as long as the temperature of the surface of the rolled steel is controlled to be higher than 600 ℃, and the requirement that the controlled structure is ferrite plus pearlite can be met.
Therefore, the rapid cooling mode is adopted in the stage from the finish rolling to the cooling of the surface temperature of the rolled material to 650 ℃, the cooling intensity in the stage is increased as much as possible, and the length of the cooling line occupied by the cooling in the stage is reduced. Therefore, the front section of cooling after rolling is designed to be in a rapid cooling mode.
The length of the fast cooling section is about 8-12 m, and the temperature of the rolled material is reduced by about 150 ℃ in the fast cooling section.
The temperature difference between the surface of the rolled stock and the core is large due to the fact that the rolled stock is rapidly cooled in the rapid cooling section, and according to production experience, the temperature gradient between the surface and the core reaches 50-100 ℃ when the rolled stock enters the laminar cooling section, so that the surface temperature of the rolled stock is 650-730 ℃ when the rolled stock exits the rapid cooling section, but the average temperature of the rolled stock is above 700 ℃.
(2) The laminar cooling section is arranged behind the quick cooling section, 5-7 groups of cooling collecting pipes are arranged in the laminar cooling section, each group of cooling collecting pipes is 3-4m long, each group of cooling collecting pipes comprises 5-7 upper cooling collecting pipes and 10-14 lower cooling collecting pipes, the upper cooling collecting pipes are arranged right above the conveying rollers and are arranged in parallel to the conveying rollers, and the flow range of the single upper cooling collecting pipe is as follows: 70-100m3Flow range of single lower cooling header: 42-75m3Taking the distance a between two adjacent conveying rollers as a unit, the distance between two adjacent lower cooling headers of the laminar cooling section as a, and arranging one lower cooling set in the gap between every two conveying rollers of the laminar cooling sectionAnd the interval between two adjacent upper cooling headers of the fast cooling section is 2a, the upper cooling header is arranged between every two lower cooling headers, and each two lower cooling headers correspond to one upper cooling header.
Arranging a pyrometer at the position of a laminar flow outlet, detecting the surface temperature of a rolled material by using the pyrometer, numbering the cooling headers of the laminar flow cooling section, wherein each number corresponds to one upper cooling header and two lower cooling headers, and setting the opening priority of the cooling headers, the principle of the opening priority sequence of the cooling headers of the laminar flow cooling section is the same as that of the cooling headers of the rapid cooling section, and if the headers from the inlet to the outlet are respectively numbered as 13#、14#、 15#、16#、17#、18#、19#、20#、21#、22#、23#、24#、25#、26#、27#、28#、29#、30#、 31#、32#、33#、34#、35#、36#、37#、38#、39#、40#、41#、42#、43#、44#、45#、46#、 47#、48#Then the cooling manifold priority is 30 in order from high to low#→13#→48#→21#→39#→17#→25#→35#→44#→19#→22#→27#→32#→37#→42#→46#→15#→18#→20#→23#→29#→22#→31#→33#→36#→38#→40#→43#→45#→47#→14#→ 16#→24#→26#→28#→34#→41#。
The control of the preferential opening sequence of the cooling header pipes is adopted to achieve the aim of enabling the cooling water to be uniformly distributed in the laminar cooling as much as possibleBut for the purpose of the paragraph. The number of the cooling headers needing to be opened is obtained through settlement, and the number of the cooling headers with the highest priority is opened, namely if only 5 cooling headers with the corresponding numbers need to be opened, 30#、13#、48#、 21#、39#Cooling manifold, if 10 cooling manifolds corresponding to the number of the cooling manifolds are required to be opened, 30 cooling manifolds are opened#、13#、48#、 21#、39#、17#、25#、35#、44#、19#The corresponding cooling manifold is numbered. The surface temperature of a rolled material at the outlet position of the laminar cooling section is controlled to be 630-650 ℃ by controlling the opening group number of the cooling collecting pipes of the laminar cooling section and matching with a high-temperature detector at the outlet of the laminar cooling section.
The laminar flow section cooling line is long, the length is about 18-22m, the cooling strength is weak, the rolled stock is subjected to weak cooling in the laminar flow cooling section, the average temperature of the rolled stock is reduced by about 50 ℃, and the temperature gradient of the surface and the core of the rolled stock is reduced to 10-20 ℃.
(3) The rear section of the cooling line is a fine adjustment section, 1-3 groups of cooling headers are arranged in the fine adjustment section, each group of cooling headers is 4-6m long, each group of cooling headers comprises 2-6 upper cooling headers and 4-12 lower cooling headers, the upper cooling headers are arranged right above the conveying rollers and are parallel to the conveying rollers, and the flow range of the single upper cooling header is as follows: 70-100m3Flow range of single lower cooling header: 42-75m3And h, taking the distance a between two adjacent rollers of the conveying rollers as a unit, wherein the distance between two adjacent lower cooling headers of the fine adjustment section is 2a, the lower cooling headers are arranged in the gap between the two conveying rollers, one conveying roller is arranged between every two lower cooling headers, the distance between two adjacent upper cooling headers of the fine adjustment section is 4a, the upper cooling headers are arranged between every two lower cooling headers, and each two lower cooling headers correspond to one upper cooling header.
Arranging a pyrometer at the inlet position of the coiling equipment, detecting the surface temperature of the rolled stock by using the pyrometer, numbering the cooling headers at the fine adjustment section, wherein each number corresponds to one upper cooling header and two lower cooling headers, setting the priority of the opening of the cooling headers, and opening the cooling headers at the fine adjustment sectionThe principle of priority order is the same as the principle of the open priority order of the cooling headers of the rapid cooling sections, if the headers from the inlet to the outlet are numbered 49 respectively#、50#、51#、 52#、55#、56#、57#、58#Then the cooling header priority is 52 in order from high to low#→49#→58#→51#→56#→50#→55#→57#The aim of uniformly distributing cooling water in the fine adjustment section as much as possible is achieved by controlling the preferential opening sequence of the cooling header. The number of cooling headers that need to be switched on is found by the settlement and the number of cooling headers that are in the top priority is switched on, i.e. if only 3 numbered cooling headers are required, then the switching on 52 is performed#、49#、58#Cooling headers, if 5 numbered cooling headers are to be opened, then 52#、49#、58#、51#、56#. The coiling temperature is controlled to be 620-650 ℃ by controlling the number of the opening groups of the cooling header of the fine adjustment section and matching with a high-temperature detector at the inlet of the coiling equipment.
The length of the fine adjustment section is about 10m, the temperature of the rolled material is reduced by 10-20 ℃ in the fine adjustment section, the coiling temperature is controlled to be 620-650 ℃, and ferrite and pearlite transformation occurs in the rolled material after the fine adjustment section and coiling.
And the radial inclination angles of all the lower cooling headers after rolling are A: a is 3-5 degrees, so that the cooling water outflow of the lower cooling header is inclined along the running direction of the rolling line steel plate A;
the proportion of the cooling intensity of the fast cooling section, the laminar cooling section and the fine adjustment section is 4: 2: 1, rapidly reducing the temperature of the rolled stock by using the rapid cooling of the front section, reducing the temperature of the rolled stock by using the laminar cooling section in a small range, reducing the temperature gradient of the surface and the core of the rolled stock, and accurately controlling the temperature of the rolled stock before curling by using the fine adjustment section.
3. In order to solve the problem of uneven cooling in the width direction of a rolled material, the cooling header in cooling after rolling adopts a staggered arrangement mode in the width direction of the rolled material, and the arrangement mode is as follows: every two spray pipes in the cooling headers are spaced by a distance b in the width direction of the rolled stock, and of 3 adjacent groups of cooling headers, the second group of cooling headers is shifted by b/2 in the width direction of the rolled stock on the basis of the position of the first group of cooling headers, and the third group of cooling headers is shifted by-b/2 in the width direction of the rolled stock on the basis of the position of the second group of cooling headers, so that the cooling headers are cyclically staggered in this order.
THE ADVANTAGES OF THE PRESENT INVENTION
1. When the component Q355B is designed, the strength of the steel is improved by adopting cheap titanium, and the calculated result shows that the strength of the steel is improved by 20MPa by 0.01 percent of titanium (the cost is increased by 3.3 yuan/ton steel), the 20MPa can be used for offsetting the strength loss caused by the increase of the coiling temperature of the rolled material by 20 ℃, the cooling water spraying amount after rolling can be reduced under the condition of slightly increasing the cost, and the problem of inconsistent structures at the surface and the thickness of a core part of the rolled material caused by rapid cooling under the working condition of an extremely short cooling line can be relieved.
2. By utilizing the principle that the rolling material does not generate bainite transformation at the temperature of more than 650 ℃, the rolling material is rapidly cooled in the stage of reducing the surface temperature of the rolling material to 650 ℃ after finishing finish rolling, and although the rapid cooling in the stage can cause larger temperature gradient on the surface of the rolling material and the thickness of a core part, the phase transformation from austenite to ferrite can still be generated, and the target tissue for generating ferrite and pearlite has no harmful influence; the temperature of the rolled stock is reduced as fast as possible at the front cooling section, and the length of the cooling line can be saved.
3. The cooling header priority opening levels are set in the fast cooling section, the laminar flow cooling section and the fine adjustment section which are cooled after rolling, and after the opening group number of the cooling header of each cooling section is calculated, the opened cooling water can be uniformly distributed in each cooling section, so that the uniformity of cooling is improved, and the consistency of the structures on the surface of a rolled material and the thickness of a core part is improved; the phenomenon that bainite transformation occurs due to the fact that the surface temperature of the rolled stock is too low as the adjacent cooling headers are opened and sprayed water onto the rolled stock in a concentrated mode can be avoided.
4. The cooling headers are arranged in a staggered mode in the width direction of the rolled stock, the cooling headers in the later group move +/-b/2 in the width direction of the rolled stock on the basis of the positions of the cooling headers in the former group, and b is the distance between every two spray pipes in the cooling headers in the width direction of the rolled stock, so that the cooling uniformity in the width direction of the rolled stock can be improved.
Description of the drawings:
FIG. 1 is a diagram showing a state where the transverse cooling of a rolled material is not uniform due to the improper arrangement of cooling equipment after rolling.
Fig. 2 is a schematic layout of the post-rolling cooling apparatus provided in the present application.
Fig. 3 is a schematic diagram of a group of cooling structures in the rapid cooling section provided by the present application.
Fig. 4 is a schematic view of a group of cooling structures in the laminar cooling section provided in the present application.
Fig. 5 is a schematic diagram of a set of cooling structures in the fine tuning section provided in the present application.
FIG. 6 is a schematic view of the cooling header arrangement provided by the present application to solve the problem of uneven cross cooling of rolled stock.
Fig. 7 is a partially enlarged view of fig. 3 at the position B.
Wherein the numbering in figures 1-6 has the meaning: 1. rolling the material; 2. a cooling header; 3. a gooseneck; 4. areas where the rolled stock is high intensity cooled; 5. the area of the rolled stock cooled by weak strength; 6. a rolling mill; 7. a rapid cooling section; 8. a laminar cooling section; 9. fine adjustment section; 10. a pyrometer at the exit of the rapid cooling section; 11. a pyrometer at the exit of the laminar cooling section; 12. a pyrometer at the coiler inlet location; 13. a coiler; 14. a lower cooling header of the rapid cooling section; 15. a transport roller; 16. an upper cooling header of the rapid cooling section; 17. a gooseneck at the fast cooling section; 18. a lower cooling header of the laminar flow cooling section; 19. an upper cooling header of the laminar flow cooling section; 20. a gooseneck of the laminar cooling section; 21. a lower cooling header of the fine conditioning section; 22. an upper cooling header of the laminar flow cooling section; 23. a gooseneck of the laminar cooling section.
The specific implementation mode is as follows:
the following description will further describe a method for producing a hot-rolled wide steel strip Q355B which can be adapted to an extremely short post-rolling cooling line, by way of specific examples, with reference to the accompanying drawings of FIGS. 1 to 6.
Example 1
1. The titanium content in the components of the Q355B hot-rolled wide steel strip is properly increased, and the strength of the steel is improved by using a cheap titanium element, so that the strength of the steel improved by the water alloy after rolling can be reduced, the water cooling and spraying amount after rolling can be reduced, and the problem of uneven cooling of the surface and the core of the rolled steel under the working condition of an extremely short cooling line can be solved.
A cast slab of a furnace Q355B, comprising the following components: 0.16 percent of C, 0.15 percent of Si, 0.48 percent of Mn, 0.018 percent of P, 0.007 percent of S and 0.043 percent of Ti are produced by the following steps: molten iron pretreatment, 120t converter smelting, LF refining, slab caster and 1500mm semi-continuous rolling wide-belt rolling mill.
At the end of the pretreatment of the molten iron, controlling the sulfur in the molten iron to be below 0.020%, and completely removing slag on the surface of the molten iron after the desulfurization is finished; controlling the alkalinity of final slag smelted by the converter to be 3.0-3.5, carrying out deoxidation alloying in the tapping process of the converter, uniformly adding alloy when molten steel is discharged to 1/4, finishing alloy addition when the molten steel is discharged to 3/4, and adding the alloy aiming at a steel flow impact area; the alkalinity of final slag of LF refining is controlled to be more than 2.5, the slag on the top of a steel ladle before LF is discharged is required to be white slag, titanium iron or a titanium wire is adopted for titanium alloying after the white slag is produced, the LF refining period is not less than 35 minutes, wherein the soft blowing time is not less than 12 minutes, the molten steel in the ladle is required to be slightly moved by soft blowing, and the molten steel is not exposed; the liquidus temperature of the molten steel of Q355B is 1518 ℃ according to the target component, the superheat degree of the molten steel of the tundish is controlled to be 10-25 ℃, medium carbon steel covering slag is adopted, the drawing speed of a continuous casting machine is 1.20m/min, and the thickness of a continuous casting slab is 175 mm.
2. The 1500mm semi-continuous rolling wide belt rolling mill comprises the following process flows: continuous casting, heating, high-pressure water descaling, rough rolling reversible rolling (single-stand reciprocating rolling), hot rolling, flying shears, finish rolling (7-stand finishing mill set continuous rolling), laminar cooling and coiling.
Controlling the temperature of a certain Q355B casting blank in a heating furnace to be 1200-1250 ℃, controlling the time of the casting blank in the furnace to be 120min, carrying out 5-pass reciprocating rough rolling after the casting blank is discharged from the heating furnace, and controlling the temperature of the last rough rolling: 1050 ℃, then carrying out finish rolling on the blank, wherein the finish rolling temperature is 7 rolling mills: 870 ℃, the thickness of the finished rolled material is 14mm, and the final rolling speed is 2.6 m/s.
3. The length parameters and the cooling water flow parameters of the fast cooling section, the laminar cooling section and the fine adjustment section are configured properly, the structure of the rolled material is controlled to be ferrite plus pearlite, the structure difference between the surface of the rolled material and the core part is reduced as much as possible, and the method mainly comprises the following steps:
(1) as shown in fig. 2, the cooling process after rolling of the rolled material 1 is: after the rolled material 1 exits the rolling mill 6, the rolled material enters a post-rolling cooling line for cooling, is sequentially cooled by a fast cooling section 7, a laminar cooling section 8 and a fine adjusting section 9, is cooled to 650 ℃, and then enters a coiling machine for coiling.
(2) As shown in fig. 3, the front section of the post-rolling cooling line is a fast cooling section 7, the fast cooling section is provided with 3 groups of cooling headers, each group of cooling headers of the fast cooling section is 3m long, each group of cooling headers contains 4 upper cooling headers 16 and 8 lower cooling headers 14, the upper cooling headers 16 are arranged right above the transport rollers 15 and are arranged in parallel to the transport rollers 15, each upper cooling header 16 contains 2 gooseneck pipes 17, and the flow range of each upper cooling header is as follows: 140m3Flow range of the single lower cooling header 14: 85m3And h, taking the distance a between two adjacent rollers of the conveying rollers 15 as a unit, the distance a between two adjacent lower cooling headers 14 of the quick cooling section is, one lower cooling header 14 is arranged in the middle of the gap between every two conveying rollers 15 of the quick cooling section, the distance 2a between two adjacent upper cooling headers 16 of the quick cooling section is, the upper cooling headers 16 are arranged in the middle of every two lower cooling headers 14, and every two lower cooling headers 14 correspond to one upper cooling header 16.
The method comprises the steps of arranging a pyrometer (10) at a rapid cooling outlet position, detecting the surface temperature of a rolled product (1) by using the pyrometer (10), numbering the cooling headers of a rapid cooling section (7), and setting the priority of opening the cooling headers in such a manner that the cooling headers opened in the cooling section are distributed as uniformly as possible in the cooling section, assuming that the total number of the numbers of the cooling headers in the section is M and the distance between every two adjacent cooling headers is L, the first-stage preferentially-opened cooling header is the cooling header numbered (1+ M)/2, wherein if the calculated value of (1+ M)/2 is not an integer, the closest integer to the calculated value is taken as the value of (1+ M)/2, the second-stage preferentially-opened cooling header is the cooling header spaced from the previous-stage-opened cooling header by × L }/2, the third-stage preferentially-opened cooling header is the cooling header spaced from the previous-stage-opened cooling header by the integer of { M-1) × L }/2, the third-stage preferentially-opened cooling header is the cooling header × L }, the highest-n-1, and the calculated value of the cooling headers are sequentially decreased from the highest-n + n-n + n-.
One upper cooling header 16 and two lower cooling headers 14, each numbered 1 from inlet to outlet#、2#、3#、4#、5#、6#、7#、8#、9#、10#、11#、12#And setting the priority of the opening of the cooling header to be 6 in the order of high to low#→1#→12#→3#→9#→2#→11#→4#→7#→10#→5#→8#。
The cooling model after rolling calculates the number of cooling headers to be opened according to the finish rolling temperature, the target cooling temperature of the quick cooling section, the flow rate of the cooling headers, the thickness of the rolled material and the finish rolling speed of the rolled material, and opens the cooling headers with the number of the front priority, namely if only 5 cooling headers with the corresponding numbers are opened, 6 cooling headers with the corresponding numbers are opened#、1#、12#、3#、9#Cooling manifold, if 10 cooling manifolds corresponding to the number of the cooling manifolds need to be opened, then 6 are opened#、1#、12#、3#、9#、2#、 11#、4#、7#、10#The corresponding cooling manifold is numbered.
The surface temperature of the rolled material 1 is detected in real time through the pyrometer 10, the detected temperature value is compared with a target temperature value, and the detected temperature value and the target temperature value are close to the same value by adjusting the number of the opening groups of the cooling header of the rapid cooling section.
The aim of uniformly distributing cooling water in the quick cooling section 7 as much as possible is achieved by controlling the preferential opening sequence of the cooling header. The surface temperature of the rolled material 1 at the position of the fast cooling outlet is controlled to be 650 ℃ by controlling the opening group number of the cooling header of the fast cooling section and matching with the high temperature detector 10 at the outlet of the fast cooling section. Since the temperature at which transformation from austenite to bainite occurs in the rolled steel material 1 at a relatively high cooling rate is generally 600 ℃ or lower, it is an ideal target structure that bainite does not occur as long as the temperature of the surface of the rolled steel material 1 is controlled to be higher than 600 ℃, and the requirement that the controlled structure is ferrite plus pearlite can be achieved.
Therefore, the rapid cooling mode is adopted in the stage from the finish rolling to the cooling of the surface temperature of the rolled material to 650 ℃, the cooling intensity in the stage is increased as much as possible, and the length of the cooling line occupied by the cooling in the stage is reduced. Therefore, the front section of cooling after rolling is designed to be in a rapid cooling mode.
The length of the rapid cooling section 7 is about 9 meters, and the rolled stock 1 generates a temperature drop of about 150 ℃ in the rapid cooling section 7.
The temperature difference between the surface of the rolled stock and the core part is large due to the fact that the rolled stock is rapidly cooled in the rapid cooling section, and according to production experience, the temperature gradient between the surface and the core part reaches 50-100 ℃ when the rolled stock enters the laminar cooling section, so that the surface temperature of the rolled stock exiting the rapid cooling section reaches 650 ℃, but the average temperature of the rolled stock is about 700 ℃.
(3) As shown in fig. 4, the fast cooling section 7 is followed by the laminar cooling section 8, the laminar cooling section 8 is provided with 5 groups of cooling headers, each group of cooling headers is 3m long, each group of cooling headers comprises 6 upper cooling headers 19 and 12 lower cooling headers 18, the upper cooling headers 19 are arranged right above the transport rollers 15 and are arranged parallel to the transport rollers 15, each upper cooling header 19 comprises 2 gooseneck pipes 20, and the flow range of each upper cooling header 19 is as follows: 70m3Flow range of the single lower cooling header 18: 42m3Taking the distance a between two adjacent rollers of the conveying rollers 15 as a unit, the distance a between two adjacent lower cooling headers 18 of the laminar cooling section 8 is, one lower cooling header 18 is arranged in the gap between every two conveying rollers 15 of the laminar cooling section 8, the distance 2a between two adjacent upper cooling headers 19 of the quick cooling section is, the upper cooling header 19 is arranged between every two lower cooling headers, and every two lower cooling headers 18 correspond to one upper cooling header 18A header 19.
A pyrometer (11) is arranged at the position of a laminar flow outlet, the pyrometer (11) is used for detecting the surface temperature of a rolled material (1), cooling headers of a laminar flow cooling section are numbered, the opening priority of the cooling headers is set, the principle of the opening priority sequence of the cooling headers of the laminar flow cooling section is the same as that of the cooling headers of a rapid cooling section, each number corresponds to an upper cooling header (19) and two lower cooling headers (18), and the headers from the inlet of the laminar flow cooling section to the outlet of the laminar flow cooling section are respectively numbered as 13#、14#、15#、16#、17#、18#、19#、20#、21#、22#、23#、 24#、25#、26#、27#、28#、29#、30#、31#、32#、33#、34#、35#、36#、37#、38#、39#、 40#、41#、42#、43#、44#、45#、46#、47#、48#And priority of cooling header opening is set, and the priority is 30 in the order from high to low#→13#→48#→21#→39#→17#→25#→35#→44#→19#→22#→ 27#→32#→37#→42#→46#→15#→18#→20#→23#→29#→22#→31#→33#→36#→38#→40#→43#→45#→47#→14#→16#→24#→26#→28#→34#→41#。
The aim of uniformly distributing cooling water in the laminar cooling section 8 as much as possible is achieved by controlling the preferential opening sequence of the cooling header. The cooling model after rolling is based on the inlet temperature and layer of the laminar cooling section detected by the pyrometer 10Calculating the number of cooling headers needing to be opened according to the target cooling temperature, the flow rate of the cooling headers, the thickness of the rolled material and the final rolling speed of the rolled material in the flow cooling section, and opening the cooling headers with the number of the cooling headers with the front priority, namely opening 30 if only 5 cooling headers with the corresponding numbers need to be opened#、13#、48#、21#、39#Cooling manifold, if 10 cooling manifolds corresponding to the number of the cooling manifolds are required to be opened, 30 cooling manifolds are opened#、13#、48#、21#、39#、17#、25#、35#、44#、19#The corresponding cooling manifold is numbered. The surface temperature of a rolled product at the position of a laminar cooling outlet is controlled to be 640 ℃ by controlling the opening group number of the cooling headers of the laminar cooling section 8 and matching with a high temperature detector 11 at the outlet of the laminar cooling section.
The surface temperature of the rolled material 1 is detected in real time through the pyrometer 11, the detected temperature value is compared with a target temperature value, and the detected temperature value and the target temperature value are close to the same value by adjusting the number of the opening groups of the laminar flow cooling section cooling header.
The laminar flow section cooling line 8 is long, the length is about 15m, the cooling strength is weak, the rolled stock 1 is subjected to weak cooling in the laminar flow cooling section 8, the average temperature of the rolled stock is reduced by about 50 ℃, and the temperature gradient of the surface and the core of the rolled stock 1 is reduced to 10-20 ℃.
(4) As shown in fig. 5, the rear section of the cooling line is a fine adjustment section 9, the fine adjustment section 9 has 2 groups of cooling headers, each group of cooling headers is 6m long, each group of cooling headers has 4 upper cooling headers 22 and 8 lower cooling headers 21, the upper cooling headers 22 are arranged right above the transport rollers 15 and are arranged parallel to the transport rollers 15, each upper cooling header 22 includes 2 gooseneck pipes 23, and the flow range of each upper cooling header 22 is as follows: 70m3H, flow range of single lower header 21 pipe: 42m3Fine adjusting the distance between two adjacent lower cooling headers 21 to be 2a by taking the distance a between two adjacent rollers 15 of the conveying roller as a unit, arranging the lower cooling headers 21 in the gap between the two conveying rollers 15, spacing one conveying roller 15 between every two lower cooling headers 21, arranging the distance between two adjacent upper cooling headers 22 of the fast cooling section to be 4a, and arranging the upper cooling headers 22 in every two lower cooling headers 2221 and one upper cooling header 22 for each two lower cooling headers 21.
Arranging a pyrometer (12) at the inlet position of a coiling device, detecting the surface temperature of a rolled material by using the pyrometer (12), numbering cooling headers at a fine adjustment section, wherein each number corresponds to an upper cooling header and two lower cooling headers, and setting the opening priority of the cooling headers, the principle of the opening priority sequence of the cooling headers at the fine adjustment section is the same as that of the cooling headers at a quick cooling section, and the headers from an inlet to an outlet are respectively numbered 49#、50#、51#、 52#、55#、56#、57#、58#And priority of cooling header opening is set, the priority is 52 from high to low#→49#→58#→51#→56#→50#→55#→57#The aim of uniformly distributing cooling water in the fine adjustment section as much as possible is achieved by controlling the preferential opening sequence of the cooling header. The cooling model after rolling calculates the number of cooling headers to be opened according to the inlet temperature of the fine adjustment section, the coiling temperature, the flow of the cooling headers, the thickness of the rolled material and the final rolling speed of the rolled material detected by the pyrometer 11, and opens the cooling headers with the number of the cooling headers with the front priority, namely if only 3 cooling headers with the corresponding numbers need to be opened, the cooling headers with the front priority are opened 52#、49#、58#Cooling headers, if 5 numbered cooling headers are to be opened, then 52#、49#、58#、51#、56#. The coiling temperature is controlled to be 650 ℃ by controlling the number of open groups of the cooling header of the fast cooling section and matching with a high temperature detector 12 at the inlet of the coiling equipment.
The surface temperature of the rolled material 1 is detected in real time through the pyrometer 12, the detected temperature value is compared with a target temperature value, and the detected temperature value and the target temperature value are close to the same value by adjusting the number of the opening groups of the cooling header of the fine adjustment section.
The length of the fine adjustment section is about 10m, the temperature of the rolled material is reduced by 10 ℃ in the fine adjustment section, the coiling temperature is controlled to be 650 ℃, and the rolled material generates ferrite and pearlite transformation after the fine adjustment section and coiling.
And the radial inclination angles of all the lower cooling headers after rolling are A: a is 3 degrees, so that the cooling water outflow of the lower cooling header is inclined A along the running direction of the rolled steel plate.
The proportion of the cooling intensity of the fast cooling section 7, the laminar cooling section 8 and the fine adjustment section 9 is 4: 2: 1, rapidly cooling by using a rapid cooling section 7 to rapidly reduce the temperature of a rolled stock, reducing the temperature of the rolled stock by using a laminar cooling section 8 in a small range, reducing the temperature gradient of the surface and the core of the rolled stock, and accurately controlling the temperature of the rolled stock before coiling by using a fine adjustment section 9.
4. As shown in fig. 1 and 6, in order to solve the problem of uneven cooling in the width direction of the rolled stock, the cooling headers in post-rolling cooling are arranged in a staggered manner in the width direction of the rolled stock 1 in the following manner: every two spray pipes 3 of the cooling headers 2 are spaced apart by a distance b in the width direction of the rolled stock, and of the adjacent 3 groups of cooling headers, the second group is shifted by b/2 in the width direction of the rolled stock 1 on the basis of the position of the first group, and the third group is shifted by-b/2 in the width direction of the rolled stock 1 on the basis of the position of the second group, thereby cyclically staggering the cooling headers 2 in this order.
5. The mechanical properties, grain size and structure of the rolled material are shown in the attached table 4:
TABLE 4 measured Performance of Q355B rolled stock in example
As can be seen from the attached table 4, the performance of the rolled material completely meets the national standard requirements, the grain size is fine, the structures of the surface and the core of the rolled material are ferrite and pearlite, and the surface and the core of the rolled material have no structural difference, so that the technology provided by the application has good effect.
Example 2
The description of embodiment 2 is omitted where it is the same as embodiment 1.
A certain Q355B cast slab, comprising the following components: 0.17% of C, 0.12% of Si, 0.50% of Mn, 0.019% of P, 0.006% of S, 0.045% of Ti, and the final temperature of rough rolling: 1040 ℃, and the finish rolling temperature is as follows: 875 ℃, the thickness of the finished rolled material is 4mm, and the final rolling speed is 8 m/s.
As shown in fig. 3, the front section of the post-rolling cooling line is a fast cooling section 7, 4 groups of cooling headers are arranged in the fast cooling section, each group of cooling headers in the fast cooling section is 2m long, each group of cooling headers comprises 3 upper cooling headers 16 and 6 lower cooling headers 14, and the flow range of a single upper cooling header is as follows: 200m3Flow range of the single lower cooling header 14: 150m3/h。
The surface temperature of the rolled material 1 at the position of the fast cooling outlet is controlled to be 730 ℃ by controlling the opening group number of the cooling header of the fast cooling section and matching with the high temperature detector 10 at the outlet of the fast cooling section.
The length of the rapid cooling section 7 is about 12 meters, and the rolled stock 1 generates a temperature drop of about 150 ℃ in the rapid cooling section 7.
According to the production experience, the temperature gradient of the surface and the core of the rolled stock reaches 50 ℃ when the rolled stock enters a laminar cooling section, so that the surface temperature of the rolled stock when the rolled stock exits the rapid cooling section reaches 730 ℃, but the average temperature of the rolled stock is about 700 ℃ or above.
As shown in fig. 4, the fast cooling section 7 is followed by the laminar cooling section 8, the laminar cooling section 8 is provided with 5 groups of cooling headers, each group of cooling headers is 4m long, each group of cooling headers comprises 7 upper cooling headers 19 and 14 lower cooling headers 18, the upper cooling headers 19 are arranged right above the transport rollers 15 and are arranged parallel to the transport rollers 15, the single upper cooling header 19 comprises 2 gooseneck pipes 20, and the flow range of the single upper cooling header 19 is as follows: 100m3Flow range of the single lower cooling header 18: 75m3/h。
The surface temperature of the rolled stock at the position of the laminar cooling outlet is controlled to be 650 ℃ by controlling the opening group number of the cooling header of the laminar cooling section 8 and matching with a high temperature detector 11 at the outlet of the laminar cooling section.
The laminar cooling section 8 is long, has a length of about 20m and has weak cooling strength, and the rolled stock 1 is subjected to weak cooling in the laminar cooling section 8, so that the average temperature of the rolled stock is reduced by about 50 ℃, and the temperature gradient of the surface and the core of the rolled stock 1 is reduced to 20 ℃.
As shown in FIG. 5, the rear section of the cooling line isFine adjustment section 9, fine adjustment section 9 sets 1 group of cooling headers, each group of cooling headers is 6m long, each group of cooling headers comprises 6 upper cooling headers 22 and 12 lower cooling headers 21, and upper cooling headers 22 are arranged in the flow range of single upper cooling headers 22: 100m3H, flow range of single lower header 21 pipe: 75m3/h。
The surface temperature of the rolled material 1 is detected in real time through the pyrometer 12, the detected temperature value is compared with a target temperature value, and the detected temperature value and the target temperature value are close to the same value by adjusting the number of the opening groups of the cooling header of the fine adjustment section.
The length of the fine adjustment section is about 10m, the temperature of the rolled material is reduced by 20 ℃ in the fine adjustment section, the coiling temperature is controlled to be 620 ℃, and the rolled material generates ferrite and pearlite transformation after the fine adjustment section and coiling.
And the radial inclination angles of all the lower cooling headers after rolling are A: a is 5 degrees, so that the cooling water outflow of the lower cooling header is inclined A along the running direction of the rolled steel plate.
In order to achieve the effect of uniformly cooling the rolled stock, embodiment 2 may be provided with the priority of the opening of the cooling headers, and the principle of the opening priority order of the cooling headers in embodiment 2 is the same as that in embodiment 1.
The mechanical property, the grain size and the structure of the detected rolled material are shown in the attached table 5:
TABLE 5 measured Performance of Q355B rolled stock in example
Claims (11)
1. A cooling device which can adapt to a cooling line after the extremely short rolling of a hot-rolled wide steel strip is characterized in that,
a conveying roller is arranged along the conveying direction of the steel rolling steel plate, a cooling line is arranged on the plane of the conveying roller,
the cooling line is sequentially provided with a quick cooling section, a laminar cooling section and a fine adjustment section from front to back,
the upper parts of the quick cooling section, the laminar cooling section and the fine adjustment section are all provided with fixed beams which are used for fixing the cooling header;
2-4 groups of cooling headers are arranged at the quick cooling section,
the laminar flow cooling section is provided with 5-7 groups of cooling headers,
1-3 groups of cooling headers are arranged in the adjusting section;
each set of cooling headers includes an upper cooling header and a lower cooling header;
a group of upper cooling collecting pipes are formed by a plurality of gooseneck pipes, the upper cooling collecting pipes are arranged right above the conveying rollers and are parallel to the conveying rollers, and the upper cooling collecting pipes are arranged on the fixed beams.
2. The cooling apparatus adapted to an extremely short post-rolling cooling line of a hot-rolled wide steel strip according to claim 1, wherein a pyrometer is provided at an outlet position of the rapid cooling section, the laminar cooling section and/or the fine adjustment section, or
And pyrometers are arranged at the inlet positions of the quick cooling section, the laminar flow cooling section and/or the fine adjustment section and the inlet position of the coiling equipment.
3. The cooling apparatus adapted to an extremely short post-rolling cooling line of a hot-rolled wide steel strip according to claim 1, wherein the rapid cooling section is provided with 2 to 4 groups of cooling headers each having a length of 2 to 3m, and each group of cooling headers has 3 to 5 upper cooling headers and 6 to 10 lower cooling headers.
4. The cooling apparatus adapted to an extremely short post-rolling cooling line of a hot-rolled wide steel strip according to claim 1, wherein the length of the rapid cooling section is about 8 to 12 m.
5. The cooling apparatus adapted to an extremely short post-rolling cooling line of a hot-rolled wide steel strip according to claim 1, wherein the laminar-flow cooling section is provided with 5 to 7 groups of cooling headers each having a length of 3 to 4m, and each group of cooling headers has 5 to 7 upper cooling headers and 10 to 14 lower cooling headers.
6. The cooling apparatus adapted to an extremely short post-rolling cooling line of a hot-rolled wide steel strip according to claim 1, wherein the laminar cooling section has a length of 18 to 22 m.
7. The cooling apparatus adapted to an extremely short post-rolling cooling line of a hot-rolled wide steel strip according to claim 1, wherein the fine adjustment section is provided with 1 to 3 groups of cooling headers each having a length of 4 to 6m, and each group of cooling headers has 2 to 6 upper cooling headers and 4 to 12 lower cooling headers.
8. The cooling apparatus adaptable to an extremely short post-rolling cooling line of a hot-rolled wide steel strip according to any one of claims 1 to 7,
a lower cooling header is arranged between the gaps of every two transport rollers of the quick cooling section and the laminar flow cooling section, an upper cooling header is arranged between every two lower cooling headers, and every two lower cooling headers correspond to one upper cooling header;
in the fine adjustment section, the lower cooling headers are arranged in the gap between the two conveying rollers, every two lower cooling headers are separated by one conveying roller, the upper cooling headers are arranged in the middle of every two lower cooling headers, and every two lower cooling headers correspond to one upper cooling header.
9. The cooling apparatus adapted to an extremely short post-rolling cooling line of a hot-rolled wide steel strip according to claim 1, wherein the lower cooling header has a radial inclination angle a of 2 to 8 degrees.
10. The cooling apparatus adapted to an extremely short post-rolling cooling line of a hot-rolled wide steel strip according to claim 9, wherein a is 3 to 5 degrees.
11. The cooling apparatus adapted to an extremely short post-rolling cooling line of a hot-rolled wide steel strip according to claim 1, wherein the cooling headers in the post-rolling cooling are arranged in a staggered manner in the width direction of the rolled material.
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| CN110404987A (en) * | 2019-09-03 | 2019-11-05 | 山东钢铁股份有限公司 | A kind of cooling device and method adapting to the extremely short roller repairing line of hot rolled broad steel strip |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110404987A (en) * | 2019-09-03 | 2019-11-05 | 山东钢铁股份有限公司 | A kind of cooling device and method adapting to the extremely short roller repairing line of hot rolled broad steel strip |
| CN110404987B (en) * | 2019-09-03 | 2023-12-22 | 山东钢铁股份有限公司 | Cooling equipment and method capable of adapting to cooling line after extremely short rolling of hot-rolled wide steel strip |
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Effective date of registration: 20210622 Address after: 271100 Shuangquan Road, Gangcheng District, Jinan City, Shandong Province Patentee after: LAIGANG GROUP YINSHAN SHAPED STEEL Co.,Ltd. Address before: 250000 building 4, Shuntai Plaza, 2000 Shunhua Road, high tech Zone, Licheng District, Jinan City, Shandong Province Patentee before: SHANDONG IRON AND STEEL Co.,Ltd. |