A flexible post-processing production line for cold-rolled strip steel suitable for producing various high-strength steels

Abstract

A flexible post-processing production line for cold-rolled strip steel suitable for producing various high-strength steels includes the following stations in sequence: uncoiling – welding – inlet looper – cleaning – central continuous post-processing – intermediate looper – leveling – outlet looper – finishing – coiling. The central continuous post-processing station includes, in sequence: a jet radiant tube preheating section, a radiant tube heating section, a transverse magnetic induction heating section or a jet radiant composite heating section, a jet radiant composite homogenizing section, a slow cooling section, a rapid cooling section, a reheating section, parallel sections (furnace nose section + zinc pot section + air knife section + alloying heating section + alloying homogenizing section + post-plating cooling section) and (moving channel section + over-aging section + final jet cooling section), a final water cooling section, and optional pickling and flash plating sections. This invention can produce five varieties of ultra-high-strength strip steel products—cold-rolled annealed, pickled, flash-plated, hot-dip pure zinc, and alloyed hot-dip galvanized—on the same production line.

Description

Technical Field

[0001] This invention relates to the field of continuous annealing heat treatment technology for strip steel, and in particular to a flexible post-processing production line for cold-rolled strip steel suitable for producing a variety of high-strength steels. Background Technology

[0002] With the increasing market demand for ultra-high strength steel, in recent years, many steel companies in my country have built multiple continuous heat treatment production lines for cold-rolled strip steel capable of producing ultra-high strength steel through joint ventures or technology introduction. These lines include continuous strip annealing production lines, hot-dip galvanizing (GI) production lines, alloyed hot-dip galvanizing (GA) production lines, and continuous annealing / hot-dip galvanizing dual-purpose production lines. These production lines primarily employ traditional processes to produce ultra-high strength steel.

[0003] Traditional strip steel processing lines, in addition to the various looper stations, typically include the following stations: uncoiling, welding, cleaning, central continuous post-processing, leveling, finishing, and coiling. Some processing lines also have a tension leveling station between the leveling and finishing stations, some have a post-processing station between the leveling and finishing stations, and some have both tension leveling and post-processing stations between the leveling and finishing stations.

[0004] The aforementioned central continuous post-processing station, when producing continuously annealed cold-rolled products, typically includes equipment such as a general preheating section, a heating section, a soaking section, a slow cooling section, a rapid cooling section, an over-aging (OA) section, a jet cooling section, and a final water cooling section. Figure 1 As shown. Some processing lines have a reheating section between the rapid cooling section and the over-aging section, while other units have both a pickling section and a reheating section between the rapid cooling section and the over-aging section. When producing GI products, the central continuous post-processing station typically includes the following equipment in sequence: a general preheating section, a heating section, a soaking section, a slow cooling section, a rapid cooling section, a uniform heat preservation section, a furnace nose section, a zinc pot section, an air knife section, a post-plating cooling section, and a final water cooling section. Figure 2 As shown. Some GI processing lines have a reheating section between the rapid cooling section and the equalization heat preservation section, while some units have both a pickling section and a reheating section between the rapid cooling section and the equalization heat preservation section. Some processing lines have a movable post-plating rapid cooling section within 10 meters above the air knife between the air knife section and the fixed post-plating cooling section (usually in the upper part of the APC tower). When producing GA products, the central continuous post-processing station typically includes the following equipment in sequence: ordinary preheating section – heating section – soaking section – slow cooling section – rapid cooling section – equalization heat preservation section – furnace nose section – zinc pot section – air knife section – alloying heating section – alloying soaking section – fixed post-plating cooling section and final water cooling section. Figure 3As shown. Some processing lines have a reheating section between the rapid cooling section and the equalization heat preservation section, while other units have both a pickling section and a reheating section between the rapid cooling section and the equalization heat preservation section. Dual-purpose units producing cold-rolled products and GI products, dual-purpose units producing cold-rolled products and GA products, and tri-purpose units producing cold-rolled products, GI products, and GA products also have a movable channel section above the air knife section to achieve switching between two or three products. The movable channel section (used only for cold-rolled products), the movable post-plating rapid cooling section (used only for GI products), and the alloying heating section (used only for GA products) are arranged in parallel, and the strip steel usually needs to be cut to switch products. Production lines producing GI and GA products use a movable post-plating rapid cooling section (used only for GI products) and an alloying heating section (used only for GA products) arranged in parallel to achieve switching between the two products.

[0005] For the aforementioned ordinary preheating and heating sections, a common method is to use radiant tube heating. The exhaust gas from the radiant tubes is then used to heat a protective gas via an external heat exchanger. Finally, the protective gas is sprayed onto the strip surface to preheat the strip to approximately 200°C. This preheating method has the following advantages compared to directly spraying the strip surface with radiant tube exhaust gas for preheating:

[0006] (1) It eliminates the pollution of the strip surface by combustion exhaust gas. Both mixed coal gas and coke oven gas contain a certain amount of impurities, such as tar, dust, organic sulfur, etc. If the combustion exhaust gas is directly sprayed onto the strip surface to preheat the strip, it will cause pollution to the strip surface. This situation should be avoided, especially when producing high surface quality strips.

[0007] (2) The combustion exhaust gas contains a certain amount of oxygen (3%~5%). If such combustion exhaust gas is directly sprayed onto the surface of the strip steel, it is easy to cause oxidation on the surface of the strip steel, which will also affect the surface quality of the steel strip product. However, by using an external heat exchanger to heat the protective gas, and then spraying the protective gas onto the surface of the strip steel, oxidation will not occur because the protective gas contains 3%~7% hydrogen. Using this method of preheating can save about 10% of fuel.

[0008] However, this technology still has the following drawbacks:

[0009] (1) The temperature of the combustion exhaust gas after the preheating steel is still relatively high. When producing high temperature annealing materials, it usually exceeds 350°C. It is necessary to add a boiler or superheated water heating device to make secondary use of the waste heat of the combustion exhaust gas, which significantly reduces economic efficiency and the equipment occupies a large area.

[0010] (2) The proportion of energy directly utilized on the strip steel is low, that is, a large amount of heat is still carried away by the exhaust gas after the preheating of the strip steel (the higher the temperature of the exhaust gas after the preheating of the strip steel, the more heat is carried away), and the heat of combustion is not fully transferred to the strip steel (that is, the primary utilization rate of energy is low).

[0011] (3) The temperature of the preheated strip is limited, and it is usually difficult for the preheated strip to exceed 250°C.

[0012] (4) The strip steel is heated slowly. For high-strength steel, especially ultra-high-strength steel, the incoming plate shape is generally worse than that of ordinary products. The low heating rate means that the strip steel runs in the furnace for a long time and is prone to deviation in the furnace.

[0013] (5) Due to the large thermal inertia of the radiant tube heating furnace, when the thickness specification and annealing target temperature change significantly, the strip temperature adjustment speed is slow and the temperature control accuracy is poor, which is very unfavorable for the production of ultra-high strength steel and results in a large loss of product quality.

[0014] (6) Radiant tube heat treatment: Due to the large thermal inertia of the radiant tube heat treatment furnace, when the thickness specification and annealing target temperature change significantly, the heat treatment temperature of the strip steel is adjusted slowly, requiring the addition of transition material, or causing large fluctuations in the actual heat treatment temperature of the strip steel. Summary of the Invention

[0015] The purpose of this invention is to provide a flexible post-processing production line for cold-rolled strip steel suitable for producing various high-strength steels. This line can achieve the following: 1) Full utilization of waste heat from radiant tube combustion exhaust gas, rapidly preheating the strip steel to at least 250°C; 2) After thorough preheating of the strip steel, the radiant tube combustion exhaust gas cools significantly and can be directly discharged without the need for a boiler or superheated water heating device for secondary utilization, significantly reducing investment and equipment footprint; 3) The waste heat from radiant tube combustion exhaust gas is almost entirely transferred to the strip steel, resulting in a high primary heat energy utilization rate; 4) Rapid and efficient preheating and rapid heating (longitudinal magnetic induction heating) can quickly heat the strip steel to above 650°C. If combined with transverse magnetic induction heating and jet radiant composite heating, the strip steel can be rapidly and uniformly heated. 5) The heating temperature and homogenization temperature of the strip steel can be rapidly adjusted; 6) The flexible high-strength steel production line can flexibly produce various cold-rolled annealed, pickled, flash-galvanized, hot-dip pure zinc (GI) and alloyed hot-dip galvanized (GA) products, thus the production line can better meet market needs; 7) The plating versatility of ultra-high-strength steel products can be greatly improved, thus the surface quality of ultra-high-strength hot-dip galvanized products can also be significantly improved; 8) The application of the rapid heating, rapid cooling and rapid heat treatment technology of this invention can produce various advanced high-strength steel products with higher strength grades using lower alloy composition, which can not only reduce production costs, but also improve the mechanical properties of various ultra-high-strength steel products, and significantly improve the market competitiveness of high-strength steel products.

[0016] To achieve the above objectives, the technical solution of the present invention is as follows:

[0017] A flexible post-processing production line for cold-rolled strip steel suitable for producing various high-strength steels includes the following stations in sequence: uncoiling – welding – inlet looper – cleaning – central continuous post-processing – intermediate looper – leveling – outlet looper – finishing – coiling; wherein...

[0018] The central continuous post-processing station sequentially includes a jet radiation tube preheating section, a radiation tube heating section, a transverse magnetic induction heating section or a jet radiation combined heating section, a jet radiation combined homogenization section, a slow cooling section, a rapid cooling section, a reheating section, parallel-connected sections (furnace nose section + zinc pot section + air knife section + alloying heating section + alloying homogenization section + post-plating cooling section) and (moving channel section + over-aging section + final jet cooling section), a final water cooling section, and optional pickling and flash plating sections;

[0019] The radiant tube heating section burns natural gas, liquefied petroleum gas, or coal gas, etc.

[0020] The preheating section of the radiant tube uses the combustion exhaust gas from the radiant tube heating section to heat the recycled nitrogen-hydrogen protective gas in the furnace, and then the nitrogen-hydrogen protective gas is sprayed onto the upper and lower surfaces of the strip to achieve forced convection heat transfer.

[0021] The aforementioned transverse magnetic induction heating section or jet radiation composite heating section is arranged in parallel or series, with series arrangement being preferred. Transverse magnetic induction heating can be selected according to peak and off-peak electricity prices to reduce production costs.

[0022] The jet radiation composite heat-soaking section uses a combination of forced convection and radiation to rapidly heat the strip, improving the temperature uniformity of the strip and enabling rapid adjustment of the strip heat-soaking temperature.

[0023] The rapid cooling section includes a high-hydrogen cooling section and / or an aerosol cooling section and / or a water quenching cooling section;

[0024] Between the leveling station and the exit looper station, there is an optional tension leveling station and / or a surface post-treatment station such as passivation or fingerprint resistance, which can be used to perform tension leveling and / or surface post-treatment on the strip.

[0025] The production line uses a jet radiation tube preheating section while employing high-hydrogen cooling, gas mist cooling, and / or water quenching for rapid cooling, followed by reheating, and then galvanizing or over-aging treatment.

[0026] The furnace nose section and the moving channel section are arranged in parallel. The strip steel passes through the furnace nose section to produce hot-dip pure zinc or alloyed hot-dip galvanized products, and the strip steel passes through the moving channel section to produce cold-rolled or flash-dip galvanized products.

[0027] A pickling section is set after the final water cooling section. The strip can be selected to go through the pickling section to produce cold-rolled pickled products, or it can bypass the pickling section to produce cold-rolled products.

[0028] A flash plating section is set up after the pickling section after the final water cooling section. The pickled strip steel can also be flash plated to produce flash plated products.

[0029] Thus, the production line has more than three selectable process paths, enabling the production of five different types of high-strength steel: cold rolling annealing, pickling, flash plating, hot-dip pure zinc plating, and alloyed hot-dip galvanizing.

[0030] Furthermore, a balanced insulation section is set between the reheating section and the furnace nose section, and the balanced insulation section is then connected to the furnace nose section and the moving channel section respectively; the strip steel can be insulated before hot-dip galvanizing.

[0031] Furthermore, a mobile post-plating rapid cooling section is set between the air knife section and the post-plating cooling section. This mobile post-plating rapid cooling section is arranged in parallel with the alloying heating section to achieve rapid cooling of the hot-dip pure zinc high-strength steel strip after plating. More preferably, the mobile post-plating rapid cooling section is set within 10 meters above the air knife section.

[0032] Furthermore, a secondary reheating section is set after the equalization insulation section, and the secondary reheating section is then connected to the furnace nose section and the moving channel section respectively; the strip steel that has been equalized and insulated is reheated a second time, and then hot-dip galvanized or over-aging treatment is performed.

[0033] Furthermore, a pickling section is set between the rapid cooling section and the reheating section. This pickling section includes a pickling unit, a hot water brushing unit, a hot water rinsing unit, and a hot air drying unit. This allows for the pickling of the strip steel surface and can be used to remove the oxide layer on the strip steel surface after air mist cooling or / and water quenching. For hot-dip pure zinc or alloyed hot-dip galvanized products, it can also improve the plating applicability of high-strength strip steel, especially ultra-high-strength strip steel.

[0034] Preferably, a flash plating section of iron or nickel is set after the pickling section and before the reheating section, and the flash plating section of iron or nickel is connected to the reheating section, which can further improve the plating versatility of ultra-high strength strip steel.

[0035] Preferably, a longitudinal magnetic induction heating section is provided before the radiant tube heating section to further and rapidly increase the heating temperature of the strip steel.

[0036] In addition, the present invention also provides a preheating device for a jet radiation tube, comprising:

[0037] A radiant tube heating furnace, with a top roller chamber above the furnace body, and a steering roller installed inside the top roller chamber;

[0038] The exhaust gas collection chamber of the radiant tube is connected to the furnace body of the radiant tube heating furnace via a connecting pipe;

[0039] Preheating furnace, including:

[0040] The preheating furnace body has a connecting hole on its upper side wall, which is connected to the exhaust gas collection chamber of the radiant tube through a connecting pipe; the top of the preheating furnace body has a furnace throat corresponding to the top roller chamber of the radiant tube heating furnace, through which the strip steel passes; the bottom of the preheating furnace body has a strip steel inlet, an inlet sealing device, and an inlet turning roller; the upper part of the preheating furnace body has a preheating furnace gas collection chamber; the lower part of the furnace body has a lower partition with a strip steel through hole to form an exhaust gas collection chamber, which is connected to an exhaust gas fan through an exhaust gas discharge pipe. Preferably, a control valve is installed on the exhaust gas discharge pipe.

[0041] Several heat exchange and jet air box units are arranged on both sides below the preheating furnace gas collecting chamber inside the preheating furnace body along the furnace height direction, forming a strip-passing channel in the middle for the strip steel to pass through; each heat exchange and jet air box unit includes,

[0042] The wind box body has several heat exchange pipes vertically arranged inside, and several nozzles are arranged on one side of the wind box body opposite to the belt passage; a secondary mixing chamber for exhaust gas is arranged between the upper and lower wind box bodies and is connected to the heat exchange pipes; a protective gas is introduced into the wind box body, preferably a nitrogen-hydrogen protective gas.

[0043] The circulating fan has its inlet pipe located inside the belt-passing channel and its outlet pipe located inside the air box.

[0044] Sealing devices that allow the strip steel to pass through are respectively installed at the lower port of the strip passage and at the strip passage holes of the upper and lower partitions.

[0045] Preferably, the inlet sealing device and the sealing device through which the strip steel can pass are nitrogen sealing structures, employing a nitrogen sealing chamber with a nitrogen injection pipe.

[0046] The radiant tube preheating device described in this invention directly uses in-furnace heat exchange (the heat exchanger is not located outside the furnace) to heat the recycled nitrogen-hydrogen protective gas. The heated nitrogen-hydrogen protective gas is then injected at high speed onto the upper and lower surfaces of the strip steel, forcing convection heat transfer to achieve rapid and efficient preheating. Compared with traditional external furnace heat exchange, this method results in less furnace heat loss, more complete utilization of waste heat from combustion exhaust gas, higher heating efficiency, and a faster heating rate. Furthermore, the radiant tube combustion exhaust gas enters the preheating furnace's gas collection chamber from the radiant tube exhaust gas collection chamber through a connecting pipe, and then passes from top to bottom through the heat exchanger chamber inside the preheating furnace (the heat exchanger is not located outside the furnace). The combustion exhaust gas in the tube side and the nitrogen-hydrogen protective gas in the shell side undergo thorough heat exchange in the heat exchanger, heating the nitrogen-hydrogen protective gas. Therefore, the combustion exhaust gas in the radiant tubes in the preheating furnace never comes into direct contact with the strip steel, thus avoiding oxidation of the strip steel surface. In addition, using the aforementioned preheating device, the strip steel preheating temperature is high, reaching at least 250°C or above, which is at least 50°C higher than the temperature of ordinary preheated strip steel. If the number of injection preheating units is sufficient, the temperature of the radiant tube combustion exhaust gas exiting the multi-stage preheating furnace can usually be below 200°C, which can be directly discharged without any additional investment in the external secondary utilization of the combustion exhaust gas waste heat.

[0047] Furthermore, the present invention also provides a jet radiation combined heating / heating device, which includes:

[0048] A furnace body, wherein a composite heating element is disposed along its height; the composite heating element includes,

[0049] The insulated box has an inner wall lined with insulation material; a mounting hole is provided in the center of one side of the insulated box.

[0050] A circulating fan is installed at the mounting hole of the insulation box, with its air intake corresponding to the axis of the mounting hole and its air outlet located on the side of the casing.

[0051] A buffer chamber is provided inside the insulation box at the air inlet of the circulating fan. A hot air outlet corresponding to the air inlet of the circulating fan is provided on the back of the buffer chamber, and a hot air inlet is provided on the front of the buffer chamber. Preferably, the buffer chamber and the high-temperature jet box are an integral structure.

[0052] Two high-temperature jet air boxes are vertically and symmetrically arranged on both sides of the hot air inlet on the front of the buffer cavity inside the insulation box, forming a strip passage for the strip steel to pass through. Several rows of jet nozzles are spaced apart along the height direction on one side of each of the two high-temperature jet air boxes located on both sides of the strip passage, and a gap is provided between n rows of jet nozzles, where n≥1. When n=1, the radiant tube is arranged parallel above or below one row of jet nozzles. Preferably, the diameter of the jet nozzle is 1 / 10 to 1 / 5 of the distance from the jet nozzle to the strip steel. More preferably, the jet nozzle adopts a circular hole structure.

[0053] Several radiant tubes are symmetrically arranged inside the two high-temperature jet air boxes. Each radiant tube includes a connecting pipe section connected to the burner, a radiant tube section extending from one end of the connecting pipe section by bending, and a heat exchange tube section extending from one end of the radiant tube section by bending. The radiant tube section corresponds to the gap between n rows of jet nozzles in the high-temperature jet air box, forming an alternating jet and radiation structure. Preferably, the radiant tube section, connecting pipe section, and heat exchange tube section of the radiant tube are arranged in parallel.

[0054] The jet-radiation composite heating / heating device of this invention adopts composite heating technology, which can organically combine high-speed high-temperature jet heating technology with radiant tube heating technology, giving full play to the technical advantages of both technologies. By optimizing the structure of the radiant tube and installing it inside the high-speed high-temperature jet box, the heat generated by the combustion gas in the radiant tube is rapidly transferred to the strip steel through both high-speed high-temperature jet and radiation, achieving rapid heating of the strip steel. For 1mm strip steel, the average heating rate is no less than 40℃ / s, which can greatly shorten the length of the heating furnace. For a unit with an annual output of 300,000 tons, the heating section is about 2 passes, reducing the thermal inertia of the furnace body.

[0055] Secondly, since the heat generated by the gas is carried away by the circulating gas (N2+H2) in the bellows, this can not only reduce the exhaust temperature of the radiant tube by about 100°C under the same conditions, and improve the thermal efficiency of the radiant tube by about 5%, but also reduce the average operating temperature of the radiant tube and extend its service life.

[0056] Secondly, the heated circulating gas has a relatively uniform temperature, resulting in a more uniform temperature distribution along the width of the strip during heating. Based on actual operation, the uniformity along the strip width is controlled within ±5℃, thus ensuring stable unit operation. The high-speed jet and radiation combined heating technology will significantly improve the production capacity of existing units and solve the problem of insufficient heating capacity on the production line.

[0057] The radiant tube of the jet radiation composite heating / heating device of the present invention has both combustion radiation function (referring to the high-temperature section of the radiant tube between the two rows of nozzles) and heat exchanger function to heat the circulating gas. In this way, the heat of the combustion gas in the radiant tube can be quickly transferred to the strip steel through forced heat exchange, realizing rapid heating of the strip steel. This can greatly shorten the length of the heating furnace and reduce the thermal inertia of the large vertical continuous annealing furnace body.

[0058] The production line described in this invention differs from traditional processes in that:

[0059] 1) This invention has three or more selectable process paths;

[0060] 2) This invention can realize the production of five different types of high-strength steel, especially ultra-high-strength steel, through cold rolling annealing, pickling, flash plating, hot-dip galvanizing, and alloyed hot-dip galvanizing.

[0061] 3) This invention can perform tension leveling or / and passivation or fingerprint-resistant surface treatments on five different types of ultra-high strength steel: cold-rolled annealing, pickling, flash plating, hot-dip pure zinc plating, and alloyed hot-dip galvanizing.

[0062] 4) The present invention is equipped with a secondary reheating section, which realizes two temperature increases of strip steel before hot-dip galvanizing or over-aging treatment. It can enable third-generation high-strength steel (QP steel) products to be quickly cooled to a lower temperature, and then immediately and rapidly heated to a higher temperature for long-term carbon redistribution treatment. After the treatment, it is rapidly reheated again to the temperature of hot-dip galvanizing zinc pot for galvanizing treatment.

[0063] 5) This invention replaces the ordinary preheating section with a jet radiation tube preheating section, more precisely, a high-temperature nitrogen-hydrogen protective gas jet radiation tube preheating section. This is one of the novelty, inventiveness, and practicality aspects of this invention. Its significant feature, distinguishing it from the ordinary preheating section, is as follows:

[0064] ① The radiant tube combustion exhaust gas is directly used to heat the recycled nitrogen-hydrogen protective gas in the furnace (the heat exchange is not arranged outside the furnace). The heated nitrogen-hydrogen protective gas is then sprayed at high speed onto the upper and lower surfaces of the strip steel for forced convection heat exchange to achieve rapid and efficient preheating of the strip steel. Compared with the traditional external furnace heat exchange, this method results in less heat loss outside the furnace, more complete utilization of the waste heat of the combustion exhaust gas, higher heating efficiency, and faster heating rate.

[0065] ② In the preheating section, the radiant tube combustion exhaust gas enters the preheating furnace collection chamber from the radiant tube exhaust gas collection chamber through the connecting pipe, and then passes from top to bottom through the heat exchanger chamber in the preheating section (the heat exchanger is not set outside the furnace). During the process, the combustion exhaust gas flowing through the tubes and the nitrogen-hydrogen protective gas flowing through the shell undergo sufficient heat exchange in the heat exchanger. The combustion exhaust gas heats the nitrogen-hydrogen protective gas. Therefore, the radiant tube combustion exhaust gas never comes into direct contact with the strip steel in the preheating section, thus avoiding oxidation of the strip steel surface.

[0066] ③ The strip steel has a high preheating temperature, which can reach at least 250℃ and above, which is at least 50℃ higher than the temperature of ordinary preheating strip steel;

[0067] ④ If the number of injection preheating units is sufficient, the temperature of the radiant tube combustion exhaust gas from the preheating section can usually be below 200℃, and it can be discharged directly without any additional investment for the secondary utilization of the combustion exhaust gas waste heat outside the furnace.

[0068] ⑤ The preheating section is designed as a jet radiant tube preheating section;

[0069] 6) This invention includes a transverse magnetic induction heating section after the preheating section of the jet radiant tube. A preferred embodiment includes a longitudinal magnetic induction heating section before the radiant tube heating section, for further rapid increase in strip heating temperature. To improve heating temperature uniformity, a combined radiant tube jet radiant heating section is preferred to uniformly heat the strip and adjust its shape. The simultaneous use of the jet radiant tube preheating section and the rapid heating section further demonstrates the novelty, inventiveness, and practicality of this invention.

[0070] 7) A rapid homogenization section combining radiant tube jet heating and radiation is used in the homogenization section before the slow cooling section. By using a combination of forced convection and radiation to homogenize the strip, the uniformity of the homogenization temperature of the strip can be improved and the rapid adjustment of the homogenization temperature of the strip can be achieved, reducing the fluctuation of the actual temperature of the strip in the homogenization section.

[0071] The beneficial effects of using the rapid heating section in this invention are as follows: ① It enables rapid adjustment of the strip heating temperature, which is crucial for the production of high-strength steel, especially ultra-high-strength steel, and can reduce quality loss caused by temperature mismatch in the strip; ② It can heat the strip to a higher temperature. Existing projects have already achieved rapid heating of the strip to 880℃ by connecting multiple induction heaters with longitudinal and transverse magnetic fields; ③ When used in conjunction with the radiant tube jet radiation composite heating section, the temperature uniformity of the heated strip is good, and the temperature uniformity along the width of the strip can be controlled within ±5℃.

[0072] The beneficial effects of this invention are as follows:

[0073] 1) The waste heat from radiant tube heating and heat equalization can be fully utilized online, which can preheat the strip temperature to at least 250°C.

[0074] 2) When longitudinal and transverse magnetic induction heating is used in the rapid heating section, the strip steel can be rapidly heated to above 850°C, thereby achieving high-temperature annealing;

[0075] 3) In the rapid heating section, the strip steel can be rapidly heated to at least 650°C in one pass, which reduces the risk of strip steel deviation in the furnace, especially for high-strength steel and ultra-high-strength steel, and the requirements for the shape of the incoming material can be appropriately reduced.

[0076] 4) The application of jet radiation combined heating technology enables rapid adjustment of the strip temperature in the heating section and the strip temperature in the soaking section;

[0077] 5) The same production line can produce ultra-high strength steels such as continuously annealed cold-rolled DP steel, MS steel, TRIP steel, QP steel, and hot-dip galvanized DP steel, TRIP steel, QP steel, etc.

[0078] 6) Using water mist cooling + pickling or + pickling and flash plating can produce martensitic ultra-high strength steel with a strength of up to 1500MPa, and the surface quality is high, and the strip steel has good plating properties during hot-dip galvanizing.

[0079] 7) This invention can realize the production of five different types of high-strength steel, especially ultra-high-strength steel, through cold rolling annealing, pickling, flash plating, hot-dip pure zinc plating, and alloyed hot-dip galvanizing. Attached Figure Description

[0080] Figure 1 A schematic diagram of the workstation layout for a traditional continuous annealing production line;

[0081] Figure 2 This is a layout diagram of the workstations for a traditional hot-dip galvanizing (GI) production line.

[0082] Figure 3 This is a layout diagram of the workstations on a traditional alloy hot-dip galvanizing (GA) production line.

[0083] Figure 4 This is a production line workstation layout diagram of Embodiment 1 of the present invention;

[0084] Figure 5 This is a production line workstation layout diagram according to Embodiment 2 of the present invention;

[0085] Figure 6 This is a production line workstation layout diagram of Embodiment 3 of the present invention;

[0086] Figure 7 This is a production line workstation layout diagram of Embodiment 4 of the present invention;

[0087] Figure 8 This is a production line workstation layout diagram of Embodiment 5 of the present invention;

[0088] Figure 9 This is a production line workstation layout diagram of Embodiment 6 of the present invention;

[0089] Figure 10 This is a schematic diagram of an embodiment of the jet radiation tube preheating device of the present invention;

[0090] Figure 11 This is a schematic diagram of the preheating furnace in an embodiment of the jet radiation tube preheating device of the present invention;

[0091] Figure 12 This is a schematic diagram of the structure of an embodiment of the jet radiation combined heating / heating device of the present invention. Figure 1 ;

[0092] Figure 13 This is a schematic diagram of the structure of an embodiment of the jet radiation combined heating / heating device of the present invention. Figure 2 ;

[0093] Figure 14 This is a schematic diagram of the structure of the composite heating element in an embodiment of the jet radiation composite heating / heating device of the present invention;

[0094] Figure 15 This is a partial perspective view of the high-temperature jet fan box in an embodiment of the jet radiation combined heating / heating device of the present invention;

[0095] Figure 16 This is a perspective view of the radiant tube in an embodiment of the jet radiation combined heating / heating device of the present invention. Detailed Implementation

[0096] The implementation method of the present invention will be further described below with reference to embodiments and accompanying drawings. It should be noted that the concept of the present invention can be used to simplify and combine various production lines. This embodiment only provides one implementation method; the patent family of the present invention will provide other implementation methods. Even the embodiments of the entire patent family only provide partial implementation methods. All combinations resulting from the selection or non-selection of selectable workstations as described in the present invention are within the protection scope of the present invention. Various production lines derived from the concept of the present invention are also within the protection scope of the present invention. Furthermore, conventional workstations, such as cleaning workstations including alkaline spray sections, alkaline brushing sections, electrolytic cleaning sections, hot water brushing or cold water abrasive roller brushing sections, and hot water rinsing sections, and even simplified or combined use of new cleaning technology equipment such as high-pressure water jet brushing sections, ultrasonic cleaning sections, and high-pressure cleaning sections, are all considered derivative production lines of the present invention and are also within the protection scope of the present invention. For example, finishing workstations including edge trimming and oiling equipment are also within the protection scope of the present invention.

[0097] See Figure 4 According to Embodiment 1 of the present invention, the flexible post-processing production line for cold-rolled strip steel suitable for producing various high-strength steels includes the following stations in sequence: uncoiling – welding – inlet looper – cleaning – central continuous post-processing – intermediate looper – leveling – outlet looper – finishing – coiling; wherein,

[0098] The central continuous post-processing station sequentially includes a jet radiation tube preheating section, a radiation tube heating section, a transverse magnetic induction heating section or a jet radiation combined heating section, a jet radiation combined homogenization section, a slow cooling section, a rapid cooling section (high hydrogen cooling or aerosol cooling or / and water quenching cooling section), a reheating section, and parallel sections (furnace nose section + zinc pot section + air knife section + alloying heating section + alloying homogenization section + post-plating cooling section) and (moving channel section + over-aging section + final jet cooling section), and a final water cooling section;

[0099] Between the leveling station and the exit looper station, there are also optional tensioning and straightening stations and / or surface post-treatment stations such as passivation or fingerprint resistance stations.

[0100] The aforementioned transverse magnetic induction heating section or jet radiation composite heating section is arranged in parallel or series;

[0101] The furnace nose section and the moving channel section are arranged in parallel. The strip steel passes through the furnace nose section to produce hot-dip pure zinc or alloyed hot-dip galvanized products, and the strip steel passes through the moving channel section to produce cold-rolled or flash-dip galvanized products.

[0102] A pickling section is arranged after the final water cooling section. The strip can be selected to go through the pickling section to produce cold-rolled pickled products, or it can bypass the pickling section to produce cold-rolled products.

[0103] After the final water cooling section and the pickling section, a flash plating section is arranged. The pickled strip steel can also be flash plated to produce flash plated products.

[0104] Thus, the production line of the present invention has more than three selectable process paths, which can realize the production of five different types of high-strength steel, namely cold rolling annealing, pickling, flash plating, hot-dip pure zinc plating, and alloyed hot-dip galvanizing.

[0105] See Figure 5 The figure shows Embodiment 2 of the present invention. In Embodiment 2, a balanced heat preservation section is set between the reheating section and the furnace nose section to heat preservation the strip steel before hot-dip galvanizing.

[0106] See Figure 6 In Embodiment 3 of the present invention, based on Embodiment 2, a movable post-plating rapid cooling section is provided between the air knife section and the post-plating cooling section. This movable post-plating rapid cooling section is arranged in parallel with the alloying heating section to achieve rapid cooling of the strip steel after hot-dip galvanized high-strength steel products.

[0107] See Figure 7 The above is an example of embodiment 4 of the present invention. In embodiment 4, a secondary reheating section is set after the equalization heat preservation section to reheat the equalized heat preservation strip steel a second time, and then perform hot-dip galvanizing or over-aging treatment.

[0108] See Figure 8 The illustration shows Embodiment 5 of the present invention. In Embodiment 5, an acid pickling section is provided between the rapid cooling section (high hydrogen cooling or aerosol cooling or / and water quenching cooling section) and the reheating section. The acid pickling section includes an acid pickling unit, a hot water brushing unit, a hot water rinsing unit, and a hot air drying unit to achieve acid pickling of the strip steel surface. It can be used to remove the oxide layer on the strip steel surface after aerosol cooling or / and water quenching cooling. For hot-dip pure zinc or alloyed hot-dip galvanized products, it can also improve the plating susceptibility of high-strength strip steel, especially ultra-high-strength strip steel.

[0109] See Figure 9The example shown is Embodiment 6 of the present invention. In Embodiment 6, a flash iron or flash nickel plating section is set after the pickling section and before the reheating section, and then the reheating treatment is performed, which can further improve the plating properties of ultra-high strength strip steel.

[0110] Preferably, a longitudinal magnetic induction heating section is arranged before the radiant tube heating to further and rapidly increase the heating temperature of the strip steel.

[0111] See Figure 10 , Figure 11 The jet radiation tube preheating device of the present invention comprises:

[0112] Radiant tube heating furnace 1, with a furnace top roller chamber 101 above the furnace body, and a turning roller 102 installed inside the furnace top roller chamber 101;

[0113] The exhaust gas collection chamber 2 of the radiant tube is connected to the furnace body of the radiant tube heating furnace 1 via a connecting pipe 21;

[0114] Preheating furnace 3 includes:

[0115] The preheating furnace body 31 has a connecting hole on its upper side wall, which is connected to the radiant tube exhaust gas collection chamber 2 through a connecting pipe 32; the top of the preheating furnace body 31 has a furnace throat 311 corresponding to the furnace top roller chamber 101 of the radiant tube heating furnace 1, through which the strip steel passes; the bottom of the preheating furnace body 31 has a strip steel inlet, an inlet sealing device 33, and an inlet turning roller; the upper part of the preheating furnace body 31 has a preheating furnace gas collection chamber 312; the lower part of the preheating furnace body 31 has a lower partition 313 with a strip steel through hole, forming an exhaust gas collection chamber 314, which is connected to an exhaust gas fan 35 through an exhaust gas discharge pipe 34 and discharged from the chimney 500.

[0116] Several heat exchange and jet fan units 36 are arranged on both sides below the preheating furnace gas collecting chamber 312 inside the preheating furnace body 31 along the height direction of the preheating furnace body 31, forming a strip-passing channel 315 in the middle for the strip steel to pass through; each heat exchange and jet fan unit 36 ​​includes,

[0117] The air box body 361 has several heat exchange pipes 362 vertically arranged inside it, and several nozzles 363 are arranged on one side of the air box body 361 opposite to the belt passage 315; a secondary mixing chamber for exhaust gas is arranged between the upper and lower air box bodies 361 and is connected to the heat exchange pipes 362; nitrogen-hydrogen protective gas is introduced into the air box body 361.

[0118] The inlet port of the circulating fan 364 is located in the belt-passing channel 315, and the outlet port is located in the air box 361.

[0119] A sealing device 37, which allows the strip steel to pass through, is provided at the lower port of the strip passage 315 and the strip hole of the lower partition 313.

[0120] Preferably, the inlet sealing device 33 and the sealing device 37 are nitrogen sealing structures, employing a nitrogen sealing chamber, on which a nitrogen injection pipe is provided.

[0121] Preferably, a control valve 38 is provided on the exhaust gas discharge pipe 34.

[0122] After being turned by the inlet guide roller, the strip steel 100 moves upward and is sealed by the inlet sealing device before entering the preheating furnace 3 for preheating treatment. Then it enters the furnace top roller chamber and, after being turned by the guide roller, enters the radiant tube heating furnace 1. The radiant tube heating combustion exhaust gas enters the radiant tube exhaust gas collection chamber and is connected to the preheating furnace collection chamber of the preheating furnace 1 through a connecting pipe. The preheating furnace collection chamber is a closed collection chamber to ensure that the exhaust gas inside does not come into contact with the strip steel 100. The radiant tube combustion exhaust gas accumulates in the preheating furnace collection chamber and is first used to preheat its combustion air.

[0123] Under the suction of the exhaust fan, the high-temperature radiant tube combustion exhaust gas in the preheating furnace gas collection chamber is continuously fed through a series of jet fan units. The jet fan unit is equipped with heat exchange tubes that serve as heat exchangers (the tube side is high-temperature combustion exhaust gas, and the shell side is a nitrogen-hydrogen mixture). After the radiant tube combustion exhaust gas is heated by the heat exchanger, it is then sprayed onto the upper and lower surfaces of the strip steel for preheating under the action of the circulating fan.

[0124] The exhaust gas from the radiant tube combustion flows from top to bottom through the inside of the heat exchange tube. During the flow, it undergoes heat exchange and heating with the nitrogen and hydrogen protective gas injected in a cycle. Then it enters the secondary mixing chamber between the jet blower units for secondary mixing, which homogenizes the temperature of the exhaust gas. Then it enters the downward furnace heat exchange and jet blower unit until it reaches the bottom nitrogen sealing device, and finally enters the exhaust gas collection chamber.

[0125] Nitrogen-hydrogen protective gas passes through the heat exchange tube bundles, is heated, and then continuously injected from nozzles onto the upper and lower surfaces of the strip under the action of a circulating fan. The suction port of the circulating fan is connected to the DS and WS sides of the jet air box unit through a pipeline inside the furnace. Under the action of the circulating fan, the nitrogen-hydrogen mixed gas is injected onto the surface of the strip, then drawn out from both sides, and then injected back onto the upper and lower surfaces of the strip by the circulating fan through the heat exchanger, realizing the circulating injection heating of the nitrogen-hydrogen mixed gas onto the strip.

[0126] See Figures 13-16 The jet radiation combined heating / heating device of the present invention comprises:

[0127] Furnace body 4, wherein a composite heating element 5 is arranged along its height direction; the composite heating element 5 includes,

[0128] The insulated box 51 has an inner wall lined with insulation material; a mounting hole is provided in the center of one side of the insulated box 51.

[0129] A circulating fan 52 is installed at the mounting hole of the insulation box 51, with its air intake 521 corresponding to the axis of the mounting hole and its air outlet 522 located on the side of the casing.

[0130] A buffer cavity 53 is provided inside the insulation box 51 at the air inlet of the circulating fan 52. A hot air outlet corresponding to the air inlet of the circulating fan 52 is provided on the back of the buffer cavity 53, and a hot air inlet is provided on the front of the buffer cavity.

[0131] Two high-temperature jet blowers 54 and 54' are vertically and symmetrically arranged on both sides of the hot air inlet on the front of the buffer cavity 53 inside the insulation box 51, forming a strip passage 200 for the strip steel 100 to pass through; a number of jet nozzles 55 and 55' are arranged at intervals along the height direction on one side of the two high-temperature jet blowers 54 and 54' located on both sides of the strip passage 100, and a gap 300 is provided between n jet nozzles, where n≥1;

[0132] Several radiant tubes 56 and 56' are symmetrically arranged inside the two high-temperature jet blowers 54 and 54'. The radiant tube 56 (taking the radiant tube 56 as an example, the same below) includes a connecting pipe section 561 that connects to the burner, a radiant tube section 562 that extends from one end of the connecting pipe section 561 by bending, and a heat exchange tube section 563 that extends from one end of the radiant tube section 562 by bending. The radiant tube section 562 corresponds to the gap 300 set between the n rows of jet nozzles in the high-temperature jet blower 54, forming an alternating jet and radiation structure.

[0133] Preferably, the buffer cavity and the high-temperature jet box are an integral structure.

[0134] Preferably, the diameter of the jet nozzle is 1 / 10 to 1 / 5 of the distance from the jet nozzle to the strip.

[0135] Preferably, the jet nozzle has a circular hole structure.

[0136] Preferably, the radiant tube adopts a spatial four-stroke structure, forming four parallel tube segments, of which one tube segment is a radiant tube segment, and the rest are connecting tube segments and heat exchange tube segments.

[0137] Example 1

[0138] The production line layout for manufacturing a high-strength steel strip is as follows: Figure 4As shown, the strip steel with a substrate main chemical composition (mass%) of 0.11%C-0.17%Si-1.95%Mn is uncoiled, welded, passed through the inlet looper, and cleaned. It is then preheated to 265°C by a jet radiation tube, then heated to 750°C by the radiation tube, followed by transverse magnetic induction heating to 895°C. At 895°C, it undergoes jet radiation composite homogenization for 50 seconds, followed by slow cooling to 670°C and high-hydrogen cooling to 475°C. It then passes through a longitudinal magnetic induction heater (a reheating device; in this embodiment, the longitudinal magnetic induction heater does not need to be started), and then is immersed in a zinc pot for hot-dip galvanizing via the furnace nose. After controlling the coating weight with an air knife, it is cooled to approximately 140°C by a post-galvanizing cooling device, and finally water-cooled to below 45°C before entering the intermediate looper. It then undergoes leveling and tension straightening, and after passing through the outlet looper, it is finished and coiled, completing the production process. The final product strip steel has a yield strength of 552MPa, a tensile strength of 859MPa, and an elongation at break of 19%.

[0139] Example 2

[0140] The production line layout for manufacturing a high-strength steel strip is as follows: Figure 5 As shown, the strip steel with a substrate main chemical composition (mass%) of 0.16%C-0.25%Si-2.4%Mn is uncoiled, welded, passed through the inlet looper, and cleaned. It is then preheated to 275℃ using a jet radiation tube, then heated to 575℃, followed by jet radiation composite heating to 820℃. After homogenization at 820℃ for 60 seconds, it is slowly cooled to 755℃, water-quenched to room temperature, and then heated to 230℃. It is then held at 230℃ for uniform temperature control, and then enters the aging section via a moving channel for aging treatment at approximately 230℃. Finally, it is jet-cooled to below 150℃, then water-cooled to room temperature, pickled, and enters the intermediate looper. After leveling and tension straightening, it enters the outlet looper, where it is finished and coiled, completing the production process. The final product strip steel has a yield strength of 1312MPa, a tensile strength of 1532MPa, and an elongation at break of 4%.

[0141] Example 3

[0142] The production line layout for manufacturing a high-strength steel strip is as follows: Figure 6As shown, the strip steel with a substrate main chemical composition (mass%) of 0.14%C-1.6%Si-2.1%Mn is uncoiled, welded, passed through the inlet looper, and cleaned. It is then preheated to 260℃ using a jet radiation tube, then heated to 560℃ using another radiation tube, followed by transverse magnetic induction heating to 830℃, and then combined jet radiation heating to 850℃. It is then homogenized at 850℃ for 60 seconds, slowly cooled to 670℃, and then cooled to 280℃ using high-hydrogen cooling. It is then heated again to 455℃ and held at a uniform temperature. It is then immersed in a zinc pot for hot-dip galvanizing through a furnace nose. The coating weight is controlled by an air knife, and the strip is rapidly cooled to 370℃ after galvanizing. It is then cooled to below 150℃, and finally water-cooled to room temperature. It then enters the intermediate looper, is leveled, undergoes fingerprint-resistant treatment, is finished, and coiled to complete production. The final product strip steel has a yield strength of 692MPa, a tensile strength of 1018MPa, and an elongation at break of 20%.

[0143] Example 4

[0144] The production line layout for manufacturing a high-strength steel strip is as follows: Figure 7 As shown, the strip steel with the main chemical composition (mass%) of 0.16%C-1.75%Si-2.25%Mn is uncoiled, welded, passed through the inlet looper, and cleaned. It is then preheated to 255℃ using a jet radiation tube, then heated to 555℃ using a radiation tube, followed by jet radiation composite heating to 850℃. It is then homogenized at 850℃ for 70 seconds, slowly cooled to 690℃, cooled to 230℃ using high hydrogen, and then heated to 420℃. It is then held at 420℃ for uniform temperature, and then reheated to 460℃ before being immersed in a zinc pot for hot-dip galvanizing. The coating weight is controlled by an air knife, and the strip steel passes through an alloying heating section (heating function not activated) and an alloying homogenization section (heating function not activated). After plating, it is cooled to below 150℃, and then finally water-cooled to room temperature. It then enters the intermediate looper, is flattened, and treated for fingerprint resistance. After exiting the looper, it is finished and coiled to complete the production process. The final product strip has a yield strength of 762 MPa, a tensile strength of 1039 MPa, and an elongation at break of 18%.

[0145] Example 5

[0146] The production line layout for manufacturing a high-strength steel strip is as follows: Figure 8As shown, the strip steel with the main chemical composition (mass%) of the substrate being 0.11%C-0.08%Si-2.0%Mn is uncoiled, welded, passed through the inlet looper, and cleaned. It is then preheated to 250℃ using a jet radiation tube, then heated to 550℃ using a radiation tube, followed by transverse magnetic induction heating to 700℃, and then jet radiation composite heating to 810℃. It is then subjected to jet radiation composite heating at 810℃ for 60 seconds, followed by slow cooling to 675℃, water quenching to room temperature, pickling, and then heating to 220℃. It is then held at 220℃ for uniform temperature, passes through a secondary reheating section (heating function not activated), then through a moving channel section, and enters the over-aging section. It undergoes over-aging treatment at around 220℃, followed by final jet cooling to below 150℃, and finally water cooling to room temperature. It then enters the intermediate looper, where it is leveled, straightened, and then subjected to chromium-free passivation treatment. After finishing at the exit looper, it is coiled to complete the production process. The final product strip has a yield strength of 785 MPa, a tensile strength of 1033 MPa, and an elongation at break of 7%.

[0147] Example 6

[0148] The production line layout for manufacturing a high-strength steel strip is as follows: Figure 9 As shown, the strip steel with a substrate main chemical composition (mass%) of 0.088%C-0.28%Si-2.1%Mn is uncoiled, welded, passed through the inlet looper, and cleaned. It is then preheated to 277℃ using a jet radiant tube, then heated to 575℃ using the radiant tube, followed by transverse magnetic induction heating to 780℃, and then combined jet radiant heating to 810℃. It is then uniformly heated in the radiant tube at 810℃ for 60 seconds, slowly cooled to 680℃, and finally cooled to 50℃ by aerosol cooling. The strip undergoes pickling, flash nickel plating, and then heating to 400℃. It is held at 400℃ for a period of time, then reheated to 460℃ before immersion in a zinc bath for hot-dip galvanizing. After controlling the coating weight with an air knife, it is heated to 520℃ for alloying treatment. The alloying process is then homogenized at approximately 515℃ for 20 seconds. After plating, the strip is cooled to below 150℃ and finally water-cooled to room temperature. It then enters an intermediate looper, where it is leveled and tensioned. At the exit looper, it undergoes finishing and coiling to complete production. The final product strip has a yield strength of 918MPa, a tensile strength of 1192MPa, and an elongation at break of 8.5%.

Claims

1. A flexible post-processing production line for cold-rolled strip steel suitable for producing various high-strength steels, characterized in that, The process includes the following stations in sequence: uncoiling – welding – inlet looper – cleaning – central continuous post-processing – intermediate looper – leveling – outlet looper – finishing – winding; among which, The central continuous post-processing station sequentially includes a jet radiation tube preheating section, a radiation tube heating section, a transverse magnetic induction heating section and / or a jet radiation composite heating section, a jet radiation composite homogenization section, a slow cooling section, a rapid cooling section, a reheating section, a furnace nose section + zinc pot section + air knife section + alloying heating section + alloying homogenization section + post-plating cooling section and moving channel section + over-aging section + final jet cooling section, final water cooling section and pickling section or flash plating section; The radiant heating section of the tube burns natural gas, liquefied petroleum gas, or coal gas. The preheating section of the radiant tube uses the combustion exhaust gas from the radiant tube heating section to heat the recycled nitrogen-hydrogen protective gas in the furnace, and then the nitrogen-hydrogen protective gas is sprayed onto the upper and lower surfaces of the strip to achieve forced convection heat transfer. The transverse magnetic induction heating section and the jet radiation composite heating section are arranged in parallel or in series; The jet radiation composite heating homogenization section uses a combination of forced convection and radiation to rapidly homogenize the steel. The rapid cooling section includes a high-hydrogen cooling section and / or an aerosol cooling section and / or a water quenching cooling section; A straightening station or a surface post-treatment station is set between the leveling station and the exit looper station. The surface post-treatment station includes passivation treatment or fingerprint-resistant treatment.

2. The flexible post-processing production line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 1, characterized in that, A balanced insulation section is set between the reheating section and the furnace nose section, and the balanced insulation section is then connected to the furnace nose section and the moving channel section respectively.

3. The flexible post-processing production line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 1 or 2, characterized in that, A movable post-plating rapid cooling section is set between the air knife section and the post-plating cooling section, and this movable post-plating rapid cooling section is arranged in parallel with the alloying heating section.

4. The flexible post-processing production line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 3, characterized in that, A mobile post-plating rapid cooling section is installed within 10 meters above the air knife section.

5. The flexible post-processing production line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 2, characterized in that, A secondary reheating section is set after the equalization heat preservation section, and the secondary reheating section is then connected to the furnace nose section and the moving channel section respectively.

6. The flexible post-processing production line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 3, characterized in that, A secondary reheating section is set after the equalization heat preservation section, and the secondary reheating section is then connected to the furnace nose section and the moving channel section respectively.

7. The flexible post-processing production line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 4, characterized in that, A secondary reheating section is set after the equalization heat preservation section, and the secondary reheating section is then connected to the furnace nose section and the moving channel section respectively.

8. The flexible post-processing production line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 1 or 2, characterized in that, A pickling section is provided between the rapid cooling section and the reheating section. The pickling section includes a pickling unit, a hot water brushing unit, a hot water rinsing unit, and a hot air drying unit.

9. The flexible post-processing production line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 3, characterized in that, A pickling section is provided between the rapid cooling section and the reheating section. The pickling section includes a pickling unit, a hot water brushing unit, a hot water rinsing unit, and a hot air drying unit.

10. The flexible post-processing production line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 4, characterized in that, A pickling section is provided between the rapid cooling section and the reheating section. The pickling section includes a pickling unit, a hot water brushing unit, a hot water rinsing unit, and a hot air drying unit.

11. The flexible post-processing production line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 5, characterized in that, A pickling section is provided between the rapid cooling section and the reheating section. The pickling section includes a pickling unit, a hot water brushing unit, a hot water rinsing unit, and a hot air drying unit.

12. The flexible post-processing production line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 6, characterized in that, A pickling section is provided between the rapid cooling section and the reheating section. The pickling section includes a pickling unit, a hot water brushing unit, a hot water rinsing unit, and a hot air drying unit.

13. The flexible post-processing production line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 7, characterized in that, A pickling section is provided between the rapid cooling section and the reheating section. The pickling section includes a pickling unit, a hot water brushing unit, a hot water rinsing unit, and a hot air drying unit.

14. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 1 or 2, characterized in that, A flash plating section of iron or nickel is set after the pickling section and before the reheating section, and the flash plating section of iron or nickel is connected to the reheating section.

15. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 3, characterized in that, A flash plating section of iron or nickel is set after the pickling section and before the reheating section, and the flash plating section of iron or nickel is connected to the reheating section.

16. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 4, characterized in that, A flash plating section of iron or nickel is set after the pickling section and before the reheating section, and the flash plating section of iron or nickel is connected to the reheating section.

17. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 5, characterized in that, A flash plating section of iron or nickel is set after the pickling section and before the reheating section, and the flash plating section of iron or nickel is connected to the reheating section.

18. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 6, characterized in that, A flash plating section of iron or nickel is set after the pickling section and before the reheating section, and the flash plating section of iron or nickel is connected to the reheating section.

19. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 7, characterized in that, A flash plating section of iron or nickel is set after the pickling section and before the reheating section, and the flash plating section of iron or nickel is connected to the reheating section.

20. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 8, characterized in that, A flash plating section of iron or nickel is set after the pickling section and before the reheating section, and the flash plating section of iron or nickel is connected to the reheating section.

21. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 9, characterized in that, A flash plating section of iron or nickel is set after the pickling section and before the reheating section, and the flash plating section of iron or nickel is connected to the reheating section.

22. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 10, characterized in that, A flash plating section of iron or nickel is set after the pickling section and before the reheating section, and the flash plating section of iron or nickel is connected to the reheating section.

23. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 11, characterized in that, A flash plating section of iron or nickel is set after the pickling section and before the reheating section, and the flash plating section of iron or nickel is connected to the reheating section.

24. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 12, characterized in that, A flash plating section of iron or nickel is set after the pickling section and before the reheating section, and the flash plating section of iron or nickel is connected to the reheating section.

25. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 13, characterized in that, A flash plating section of iron or nickel is set after the pickling section and before the reheating section, and the flash plating section of iron or nickel is connected to the reheating section.

26. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 1 or 2, characterized in that, A longitudinal magnetic induction heating section is installed before the radiant tube heating section.

27. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 3, characterized in that, A longitudinal magnetic induction heating section is installed before the radiant tube heating section.

28. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 4, characterized in that, A longitudinal magnetic induction heating section is installed before the radiant tube heating section.

29. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 5, characterized in that, A longitudinal magnetic induction heating section is installed before the radiant tube heating section.

30. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 6, characterized in that, A longitudinal magnetic induction heating section is installed before the radiant tube heating section.

31. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 7, characterized in that, A longitudinal magnetic induction heating section is installed before the radiant tube heating section.

32. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 8, characterized in that, A longitudinal magnetic induction heating section is installed before the radiant tube heating section.

33. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 9, characterized in that, A longitudinal magnetic induction heating section is installed before the radiant tube heating section.

34. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 10, characterized in that, A longitudinal magnetic induction heating section is installed before the radiant tube heating section.

35. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 11, characterized in that, A longitudinal magnetic induction heating section is installed before the radiant tube heating section.

36. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 12, characterized in that, A longitudinal magnetic induction heating section is installed before the radiant tube heating section.

37. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 13, characterized in that, A longitudinal magnetic induction heating section is installed before the radiant tube heating section.

38. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 14, characterized in that, A longitudinal magnetic induction heating section is installed before the radiant tube heating section.

39. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 15, characterized in that, A longitudinal magnetic induction heating section is installed before the radiant tube heating section.

40. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 16, characterized in that, A longitudinal magnetic induction heating section is installed before the radiant tube heating section.

41. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 17, characterized in that, A longitudinal magnetic induction heating section is installed before the radiant tube heating section.

42. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 18, characterized in that, A longitudinal magnetic induction heating section is installed before the radiant tube heating section.

43. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 19, characterized in that, A longitudinal magnetic induction heating section is installed before the radiant tube heating section.

44. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 20, characterized in that, A longitudinal magnetic induction heating section is installed before the radiant tube heating section.

45. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 21, characterized in that, A longitudinal magnetic induction heating section is installed before the radiant tube heating section.

46. ​​The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 22, characterized in that, A longitudinal magnetic induction heating section is installed before the radiant tube heating section.

47. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 23, characterized in that, A longitudinal magnetic induction heating section is installed before the radiant tube heating section.

48. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 24, characterized in that, A longitudinal magnetic induction heating section is installed before the radiant tube heating section.

49. The flexible post-processing line for cold-rolled strip steel suitable for producing various high-strength steels as described in claim 25, characterized in that, A longitudinal magnetic induction heating section is installed before the radiant tube heating section.

50. A jet radiant tube preheating device for a flexible post-processing production line for cold-rolled strip steel suitable for producing various high-strength steels as described in any one of claims 1 to 49, characterized in that, include: A radiant tube heating furnace, with a top roller chamber above the furnace body, and a steering roller installed inside the top roller chamber; The exhaust gas collection chamber of the radiant tube is connected to the furnace body of the radiant tube heating furnace via a connecting pipe; Preheating furnace, including: The preheating furnace body has a connecting hole on its upper side wall, which is connected to the exhaust gas collection chamber of the radiant tube heating furnace through a connecting pipe; the top of the preheating furnace body has a furnace throat corresponding to the top roller chamber of the radiant tube heating furnace, through which the strip steel passes; the bottom of the preheating furnace body has a strip steel inlet, an inlet sealing device, and an inlet turning roller; the upper part of the preheating furnace body has a preheating furnace gas collection chamber; the lower part of the preheating furnace body has a lower partition with a strip steel passage hole, forming an exhaust gas collection chamber, which is connected to an exhaust gas fan through an exhaust gas discharge pipe; a control valve is installed on the exhaust gas discharge pipe; Several heat exchange and jet air box units are arranged on both sides below the preheating furnace gas collecting chamber inside the preheating furnace body along the furnace height direction, forming a strip-passing channel in the middle for the strip steel to pass through; each heat exchange and jet air box unit includes, The air box body has several heat exchange pipes vertically arranged inside, and several nozzles are arranged on one side of the air box body opposite to the belt passage; a secondary mixing chamber for exhaust gas is arranged between the upper and lower air boxes and connected to the heat exchange pipes; a protective gas is introduced into the air box body. The circulating fan has its inlet pipe located inside the belt-passing channel and its outlet pipe located inside the air box. Sealing devices that allow the strip steel to pass through are respectively installed at the lower port of the strip passage and at the strip passage hole of the lower partition.

51. The jet radiant tube preheating device for a flexible post-processing production line suitable for producing various high-strength steels of cold-rolled strip as described in claim 50, characterized in that, The inlet sealing device and the sealing device through which the strip steel can pass are nitrogen sealing structures, using a nitrogen sealing chamber with a nitrogen injection pipe.

52. A jet-radiation composite heating / soaking device for a flexible post-processing production line for cold-rolled strip steel suitable for producing various high-strength steels as described in any one of claims 1 to 49, characterized in that, include: The furnace body has a composite heating element installed along its height. The composite heating element includes, The insulated box has an inner wall lined with insulation material. An installation hole is provided in the center of one side of the insulated box. A circulating fan is installed at the mounting hole of the insulation box, with its air intake corresponding to the axis of the mounting hole and its air outlet located on the side of the casing. A buffer cavity is provided inside the insulation box at the air inlet of the circulating fan. A hot air outlet corresponding to the air inlet of the circulating fan is provided on the back of the buffer cavity, and a hot air inlet is provided on the front of the buffer cavity. Two high-temperature jet air boxes are vertically and symmetrically arranged on both sides of the hot air inlet on the front of the buffer cavity inside the insulation box, forming a strip passage for the strip steel to pass through; a number of jet nozzles are arranged at intervals along the height direction on one side of the two high-temperature jet air boxes located on both sides of the strip passage, and a gap is provided between n jet nozzles, n≥1. Several radiant tubes are symmetrically arranged inside the two high-temperature jet air boxes. Each radiant tube includes a connecting pipe section connected to the burner, a radiant tube section that bends and extends from one end of the connecting pipe section, and a heat exchange tube section that extends and bends from one end of the radiant tube section. The radiant tube section corresponds to the gap between the n rows of jet nozzles in the high-temperature jet air box, forming an alternating jet and radiation structure.

53. The jet radiation composite heating / soaking device for a flexible post-processing production line suitable for producing various high-strength steels in cold-rolled strip as described in claim 52, characterized in that, The buffer cavity and the high-temperature jet bellows are an integral structure.

54. The jet radiation composite heating / soaking device for a flexible post-processing production line suitable for producing various high-strength steels in cold-rolled strip as described in claim 52, characterized in that, The diameter of the jet nozzle is 1 / 10 to 1 / 5 of the distance from the jet nozzle to the strip.

55. The jet radiation composite heating / soaking device for a flexible post-processing production line suitable for producing various high-strength steels in cold-rolled strip as described in claim 52, characterized in that, The jet nozzle has a circular hole structure.

56. The jet radiation composite heating / soaking device for a flexible post-processing production line suitable for producing various high-strength steels in cold-rolled strip as described in claim 52, characterized in that, The radiant tube section, connecting tube section, and heat exchange tube section of the radiant tube are arranged in parallel.

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