A production method for controlling black lines on the edges of cold-rolled galvanized steel sheets

Abstract

The embodiment of the present application provides a production method for controlling the edge black line of a cold-rolled galvanized sheet, and the production line used in the production method comprises a heating furnace, a rough descaling device, a width setting press, and a rough rolling unit. The production method comprises the following steps: after a slab is heated by the heating furnace and descaled by the rough descaling device, the slab is sent to the width setting press to perform one-pass continuous side pressing in the full-length direction, so that the width of the slab is adjusted to the set blank width of the rough rolling unit, and the edges of the slab along the two side surfaces in the length direction are pressed into chamfers; the isosceles trapezoidal groove comprises a groove bottom surface, a groove opening, and an isosceles inclined surface, the width of the groove bottom surface is smaller than the width of the groove opening, the width of the groove bottom surface is 190 mm, the depth of the isosceles trapezoidal groove is 25 mm, the acute angle between the isosceles inclined surface and the groove bottom surface is 30 degrees, the isosceles inclined surface and the groove bottom surface are connected through a first round corner with a radius of 20 mm, and the isosceles inclined surface and the working side surface outside the groove opening are connected through a second round corner with a radius of 20 mm.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of hot rolling process, in particular to a production method for controlling edge black line of cold-rolled galvanized sheet. BACKGROUND

[0002] Galvanized sheet is mainly used in construction, household appliances, automobiles, machinery, electronics, light industry and other industries, and is a kind of metal material with large consumption. The thickness of the galvanized base plate produced by the 1780mm production line of Guangxi Steel Hot Rolling Mill is mainly 2.0-6.0mm, which is sent to cold rolling for pickling and rolling and then galvanizing. Before cold rolling, the galvanized base plate needs to be edge cut, and the edge cutting amount after pickling is between 10-15mm. However, edge black line defects are easily generated during the rolling process, and the distance between the edge black line and the edge of the strip is between 8-25mm, which may cause the cold rolling edge cutting to be unable to be cut off. The edge black line defects cannot be eliminated in the pickling process, resulting in edge quality problems of the galvanized coil produced subsequently, directly affecting the product quality and yield. If the edge cutting amount, i.e. the cold rolling cutting amount, is increased to 25mm, the yield will be significantly reduced. In order to eliminate the defects in the hot rolling process, the existing technology adopts the method of increasing the overall heating temperature of the heating furnace, which greatly increases the production energy consumption.

[0003] In the process of realizing the present application, the applicant found that at least the following problems exist in the prior art:

[0004] The problem of easily generating edge black line during rolling. SUMMARY

[0005] The embodiment of the present application provides a production method for controlling edge black line of cold-rolled galvanized sheet, which solves the problem of easily generating edge black line during rolling.

[0006] To achieve the above purpose, on the one hand, the embodiment of the present application provides a production method for controlling edge black line of cold-rolled galvanized sheet, and the production line used in the production method comprises a heating furnace, a rough descaling device arranged at the outlet side of the heating furnace, a width setting press arranged at the outlet side of the rough descaling device, and a rough rolling mill group arranged at the outlet side of the width setting press. The production method comprises the following steps:

[0007] After the slab is heated by the heating furnace and descaled by the rough descaling device, the slab is sent to the width setting press to perform one-pass continuous side pressing in the full-length direction, so that the width of the slab is adjusted to the set blank width of the rough rolling mill, and the edges of the two side surfaces of the slab along the length direction are pressed to be chamfered;

[0008] The two side pressing modules are arranged symmetrically on the width setting press, and the two side pressing modules are used to press the two side surfaces of the slab along the length direction when the slab passes through the width setting press. An isosceles trapezoidal groove in the horizontal direction is arranged on the working side of each side pressing module, so that the edges of the two side surfaces of the slab along the length direction are pressed to be chamfered by the isosceles inclined surface of the isosceles trapezoidal groove.

[0009] The isosceles trapezoidal groove includes a groove bottom, a groove opening and an isosceles inclined surface, the groove bottom width is less than the groove opening width, the groove bottom width is 190 mm, the groove depth of the isosceles trapezoidal groove is 25 mm, the isosceles inclined surface forms an acute angle of 30 degrees with the groove bottom, the isosceles inclined surface is connected with the groove bottom through a first round corner with a radius of 20 mm, and the isosceles inclined surface is connected with a working side surface outside the groove opening through a second round corner with a radius of 20 mm.

[0010] Further, the rough rolling mill group includes a first rough rolling mill and a second rough rolling mill, and the production line used in the production method further includes a hot coil box arranged at an outlet side of the second rough rolling mill, and the production method further includes:

[0011] A first heat preservation cover is arranged between the sizing press and the first rough rolling mill to preserve the slab;

[0012] A second heat preservation cover is arranged between the first rough rolling mill and the second rough rolling mill to preserve the slab;

[0013] A third heat preservation cover is arranged between the second rough rolling mill and the hot coil box to preserve the slab.

[0014] Further, the method further includes:

[0015] The heating-in slab has a furnace time greater than 100 minutes, the load distribution of the heating furnace is adjusted, the furnace gas temperature of the three-addition section of the heating furnace is higher than that of the preheating section by 1130 to 1160 degrees Celsius, the furnace gas temperature of the three-addition section of the heating furnace is higher than that of the one-addition section by 140 to 190 degrees Celsius, the furnace gas temperature of the three-addition section of the heating furnace is higher than that of the two-addition section by 40 to 60 degrees Celsius, the furnace gas temperature of the uniform heating section of the heating furnace is higher than that of the preheating section by 1100 to 1140 degrees Celsius, the furnace gas temperature of the uniform heating section of the heating furnace is higher than that of the one-addition section by 120 to 150 degrees Celsius, the furnace gas temperature of the uniform heating section of the heating furnace is higher than that of the two-addition section by 15 to 30 degrees Celsius, and the furnace gas temperature of the three-addition section of the heating furnace is higher than that of the uniform heating section by 15 to 45 degrees Celsius, so that the temperature difference of the upper surface temperature, the center temperature and the lower surface temperature of the slab is not greater than 20 degrees Celsius.

[0016] The heating-in slab has a steel charging temperature greater than 400 degrees Celsius.

[0017] Further, the method further includes:

[0018] The furnace time of the controlled cooling slab is greater than 160 minutes, the load distribution of the heating furnace is adjusted, the furnace gas temperature of the three-addition section of the heating furnace is 570-590 degrees Celsius higher than that of the preheating section, the furnace gas temperature of the three-addition section of the heating furnace is 110-130 degrees Celsius higher than that of the one-addition section, the furnace gas temperature of the three-addition section of the heating furnace is 40-60 degrees Celsius higher than that of the two-addition section, the furnace gas temperature of the equalizing section of the heating furnace is 560-590 degrees Celsius higher than that of the preheating section, the furnace gas temperature of the equalizing section of the heating furnace is 100-120 degrees Celsius higher than that of the one-addition section, the furnace gas temperature of the equalizing section of the heating furnace is 35-45 degrees Celsius higher than that of the two-addition section, and the furnace gas temperature of the three-addition section of the heating furnace is 5-15 degrees Celsius higher than that of the equalizing section, so that the temperature difference between the upper surface temperature, the center temperature and the lower surface temperature of the slab is not greater than 20 degrees Celsius.

[0019] The loading temperature of the cold loading slab is less than 110 degrees Celsius.

[0020] Further, the method further comprises: the plate surface of the vertical roll water baffle of the rough rolling mill group is perpendicular to the vertical roll surface, and the gap between the vertical roll water baffle and the vertical roll is less than 1.5 centimeters.

[0021] Further, the rough rolling adopts reversible rolling, the rough rolling mill group comprises a first rough rolling mill and a second rough rolling mill, and the method further comprises:

[0022] According to the production mode and the rolling requirements of the grade, the rolling mode of the first rough rolling mill and the second rough rolling mill is set to 0+5 mode; the 0+5 mode corresponds to 3 passes of vertical roll reduction, the vertical roll reduction amount of the first pass is less than or equal to 8 millimeters, and the vertical roll load distribution coefficient corresponding to 3 passes of vertical roll reduction is 0.15:1:1.

[0023] Further, the rough rolling adopts reversible rolling, the rough rolling mill group comprises a first rough rolling mill and a second rough rolling mill, and the method further comprises:

[0024] According to the production mode and the rolling requirements of the grade, the rolling mode of the first rough rolling mill and the second rough rolling mill is set to 1+5 mode; the 1+5 mode corresponds to 4 passes of vertical roll reduction, the vertical roll reduction amount of the first pass is less than or equal to 8 millimeters, and the vertical roll load distribution coefficient corresponding to 4 passes of vertical roll reduction is 0.1:1:1:0.6.

[0025] Further, the rough rolling adopts reversible rolling, the rough rolling mill group comprises a first rough rolling mill and a second rough rolling mill, and the method further comprises:

[0026] According to the production mode and the brand rolling requirements, the rolling modes of the first rough rolling mill and the second rough rolling mill are set to a 3+3 mode; the 3+3 mode corresponds to 4 passes of stand roll width-reducing rolling, the first pass of stand roll width-reducing rolling corresponds to a stand roll width-reducing amount less than or equal to 8 mm, and the stand roll load distribution coefficient corresponding to the 4 passes of stand roll width-reducing rolling is 0.1:1:1:0.6.

[0027] Further, the method further comprises:

[0028] The first rough rolling mill and the second rough rolling mill are set to a short stroke at the head and tail, the front pass of stand roll width-reducing rolling is set to an open roll gap to ensure the uniformity of the overall width of the intermediate blank and avoid width loss at the head and tail, and the rear pass of stand roll width-reducing rolling is set to a closed roll gap to avoid width excess at the head and tail, so that the width deviation of the strip steel is controlled to be less than or equal to 10 mm.

[0029] Further, the production line used in the production method further comprises a pre-finishing rolling area and a finishing rolling area, the pre-finishing rolling area comprises a flying shear and a flying shear front side guide plate, the finishing rolling area comprises a first finishing rolling mill, a second finishing rolling mill, a third finishing rolling mill, a fourth finishing rolling mill, a fifth finishing rolling mill, a sixth finishing rolling mill and a seventh finishing rolling mill, and the method further comprises:

[0030] In the pre-finishing rolling area, the head short stroke of the flying shear front side guide plate is set to the intermediate blank width plus 25 mm, the middle short stroke of the flying shear front side guide plate is set to the intermediate blank width plus 10 mm, and the tail short stroke of the flying shear front side guide plate is set to the intermediate blank width plus 25 mm.

[0031] In the finishing rolling area, the opening degree of the finishing rolling mill group side guide plate is set to:

[0032] The pre-position corresponding to the first finishing rolling mill is the intermediate blank width plus 5 mm, the rolling position corresponding to the first finishing rolling mill is the intermediate blank width plus 5 mm, the tail opening corresponding to the first finishing rolling mill is the intermediate blank width plus 5 mm,

[0033] The pre-position corresponding to the second finishing rolling mill is the intermediate blank width plus 10 mm, the rolling position corresponding to the second finishing rolling mill is the intermediate blank width plus 10 mm, the tail opening corresponding to the second finishing rolling mill is the intermediate blank width plus 10 mm,

[0034] The pre-position corresponding to the third finishing rolling mill is the intermediate blank width plus 15 mm, the rolling position corresponding to the third finishing rolling mill is the intermediate blank width plus 15 mm, the tail opening corresponding to the third finishing rolling mill is the intermediate blank width plus 15 mm,

[0035] The pre-position corresponding to the fourth finishing rolling mill is the intermediate blank width plus 20 mm, the rolling position corresponding to the fourth finishing rolling mill is the intermediate blank width plus 20 mm, the tail opening corresponding to the fourth finishing rolling mill is the intermediate blank width plus 20 mm,

[0036] The fifth finishing mill corresponds to a pre-positioning of the intermediate blank width plus 30 mm, the fifth finishing mill corresponds to a rolling position of the intermediate blank width plus 30 mm, and the fifth finishing mill corresponds to a tail opening of the intermediate blank width plus 30 mm,

[0037] The sixth finishing mill corresponds to a pre-positioning of the intermediate blank width plus 35 mm, the sixth finishing mill corresponds to a rolling position of the intermediate blank width plus 35 mm, and the sixth finishing mill corresponds to a tail opening of the intermediate blank width plus 35 mm,

[0038] The seventh finishing mill corresponds to a pre-positioning of the intermediate blank width plus 35 mm, the seventh finishing mill corresponds to a rolling position of the intermediate blank width plus 35 mm, and the seventh finishing mill corresponds to a tail opening of the intermediate blank width plus 35 mm.

[0039] Further, the production method adopts a production line further comprising: a coiler, and the method further comprises:

[0040] The short stroke control parameters of the side guide plate of the coiler are set as follows: the side guide plate standby position is the controlled width of the strip steel plus 30 mm, the first short stroke walking position is the controlled width of the strip steel plus 20 mm, and the second short stroke walking position is the controlled width of the strip steel plus 10 mm;

[0041] The head of the strip steel is tracked through heat detection and roller speed calculation, and the short stroke operation is started when the head of the strip steel reaches the side guide plate. When the side guide plate contacts the strip steel and the single-sided side guide plate pressure feedback reaches 6 kN, the single-sided pressure control is switched, and the other side is position control.

[0042] The above technical scheme has the following beneficial effects: the edge of the slab is pressed into a chamfer by using the side pressure module of the chamfer module for the fixed-width press, which effectively improves the shape of the edge of the slab, reduces the temperature drop of the edge of the slab in the subsequent transportation process, reduces the height of the drum after side pressing, and suppresses the upward turning of the edge metal. Reducing the temperature drop of the edge can avoid entering the two-phase region for rolling, thereby avoiding the generation of black lines, and reducing the height of the drum can reduce the distance from the black line to the edge, thereby meeting the cold rolling edge cutting condition.

[0043] By adjusting the load distribution of the heating furnace, increasing the furnace gas temperature of the three heating sections and the soaking section of the heating furnace, and reducing the furnace gas temperature of other sections, the surface temperature of the slab can be increased, the edge temperature of the slab during rough rolling is higher, and the degree of black line on the edge is reduced without increasing energy consumption.

[0044] According to the rolling mode, the stand roll reduction pass, the first pass stand roll reduction amount, and the stand roll load distribution coefficient of each pass determined according to the production mode and the rolling requirement of the brand, the distance between the edge black line and the edge can be effectively controlled within 10 mm to meet the cold rolling trimming condition, and the surface quality of the cold rolling coil is improved. By adjusting the stand roll short stroke control, the overall width uniformity of the strip steel is adjusted, the head or tail of the strip steel is prevented from being too wide to scratch the side guide plate, the edge quality of the head and tail of the strip steel is ensured, the over-wide condition of the head and tail of the intermediate blank is prevented, the width deviation of the strip steel is controlled within 10 mm, the edge black line caused by the over-wide head and tail of the strip steel scratching the side guide plate of the finishing rolling and coiling is prevented, the opening degree of the side guide plate of the pre-rolling area and the finishing rolling area is controlled, the head and tail of the intermediate blank are prevented from being seriously scratched by the side guide plate when the intermediate blank appears to be a sickle, the strip steel is centered, the scratching of the side guide plate during the strip passing is reduced, and the edge quality of the strip steel is improved. The side guide plate of the coiling machine is controlled in short stroke, even if the strip steel shape moves at the outlet of the finishing rolling, the side guide plate of the coiling machine will not be seriously rubbed with the strip steel, and the opening degree of the side guide plate of the coiling machine is stable.

[0045] By the control mode, the hot coil shape is ensured, the side guide plate rubbing is reduced, and the edge quality of the strip steel is improved. The proportion of the edge black line defects of the galvanized plate is controlled, and the proportion of the edge black line defects of the galvanized plate is reduced from 19.5% to less than 1.5%. The surface quality of the hot rolling coil and the cold rolling coil is obviously improved, the cold rolling trimming amount is reduced, and the yield of the galvanized plate is increased by 0.2%. The hot rolling mill can not control the edge black line defects by increasing the discharge temperature, the production efficiency is improved, and the energy consumption is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only show some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort based on these drawings.

[0047] Figure 1 is a flow chart of a production method for controlling the edge black line of a cold rolling galvanized plate according to an embodiment of the present application;

[0048] Figure 2 is a schematic diagram of a production line used in the production method according to an embodiment of the present application;

[0049] Figure 3 is a structural schematic diagram of a side pressing module according to an embodiment of the present application;

[0050] Figure 4 is a structural schematic diagram of a right-angle side pressing module of Comparative Example 1;

[0051] Figure 5 is a schematic diagram of a slab cross section with drumming at the edge of the slab;

[0052] Figure 6 is a physical diagram of a heat shield according to one of the embodiments of the present application;

[0053] Figure 7 is a schematic diagram of the walking of a side guide plate of a coiler according to one of the embodiments of the present application;

[0054] Figure 8 is a schematic diagram of the relative position of a water baffle and a vertical roll according to one of the embodiments of the present application.

[0055] BRIEF DESCRIPTION OF DRAWINGS 1, heating furnace; 2, rough descaling; 3, width setting press; 4, first heat shield; 5, first rough rolling mill; 6, second heat shield; 7, second rough rolling mill; 8, third heat shield; 9, hot coil box; 10, flying shear; 11, fine descaling; 12, finishing rolling area; 13, laminar cooling area; 14, coiler; 15, cooling water nozzle; 16, vertical roll; 17, water baffle; D, distance between water baffle and roll surface of vertical roll; Pw, waiting position of side guide plate; W, controlled width of strip steel; SS1, first short stroke walking; SS2, second short stroke walking; 31, side pressing module; 311, working side surface; 312, groove bottom surface; 313, groove opening; 314, isosceles bevel; 315, groove depth; A, acute angle between isosceles bevel and groove bottom surface; R1, first round corner; R2, second round corner; 201, drumming; 20, slab. DETAILED DESCRIPTION

[0056] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0057] The inventor found that the 1780mm production line of Liuzhou Iron and Steel Hot Rolling Mill has many devices, the rolling line is long, the temperature of the edge of the slab decreases greatly during transportation, and the edge black line defect is easily generated during rolling. The edge black line is 8-25mm away from the edge of the strip steel, and the cold rolling edge cutting cannot be cut off. The black line defect cannot be eliminated in the pickling process, which causes the edge quality problem of the galvanized coil produced subsequently, and directly affects the product quality and the yield. In order to eliminate the defect in the hot rolling process, the prior art adopts the method of improving the overall heating temperature of the heating furnace, which greatly improves the production energy consumption.

[0058] To solve the above problems, on the one hand, as shown in Figure 1As shown, the embodiment of the present application is directed to a 1780mm production line of a hot rolling mill, and provides a production method for controlling the black line at the edge of a cold-rolled galvanized sheet, as shown in Figure 2 As shown, the production line used in the production method includes a heating furnace 1, a rough descaling device 2 arranged at the outlet side of the heating furnace 1, a sizing press 3 arranged at the outlet side of the rough descaling device 2, and a rough rolling mill arranged at the outlet side of the sizing press 3. The production method includes the following steps:

[0059] In step S100, after the slab is heated by the heating furnace 1 and descaled by the rough descaling device 2, the slab is sent to the sizing press 3 to perform one-pass continuous side pressing in the full-length direction, so that the width of the slab is adjusted to the billet width set by the rough rolling mill, and the edge of the slab along the length direction of the two sides is pressed to be chamfered.

[0060] In the sizing press 3, two side pressing modules are symmetrically arranged on the sizing press 3, and the two side pressing modules are used to press the two sides of the slab in the length direction when the slab passes through the sizing press 3. A horizontal isosceles trapezoidal groove is arranged on the working side 311 of each side pressing module 31, so that the edge of the two sides of the slab in the length direction is pressed to be chamfered by the isosceles inclined surface 314 of the isosceles trapezoidal groove.

[0061] As shown, Figure 3 The isosceles trapezoidal groove includes a groove bottom surface 312, a groove opening 313, and an isosceles inclined surface 314. The width of the groove bottom surface 312 is smaller than the width of the groove opening 313. The width of the groove bottom surface 312 is 190mm. The groove depth 315 of the isosceles trapezoidal groove is 25mm. The acute angle A between the isosceles inclined surface 314 and the groove bottom surface 312 is 30 degrees. The isosceles inclined surface 314 and the groove bottom surface 312 are connected by a first round corner R1 with a radius of 20mm. The isosceles inclined surface 314 and the working side 311 outside the groove opening 313 are connected by a second round corner R2 with a radius of 20mm.

[0062] In some embodiments, the sizing press is used to press the slab, and the side pressing module of the sizing press is a chamfering module, as shown in Figure 3As shown, the module bottom groove depth is 25 mm, the bottom groove width is 190 mm, the acute angle A between the isosceles inclined surface and the groove bottom surface is 30 degrees, the isosceles inclined surface and the groove bottom surface are connected through a first round corner R1 with a radius of 20 mm, and the isosceles inclined surface and the working side surface outside the groove opening are connected through a second round corner R2 with a radius of 20 mm. The chamfered side pressing module can effectively improve the edge shape of the slab, reduce the edge temperature drop of the slab in the subsequent transportation process, and reduce the drum height after side pressing and inhibit the upward turning of the edge metal. The conventional use of the width setting press is to reduce the width of the slab. In the embodiment of the present application, in addition to reducing the width of the slab, the side pressing module capable of forming a chamfer on the edge of the slab is used to change the edge shape of the slab, change the right angle (the right angle has a large air contact surface and is easy to drop in temperature) to a chamfer (the chamfer has a small air contact surface and a small temperature drop), thereby reducing the temperature drop of the edge of the slab.

[0063] Table 1 is a comparison of the effects of three side pressing modules, which are the side pressing module of the present embodiment, the comparative example 1 and the comparative example 2. The comparative example 1 is a right angle side pressing module as shown in Figure 4 The comparative example 2 is a chamfered side pressing module as shown in Figure 3 The implementation effect in Table 1 is the statistical result of the test data of the product with the specifications as shown in Table 2. The chemical composition of the steel strip in Table 2 includes, by weight percentage wt%, C: ≤0.07, Si: ≤0.06, Mn: 0.1-0.25, P: ≤0.0025, S: ≤0.0025, Alt: 0.02-0.05, Ti: ≤0.010, As: ≤0.040, Cu: ≤0.10, Ni: ≤0.10, Cr: ≤0.10, and the rest is iron and unavoidable impurities. The performance requirements of the galvanized sheet are as follows: yield strength ReL: ≤280 MPa (mega pascal), tensile strength Rm: 270-410 MPa, elongation A80: ≥28%. Table 3-1 and Table 3-2 are the specific numerical values of the chemical composition of the steel strip and the performance of the galvanized sheet, wherein the same row in Table 3-1 and Table 3-2 corresponds to the same row of data.

[0064]

[0065]

[0066] Table 1 is a comparison of the effects of three side pressing modules, which are the side pressing module of the present embodiment, the comparative example 1 and the comparative example 2. The comparative example 1 is a right angle side pressing module as shown in

[0067] Slab thickness * width * length (unit: mm) Galvanized substrate thickness * length (unit: mm) 230 * 1260 * 11000 mm 4.0 * 1280 mm 230 * 1260 * 11000 mm 4.5 * 1280 mm 230 * 1260 * 11000 mm 5.0 * 1280 mm 230 * 1260 * 11000 mm 5.5 * 1280 mm 230 * 1500 * 11000 mm 4.5 * 1530 mm 230 * 1500 * 11000 mm 5.0 * 1530 mm

[0068] Table 2 is the product specification data for testing

[0069]

[0070]

[0071]

[0072] Table 3-1 Specific composition and performance data of the strip steel obtained from the test

[0073]

[0074]

[0075] Table 3-2 Specific composition and performance data of the strip steel obtained from the test

[0076] The comparison shows that the right-angle side-pressing module in Comparative Example 1 does not improve the edge shape of the slab after side-pressing; in fact, the resulting dog-bone cross-section exacerbates the black line defects at the edges. The side-pressing module in Comparative Example 2 can control the black line defects to 0.16%, but the slab exhibits a boat-shaped shape after tapping (the chamfer is too deep, severely obstructing longitudinal metal flow after tapping), resulting in a deteriorated rough-rolled slab shape. The side-pressing module in this embodiment can control the black line defects to 0.23%, which is slightly lower than the side-pressing module in Comparative Example 2, but it does not exhibit a boat-shaped shape after tapping, resulting in a good rough-rolled slab shape. Specifically, in this embodiment, a fixed-width press is used to side-press the slab. The side-pressing module of the fixed-width press is a chamfering module. Based on the slab's incoming height of 230 mm, the module's bottom groove depth is designed to be 25 mm, and the bottom groove width is 190 mm. The acute angle between the isosceles inclined plane and the bottom surface of the groove is 30 degrees. The isosceles inclined plane and the bottom surface of the groove are connected by a fillet with a radius of 20 mm. The isosceles inclined plane and the working side surface outside the groove opening are also connected by a fillet with a radius of 20 mm. The gentle slope design and shallow bottom groove depth can reduce the inhibitory effect of the chamfer on metal flow, ensuring a good slab shape after side pressing and preventing ship-shaped defects (i.e., such as...). Figure 5 The cross-section of the slab shown has bulges 201 at both edges along its length, making the cross-section of slab 20 resemble a ship's cabin. The chamfering design alters the edge shape of the slab, changing right angles to chamfers, reducing the contact area between the slab and cold air / cooling water during subsequent transportation, thus reducing temperature drop at the slab edges. It also increases the edge temperature of the slab during rough rolling, preventing the edge metal temperature from falling within the two-phase rolling temperature range.

[0077] Furthermore, such as Figure 2 As shown, the roughing mill unit includes a first roughing mill 5 and a second roughing mill 7. The production line used in the production method also includes a hot coil box 9 located on the exit side of the second roughing mill 7. The production method further includes:

[0078] A first insulation cover 4 is installed between the fixed-width press 3 and the first roughing mill 5 to insulate the slab; and / or,

[0079] A second heat preservation cover 6 is arranged between the first rough rolling mill 5 and the second rough rolling mill 7 to heat the slab; and / or,

[0080] A third heat preservation cover 8 is arranged between the second rough rolling mill 7 and the hot coil box 9 to heat the slab.

[0081] In some embodiments, the present embodiment uses a fixed-width press to side-press the slab, and the side-pressing module of the fixed-width press is a chamfering module. The design module has a bottom groove depth of 25 mm, a bottom groove width of 190 mm, an acute angle of 30 degrees between the isosceles bevel and the groove bottom surface, a radius of 20 mm connecting the isosceles bevel and the groove bottom surface, and a radius of 20 mm connecting the isosceles bevel and the working side surface outside the groove opening. The gentle slope design and the shallow bottom groove depth can reduce the inhibitory effect of chamfering on metal flow, ensure good slab shape after side-pressing, and prevent the occurrence of boat-shaped defects. The chamfering design can change the shape of the slab edge from a right angle to a chamfer, reduce the contact area of the slab edge with cold air and cooling water during subsequent transportation, and reduce the temperature drop of the slab edge. A rough rolling heat preservation cover (including a first heat preservation cover, a second heat preservation cover, and / or a third heat preservation cover, Figure 6 a physical diagram of the heat preservation cover) is installed in the rough rolling area (including between the fixed-width press and the first rough rolling mill, between the first rough rolling mill and the second rough rolling mill, and / or between the second rough rolling mill and the hot coil box),

[0082] Further, the method further comprises:

[0083] controlling the hot charging slab to have a furnace time greater than 100 minutes, adjusting the load distribution of the heating furnace, so that the furnace gas temperature of the three-addition section of the heating furnace is 1130 to 1160 degrees Celsius higher than that of the preheating section, the furnace gas temperature of the three-addition section of the heating furnace is 140 to 190 degrees Celsius higher than that of the one-addition section, the furnace gas temperature of the three-addition section of the heating furnace is 40 to 60 degrees Celsius higher than that of the two-addition section, the furnace gas temperature of the uniform heating section of the heating furnace is 1100 to 1140 degrees Celsius higher than that of the preheating section, the furnace gas temperature of the uniform heating section of the heating furnace is 120 to 150 degrees Celsius higher than that of the one-addition section, the furnace gas temperature of the uniform heating section of the heating furnace is 15 to 30 degrees Celsius higher than that of the two-addition section, and the furnace gas temperature of the three-addition section of the heating furnace is 15 to 45 degrees Celsius higher than that of the soaking section, so that the temperature difference between the upper surface temperature, the center temperature, and the lower surface temperature of the slab is not greater than 20 degrees Celsius;

[0084] wherein the hot charging slab has a steel charging temperature greater than 400 degrees Celsius.

[0085] Further, the method further comprises:

[0086] The furnace time of the controlled cooling slab is greater than 160 minutes, the load distribution of the heating furnace is adjusted, the furnace gas temperature of the three-addition section of the heating furnace is 570-590 degrees Celsius higher than that of the preheating section, the furnace gas temperature of the three-addition section of the heating furnace is 110-130 degrees Celsius higher than that of the one-addition section, the furnace gas temperature of the three-addition section of the heating furnace is 40-60 degrees Celsius higher than that of the two-addition section, the furnace gas temperature of the equalization section of the heating furnace is 560-590 degrees Celsius higher than that of the preheating section, the furnace gas temperature of the equalization section of the heating furnace is 100-120 degrees Celsius higher than that of the one-addition section, the furnace gas temperature of the equalization section of the heating furnace is 35-45 degrees Celsius higher than that of the two-addition section, and the furnace gas temperature of the three-addition section of the heating furnace is 5-15 degrees Celsius higher than that of the equalization section, so that the temperature difference of the upper surface temperature, the center temperature and the lower surface temperature of the slab is not greater than 20 degrees Celsius.

[0087] The loading temperature of the cold loading slab is less than 110 degrees Celsius.

[0088] In some embodiments, the edge black is controlled by controlling the furnace gas temperature of the heating furnace, specifically, controlling the slab in-furnace time, ensuring that the hot-charged slab in-furnace time is greater than 100 minutes, the cold-charged slab in-furnace time is greater than 160 minutes, and the temperature difference of the slab upper surface temperature, center temperature, and lower surface temperature is not greater than 20 degrees Celsius, to ensure the slab temperature uniformity. As shown in Table 4, the heating furnace is divided into a preheating section, a first heating section, a second heating section, a third heating section, and a soaking section, and Table 4 gives the furnace temperature parameters of each section for several specific product models, and Table 5 is the furnace temperature difference corresponding to each product model in Table 4. Under the condition of ensuring the total amount of coal gas consumption unchanged, adjusting the load distribution of the heating furnace and appropriately increasing the load of the rear section of the heating furnace (the intelligent combustion model can control the coal gas consumption of each heating section of the heating furnace, and the intelligent combustion model can automatically adjust the coal gas consumption of other heating sections according to the adjusted coal gas consumption of the heating section, for example, when the furnace gas temperature of the third heating section and the soaking section of the heating furnace is increased by 15 degrees Celsius, the intelligent combustion model can automatically reduce the furnace gas temperature of the preheating section, the first heating section, and the second heating section according to the constraint of keeping the coal gas consumption unchanged) can increase the surface temperature of the slab, and the slab edge temperature is higher when rough rolling starts. Specifically, the furnace gas temperature of the third heating section of the heating furnace is increased by 15 degrees Celsius, and the furnace gas temperature of the soaking section of the heating furnace is increased by 15 degrees Celsius. In the embodiment of the present application, under the condition of keeping the total amount of coal gas consumption unchanged, the core temperature of the slab is sacrificed, and the core temperature mainly penetrates slowly during the front section (including: preheating section, first heating section, and second heating section) of the heating furnace. When the front section temperature is low, the core temperature will also be relatively low. Concentrating the load on the rear section (including the third heating section and the soaking section) is to increase the surface temperature of the slab to compensate for the surface temperature drop in the subsequent rolling process. The intelligent combustion model is used to automatically control the coal gas consumption of each heating section of the heating furnace, for example, to burn the 400°C (degrees Celsius) steel to the target 1200°C out of the furnace, keep the consumed coal gas unchanged, and increase the temperature of the third heating section and the soaking section by 15°C. The intelligent combustion model will automatically calculate and reduce the temperature of the front section according to the different slab charging temperature.

[0089]

[0090] Table 4: Furnace temperature parameters corresponding to product models

[0091]

[0092]

[0093] Table 5: Furnace temperature difference corresponding to product models

[0094] The embodiment of the present application has the following technical effects: by adjusting the heating furnace load distribution, the furnace gas temperature of the three adding sections and the soaking section is increased, and the furnace gas temperature of other sections is reduced, so that in the case of constant total coal gas consumption, the load of the rear section of the heating furnace is appropriately increased, the surface temperature of the slab is increased, the temperature of the edge of the slab when rough rolling is started is higher, the edge chamfer is combined, the temperature loss of the edge is reduced, the temperature difference between the upper surface temperature, the center temperature and the lower surface temperature of the slab is not greater than 20 degrees Celsius, the uniformity of the slab temperature is ensured, the degree of black line appearing on the edge is reduced without increasing the energy consumption, the distance between the edge black line and the edge of the strip can be controlled without increasing the total coal gas consumption, the distance between the edge black line is controlled within 10mm to meet the cold rolling edge cutting condition, and the surface quality of the cold rolling coil is improved.

[0095] Further, the method further comprises: the plate surface of the edger dam of the rough rolling mill group is perpendicular to the edger roll surface, and the gap between the edger dam and the edger roll is less than 1.5cm.

[0096] In some embodiments, as shown in Figure 8 The cooling water nozzle 15 sprays water to cool the edger roll 16, the angle of the rough rolling edger dam 17 is adjusted to be perpendicular to the edger roll surface 16, the gap D between the edger dam 17 and the edger roll 16 is controlled to be less than 1.5cm, the water sealing effect of the edger dam 17 is ensured, the edger cooling water cannot be directly sprayed on the edge of the slab, and the temperature drop of the edge of the slab is reduced.

[0097] Further, the rough rolling adopts reversible rolling, the rough rolling mill group comprises a first rough rolling mill 5 and a second rough rolling mill 7 arranged at the outlet side of the first rough rolling mill 5, and the method further comprises:

[0098] According to the production mode and the rolling requirements of the grade, the rolling mode of the first rough rolling mill 5 and the second rough rolling mill 7 is set to 0+5 mode; the corresponding edger roll reducing width rolling pass of the 0+5 mode is 3 passes, the first pass edger roll reducing width is less than or equal to 8mm, and the corresponding edger roll load distribution coefficient of the 3-pass edger roll reducing width rolling is 0.15:1:1.

[0099] Further, the rough rolling adopts reversible rolling, the rough rolling mill group comprises a first rough rolling mill 5 and a second rough rolling mill 7, and the method further comprises:

[0100] According to the production mode and the rolling requirements of the grade, the rolling mode of the first rough rolling mill 5 and the second rough rolling mill 7 is set to 1+5 mode; the corresponding edger roll reducing width rolling pass of the 1+5 mode is 4 passes, the first pass edger roll reducing width is less than or equal to 8mm, and the corresponding edger roll load distribution coefficient of the 4-pass edger roll reducing width rolling is 0.1:1:1:0.6.

[0101] Furthermore, the roughing process employs reversible rolling, and the roughing mill unit includes a first roughing mill 5 and a second roughing mill 7. The method further includes:

[0102] According to the production mode and grade rolling requirements, the rolling mode of the first roughing mill 5 and the second roughing mill 7 is set to 3+3 mode; the vertical roll width reduction rolling passes corresponding to the 3+3 mode are 4 passes, the vertical roll width reduction amount of the first pass is less than or equal to 8 mm, and the vertical roll load distribution coefficient corresponding to the 4 passes of vertical roll width reduction rolling is 0.1:1:1:0.6.

[0103] In some embodiments, the inventors discovered that after the slab is rolled by vertical rolls, the edge of the rolled product thickens, forming obvious... Figure 5 As shown, the slab edge of the drum-shaped billet rises as the metal deforms, forming a high point. The temperature at this high point drops rapidly under the influence of descaling and cooling water, causing the edge metal to enter the two-phase rolling zone, resulting in a black line defect at the edge. Based on this finding, the inventors improved the rolling mode of the roughing mill; preferably, the roughing mill unit includes a first roughing mill and a second roughing mill. As a specific embodiment, a 1780 mm hot rolling mill production line has two roughing mills, namely the first roughing mill and the second roughing mill. First, confirm the rolling mode. Depending on the production mode and rolling requirements of the grade, different rolling modes can be used, such as 0+5, 1+5, or 3+3. In the 0+5 mode, the first roughing mill stand is idle, and the second roughing mill stand performs 5 passes. In the 1+5 mode, the first roughing mill stand performs 1 pass, and then the second roughing mill stand performs 5 passes. In the 3+3 mode, the first roughing mill stand performs 3 passes, and then the second roughing mill stand performs 3 passes. The width reduction of the vertical rolls differs depending on the rolling mode. After confirming the rolling mode, the number of passes for vertical roll width reduction is determined: 3 passes for 0+5 mode, and 4 passes for 1+5 and 3+3 modes. Specifically, in the 0+5 mode, vertical roll width reduction is performed only in the 1st, 3rd, and 5th passes of the second roughing mill, corresponding to the 1st, 2nd, and 3rd passes of vertical roll width reduction, respectively. In the 1+5 mode, vertical roll width reduction is performed in the 1st pass of the first roughing mill, corresponding to the 1st pass of vertical roll width reduction. Vertical roll width reduction is also performed in the 1st, 3rd, and 5th passes of the second roughing mill, corresponding to the 2nd, 3rd, and 4th passes of vertical roll width reduction, respectively. In the 3+3 mode, vertical roll width reduction is performed in the 1st and 3rd passes of the first roughing mill, corresponding to the 1st and 2nd passes of vertical roll width reduction, respectively. Vertical roll width reduction is also performed in the 1st and 3rd passes of the second roughing mill, corresponding to the 3rd and 4th passes of vertical roll width reduction, respectively.

[0104] The inventors also find that the edge black line is generated in the first pass of rough rolling, and the inventors find that the position of the edge black line can be controlled by controlling the first pass reduction amount, the first pass reduction amount of the vertical roll is controlled, the load distribution coefficient of the 3-pass reduction vertical roll is adjusted to 0.15:1:1, the load distribution coefficient of the 4-pass reduction vertical roll is adjusted to 0.1:1:1:0.6, by the load distribution coefficient, the load distribution of the first pass vertical roll is reduced, the first pass reduction amount of the vertical roll is limited to be not more than 8 mm, the inventors find that when the first pass reduction amount is greater than 8 mm, the distance from the edge black line to the edge of the hot coil often exceeds the cold rolling cutting edge amount (for example, 10-15 mm), setting the first pass reduction amount to be not more than 8 mm can stably control the distance from the black line to the edge within 10 mm to meet the cold rolling cutting edge amount. The above method also avoids the problem of drum shape of the slab edge after vertical roll rolling. Among them, the 0+5 mode is that the first rough rolling mill is empty, and the second rough rolling mill is reciprocating rolled for 5 passes. The 1+5 mode is that the first rough rolling mill is rolled for 1 pass, and the second rough rolling mill is reciprocating rolled for 5 passes. The 3+3 mode is that the first rough rolling mill is reciprocating rolled for 3 passes, and the second rough rolling mill is reciprocating rolled for 3 passes. The 0+5 mode has three reductions, and the 1+5 mode and the 3+3 mode have four reductions. Table 6 shows the parameter settings of the first rough rolling mill and the second rough rolling mill in a specific embodiment, wherein mm is millimeter, and kN is kilo Newton.

[0105]

[0106] Table 6 Parameter settings of the first rough rolling mill and the second rough rolling mill

[0107] The embodiment of the present application has the following technical effects: according to the production mode and the rolling requirements of the grade, the rolling mode, the vertical roll reduction pass, the first pass vertical roll reduction amount, and the load distribution coefficient of each pass reduction vertical roll can be determined, which can effectively control the distance from the edge black line to the edge within 10 mm to meet the cold rolling cutting edge condition, and avoid the drum shape problem, and improve the surface quality of the cold rolling coil.

[0108] Further, the method further comprises:

[0109] The first rough rolling mill 5 and the second rough rolling mill 7 are set for rough rolling head and tail short stroke, the front pass of the vertical roll reduction is set to release the roll gap to ensure the uniformity of the overall width of the intermediate blank and avoid the head and tail width deviation, and the rear pass of the vertical roll reduction is set to close the roll gap to avoid the head and tail width deviation of the intermediate blank, and the strip steel width deviation is controlled to be less than or equal to 10 mm.

[0110] In some embodiments, the short stroke of the vertical roll is adjusted to control the overall width uniformity of the strip steel, prevent the head or tail of the strip steel from being too wide to scratch the side guide plate, and ensure the quality of the edge of the head and tail of the strip steel. The adjustment idea for setting the short stroke of the head and tail of rough rolling is as follows: the previous pass of the vertical roll width reduction is to open the roll gap to ensure the uniformity of the overall width of the intermediate blank and prevent the head and tail from being too wide. The latter pass of the vertical roll width reduction is to close the roll gap to fine-tune the width of the head and tail of the intermediate blank, ensure that the head and tail of the intermediate blank are not too wide, control the width deviation of the strip steel within 10 mm, and prevent the edge from being scratched by the side guide plate of the finishing mill or coiling process due to the head and tail of the strip steel being too wide, thereby generating edge black lines. The previous pass of the vertical roll width reduction refers to the first or first two passes of the vertical roll width reduction, and the latter pass of the vertical roll width reduction refers to the last two passes of the vertical roll width reduction. For the 3+3 mode and the 1+5 mode, the previous pass of the vertical roll width reduction includes the first and second passes of the vertical roll width reduction, and the latter pass of the vertical roll width reduction includes the third and fourth passes of the vertical roll width reduction; for the 0+5 mode, the previous pass of the vertical roll width reduction includes the first pass of the vertical roll width reduction, and the latter pass of the vertical roll width reduction includes the third and fourth passes of the vertical roll width reduction;

[0111] Table 7, Table 8 and Table 9 give specific data of the delivery roll gap and the entry roll gap of some specific embodiments, wherein, one pass of the first stand represents the first pass of the first rough rolling mill, two pass of the first stand represents the first pass of the second rough rolling mill, and so on. In the 3+3 mode, the front pass of the edger reduction includes the first pass and the second pass of the edger reduction, and the rear pass of the edger reduction includes the third pass and the fourth pass of the edger reduction; the front pass of the edger reduction is set as the delivery roll gap, specifically, in the first pass of the edger reduction, from the middle billet head to the edger of the first rough rolling mill, at 0.0 meter, 0.3 meter, 0.6 meter, 0.9 meter and 1.2 meter of the middle billet head passing through the edger of the first rough rolling mill, the edger gap of the first rough rolling mill is adjusted to the set width of the edger gap plus 12 mm, 10 mm, 9 mm, 5 mm and 5 mm respectively; from the middle billet tail end not yet entering the edger of the first rough rolling mill, at 1.2 meter of the middle billet tail end from the edger of the first rough rolling mill, at 1.2 meter, 0.9 meter, 0.6 meter, 0.3 meter and 0.0 meter of the middle billet tail end from the edger, the edger gap of the first rough rolling mill is adjusted to the set width of the edger gap plus 2 mm, 4 mm, 4 mm, 8 mm and 10 mm respectively; in the second pass of the edger reduction, from the middle billet head to the edger of the first rough rolling mill, at 0.0 meter, 0.3 meter, 0.6 meter, 0.9 meter and 1.2 meter of the middle billet head passing through the edger of the first rough rolling mill, the edger gap of the first rough rolling mill is adjusted to the set width of the edger gap plus 11 mm, 9 mm, 5 mm, 5 mm and 5 mm respectively; from the middle billet tail end not yet entering the edger of the first rough rolling mill, at 1.2 meter of the middle billet tail end from the edger, at 1.2 meter, 0.9 meter, 0.6 meter, 0.3 meter and 0.0 meter of the middle billet tail end from the edger, the edger gap of the first rough rolling mill is adjusted to the set width of the edger gap plus 4 mm, 5 mm, 5 mm, 8 mm and 11 mm respectively;

[0112] The last pass of the vertical roll reducing width is set as a receiving roll gap. Specifically, in the third pass of the vertical roll reducing width, from the middle billet head to the vertical roll of the second rough rolling mill, at 0.0 m, 0.3 m, 0.6 m, 0.9 m and 1.2 m of the middle billet head passing through the vertical roll of the second rough rolling mill, the second rough rolling mill vertical roll gap is adjusted to be 6 mm, 5 mm, 4 mm, 3 mm and 3 mm less than the set width of the vertical roll gap, respectively; from the middle billet tail end that has not yet entered the vertical roll of the second rough rolling mill, starting from 1.2 m of the middle billet tail end from the vertical roll of the second rough rolling mill, at 1.2 m, 0.9 m, 0.6 m, 0.3 m and 0.0 m of the middle billet tail end from the vertical roll, the second rough rolling mill vertical roll gap is adjusted to be 2 mm, 5 mm, 5 mm, 6 mm and 7 mm less than the set width of the vertical roll gap, respectively; in the fourth pass of the vertical roll reducing width, from the middle billet head to the vertical roll of the second rough rolling mill, at 0.0 m, 0.3 m, 0.6 m, 0.9 m and 1.2 m of the middle billet head passing through the vertical roll of the second rough rolling mill, the second rough rolling mill vertical roll gap is adjusted to be 13 mm, 10 mm, 7 mm, 5 mm and 2 mm less than the set width of the vertical roll gap, respectively; from the middle billet tail end that has not yet entered the vertical roll of the second rough rolling mill, starting from 1.2 m of the middle billet tail end from the vertical roll of the second rough rolling mill, at 1.2 m, 0.9 m, 0.6 m, 0.3 m and 0.0 m of the middle billet tail end from the vertical roll of the second rough rolling mill, the second rough rolling mill vertical roll gap is adjusted to be 3 mm, 8 mm, 8 mm, 10 mm and 10 mm less than the set width of the vertical roll gap, respectively.

[0113] The release roll gap and the receiving roll gap in the 1+5 mode and the 0+5 mode can be understood according to the above description of the release roll gap and the receiving roll gap in the 3+3 mode, and will not be described again here.

[0114]

[0115]

[0116] Table 73 Release roll gap and receiving roll gap parameter table in 3+3 mode

[0117]

[0118] Table 81 Release roll gap and receiving roll gap parameter table in 1+5 mode

[0119]

[0120] Table 90 Release roll gap and receiving roll gap parameter table in 0+5 mode

[0121] Further, the production line adopted by the production method further comprises: a finishing pre-zone and a finishing zone 12, the finishing pre-zone comprises: a finishing descaling device 11, a flying shear 10 and a flying shear front side guide plate, the finishing zone 12 comprises: a first finishing mill, a second finishing mill, a third finishing mill, a fourth finishing mill, a fifth finishing mill, a sixth finishing mill, a seventh finishing mill and a finishing mill group side guide plate, and the method further comprises:

[0122] In the finishing pre-zone, the head short stroke of the flying shear front side guide plate is set as the intermediate blank width plus 25 mm, the middle short stroke of the flying shear front side guide plate is set as the intermediate blank width plus 10 mm, and the tail short stroke of the flying shear front side guide plate is set as the intermediate blank width plus 25 mm.

[0123] In the finishing zone 12, the opening degree of the finishing mill group side guide plate is set as:

[0124] The pre-position corresponding to the first finishing mill is the intermediate blank width plus 5 mm, the rolling position corresponding to the first finishing mill is the intermediate blank width plus 5 mm, and the tail opening corresponding to the first finishing mill is the intermediate blank width plus 5 mm,

[0125] The pre-position corresponding to the second finishing mill is the intermediate blank width plus 10 mm, the rolling position corresponding to the second finishing mill is the intermediate blank width plus 10 mm, and the tail opening corresponding to the second finishing mill is the intermediate blank width plus 10 mm,

[0126] The pre-position corresponding to the third finishing mill is the intermediate blank width plus 15 mm, the rolling position corresponding to the third finishing mill is the intermediate blank width plus 15 mm, and the tail opening corresponding to the third finishing mill is the intermediate blank width plus 15 mm,

[0127] The pre-position corresponding to the fourth finishing mill is the intermediate blank width plus 20 mm, the rolling position corresponding to the fourth finishing mill is the intermediate blank width plus 20 mm, and the tail opening corresponding to the fourth finishing mill is the intermediate blank width plus 20 mm,

[0128] The pre-position corresponding to the fifth finishing mill is the intermediate blank width plus 30 mm, the rolling position corresponding to the fifth finishing mill is the intermediate blank width plus 30 mm, and the tail opening corresponding to the fifth finishing mill is the intermediate blank width plus 30 mm,

[0129] The pre-position corresponding to the sixth finishing mill is the intermediate blank width plus 35 mm, the rolling position corresponding to the sixth finishing mill is the intermediate blank width plus 35 mm, and the tail opening corresponding to the sixth finishing mill is the intermediate blank width plus 35 mm,

[0130] The pre-position corresponding to the seventh finishing mill is the intermediate blank width plus 35 mm, the rolling position corresponding to the seventh finishing mill is the intermediate blank width plus 35 mm, and the tail opening corresponding to the seventh finishing mill is the intermediate blank width plus 35 mm.

[0131] In some embodiments, the finishing zone control: the short stroke of the side guide plate before the flying shear is set as: the head short stroke: the intermediate blank width + 25 mm; the middle short stroke: the intermediate blank width + 10 mm; the tail short stroke: the intermediate blank width + 25 mm. When the intermediate blank appears camber, the head and tail of the intermediate blank will not be seriously rubbed with the side guide plate. The finishing zone control: the side guide plate opening degree of the finishing mill group is shown in Table 1. In the finishing zone, the thickness of the intermediate blank gradually thins from the first finishing mill to the seventh finishing mill, and the thinner the intermediate blank is, the more likely it is to deviate, so the measured plate opening degree of the first finishing mill to the seventh finishing mill is gradually increased, so as to ensure the centering of the strip steel while reducing the friction with the side guide plate during threading, and improving the quality of the edge of the strip steel. Especially in the long-term use process, the surface of the side guide plate is grooved by the intermediate blank, and when the intermediate blank is rubbed with the side guide plate, the groove on the side guide plate will in turn cause the black line on the edge of the intermediate blank, so reducing the friction with the side guide plate during threading, thereby reducing the probability of black edge caused by friction with the side guide plate.

[0132] Further, as shown in Figure 2 the production line used in the production method also includes: a laminar cooling device 13, a coiler 14 and a side guide plate of the coiler 14, and the method further includes:

[0133] The short stroke control parameters of the side guide plate of the coiler 14 are set as: the side guide plate standby position is the controlled width of the strip steel plus 30 mm, the first short stroke walking position is the controlled width of the strip steel plus 20 mm, and the second short stroke walking position is the controlled width of the strip steel plus 10 mm;

[0134] The head of the strip steel is tracked by heat detection and roller speed calculation, the short stroke operation is started when the head of the strip steel reaches the side guide plate, and when the side guide plate contacts the strip steel and the one-sided side guide plate pressure feedback reaches 6 kN, the one-sided pressure control is converted, and the other side is position control.

[0135] In some embodiments, the coiling zone control: the short stroke parameters of the side guide plate of the coiler are set, and the short stroke control is used for the side guide plate before the coiler, as shown in Figure 7As shown, the side guide waiting position Pw is the strip control width W+30mm (millimeter), the first short stroke walking position SS1 is the strip control width W+20mm, the second short stroke walking position SS2 is the strip control width W+10mm, the head of the strip is tracked through the heat detection and the roller speed calculation, the short stroke operation is started when the head reaches the side guide, after the single side side guide pressure feedback reaches the set value (preferably, 6kN), the control mode is switched to the pressure control and position control combined control mode, that is, the single side is controlled by the pressure control and the other side is controlled by the position control, through the control mode, the hot coil winding type can be guaranteed, even if the strip shape of the finishing mill outlet appears to be wandering, the side guide of the coiler and the strip will not seriously rub, and the opening degree of the side guide of the coiler is stable. Through the control mode, the hot coil winding type can be guaranteed, the side guide rubbing is reduced, and the strip edge quality is improved.

[0136] The above technical solutions of the embodiments of the present application will be described in detail below in combination with specific application examples, and the technical details not introduced in the implementation process can refer to the related description in the foregoing.

[0137] The following is described in another embodiment, which is based on the following production line test, specifically, the 1780 production line is equipped with 1#, 2#, 3# walking beam heating furnace, the center line distance of the heating furnace is 30 meters, the effective furnace length is 49.5 meters, and the hearth width is 11.7 meters. The multi-section heating mode is used, and each heating furnace is divided into a preheating section, a first heating section, a second heating section, a third heating section and a soaking section along the furnace length direction. The function is to heat the slab loaded into the furnace to the set discharge temperature, and to send the slab in the furnace to the rolling line according to the requirements of the rolling rhythm control. The relevant dimensions of the heating furnace include: the center distance of the loading and discharging roller is 56000 mm, the furnace brick length is 51000 mm, the effective furnace length is 49500 mm, the center line of the loading roller to the loading brick line is 2500 mm, the discharging side brick line to the center line of the discharging roller is 2500 mm, and the width of the hearth is 11700 mm; the slab thickness is 230 mm, the slab width is 800 to 1650 mm, the slab length is 9000 to 11000 mm (fixed size blank), and the slab discharge temperature is 1100 to 1280 degrees Celsius. The sizing press adjusts the width of the slab according to the width of the blank required by the rough rolling mill, and continuously side-presses the slab after descaling in one pass of full-length large reduction, adjusting the width of the blank. The maximum width reduction is 350 mm, and the maximum width reduction pressure is 22000 kN. The width adjustment is large, the width of the cast blank is reduced, and the production is stable and flexible. The deformation is deep and thorough, the edge drum shape is small, the cutting loss is small, the steel coil single weight is improved, and the yield is improved. The edge quality defects of the slab can be reduced or eliminated. The second rough rolling mill is a four-high horizontal rolling mill, which is used together with the E2 edger mill to roll the slab through 3-7 passes. The specific form is: four-high reversible (electric + hydraulic pressure), rolling pressure: 45000 KN (kilonewton), rolling stiffness: 6200 KN / mm (kilonewton / millimeter), rolling speed: 0-3.14-6.28 m / s (meter / second), maximum reduction: 50 mm (millimeter), maximum opening: 300 mm (maximum roll diameter), reduction speed: 0-40 mm / s (millimeter / second); the task of the rough rolling mill is to roll the slab into a strip blank that meets the requirements of the finishing rolling mill, the surface is clean, and the primary iron scale is removed; the side edges are neat and the width meets the required size. The intermediate blank thickness meets the requirements of the finishing rolling mill, and the rough rolling mill generally uses large reduction (about 75-85% of the total deformation), the intermediate blank has good plate shape, and the strip steel is straight. The intermediate roller is equipped with a heat preservation cover (including: first heat preservation cover, second heat preservation cover and / or third heat preservation cover), which can reduce the overall temperature drop of the intermediate blank and improve the temperature uniformity of the intermediate blank along the length direction. Type: hydraulic tilting cover, with heat preservation and insulation materials inside. Length: 9 x 7260 = 65340 mm, length of each heat preservation cover: 7260 mm, working pressure: 16 MPa (megapascal), rough rolling area adds fixed heat preservation cover, which can be interchanged with the intermediate roller heat preservation cover.The finishing rolling mill group is composed of seven four-roller continuous rolling finishing rolling mills F1-F7, is a finished product mill group for hot-rolled strip steel production, and is a key mill group for controlling products. An F1E edger mill is arranged in front of the finishing rolling mill group, mainly plays a guiding role, the mill is equipped with a full-hydraulic AGC screwdown system to control the full-length thickness accuracy of the strip steel, is provided with an axial roll shifting and bending roll system to control the strip shape, is provided with a rolling lubrication system to reduce the rolling force, prolong the roll life, and improve the strip steel surface quality, is provided with a dust removal system, hydraulic loafs are arranged between the finishing rolling mill stands for speed and tension control, and the finishing rolling mill outlet is provided with multiple function meters, thickness measuring instruments, and surface inspection instruments, and the like. The strip steel cooled by the laminar flow cooling device is coiled into a coil by the coiling machine, and three coiling machines 1#-3# are arranged. Coiling into a coil provides strong conditions for increasing the raw material weight, improving the rolling speed, and reducing the head and tail temperature difference of the rolled piece. Type: full-hydraulic coiling machine, fixed coiling machine. Coiled strip thickness: 1.2-19 mm (Q345B, 25.4 mm), coiled strip width: 800-1630 mm, coiled strip temperature: maximum 750 °C, minimum 400 °C (degrees Celsius), coiling speed: <12 m / s (δ≤2 mm) when biting, maximum: 22 m / s, maximum outer diameter of the steel coil: Ф2200 mm, minimum outer diameter of the steel coil: Ф1000 mm.

[0138] The inventors found that the black line is caused by the low temperature of the slab edge (the corner of the slab is cooled quickly during transportation) and the rolling into the dual-phase zone during rolling. In view of the above finding, the inventors have made at least the following improvements:

[0139] The heating furnace load is optimized, and the surface temperature of the slab when discharged from the furnace is improved under the condition that the total gas consumption is unchanged. The edge temperature of the slab during the subsequent beating and rough rolling by the sizing press is higher, and the probability of entering the dual-phase zone during rolling is reduced.

[0140] The edge shape of the slab is changed (from a right angle to a chamfer) by beating with the chamfer module of the sizing press, and the temperature drop of the slab edge during subsequent slab transportation is reduced. The designed chamfer depth is shallow and the slope is gentle, no boat shape appears after beating, the stability of the intermediate slab shape after rough rolling is ensured, and the friction of the side guide plate can be reduced.

[0141] The rough rolling heat shield can reduce the temperature drop of the slab edge in the whole rough rolling area and reduce the probability of black line defects.

[0142] The first pass reduction amount of rough rolling is limited, and the rough rolling edger mill load is optimized, so that the black line can be controlled within 10 mm of the edge, and the black line can be cut off after cold rolling and edge cutting, without affecting the quality of the finished product.

[0143] The following describes another embodiment of the present invention, which provides a method for controlling the black line on the edge of a galvanized sheet. The process flow is heating, rough rolling, finish rolling, and coiling in sequence. The production process is carried out according to the following steps:

[0144] Step 1: Heating. Place the slab in the heating furnace and control the time it spends in the furnace. For hot-charged slabs (charging temperature greater than 400℃), the furnace time should be greater than 100 minutes; for cold-charged slabs (charging temperature less than 100℃), the furnace time should be greater than 160 minutes. Use an intelligent combustion model to control the furnace temperature and time in the preheating, heating, and soaking sections, ensuring that the temperature difference between the top surface, center, and bottom surface of the slab exiting the furnace does not exceed 20℃. Adjust the furnace load distribution, increasing the furnace gas temperature in the three heating sections and soaking section by 15℃. Appropriately increasing the load in the rear section of the furnace can increase the surface temperature of the slab, resulting in higher edge temperatures during rough rolling and reducing the probability of black line defects.

[0145] Step 2, rough rolling: The slab that has reached the furnace exit temperature enters the rough rolling zone for rolling.

[0146] 1. A fixed-width press is used to side-press the slab. The side-pressing module of the fixed-width press is a chamfering module, such as... Figure 3 As shown, the module has a bottom groove depth of 25 mm, a bottom groove width of 190 mm, an angle A of 30°, a first fillet radius R1 of 20 mm, and a second fillet radius R2 of 20 mm. Applying the chamfered module effectively improves the edge shape of the slab, reduces edge temperature drop during subsequent transportation, reduces bulging height after side pressing, suppresses edge metal upturning, and improves the edge quality of the slab. The application of a roughing rolling insulation cover in the roughing rolling area further reduces edge temperature drop during slab transportation.

[0147] 2. Rolling Mode Confirmation: The 1780mm (mm) hot rolling mill production line has two roughing mills: the first and the second. Depending on the production mode and rolling requirements of the grade, rolling modes such as 0+5, 1+5, and 3+3 can be used. The width reduction of the vertical rolls differs under different rolling modes. After confirming the rolling mode, the number of width reduction passes for the vertical rolls is determined: 3 passes for the 0+5 mode, and 4 passes for the 1+5 and 3+3 modes.

[0148] 3. Adjust the angle of the cutting plate (water baffle) of the roughing roll vertical roll to be perpendicular to the roll surface, and control the gap between the cutting plate and the vertical roll to be less than 1.5cm to ensure the water sealing effect of the cutting plate, so that the cooling water of the vertical roll will not be sprayed directly on the edge of the slab, thereby reducing the temperature drop at the edge of the slab.

[0149] 4. Control the first pass of rough rolling vertical roll reduction amount: the 3-pass reduction vertical roll load distribution coefficient is adjusted to 0.15:1:1, the 4-pass reduction vertical roll load distribution coefficient is adjusted to 0.1:1:1:0.6, and the first pass vertical roll reduction amount is limited to not more than 8 mm. After the slab passes through the vertical roll, the edge of the rolled piece will be thickened, forming a clear drum shape. The edge of the slab is turned up with the metal deformation, forming the high point of the drum shape. The drum shape high point is rapidly cooled under the scouring of descaling water and cooling water, causing the edge metal to enter the two-phase zone for rolling, thereby producing edge black line defects. By adjusting the vertical roll load and setting the maximum reduction amount of the first pass of rough rolling, the distance of the edge black line from the edge can be effectively controlled within 10 mm.

[0150] 5. Adjust the vertical roll short stroke to control the overall width uniformity of the strip, prevent the head or tail of the strip from being too wide to scratch the side guide plate, and ensure the edge quality of the head and tail of the strip. The rough rolling head and tail short stroke setting adjustment idea is: the front pass of vertical roll reduction is to open the roll gap to ensure the uniformity of the overall width of the intermediate slab and prevent the head and tail from being out of width. The rear pass of vertical roll reduction is to close the roll gap to fine-tune the head and tail width of the intermediate slab, ensure that the head and tail of the intermediate slab do not appear to be too wide, control the strip width deviation within 10 mm, and prevent the head and tail of the strip from scratching the side guide plate of the finishing mill and coiling during the coiling process, thereby producing edge black lines.

[0151] Step three, finishing rolling:

[0152] 1. Control before finishing rolling: the short stroke of the side guide plate before the flying shear is set to: head short stroke: intermediate slab width + 25 mm; middle short stroke: intermediate slab width + 10 mm; tail short stroke: intermediate slab width + 25 mm. When the intermediate slab appears to be a sickle, the head and tail of the intermediate slab will not be severely scratched by the side guide plate.

[0153] 2. Control in the finishing rolling area: the side guide plate opening degree of the finishing mill set is shown in Table 10. Ensure that the strip is centered while reducing the scratching of the side guide plate during threading to improve the edge quality of the strip.

[0154] F1E F2 F3 F4 F5 F6 F7 Pre-positioning 5 10 15 20 30 35 35 Rolling position 5 10 15 20 30 35 35 Tail opening 5 10 15 20 30 35 35

[0155] Table 10 Side guide plate opening degree parameters in the finishing rolling area

[0156] Wherein, F1E is the first finishing mill, and F2 to F7 are the second to seventh finishing mills, respectively.

[0157] Step four, coiling:

[0158] 1. Set the short stroke parameters of the side guide of the coiler, the front side guide of the coiler adopts short stroke control, the waiting position of the side guide is the controlled width of the strip + 30 mm, the first short stroke walking position is the controlled width of the strip + 20 mm, and the second short stroke walking position is the controlled width of the strip + 10 mm.

[0159] 2. Track the head of the strip by heat detection and roller speed calculation, start to perform short stroke operation when the head reaches the side guide, convert to single side pressure control after the single side guide pressure feedback reaches 6 KN when the side guide contacts the strip, the other side is position control, realize that even if the strip shape of the finishing mill outlet appears to be wandering, the side guide of the coiler and the strip will not have serious friction, and the opening degree of the side guide of the coiler is stable. Through this control mode, the hot coil shape can be guaranteed, the side guide friction is reduced, and the quality of the edge of the strip is improved.

[0160] The embodiment of the present application has the following technical effects: by ensuring the uniformity of the heating furnace temperature, improving the plate shape quality, reducing the strip scraping side guide plate. Adjust the heating furnace load distribution, increase the three plus section, the soaking section furnace gas temperature under the premise of total gas consumption, to improve the slab surface temperature. The application of fixed width press chamfer module to the slab side pressure, improve the slab edge quality, reduce the slab edge temperature drop. Control the first pass of rough rolling vertical roll reduction to control the distance between the strip edge and the black line, meet the cold rolling cutting edge condition. Set the side guide plate of the pre-finishing area and the finishing mill set to reduce the strip rubbing, improve the strip edge quality. Set the side guide plate control mode of the coiler, ensure the coil shape while reducing the strip rubbing, improve the edge quality. By using the side pressure module for the chamfer module of the fixed width press to press the slab edge to chamfer, effectively improve the shape of the slab edge, reduce the edge temperature drop of the slab in the subsequent transportation process, and reduce the drum height after side pressure, and inhibit the edge metal from turning up. By adjusting the heating furnace load distribution, increasing the furnace gas temperature of the three plus section and the soaking section of the heating furnace, and reducing the furnace gas temperature of other sections, the slab surface temperature can be increased under the condition that the total gas consumption is constant, the slab edge temperature is higher when rough rolling starts, and the degree of black line on the edge is reduced without increasing energy consumption. According to the production mode and the rolling requirements of the grade, the rolling mode, the vertical roll reduction pass, the first pass vertical roll reduction, and the load distribution coefficient of each pass are determined, which can effectively control the distance between the edge black line and the edge within 10mm to meet the cold rolling cutting edge condition and improve the surface quality of the cold rolling coil. By adjusting the vertical roll short stroke, the overall width uniformity of the strip is controlled, the head or tail of the strip is prevented from rubbing against the side guide plate due to excessive width, the edge quality of the head and tail of the strip is ensured, the intermediate slab head and tail are prevented from appearing excessive width, the strip width deviation is controlled within 10mm, the edge black line is prevented from being generated due to the excessive width of the head and tail of the strip rubbing against the side guide plate of the finishing area or the coiling process; the opening degree of the side guide plate of the pre-finishing area and the finishing area is controlled to ensure that when the intermediate slab appears camber, the head and tail of the intermediate slab will not seriously rub against the side guide plate, and to ensure that the strip is centered while reducing the rubbing against the side guide plate during threading, improving the edge quality of the strip; the side guide plate of the coiler is controlled in short stroke, so that even if the strip shape of the finishing outlet appears to be wandering, the side guide plate of the coiler will not seriously rub against the strip, and the opening degree of the side guide plate of the coiler is stable. Through the control mode, the coil shape of the hot coil can be ensured, the side guide plate rubbing is reduced, and the edge quality of the strip is improved. The proportion of the edge black line defects of the galvanized plate is controlled, and the proportion of the edge black line defects of the galvanized plate is reduced from 19.5% to less than 1.5%. The surface quality of the hot rolling coil and the cold rolling coil is obviously improved, the cold rolling cutting edge amount is reduced, and the yield of the galvanized plate is increased by 0.2%. The hot rolling mill can control the edge black line defects without increasing the discharge temperature, improve the production efficiency, and reduce the energy consumption.

[0161] It should be understood that the particular order in which the steps of processes presented in the disclosure have been presented makes no limitation as to the scope of the disclosure. Based upon the teachings provided herein, one skilled in the art should appreciate that alternative order explanations of various steps can be implemented to be simultaneously parallel or in some cases possibly performed at different times. Also, the various steps can be reordered and / or "interleaved" with one another such that the ordering presented herein and described is an example only and should not be taken as a restriction of how the steps of the processes presented herein can be implemented. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order presented by the claims.

[0162] In the foregoing detailed description, various features are grouped together in single embodiments for the purpose of streamlining the disclosure. This disclosure is not to be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than are expressly recited in each claim. Rather, as the claims below reflect, inventive subject matter lies in fewer than all features of a single disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate preferred embodiment.

[0163] The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments described herein but is to be accorded the widest scope consistent with the claims.

[0164] The foregoing description of one or more embodiments includes exemplary steps. Of course, not all possible combinations of components or methods described above can be described, but one of ordinary skill in the art will recognize that further combinations and permutations of various embodiments are possible. Accordingly, the embodiments described herein are intended to embrace all such alterations, modifications, and variations going to the scope of the appended claims. Furthermore, to the extent that the term "includes" is used in either the detailed description or the claims, it is intended to be inclusive in a manner similar to the term "comprising" as contrasted to "consisting of. Moreover, any one of the terms "or" in the claims is intended to mean "nonexclusive or" as contrasted to "either / or".

[0165] The above detailed description describes the application in conjunction with specific embodiments, however it should be understood that the above description is meant to illustrate the application and not to limit the scope of the application. Therefore, many modifications and variations of this application can be effected without departing from the spirit and scope of the novel concept. No limitation is intended to the details of construction or design herein shown, other than as described in the claims below. It is specifically intended that changes in the above-described embodiments be included within the scope of the claimed application, but shall be construed as being limited to the spirit and scope of the disclosed inventive concept.

Claims

1. A production method for controlling black lines on the edges of cold-rolled galvanized steel sheets, characterized in that, The production line used in the production method includes a heating furnace (1), a roughing descaling unit (2) located at the outlet side of the heating furnace (1), a fixed-width press (3) located at the outlet side of the roughing descaling unit (2), and a roughing mill unit located at the outlet side of the fixed-width press (3). The production method includes: After the slab is heated in the heating furnace (1) and descaled by rough descaling (2), it is sent to the fixed width press (3) for continuous side pressing along the entire length in one pass, so that the width of the slab is adjusted to the width of the billet set by the roughing mill, and the edges of the two sides of the slab along the length direction are pressed into chamfers. Without increasing energy consumption, adjust the load distribution of the heating furnace, increase the furnace gas temperature of the three heating sections and the soaking section of the heating furnace, and reduce the furnace gas temperature of other sections, and control the temperature difference between the upper surface temperature, center temperature and lower surface temperature of the slab to be no more than 20 degrees Celsius. Among them, the fixed width press (3) is symmetrically provided with two side pressing modules (31). The two side pressing modules (31) are used to press the two sides of the slab in the length direction when the slab passes through the fixed width press (3). A horizontal isosceles trapezoidal groove is provided on the working side (311) of each side pressing module (31) so that the edges of the two sides in the length direction of the slab are pressed into chamfers by the isosceles inclined surface of the isosceles trapezoidal groove. The isosceles trapezoidal groove includes a groove bottom surface (312), a groove opening (313), and an isosceles inclined surface (314). The width of the groove bottom surface (312) is smaller than the width of the groove opening (313), and the groove bottom surface (312) is 190 mm wide. The groove depth (315) of the isosceles trapezoidal groove is 25 mm. The acute angle (A) formed by the isosceles inclined surface (314) and the groove bottom surface (312) is 30 degrees. The isosceles inclined surface (314) and the groove bottom surface (312) are connected by a first fillet (R1) with a radius of 20 mm. The isosceles inclined surface (314) and the working side surface (311) outside the groove opening (313) are connected by a second fillet (R2) with a radius of 20 mm. The roughing process employs reversible rolling, and the roughing mill unit includes a first roughing mill (5) and a second roughing mill (7). The method further includes: According to the production mode and grade rolling requirements, the rolling mode of the first roughing mill (5) and the second roughing mill (7) is set to 0+5 mode; the vertical roll width reduction rolling pass corresponding to the 0+5 mode is 3 passes, the vertical roll width reduction amount of the first pass is less than or equal to 8 mm, and the vertical roll load distribution coefficient corresponding to the 3 passes of vertical roll width reduction rolling is 0.15:1:1; Alternatively, based on the production mode and grade rolling requirements, the rolling mode of the first roughing mill (5) and the second roughing mill (7) can be set to the 1+5 mode; the vertical roll width reduction rolling pass corresponding to the 1+5 mode is 4 passes, the vertical roll width reduction amount of the first pass is less than or equal to 8 mm, and the vertical roll load distribution coefficient corresponding to the 4 passes of vertical roll width reduction rolling is 0.1:1:1:0.

6.

2. The production method for controlling the black line on the edge of cold-rolled galvanized sheet as described in claim 1, characterized in that, The production line used in the production method also includes a hot coil box (9) located on the exit side of the second roughing mill (7), and the production method further includes: A first heat insulation cover (4) is installed between the fixed width press (3) and the first roughing mill (5) to keep the slab warm; A second insulation cover (6) is installed between the first roughing mill (5) and the second roughing mill (7) to keep the slab warm; A third insulation cover (8) is installed between the second roughing mill (7) and the hot rolling box (9) to keep the slab warm.

3. The production method for controlling the black line on the edge of cold-rolled galvanized sheet according to claim 1, characterized in that, The method further includes: Control the hot-charged slab time in the furnace to be greater than 100 minutes, adjust the furnace load distribution so that the furnace gas temperature in the third heating section is 1130°C to 1160°C higher than that in the preheating section, 140°C to 190°C higher than that in the first heating section, 40°C to 60°C higher than that in the second heating section, 1100°C to 1140°C higher than that in the preheating section, 120°C to 150°C higher than that in the first heating section, 15°C to 30°C higher than that in the second heating section, and 15°C to 45°C higher than that in the homogenizing section, so that the temperature difference between the top surface temperature, center temperature, and bottom surface temperature of the slab is no greater than 20°C. The loading temperature of the hot-charged slab is greater than 400 degrees Celsius.

4. The production method for controlling the black line on the edge of cold-rolled galvanized steel sheet according to claim 1, characterized in that, The method further includes: Control the time of cold-charged slabs in the furnace to be greater than 160 minutes, adjust the load distribution of the heating furnace, so that the furnace gas temperature of the third heating section is 570 to 590 degrees Celsius higher than that of the preheating section, 110 to 130 degrees Celsius higher than that of the first heating section, 40 to 60 degrees Celsius higher than that of the second heating section, 560 to 590 degrees Celsius higher than that of the preheating section, 100 to 120 degrees Celsius higher than that of the first heating section, 35 to 45 degrees Celsius higher than that of the second heating section, and 5 to 15 degrees Celsius higher than that of the homogenizing section, so that the temperature difference between the top surface temperature, center temperature, and bottom surface temperature of the slab is no greater than 20 degrees Celsius. The loading temperature of the cold-loaded slab is less than 110 degrees Celsius.

5. The production method for controlling the black line on the edge of cold-rolled galvanized sheet as described in claim 1, characterized in that, The method further includes: making the surface of the vertical roll baffle of the roughing mill perpendicular to the surface of the vertical roll, and controlling the gap between the vertical roll baffle and the vertical roll to be less than 1.5 cm.

6. The production method for controlling the black line on the edge of cold-rolled galvanized sheet as described in claim 1, characterized in that, The method further includes: For the first roughing mill (5) and the second roughing mill (7), the short stroke settings for the head and tail of the roughing mill are implemented. The first pass of the vertical roll widening is set as the roll gap release to ensure the uniformity of the overall width of the intermediate billet and avoid the head and tail loss of width. The last pass of the vertical roll widening is set as the roll gap retraction to avoid the head and tail of the intermediate billet being too wide. The strip width deviation is controlled to be less than or equal to 10 mm.

7. The production method for controlling the black line on the edge of cold-rolled galvanized steel sheet as described in claim 1, characterized in that, The production line used in the production method further includes: a pre-finishing rolling zone and a finishing rolling zone (12). The pre-finishing rolling zone includes: a flying shear (10) and a flying shear front guide plate. The finishing rolling zone (12) includes: a first finishing mill, a second finishing mill, a third finishing mill, a fourth finishing mill, a fifth finishing mill, a sixth finishing mill, and a seventh finishing mill. The method further includes: In the finishing rolling zone, the short stroke of the head of the flying shear front guide plate is set to the width of the intermediate billet plus 25 mm, the short stroke of the middle part of the flying shear front guide plate is set to the width of the intermediate billet plus 10 mm, and the short stroke of the tail part of the flying shear front guide plate is set to the width of the intermediate billet plus 25 mm. In the finishing rolling zone, the opening degree of the side guide plate of the finishing mill is set as follows: The pre-position corresponding to the first finishing mill is the width of the intermediate billet plus 5 mm; the rolling position corresponding to the first finishing mill is the width of the intermediate billet plus 5 mm; the tail opening corresponding to the first finishing mill is the width of the intermediate billet plus 5 mm. The pre-positioning position corresponding to the second finishing mill is the width of the intermediate billet plus 10 mm; the rolling position corresponding to the second finishing mill is the width of the intermediate billet plus 10 mm; and the tail opening position corresponding to the second finishing mill is the width of the intermediate billet plus 10 mm. The pre-positioning position corresponding to the third finishing mill is the width of the intermediate billet plus 15 mm; the rolling position corresponding to the third finishing mill is the width of the intermediate billet plus 15 mm; and the tail opening corresponding to the third finishing mill is the width of the intermediate billet plus 15 mm. The pre-positioning position corresponding to the fourth finishing mill is the width of the intermediate billet plus 20 mm; the rolling position corresponding to the fourth finishing mill is the width of the intermediate billet plus 20 mm; and the tail opening position corresponding to the fourth finishing mill is the width of the intermediate billet plus 20 mm. The pre-positioning position corresponding to the fifth finishing mill is the width of the intermediate billet plus 30 mm; the rolling position corresponding to the fifth finishing mill is the width of the intermediate billet plus 30 mm; and the tail opening corresponding to the fifth finishing mill is the width of the intermediate billet plus 30 mm. The pre-positioning position corresponding to the sixth finishing mill is the width of the intermediate billet plus 35 mm; the rolling position corresponding to the sixth finishing mill is the width of the intermediate billet plus 35 mm; and the tail opening corresponding to the sixth finishing mill is the width of the intermediate billet plus 35 mm. The pre-position corresponding to the seventh finishing mill is the width of the intermediate billet plus 35 mm, the rolling position corresponding to the seventh finishing mill is the width of the intermediate billet plus 35 mm, and the tail opening corresponding to the seventh finishing mill is the width of the intermediate billet plus 35 mm.

8. The production method for controlling the black line on the edge of cold-rolled galvanized sheet as described in claim 1, characterized in that, The production line used in the production method further includes: a winding machine (14), and the method further includes: The short-stroke control parameters of the side guide plate of the coiler (14) are set as follows: the waiting position of the side guide plate is the strip control width plus 30 mm, the first short-stroke movement is the strip control width plus 20 mm, and the second short-stroke movement is the strip control width plus 10 mm. The strip head is tracked by thermal detection and roller speed calculation. When the strip head reaches the side guide plate, short-stroke operation is started. After the side guide plate contacts the strip and the pressure feedback of one side guide plate reaches 6 kN, it is switched to single-side pressure control, and the other side is position control.

Images