An on-line control device and control method for quenching spots of tin-plated plate

Abstract

The present application relates to a kind of tinned plate quenching spot online control device, the control device includes quenching system, quenching spray system, quenching cooling circulation system and quenching tank pass nozzle device, quenching spray system is set on quenching system, quenching cooling circulation system is set on the side of quenching system, through the mutual cooperation of quenching system, quenching spray system, quenching cooling circulation system and quenching tank pass nozzle device in the scheme, tinned plate quenching spot can be thoroughly eliminated online.

Description

TECHNICAL FIELD

[0001] The application relates to a control device, in particular to an online control device for quenching spots of tinned plate, and belongs to the technical field of tinning. BACKGROUND

[0002] Tinned products produced by a tinning unit of a cold rolling mill combine the strength and formability of steel with the corrosion resistance, solderability and beautiful appearance of tin, and are important materials for food packaging and household appliance manufacturing. Quenching spots are a common quality defect of tinned plate.

[0003] In the production of tinned plate, the surface of tinned plate just after tinning is whitish. Softening treatment is to heat the tinned plate to above 232 DEG C so that tin (the melting point of tin is 232 DEG C) is melted. In order to prevent the tin layer after softening from being rapidly oxidized at high temperature and to maintain the lustrous surface produced during softening, the tinned plate must be quickly put into water for cooling and reduced to below 100 DEG C in a very short time to form tinned plate with mirror-like luster. However, when the tinned plate is cooled and quenched, quenching spots are easily produced on the surface of the tinned plate. Such quenching spots not only affect the surface luster of the tinned plate and the appearance of cans made by users, but also cause rust at the quenching spot positions, thus reducing the corrosion resistance of the tinned plate. When used as cans for acidic food, the quenching spot positions are often corroded and perforated. Therefore, it is necessary to prevent the production of quenching spots during the production of tinned plate, which is a common problem existing in high-speed tinning lines at home and abroad.

[0004] There are various theories about the formation mechanism of quenching spots of tinned plate. All of them explain the influence of quenching process conditions on the formation of quenching spots through experimental methods. However, different from the laboratory conditions, the tinned steel plate is rapidly passed through water in production, and the water in the quenching tank is also strongly circulated, which will have a great influence on heat transfer. In addition, the thickness d and width b of the steel plate (which affect the heat capacity Q of the steel plate), the water temperature T 水 of the quenching tank and foreign matters on the surface of the steel plate will all affect heat transfer and the formation of quenching spots. Therefore, the results of theoretical experiments cannot effectively control quenching spots in production. Through the research on the formation mechanism of quenching spots, combined with production experience for more than ten years, it can be determined that the cause of the quenching spots of tinned plate is that the surface temperature of the steel plate does not match the water temperature when the steel plate is quenched. Only by maintaining the dynamic balance of the matching of the surface temperature of the steel plate and the water temperature when the steel plate is quenched can the quenching spots be completely eliminated. This matching relationship can be realized through calculation, production verification, solidification parameters and standard formation, and is related to the quenching process, the thickness of the steel plate and the speed of the unit.

[0005] 1. Quenching process, the water temperature T 水The water quality, the spraying water flow, the temperature difference when quenching the tin-plated plate, etc. directly affect the generation of the quenching spot on the surface of the tin-plated plate. Among them, the spraying water flow is related to the spraying pump pressure, the angle of the spraying pipe, the levelness, the position accuracy, and the nozzle state, and the water quality is related to the desalted water supplement flow.

[0006] 2. The thickness of the strip, the quenching spot is very sensitive to the thick plate (d≥0.30 mm), when the thickness of the plate is above 0.30 mm, the occurrence probability of the quenching spot is very large, and the occurrence amount accounts for more than 80% of the total occurrence amount of the quenching spot.

[0007] 3. The speed of the unit, for the specification switching and the speed change, especially when the thick plate is reduced in speed, the occurrence amount of the quenching spot is large, and the proportion is also more than 80%. The specific reason is that the heat Q carried by the steel plate is large, when the specification is switched, that is, when the speed is reduced, the heat △Q of the steel plate brought into the quenching tank is rapidly reduced, while the desalted water in the quenching tank is still being supplemented, and the two parts of heat are not matched well, which will lead to the generation of the low-temperature quenching spot on the surface of the tin-plated plate. The low-temperature quenching spot is a kind of surface defect of the tin-plated plate due to the existence of local rapid or slow cooling of the strip in the quenching tank.

[0008] At present, in the production process of the tin-plating unit, after the quenching spot defect is found by the outlet quality inspection, the unit is generally reduced in speed, the quenching process parameters are adjusted, or the operator drills into the quenching tank to pass the nozzle until the quenching spot is eliminated, and then the normal production is resumed. The number of times of stopping the machine to pass the nozzle is up to 10 times per month, and the quality loss is more than 30.625 t. The advanced high-speed tin-plating unit at home and abroad generally uses the method of reducing the speed of the unit, adjusting the quenching process parameters, or stopping the machine to pass the nozzle, or removing the material, or adding chemical solution into the quenching tank to control the quenching spot of the tin-plated plate. These methods can control the quenching spot of the tin-plated plate, but the quality loss is large, and the disadvantages are obvious. Therefore, the unit urgently needs an on-line control method for the quenching spot of the tin-plated plate to solve the above problems by the non-stop, effective standardized operation method.

[0009] Through the retrieval, the patent CN 104141034 A "for electroplated tin plate water quenching spot additive" specification describes a kind of for electroplated tin plate water quenching spot additive formula, when quenching, add 1.0∽1.5% the additive, can effectively improve the performance of steel plate water quenching spot, there is no application data for the production line about the running and quality state of strip steel, there is no process adjustment step and method related to the control of tin-plated steel water quenching spot.The patent CN 202369627 U "treatment device of tin-plated steel strip surface watermark" specification describes a kind of treatment device of tin-plated steel strip surface watermark, including quenching tank, constant-temperature clean water pool arranged below quenching tank, constant-temperature control system consisting of circulating water pump, cooling heat exchanger, quenching main spray pump and steam heat exchanger for heating, by ensuring the cleanliness and constant temperature of water, the generation of watermark is better controlled, by adjusting the flow, flow direction, pressure and water level of main spray pipe, to achieve the best state without watermark generation, the utility model patent has no application data for the production line about the running and quality state of strip steel, there is no process adjustment step and method related to the control of tin-plated steel water quenching spot. SUMMARY

[0010] The present application is just for the problems existing in the prior art, provide a kind of tin-plated steel water quenching spot on-line control device, the technical scheme overcomes the above-mentioned shortcomings of prior art, provide a kind of tin-plated steel water quenching spot on-line control method, the idea of the present application is: first, utilize the machine set downtime, adjust the position precision a of spray pipe in quenching tank, angle (d1, d2), and the distance (b, c) of strip steel, error is controlled within 2mm, then adjust the position of on-line nozzle device, blade is inserted into nozzle, must be adjusted when replacing spray pipe each time.Before machine set operation, calculate quenching tank water temperature change reference table (unless a adjustment is large, generally only need to calculate once, reference table can be included into operation standard), quenching tank is first filled with water (liquid level depends on a, in overflow state), adjust water temperature T 水 , strip steel temperature T 带 , adjust the opening degree C1 of quenching tank added desalted water automatic valve, the opening degree C2 of circulating cooling water automatic valve, start quenching tank cooling circulating pump and spray pump again, adjust the water pressure of spray pump outlet, require water spray height to be 10-15cm higher than the horizontal plane of spray beam, and water surface is continuous and seamless.When machine set operation, according to the thickness d of strip steel, adjust quenching process parameters (C1 and C2) and machine set speed u or on-line nozzle device, can completely eliminate tin-plated steel water quenching spot on line.

[0011] In order to achieve the above object, the technical scheme of the present application is as follows: a quenching water spot on-line control device for tin-plated plate, characterized in that the control device comprises a quenching water system, a quenching water spraying system, a quenching water cooling circulation system and a quenching water tank through nozzle device, the quenching water spraying system is arranged on the quenching water system and located at the working side of the quenching water system, the quenching water cooling circulation system is arranged at the transmission side of the quenching water system, and the quenching water tank through nozzle device is arranged on the quenching water spraying system and located at the transmission side of the quenching water system.

[0012] As an improvement of the present application, the quenching water system comprises a quenching water tank, a submerged roller, an overflow port baffle, a bolt, a muffle furnace top roller (including NO.1 furnace top roller and NO.2 furnace top roller, in total two) and a soft melting device, the submerged roller is arranged in the quenching water tank, the overflow port baffle is arranged above the quenching water tank, the overflow port baffle is adjusted by the bolt, the muffle furnace top roller is arranged above the quenching water tank, and the soft melting device is arranged between the submerged roller and the muffle furnace top roller, the quenching water system can quickly realize soft melting quenching of the tin-plated plate and can prevent tin layer oxidation after soft melting from generating floating ash defects.

[0013] As an improvement of the present application, the quenching water spraying system comprises a spraying pump, a hand valve, an upper spraying pipe, a lower spraying pipe, a nozzle, a spraying pipe fixing device, a spraying pipe angle adjusting device and a spraying pipe spacing adjusting device, the spraying pump is arranged on the pipeline at the working side of the quenching water tank, the hand valve is arranged above the spraying pump, the upper spraying pipe is arranged on the upper surface of the strip steel, the lower spraying pipe is arranged on the lower surface of the strip steel, a linear nozzle is opened on the upper spraying pipe along the length direction, the spraying pipe fixing device is arranged at the working side of the quenching water tank and can fix the position of the spraying pipe, the spraying pipe angle adjusting device is arranged at the working side of the quenching water tank and can adjust the angle of the spraying pipe and the nozzle, the spraying pipe spacing adjusting device is arranged at the working side of the quenching water tank and can adjust the spacing between the spraying pipe, the nozzle and the strip steel, and the opening degree of the hand valve can be adjusted to adjust the water pressure and flow rate of the spraying pump outlet. The quenching water spraying system can accurately control the position precision of the spraying pipe and the nozzle and can on-line adjust the spraying water flow rate and pressure.

[0014] As an improvement of the present application, the quenching water cooling circulation system comprises a desalted water automatic valve, a circulating cooling water automatic valve, a cooling plate heat exchanger, a steam automatic valve and a cooling circulation pump, the pipeline at the other side of the quenching water tank is provided with the cooling circulation pump, the cooling plate heat exchanger and the circulating cooling water automatic valve are arranged above the cooling circulation pump, the desalted water automatic valve and the steam automatic valve are arranged on the pipeline above the quenching water tank, and the opening degree of the desalted water automatic valve or the steam automatic valve can be adjusted to adjust the water temperature in the quenching water tank. The cooling circulation pump can pump out the water in the quenching water tank, supply the water after passing through the cooling plate heat exchanger and return the water into the quenching water tank through the circulating pipeline; the circulating cooling water automatic valve is arranged on the other circulating pipeline passing through the cooling plate heat exchanger, and the opening degree of the circulating cooling water automatic valve can be adjusted to adjust the cooling capacity of the cooling plate heat exchanger.

[0015] As an improvement of the present application, the water quenching tank nozzle device comprises a transmission mechanism, a screw rod, a copper nut, a connecting rod mechanism, a nozzle device blade support and a nozzle device blade, the transmission mechanism drives the screw rod, the nozzle device blade is arranged on the nozzle device blade support, the connecting rod mechanism connects the screw rod through the copper nut, and the nozzle device blade is inserted into the nozzle.

[0016] A tinned plate quenching spot online control method, the control method comprises the following steps:

[0017] Step one: when the unit is stopped, first empty the water in the quenching tank, and the strip steel in the quenching tank area is tensioned (when there is no strip steel, a heavy vertical line is placed from the WS side and the DS side of the No. 2 muffle furnace top roller to the quenching tank sinking roller, and after one circle around the sinking roller, the strip steel position is simulated by straightening and tightening), a straight wood or steel ruler is horizontally placed above the nozzle,

[0018] Step two: the distance a [30mm, 60mm] between the overflow baffle and the bottom end of the wood is measured and adjusted by the ruler;

[0019] Step three: the nozzle gap center and the bottom end of the wood are measured by the ruler, and the nozzle angle is adjusted to achieve the appropriate distance d1 [60mm, 90mm] and d2 [≥d1+5mm] in the quenching tank;

[0020] Note: according to production experience, the capacity of the lower surface of the strip steel contacting water is smaller than that of the upper surface, see Figure 2 Therefore, the heat exchange speed of the water in this area is relatively slow, so the lower nozzle angle is larger than the upper nozzle angle, and generally d2≥d1+5 can keep the water temperature balance on both sides of the strip steel.

[0021] Step four: after the angle adjustment is completed, the nozzle gap center and the strip steel are measured and adjusted by the steel ruler to make b=c=100mm, one person is arranged on the outside of the quenching tank, i.e. the WS side and the DS side, and one person is arranged in the quenching tank, and the nozzle pipe fixing device on the outside of the quenching tank is loosened;

[0022] Step five: check and confirm that the nozzle device blade is inserted into the nozzle and stopped at the most edge position,

[0023] Note: after the nozzle angle is adjusted, the nozzle device blade must be adjusted synchronously to ensure that it is inserted into the nozzle and does not stagger, otherwise there is a risk of blockage when the nozzle device is started.

[0024] Step six: before the unit is started and operated, the quenching tank is first filled with water, the water temperature T1 [77℃, 93℃] and the strip steel temperature T 带[240°C, 265°C], adjust the opening degree C1 [5%, 50%] of the automatic valve of the desalted water added to the quenching tank, the opening degree C2 [5%, 50%] of the valve of the circulating cooling water, and then start the cooling circulating pump and the spraying pump of the quenching tank, adjust the water pressure p [3.5 kg, 4.5 kg] of the outlet of the spraying pump, and require the water spray height to be 10-15 cm higher than the horizontal plane of the spraying beam, and the water surface to be continuous and seamless;

[0025] Note: According to production experience, the opening degree C1 of the automatic valve of the desalted water added to the quenching tank must be more than 5% to ensure the cleanliness of the water quality in the tank; and in order to maintain the dynamic balance of the water temperature in the tank, the opening degree C2 of the valve of the circulating cooling water must also be more than 5%.

[0026] Step seven: calculate the quenching tank water temperature change reference table according to the value of a, and suppose that the heat Q1 brought into the quenching tank per unit time Δt during the quenching of the tin-plated plate is:

[0027]

[0028] Wherein, m: the mass (kg) of the strip passing through the quenching tank per unit time Δt, m = ρbdl;

[0029] c: the specific heat of the tin-plated plate, 0.46 KJ / Kg℃;

[0030] ρ: the density of the tin-plated plate, 7.96 × 10 3 kg / m 3 ;

[0031] b: the width of the strip (mm);

[0032] d: the thickness of the strip (mm);

[0033] l: the length (m) of the strip passing through the quenching tank per unit time Δt, l = uΔt, and u is the speed of the unit;

[0034] T 带 : the temperature of the strip (℃);

[0035] The heat Q2 added to the quenching tank per unit time Δt to increase the water temperature ΔT is:

[0036] Q2 = m 水 c 水 ΔT = ρ 水 V 水 c 水 ΔT (2)

[0037] Wherein, m 水 : the mass (kg) of the water in the quenching tank, m 水 = ρ 水 V 水 ;

[0038] c 水 Specific heat of water: 4.2 kJ / kg℃;

[0039] ρ 水 The density of water is 1.0 × 10⁻⁶. 3 kg / m 3 ;

[0040] V 水 Volume of water in the quenching tank (m³) 3 After a is adjusted, V 水 It is a dynamically constant value;

[0041] According to the principle of energy conservation, the heat brought into the quenching tank per unit time Δt during quenching of tinplate is the same as the heat increase caused by the temperature rise ΔT in the quenching tank, i.e., Q1 = Q2. Substituting formulas (1) and (2), we can obtain:

[0042] ρbduΔtcT 带 =ρ 水 V 水 c 水 ΔT (3)

[0043] Simplifying formula (3), we get:

[0044]

[0045] In formula (4), the density ρ of strip steel, specific heat c, unit time Δt, and density ρ of water are... 水 Specific heat c 水 Volume V 水 These are all fixed values ​​and can be set. Assuming it is a constant value, substituting it into formula (4) yields:

[0046] ΔT=K·bduT 带 (5)

[0047] Considering that the width of the tinplate changes very little, and the impact of width on the water temperature in the quenching tank is limited when switching specifications, the temperature rise ΔT of the water in the quenching tank during tinplate quenching is related to the strip thickness d, the unit speed u, and the strip temperature T. 带 It is directly proportional, as long as the water temperature T is adjusted in advance according to the production plan. 水 strip temperature T 带 By adjusting the unit speed, a dynamic balance between the surface temperature and water temperature of the strip steel during quenching can always be maintained.

[0048] Using the strip thickness d as a variable, the water temperature change ΔT value during normal production of several common and critical specifications of tinplate is calculated according to formula (4) and used as a reference table for the water temperature change of the quenching tank.

[0049] Step eight: when the unit is running, according to the strip thickness d, refer to the water temperature change reference table, adjust the quenching process parameters (C1 and C2) and the unit speed u or the online nozzle device, which can completely eliminate the quenching spot of the tin-plated plate online.

[0050] Compared with the prior art, the present application has the following advantages: the technical scheme proposes an online control method for quenching spot defects generated in the production of tin-plated plate (0.17mm-0.55mm) in the cold rolling mill. First, the position precision a, angle (d1, d2) and distance (b, c) of the spray pipe in the quenching tank are adjusted during the shutdown of the unit. Then, the position of the online nozzle device is adjusted, and the blade is inserted into the nozzle. Before the unit is started, the water temperature change reference table of the quenching tank is calculated. The quenching tank is first filled with water, and the water temperature T 水 , the strip temperature T 带 is adjusted. The opening degree C1 of the automatic valve for adding desalted water and the opening degree C2 of the automatic valve for circulating cooling water are adjusted. Then, the cooling circulating pump and the spray pump of the quenching tank are started, the outlet water pressure of the spray pump is adjusted, the water spray height is required to be 10-15cm higher than the horizontal plane of the spray beam, and the water surface is continuous and seamless. When the unit is running, according to the strip thickness d and the water temperature change reference table, the quenching process parameters (C1 and C2) and the unit speed u or the online nozzle device are adjusted, which can completely eliminate the quenching spot of the tin-plated plate online, avoid frequent speed limiting or shutdown of the unit for nozzle, and reduce the product waste of the unit. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 It is a schematic diagram of the quenching tank spray pipe.

[0052] Figure 2 It is a schematic diagram of the quenching tank equipment.

[0053] Figure 3 It is a schematic diagram of the quenching tank circulating system.

[0054] Figure 4 It is a schematic diagram of the quenching tank nozzle device.

[0055] In the figure: 1-quenching tank; 2-muffle furnace top roller; 3-submerged roller; 4-overflow baffle; 5-bolt; 6-upper spray pipe; 7-lower spray pipe; 8-nozzle; 9-spray pipe fixing device; 10-spray pipe angle adjusting device (handle); 11-spray pipe spacing adjusting device (handle); 12-automatic valve for adding desalted water; 13-automatic valve for circulating cooling water; 14-plate heat exchanger; 15-steam automatic valve; 16-spray pump; 17-hand valve; 18-cooling circulating pump; 19-softening device; 20-nozzle device blade; 21-transmission mechanism; 22-screw; 23-copper nut; 24-linkage mechanism; 25-nozzle device blade support. DETAILED DESCRIPTION

[0056] In order to deepen the understanding of the present application, the following detailed description of the present embodiment is made in conjunction with the accompanying drawings.

[0057] Example 1: see Figure 1 The present application discloses a quenching water spot online control device for a tinned plate, which comprises a quenching water system, a quenching water spraying system, a quenching water cooling circulation system and a quenching water tank nozzle device. The quenching water spraying system is arranged on the quenching water system and located at the working side of the quenching water system. The quenching water cooling circulation system is arranged at the transmission side of the quenching water system. The quenching water tank nozzle device is arranged on the quenching water spraying system and located at the transmission side of the quenching water system.

[0058] The quenching water system comprises a quenching water tank 1, a submerged roll 3, an overflow baffle 4, a bolt 5, a muffle furnace top roll (including a NO.1 furnace top roll and a NO.2 furnace top roll) 2 and a softening device 19. The submerged roll 3 is arranged in the quenching water tank. The overflow baffle 4 is arranged above the quenching water tank. The overflow baffle 4 is adjusted by the bolt 5. The muffle furnace top roll 2 is arranged above the overflow baffle 4. The softening device 19 is arranged between the submerged roll 3 and the muffle furnace top roll 2.

[0059] The quenching water spraying system comprises a spraying pump 16, a hand valve 17, an upper spraying pipe 6, a lower spraying pipe 7, a nozzle 8, a spraying pipe fixing device 9, a spraying pipe angle adjusting device 10 and a spraying pipe spacing adjusting device 11. The spraying pump 16 is arranged on a pipeline at one side of the quenching water tank 1. The hand valve 17 is arranged above the spraying pump 16. The upper spraying pipe 6 is arranged on the upper surface of the strip steel. The lower spraying pipe 7 is arranged on the lower surface of the strip steel. A linear nozzle 8 is arranged on the spraying pipe in the length direction. The spraying pipe fixing device 9 is arranged at the working side of the quenching water tank 1 and can fix the position of the spraying pipe. The spraying pipe angle adjusting device 10 is arranged at the working side of the quenching water tank 1 and can adjust the angle of the spraying pipe and the nozzle. The spraying pipe spacing adjusting device 11 is arranged at the working side of the quenching water tank 1 and can adjust the spacing between the spraying pipe, the nozzle and the strip steel. The opening degree of the hand valve 17 can be adjusted to adjust the water pressure and flow rate of the outlet of the spraying pump 16.

[0060] The quenching water cooling circulation system comprises a desalted water automatic valve 12, a circulating cooling water automatic valve 13, a cooling plate heat exchanger 14, a steam automatic valve 15 and a cooling circulation pump 18, the pipeline on the other side of the quenching tank 1 is provided with the cooling circulation pump 18, the upper side of the cooling circulation pump 18 is provided with the cooling plate heat exchanger 14 and the circulating cooling water automatic valve 13; the desalted water automatic valve 12 and the steam automatic valve 15 are respectively arranged on the pipeline on the upper side of the quenching tank 1, and the opening degree of the desalted water automatic valve 12 or the steam automatic valve 15 can be adjusted to adjust the water temperature in the quenching tank 1. The cooling circulation pump 18 can pump out the water in the quenching tank 1, supply the water after passing through the cooling plate heat exchanger 14, and return the water into the quenching tank 1 through the circulating pipeline; the circulating cooling water automatic valve 13 is arranged on another circulating pipeline passing through the cooling plate heat exchanger 14, and the opening degree of the circulating cooling water automatic valve 13 can be adjusted to adjust the cooling capacity of the cooling plate heat exchanger 14.

[0061] The quenching water tank nozzle device comprises a transmission mechanism 21, a screw rod 22, a copper nut 23, a connecting rod mechanism 24, a nozzle device blade support 25 and a nozzle device blade 20, the transmission mechanism 21 drives the screw rod 22, the nozzle device blade 20 is arranged on the nozzle device blade support 25, the connecting rod mechanism 24 is connected with the screw rod 22 through the copper nut 23, and the nozzle device blade 20 is inserted into the nozzle 8.

[0062] Embodiment 2: see Figure 1 A quenching water spot online control method for a tinned plate, the control method comprising the following steps:

[0063] Step one: when the unit is stopped, first empty the water in the quenching tank, and the strip steel in the quenching tank area is tensioned (when there is no strip steel, a heavy vertical line is placed from the WS side and the DS side of the No. 2 muffle furnace top roller to the quenching tank sinking roller, and after one circle around the sinking roller, the strip steel position is simulated by straightening and tightening), a straight wood or steel ruler is horizontally placed above the nozzle, see Figure 1 .

[0064] Step two: the distance a [30mm, 60mm] between the overflow baffle and the bottom end of the wood is measured and adjusted by a ruler;

[0065] Step three: the nozzle angle is adjusted, the distances d1, d2 between the center of the nozzle gap and the bottom end of the wood are measured by a ruler, and the nozzle angle in the quenching tank is adjusted to achieve appropriate distances d1 [60mm, 90mm], d2 [≥d1+5mm];

[0066] Note: according to production experience, the capacity of the water contacting the lower surface of the strip steel is smaller than that of the upper surface, see Figure 2 , so the heat exchange speed of the water in this area is relatively slow, and therefore the lower nozzle angle is larger than the upper nozzle angle, and generally d2≥d1+5 can keep the water temperature balance on both sides of the strip steel.

[0067] Step four: After the angle adjustment, adjust the nozzle spacing, one person on the outside of the quenching tank, one person on the inside, loosen the nozzle fixing device on the outside of the quenching tank, see Figure 2 , and adjust the spacing between the nozzle gap center and the strip b, c to b = c = 100 mm with a steel ruler.

[0068] Step five: Check and confirm that the online nozzle device blade is inserted into the nozzle and stopped at the most edge position, see Figure 4 .

[0069] Note: After adjusting the nozzle angle, the nozzle device blade must be adjusted synchronously to ensure that it is inserted into the nozzle and does not sag. Otherwise, there is a risk of jamming when starting the nozzle device.

[0070] Step six: Before the unit is started, fill the quenching tank with water, adjust the water temperature T1 [77℃, 93℃], the strip temperature T 带 [240℃, 265℃], adjust the quenching tank desalination water automatic valve opening degree C1 [5%, 50%], the circulating cooling water valve opening degree C2 [5%, 50%], then start the quenching tank cooling circulating pump and the spray pump, adjust the spray pump outlet water pressure p [3.5kg, 4.5kg], the water spray height should be 10-15cm higher than the spray beam level, and the water surface should be continuous and seamless.

[0071] Note: According to production experience, the quenching tank desalination water automatic valve opening degree C1 must be above 5% to ensure the cleanliness of the water quality in the tank; and in order to maintain the dynamic balance of the water temperature in the tank, the circulating cooling water valve opening degree C2 must also be above 5%.

[0072] Step seven: Calculate the quenching tank water temperature change reference table according to the value of a. Assuming that the heat brought into the quenching tank per unit time Δt for tin-plated plate quenching is Q1, then:

[0073] Q1 = m∫t t1 2cT 带 dt = ρbduΔtcT 带 (1)

[0074] Where m: the mass of the strip passing through the quenching tank per unit time Δt (kg), m = ρbdl;

[0075] c: specific heat of tin-plated plate, 0.46 KJ / Kg℃;

[0076] ρ: density of tin-plated plate, 7.96 × 10 3 kg / m 3 ;

[0077] b: strip width (mm);

[0078] d: strip thickness (mm);

[0079] l: strip length (m) in the quenching tank per unit time Δt, l = uΔt, u is the speed of the unit;

[0080] T 带 : strip temperature (°C);

[0081] The heat Q2 added to the water temperature rise ΔT in the quenching tank per unit time Δt is:

[0082] Q2 = m 水 c 水 ΔT (2) 水 V 水 c 水 ΔT (2)

[0083] Wherein, m 水 : mass of water in the quenching tank (kg), m 水 = ρ 水 V 水 ;

[0084] c 水 : specific heat of water, 4.2 KJ / Kg°C;

[0085] ρ 水 : density of water, 1.0 x 10 3 kg / m 3 ;

[0086] V 水 : volume of water in the quenching tank (m 3 ), a is adjusted, V 水 is a dynamic constant value;

[0087] According to the principle of energy conservation, the heat brought into the quenching tank per unit time Δt is the same as the heat added to the water temperature rise ΔT in the quenching tank, i.e. Q1 = Q2, which is brought into formula (1) and (2), and the following is obtained:

[0088] ρbduΔtcT 带 = ρ 水 V 水 c 水 ΔT (3)

[0089] The formula (3) is arranged to obtain:

[0090]

[0091] In formula (4), the strip density ρ, specific heat c, unit time Δt, water density ρ 水 , specific heat c 水 , volume V 水 are all constant values, which can be set Assuming it is a constant value, substituting it into formula (4) yields:

[0092] ΔT=K·bduT 带 (5)

[0093] Considering that the width of the tinplate changes very little, and the impact of width on the water temperature in the quenching tank is limited when switching specifications, the temperature rise ΔT of the water in the quenching tank during tinplate quenching is related to the strip thickness d, the unit speed u, and the strip temperature T. 带 It is directly proportional, as long as the water temperature T is adjusted in advance according to the production plan. 水 strip temperature T 带 By adjusting the unit speed, a dynamic balance between the surface temperature and water temperature of the strip steel during quenching can always be maintained.

[0094] Using the strip thickness d as a variable, the water temperature change ΔT value during normal production of several common and critical specifications of tinplate is calculated according to formula (4) and used as a reference table for the water temperature change of the quenching tank.

[0095] Step 8: When the unit is running, adjust the quenching process parameters (C1 and C2) and the unit speed u according to the strip thickness d and the reference table of quenching tank water temperature change, or use the online nozzle device to completely eliminate quenching spots on the tinplate online.

[0096] Specific implementation method: Refer to Figure 1 — Figure 4 A method for online control of quenching spots on tin-plated sheets, the method comprising the following steps:

[0097] Step 1: When the unit is shut down, first drain the water from quenching tank 1. Then, stretch the strip in the quenching tank area (if there is no strip, place a plumb line from the WS side and DS side of the top roller 2 of the NO.2 muffle furnace to the submerged roller in the quenching tank, wrap it around the submerged roller once, and then straighten and tighten it to simulate the position of the strip). Place a straight wooden strip or steel ruler horizontally above nozzles 6 and 7, see... Figure 1 .

[0098] Step 2: Measure the distance 'a' from the top of the overflow baffle 4 to the bottom of the wooden strip. Adjust the overflow baffle adjusting bolt 5 so that 'a' is 60mm, corresponding to the water volume V in the quenching tank. 水 4m 3 See Table 1.

[0099] Step 3: Adjust the nozzle angle adjustment device 10, and use a ruler to measure the distances d1 and d2 between the center of the nozzle gap and the bottom of the wooden strip, so that d1 is 90mm and d2 is 95mm.

[0100] Step 4: After the angle adjustment is complete, adjust the nozzle spacing. One person on each of the WS and DS sides outside the quenching tank, and one person inside the quenching tank, loosen the nozzle fixing device 9 outside the quenching tank.Figure 2 Use a steel ruler to measure the distance b and c between the center of the nozzle gap and the strip steel. Adjust the nozzle spacing adjustment device 11 outside the groove, and confirm that b is 100mm and c is 100mm inside the groove.

[0101] Step 5: Check and confirm that the online nozzle device blade 20 is inserted into the nozzle 8, and the nozzle device blade support 25 is stopped at the outermost position. Figure 4 .

[0102] Table 1. Location parameters of the nozzles inside the quenching tank

[0103]

[0104] Step Six: Before starting the unit, fill the quenching tank 1 with water. According to the strip steel specifications (taking the common specification 0.25*864mm as an example), refer to Table 2 and open the automatic steam valve 15 to adjust the water temperature T. 水 The temperature is 89℃, and a softening device is set for the strip steel temperature T. 带 Set the temperature to 265℃. Adjust the opening degree C1 of the automatic demineralized water valve 12 in the quenching tank to 20%, and the opening degree C2 of the automatic circulating cooling water valve 13 to 20%. Then start the cooling circulation pump 18 and the spray pump 16. Adjust the manual valve 17 to make the pump outlet water pressure p 4kg. The water spray height should be 10-15cm higher than the horizontal plane of the spray beam, and the water surface should be continuous and without gaps.

[0105] Table 2 Reference Table for Tin Plating Quenching Process Parameters

[0106]

[0107] Step 7: Calculate the reference table for water temperature changes in the quenching tank based on the value of 'a'. Assume the heat Q1 carried into the quenching tank per unit time Δt during tinplate quenching is:

[0108]

[0109] Where m: the mass (kg) of strip steel passing through the quenching tank per unit time Δt, m=ρbdl;

[0110] c: Specific heat of tin-plated sheet, 0.46 KJ / Kg℃;

[0111] ρ: Density of tinplate, 7.96 × 10⁻⁶ 3 kg / m 3 ;

[0112] b: Strip width (mm);

[0113] d: Strip thickness (mm);

[0114] l: Length of strip steel passing through the quenching tank per unit time Δt (m), l=uΔt, u is the unit speed;

[0115] T 带 Strip temperature (°C).

[0116] The heat increase Q2 caused by the temperature rise ΔT of the water in the quenching tank per unit time Δt is:

[0117] Q2 = m 水 c 水 ΔT=ρ 水 V 水 c 水 ΔT (2)

[0118] Where, m 水 Mass of water in the quenching tank (kg), m 水 =ρ 水 V 水 ;

[0119] c 水 Specific heat of water: 4.2 kJ / kg℃;

[0120] ρ 水 The density of water is 1.0 × 10⁻⁶. 3 kg / m 3 ;

[0121] V 水 Volume of water in the quenching tank (m³) 3 After a is adjusted, V 水 It is a dynamically constant value;

[0122] According to the principle of energy conservation, the heat brought into the quenching tank per unit time Δt during quenching of tinplate is the same as the heat increase caused by the temperature rise ΔT in the quenching tank, i.e., Q1 = Q2. Substituting formulas (1) and (2), we can obtain:

[0123] ρbduΔtcT 带 =ρ 水 V 水 c 水 ΔT (3)

[0124] Simplifying formula (3), we get:

[0125]

[0126] Using the strip thickness d as a variable, the water temperature change ΔT value within 1 minute during normal production of several common and critical specifications of tinplate is calculated according to formula (4), as shown in Table 3 below.

[0127] Table 3 Reference Table for Water Temperature Changes in Tin Plating Quenching Bath

[0128]

[0129] Step eight: when the unit is running, according to the strip thickness d, refer to Table 3 to adjust the quenching process parameters (C1 and C2) and the unit speed u or the online through nozzle device, which can completely eliminate the quenching spots of tinplate online. Take the normal switching production of common specifications 0.25*864mm and 0.35*950mm as an example:

[0130] The first case: when quenching spots appear during the production of 0.25*864mm material, refer to Table 2 to adjust C1 and the opening degree of C2, and take the sample under the sunlight that the quenching spots are invisible as the standard.

[0131] The second case: when the strip (0.25*864mm) switches to thick strip (0.35*950mm), in order to avoid the quenching spots caused by the speed reduction of the weld over the straightener, the speed is stably reduced to 200mpm for the previous roll, and according to Table 3, the water temperature T 水 is stably increased by ΔT1 value of 2.45℃ per minute. The water temperature T 带 of the quenching tank is quickly reduced to 240℃, and after the weld passes through the straightener, the speed is stably increased to more than 350mpm. According to Table 3, the water temperature increases by ΔT2 value of 3.48℃-6.09℃ (3.48℃×350mpm / 200mpm) per minute, which is greater than 2.45℃. During normal production, the surface temperature of the strip matches the water temperature when quenching, which is a dynamic balance. At this time, the water temperature ΔT increases by ave[1.03℃, 3.64℃] per minute, so the opening degree of C1 or C2 should be immediately adjusted to increase the cooling capacity of the water temperature by about 2.34℃ per minute, and take the sample under the sunlight that the quenching spots are invisible as the standard, and finally steadily increase to the required unit speed.

[0132] The third case: when quenching spots appear during the production of 0.35*950mm material, refer to Table 2 to adjust C1 and the opening degree of C2, or fine-tune the water temperature T 水 of the quenching tank, and take the sample under the sunlight that the quenching spots are invisible as the standard.

[0133] The fourth case: when the thick strip (0.35*950mm) switches to the thin strip (0.25*864mm), in order to avoid the quenching spots caused by the speed reduction of the weld over the straightener, the speed is stably adjusted to 300mpm for the previous roll, and according to Table 3, the water temperature T 水 is stably reduced by ΔT3 value of 5.22℃ per minute (3.48℃×300mpm / 200mpm). The water temperature T 带Rapidly rise to 260 ℃, after the weld over the pull straightening machine to 350 mpm above the smooth speed of 30 mpm per time, refer to table 3, at this time the water temperature increases ΔT4 value is 3.675 ℃ (2.45 ℃ × 300 mpm / 200 mpm) -4.28 ℃ <5.22 ℃ per minute. In the normal production process, the surface temperature of the strip water when the match is dynamic balance, at this time the water temperature ΔT per minute less increase ave [0.94 ℃, 1.645 ℃], so to immediately adjust the opening of C1 or C2, the water temperature per minute cooling capacity to reduce about 1.29 ℃, to sample in the sunlight under the light can not be seen quenching spot, finally steadily to the required unit speed.

[0134] The fifth case: the strip surface appears fixed area local quenching spot, generally is the nozzle some point clogged, spraying water flower discontinuity, start online through nozzle device, until the water surface continuous seamless.

[0135] It should be noted that the above examples, not to limit the scope of the protection of the present application, on the basis of the above technical solutions made of equivalent transformation or substitution fall within the scope of the claims of the present application is protected.

Claims

1. A method for on-line control of quench spot of tinned plate, characterized by, The control method comprises the following steps: Step one: when the unit is stopped, first empty the water in the quenching tank, and build the strip in the quenching tank, a straight wood or steel ruler is horizontally placed above the spray pipe, Step two: measure and adjust the distance a [30mm, 60mm] between the overflow damper and the bottom end of the wood with a ruler; Step three: adjust the angle of the spray pipe, measure the distance d1, d2 between the center of the nozzle gap and the bottom end of the wood with a ruler, and adjust the angle of the spray pipe in the quenching tank to achieve a suitable distance d1 [60mm, 90mm], d2 [≥d1+5mm]; Step four: after the angle adjustment is completed, adjust the nozzle spacing, one person on the working side WS and one person on the drive side DS outside the quenching tank, and one person inside the quenching tank, loosen the fixing device of the spray pipe outside the quenching tank, and measure and adjust the distance b, c between the center of the nozzle gap and the strip with a steel ruler, so that b=c=100mm; Step five: check and confirm that the online through nozzle device blade is inserted in the nozzle and stopped at the most edge position, Step six: before the unit operation, the quenching tank is first filled with water, the water temperature T1 [77℃, 93℃] is adjusted, the strip temperature T 带 [240℃, 265℃] is adjusted, the quenching tank desalination water automatic valve opening degree C1 [5%, 50%] and the circulating cooling water valve opening degree C2 [5%, 50%] are adjusted, then the quenching tank cooling circulating pump and the spraying pump are started, the spraying pump outlet water pressure p [3.5kg, 4.5kg] is adjusted, the water spray height is required to be 10-15cm higher than the spraying beam level, and the water surface is continuous and seamless; Step seven: Calculate the reference table of the water temperature change in quenching tank according to the value of a, assuming that the heat brought into the quenching tank per unit time Δt is Q when the tin-plated plate is quenched 1， Then: （1） wherein m: mass kg of the strip passing through the quenching tank in unit time Δt, ; c: specific heat of tin-plated sheet, 0.46 kJ / kg℃; p: density of tin-plated sheet, 7.96 x 10 3 kg / m 3 ; b: strip width mm; d: strip thickness mm; l: length of strip passing through the quenching tank per unit of time Δt, u is the speed of the unit; T 带 : strip temperature °C; The heat Q2 added to the quenching tank in the unit time Δt for the temperature rise ΔT of the water is: （2） wherein m 水 : mass of water in quenching tank, kg, ; c 水 : specific heat of water, 4.2 kJ / kg°C; p 水 : density of water, 1.0 x 10 3 kg / m 3 ; V 水 : volume of water in quenching tank m 3 , a, after adjusting, V 水 is a dynamic constant value; According to the principle of energy conservation, the heat brought into the quenching tank per unit time Δt is equal to the heat increased by the water temperature rise ΔT in the quenching tank, i.e. Bringing formula (1) and (2) into the equation, we have: （3） After rearranging formula (3), we get: （4） In formula (4), the strip density p, specific heat c, unit time At, the density of water p 水 , specific heat c 水 , volume V 水 are all constant values, set as a constant value, and substituting into formula (4) gives: （5） When tinned plate is quenched, the temperature rise ΔT of water in the quenching tank is proportional to the thickness d of the strip, the speed u of the unit, and the temperature T of the strip 带 proportional Taking the strip thickness d as the variable, calculate the water temperature change ΔT value of several common and critical specifications of tin-plated sheet in normal production according to formula (4) as a quenching tank water temperature change reference table; Step eight: when the unit is running, according to the strip thickness d, refer to the quenching tank water temperature change reference table, adjust the quenching process parameters C1 and C2 and the unit speed u or the online through nozzle device, and completely eliminate the quenching spots of tin-plated sheet online.

2. An apparatus for on-line control of quench spot of a tin-plated sheet, characterized by A tin-plated sheet quenching spot online control method for realizing the claim 1, the control device comprises a quenching system, a quenching spray system, a quenching cooling circulation system and a quenching tank through nozzle device, the quenching spray system is arranged on the quenching system and located on the working side of the quenching system, the quenching cooling circulation system is arranged on the drive side of the quenching system, and the quenching tank through nozzle device is arranged on the quenching spray system and located on the drive side of the quenching system; The quenching system comprises a quenching tank, a submerged roller, an overflow damper, a bolt, a furnace top roller of a muffle furnace and a softening device, the submerged roller is arranged in the quenching tank, the overflow damper is arranged above the quenching tank, the bolt is used to adjust the overflow damper, the furnace top roller of the muffle furnace is arranged above the quenching tank, and the softening device is arranged between the submerged roller and the furnace top roller of the muffle furnace; The quenching spray system comprises a spray pump, a hand valve, an upper spray pipe, a lower spray pipe, a nozzle, a spray pipe fixing device, a spray pipe angle adjusting device and a spray pipe spacing adjusting device, the spray pump is arranged on a pipeline at a working side of the quenching tank, the hand valve is arranged above the spray pump, the upper spray pipe is arranged on an upper surface of the strip steel, the lower spray pipe is arranged on a lower surface of the strip steel, a linear nozzle is arranged on the spray pipe in a length direction, the spray pipe fixing device is arranged at the working side of the quenching tank to fix the position of the spray pipe, the spray pipe angle adjusting device is arranged at the working side of the quenching tank to adjust the angle of the spray pipe and the nozzle, and the spray pipe spacing adjusting device is arranged at the working side of the quenching tank to adjust the spacing between the spray pipe, the nozzle and the strip steel; the opening degree of the hand valve is adjusted, and the outlet water pressure and flow of the spray pump are adjusted. The quenching cooling circulation system comprises a desalted water automatic valve, a circulating cooling water automatic valve, a cooling plate heat exchanger, a steam automatic valve and a cooling circulation pump, a pipeline at another side of the quenching tank is provided with the cooling circulation pump, the cooling plate heat exchanger and the circulating cooling water automatic valve are arranged above the cooling circulation pump, the desalted water automatic valve and the steam automatic valve are arranged on a pipeline above the quenching tank, the water temperature in the quenching tank is adjusted by adjusting the opening degree of the desalted water automatic valve or the steam automatic valve, the water in the quenching tank is pumped out by the cooling circulation pump, supplied through the cooling plate heat exchanger, and returned to the quenching tank through a circulating pipeline, and the circulating cooling water automatic valve is arranged on another circulating pipeline through the cooling plate heat exchanger, and the cooling capacity of the cooling plate heat exchanger is adjusted by adjusting the opening degree of the circulating cooling water automatic valve. The quenching tank through nozzle device comprises a transmission mechanism, a lead screw, a copper nut, a connecting rod mechanism, a through nozzle device blade support and a through nozzle device blade, the transmission mechanism drives the lead screw, the through nozzle device blade is arranged on the through nozzle device blade support, the connecting rod mechanism is connected with the lead screw through the copper nut, and the through nozzle device blade is inserted into the nozzle.

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