CN117737635A - Flexible cold-rolled strip steel post-treatment line suitable for producing various high-strength steel - Google Patents
Flexible cold-rolled strip steel post-treatment line suitable for producing various high-strength steel Download PDFInfo
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- Heat Treatment Of Strip Materials And Filament Materials (AREA)
Abstract
A flexible cold-rolled strip steel post-treatment line suitable for producing various high-strength steels sequentially comprises the following stations: uncoiling, welding, inlet looping, cleaning, central continuous post-treatment, intermediate looping, flattening, outlet looping, finishing and coiling; the central continuous post-treatment station sequentially comprises a jet direct-fire preheating section, a direct-fire heating section, a radiant tube heating section, an optional transverse magnetic induction heating section or a muffle furnace section which are arranged in parallel, a jet-radiation composite soaking section, a slow cooling section, a quick cooling section, a reheating section, a (furnace nose section+zinc pot section+air knife section+alloying heating section+alloying soaking section+post-plating cooling section) and (moving channel section+overaging section+final jet cooling section) which are arranged in parallel, a final water cooling section, an optional pickling section and a flash plating section. The production line provided by the invention has more than three selectable process paths, and can realize the production of five different types of high-strength steel including cold rolling annealing, pickling, flash plating, hot plating pure zinc and alloying hot galvanizing.
Description
Technical Field
The invention relates to the technical field of cold rolling post-treatment of strip steel, in particular to a flexible cold-rolled strip steel post-treatment line suitable for producing various high-strength steel.
Background
In recent years, the automobile industry in China is rapidly developed, and the automobile sales volume is continuous for many years and the world is first. However, the use proportion of the high-strength steel, particularly the ultra-high-strength steel for automobiles in China is still low. The weight of the vehicle body can be reduced by adopting high-strength steel, particularly ultrahigh-strength steel, so that the oil consumption and the automobile exhaust emission can be reduced on the premise of ensuring the safety performance. With the improvement of the safety performance requirements and the environmental protection regulation requirements of automobiles, the use proportion of the high-strength steel, particularly the ultra-high-strength steel for automobiles in China is gradually improved in the future. The demand for high-strength steel strips for car bodies, particularly ultra-high-strength steel strips, including continuously annealed cold-rolled steel strips, hot-dip galvanized steel strips (hereinafter abbreviated as GI) and galvannealed steel strips (hereinafter abbreviated as GA), has increased year by year.
Conventional strip processing lines, in addition to each looper station apparatus, typically include the following stations: uncoiling, welding, cleaning, central continuous post-treatment, flattening, finishing and coiling, wherein a withdrawal and straightening station is further arranged between a flattening station and a finishing station on some treatment lines, a post-treatment station is arranged between the flattening station and the finishing station on some treatment lines, and a withdrawal and straightening station and a post-treatment station are simultaneously arranged between the flattening station and the finishing station on other treatment lines.
The above-mentioned central continuous post-treatment station generally comprises the equipment of a general preheating section-heating section-soaking section-slow cooling section-fast cooling section-Overaging (OA) section-air-jet cooling section and final water-cooling section when producing continuously annealed cold rolled products, as shown in fig. 1.
And a reheating section is arranged between the quick cooling section and the overaging section of some treatment lines, and an acid washing section and a reheating section are simultaneously arranged between the quick cooling section and the overaging section of some units. In the production of GI products, the central continuous post-treatment station typically comprises in sequence the equipment of a common preheating section-heating section-soaking section-slow cooling section-fast cooling section-balanced heat preservation section-furnace nose section-zinc pot section-air knife section-post-plating cooling section-final water cooling section, as shown in fig. 2.
And a reheating section is arranged between the quick cooling section and the balanced heat preservation section in some GI processing lines, and an acid washing section and a reheating section are simultaneously arranged between the quick cooling section and the balanced heat preservation section in some units. Some treatment lines have a movable post-plating quench section disposed within 10 meters above the air knife between the air knife section and a stationary post-plating quench section (typically in the upper half of the APC tower). In the production of GA products, the central continuous post-treatment station typically comprises in sequence the equipment of a common preheating section-heating section-soaking section-slow cooling section-fast cooling section-balanced heat-preserving section-furnace nose section-zinc pot section-air knife section-alloying heating section-alloying soaking section-stationary post-plating cooling section and final water cooling section, as shown in fig. 3.
And a reheating section is arranged between the quick cooling section and the balanced heat preservation section in some processing lines, and an acid washing section and a reheating section are simultaneously arranged between the quick cooling section and the balanced heat preservation section in some units. The movable channel section is also arranged above the air knife section, so that the switching of two or three products is realized, wherein the movable channel section (only cold-rolled product is produced), the quick cooling section (only GI product is produced) after movable plating and the alloying heating section (only GA product is produced) are arranged in parallel, and strip steel is usually cut off for product switching. And the production line for producing the GI products and the GA products adopts parallel arrangement of a quick cooling section (only the GI products are put into use) and an alloying heating section (only the GA products are put into use) after mobile plating, so that the switching of the two products is realized.
For the common preheating section and the heating section, a common mode is direct fire heating, and clean natural gas is preferably adopted for direct fire heating, so that unclean combustion waste gas is prevented from polluting the surface of the strip steel, the strip steel is directly preheated by the direct fire combustion waste gas, the temperature of the strip steel is generally lower than 750 ℃ after the direct fire heating, and the strip steel is further heated by a radiant tube and can be heated to about 850 ℃. Namely: directly preheating strip steel by using combustion waste gas of a direct-fired furnace, heating by using direct fire, heating by using a radiant tube, and then carrying out soaking and other treatments. The prior art has the following defects:
1) The exhaust gas emission temperature after preheating the strip steel is still relatively high, and is usually over 800 ℃, sometimes over 850 ℃, and when the exhaust gas emission temperature exceeds 850 ℃, cold air is usually doped to control the exhaust gas emission temperature to 850 ℃ or below so as to carry out secondary off-line utilization. The higher the exhaust gas temperature means more thermal energy is lost. According to the method, the primary online utilization rate of heat energy is low, and steam or hot water generated by secondary offline utilization cannot be completely consumed in the unit, so that the energy balance of the area is difficult;
2) Because the direct-fired waste gas directly contacts the strip steel and the contact time is longer, in addition, excessive fuel gas in the direct-fired waste gas needs to be subjected to secondary combustion in a preheating section, the secondary combustion flame is often an oxidizing flame, the improvement of the preheating temperature of the strip steel is necessarily limited, otherwise, an excessively thick oxide layer is easily formed on the surface of the strip steel, the surface quality problem is caused, and the preheating temperature of the strip steel can only be preheated to about 250 ℃ generally, and the preheating effect is poor;
3) The direct fire heating section has limited heating capacity and cannot be too high, the strip steel can be heated to 750 ℃ or below, the strip steel is easy to be severely oxidized after the heating temperature is further increased, and the temperature uniformity along the width direction of the strip steel is relatively poor;
4) The traditional process generally adopts a radiant tube for further heating when the strip steel is annealed at the temperature higher than 750 ℃, and because the thermal inertia of a radiant tube heating furnace is large, when the thickness specification and the annealing target temperature change greatly, the temperature of the strip steel is slowly regulated, the temperature control precision is poor, the method is very unfavorable for producing the ultra-high strength steel, or consumes excessive temperature transition materials, or causes large mass loss due to inconsistent annealing temperature;
5) The radiation tube is used for heating at the temperature of more than 750 ℃, the heating efficiency is low, the heating speed is low, and the higher the heating temperature is, the lower the thermal efficiency and the heating speed are, and the lower the one-time direct utilization efficiency of corresponding energy is.
6) Due to the fact that the thermal inertia of the radiant tube soaking furnace is large, when the thickness specification and the annealing target temperature change greatly, the soaking temperature of the strip steel is adjusted slowly, the actual soaking temperature fluctuation of the strip steel is large, the actual performance fluctuation of the high-strength steel is large when the thickness is switched or the annealing target temperature is switched, and the performance stability of the product is insufficient.
Disclosure of Invention
The invention aims to provide a flexible cold-rolled strip steel post-treatment line suitable for producing various high-strength steels, which can realize the following purposes: 1) The waste heat of the combustion waste gas in the straight fire section is fully utilized, and the temperature of the strip steel can be quickly preheated to at least 350 ℃; 2) The direct-fired combustion waste gas is prevented from directly contacting the strip steel in the preheating furnace for a long time, so that an excessively thick oxide layer is prevented from being generated on the surface of the strip steel; 3) The strip steel temperature can be quickly heated to more than 750 ℃ by utilizing quick and efficient preheating and direct fire heating, and the strip steel can be quickly and uniformly heated to more than 850 ℃ by matching with the subsequent use of transverse magnetic induction heating and jet radiation composite heating, so that quick, efficient and uniform heating is completed; 4) The rapid adjustment of the soaking temperature of the strip steel is realized by utilizing jet-air radiation composite soaking, and the fluctuation of the soaking temperature of the actual strip steel is reduced; 5) The rapid adjustment of the annealing temperature of the strip steel can be realized due to the remarkable reduction of the heating furnace, the reduction of the thermal inertia of the furnace and the rapid response speed of transverse magnetic induction heating; 6) The whole rapid heat treatment furnace can be remarkably simplified, miniaturized and highly-efficient, so that energy conservation and emission reduction can be realized, and the occupied area can be reduced; 7) The flexible high-strength steel special production line can flexibly produce various cold-rolled annealed, acid-washed, flash-plated, hot-dip pure zinc (GI) and alloyed hot-dip Galvanized (GA) products, so that the flexible production line can better meet market demands; 8) The platability of the ultra-high strength steel product can be greatly improved, so that the surface quality of the ultra-high strength hot dip product can also be obviously improved; 9) The application of the rapid heating, rapid cooling and rapid heat treatment process technology can adopt lower alloy components to produce various advanced high-strength steel products with higher strength grades, thereby not only reducing the production cost of the high-strength steel, but also improving the mechanical properties and subsequent processing properties (such as welding properties) of various super-high-strength steel products.
In order to achieve the above purpose, the technical scheme of the invention is as follows:
a flexible cold-rolled strip steel post-treatment line suitable for producing various high-strength steels sequentially comprises the following stations: uncoiling, welding, inlet looping, cleaning, central continuous post-treatment, intermediate looping, flattening, outlet looping, finishing and coiling; wherein,
the central continuous post-treatment station sequentially comprises a jet direct-fire preheating section, a direct-fire heating section, a radiant tube heating section or a jet-radiation composite heating section, a selectable transverse magnetic induction heating section or a muffle furnace section which are arranged in parallel, a jet-radiation composite soaking section, a slow cooling section, a quick cooling section, a reheating section, a (furnace nose section+zinc pot section+air knife section+alloying heating section+alloying soaking section+cooling section after plating) and (moving channel section+overaging section+final jet cooling section), a final water cooling section and a selectable pickling section and flash plating section which are arranged in parallel;
the rapid cooling section comprises a high-hydrogen cooling section and/or an aerosol cooling section and/or a water quenching cooling section;
the direct-fire heating section burns gas fuel such as natural gas or liquefied petroleum gas;
the injection direct-fire preheating section utilizes the combustion waste gas of the direct-fire heating section to exchange heat in the furnace to heat the recycled nitrogen-hydrogen protective gas, and then the nitrogen-hydrogen protective gas is injected to the upper surface and the lower surface of the strip steel to realize forced convection heat exchange;
The jet-radiation composite soaking section adopts a mode of combining forced convection and radiation to quickly soak the strip steel, improves the uniformity of the strip steel temperature and realizes the quick adjustment of the soaking temperature of the strip steel.
The production line adopts high hydrogen cooling or aerosol cooling or/and water quenching cooling to perform rapid cooling treatment while adopting a jet direct fire preheating section, then reheating and then galvanization or overaging treatment.
The furnace nose section and the moving channel section are arranged in parallel, the strip steel passes backwards from the furnace nose section and is used for producing hot-dip pure zinc or alloyed hot dip galvanized products, and the strip steel passes from the moving channel section and is used for producing cold-rolled or flash-plated products.
And an acid washing section is arranged after the final water cooling section, and a flash plating section is arranged next, so that the strip steel can be selectively subjected to the acid washing section to produce cold-rolled acid washing products, can be bypassed to cross the acid washing section to produce cold-rolled annealed products, and can be selectively subjected to the flash plating section to produce flash plating products such as flash nickel plating or flash zinc plating.
The production line has more than three selectable process paths, and can realize the production of five different types of high-strength steel including cold rolling annealing, acid washing, flash plating, hot plating pure zinc and alloying hot galvanizing.
Further, an optional withdrawal and straightening station and/or a surface post-treatment station such as passivation or fingerprint resistance is arranged between the flattening station and the outlet looper station, and the strip steel can be withdrawn and straightened and/or subjected to surface post-treatment.
Preferably, the muffle furnace section is provided with sealing devices at the front and back, and is also provided with an atmosphere regulating device which can independently regulate and control the hydrogen content, the oxygen content and the dew point in the muffle furnace section.
Furthermore, an equilibrium heat preservation section is arranged between the reheating section and the furnace nose section, and the equilibrium heat preservation section is connected with the furnace nose section and the moving channel section. And carrying out heat preservation treatment on the strip steel, and then carrying out hot galvanizing.
A movable post-plating quick cooling section is arranged between the air knife section and the post-plating cooling section, and the movable post-plating quick cooling section and the alloying heating section are arranged in parallel to realize quick cooling of the strip steel after the hot-dip pure zinc high-strength steel product is plated; preferably, a mobile plating post-fast cooling section is arranged within a range of 10 meters above the air knife section.
And a secondary reheating section is arranged after the balanced heat preservation section and is connected with the furnace nose section and the moving channel section. And (3) carrying out secondary reheating on the balanced heat-preserving strip steel, and then carrying out hot galvanizing or overaging treatment.
Preferably, a pickling section is arranged between the rapid cooling section and the reheating section, and the pickling section equipment comprises a pickling unit, a hot water scrubbing unit, a hot water rinsing unit and a hot air drying unit. The method realizes the acid washing of the surface of the strip steel, can be used for removing an oxide layer on the surface of the strip steel after aerosol cooling or/and water quenching cooling, and can also improve the platability of high-strength strip steel, particularly ultra-high-strength strip steel for hot dip galvanizing products or alloyed hot dip galvanizing products.
Preferably, the flash iron plating or the flash nickel plating section is arranged before the reheating section after the pickling section, and then the reheating section is connected for reheating treatment, so that the platability of the ultra-high-strength strip steel can be further improved.
Preferably, the radiant tube heating section can be changed into an air jet radiant composite heating section, so that the rapid adjustment of the heating temperature of the strip steel is realized.
Preferably, the mobile post-plating quick cooling section adopts a mobile jet quick cooling section or a mobile aerosol cooling section.
In addition, the invention also provides a jet direct-fire preheating device, which comprises: a direct fire furnace and a preheating furnace; wherein,
the direct fire includes:
a furnace shell, the upper end and the lower end of which are respectively provided with a furnace top roller chamber and a furnace bottom roller chamber; steering rollers are respectively arranged in the furnace top roller chamber and the furnace bottom roller chamber; a plurality of direct-fire heating areas are arranged in the furnace shell along the height direction, and a plurality of direct-fire burners are arranged in the direct-fire heating areas; the side wall of the upper part of the furnace shell is provided with at least two through holes which are symmetrically arranged left and right;
The preheating furnace comprises:
the side wall of the upper part of the furnace body is provided with at least two connecting holes which are symmetrically arranged left and right and are respectively connected with the through holes on the upper part of the furnace shell of the direct-fired furnace through communicating pipes; the top end of the furnace body is provided with a furnace throat which corresponds to the furnace top roller chamber of the direct furnace and is used for the strip steel to pass through; the bottom of the furnace body is provided with a strip steel inlet, a corresponding sealing device and a corresponding steering roller; an upper partition plate with a through hole is arranged at the upper part in the furnace body to form an upper gas collection chamber of the direct-fire waste gas; a direct-fire combustion waste gas secondary combustion chamber is arranged below the upper gas collection chamber of the direct-fire waste gas, and at least one open-fire burner is arranged in the direct-fire combustion waste gas secondary combustion chamber; preferably, a combustion waste gas thermometer is further arranged in the direct-fired combustion waste gas secondary combustion chamber; a lower partition plate with a penetrating hole is arranged at the lower part in the furnace body to form a lower straight fire waste gas collecting chamber, and the lower straight fire waste gas collecting chamber is connected with a waste gas fan through a waste gas discharge pipeline; a control valve is arranged on the waste gas discharge pipeline;
the heat exchange and air injection bellows units are arranged on two sides below the direct-fired combustion waste gas secondary combustion chamber in the furnace body along the height direction of the furnace body, and a strip penetrating channel for strip steel to pass through is formed in the middle of the heat exchange and air injection bellows units; each heat exchange and air injection bellows unit comprises,
the air box body is vertically provided with a plurality of heat exchange tubes, and a plurality of nozzles are arranged on one side surface of the air box body, which is opposite to the threading channel; an exhaust gas secondary mixing chamber communicated with the heat exchange tube is arranged between the upper and lower bellows bodies; introducing nitrogen and hydrogen protective gas into the bellows body;
The port of the inlet pipeline of the circulating fan is arranged in the threading channel, and the port of the outlet pipeline of the circulating fan is positioned in the bellows body;
the sealing devices are respectively arranged at the upper and lower ports of the threading channel and the threading holes of the upper and lower partition plates; preferably, the sealing device is of a nitrogen sealing structure, a nitrogen sealing chamber is adopted, and a nitrogen injection pipeline is arranged on the sealing device.
In the production process, high-temperature combustion waste gas generated by direct fire combustion of a direct fire furnace enters a preheating furnace through a communicating pipe, a plurality of heat exchange and air injection bellows units which are sequentially arranged up and down are arranged in the preheating furnace, a heat exchange pipeline (high-temperature combustion waste gas tube side and protective gas tube side) of the heat exchange and air injection bellows units heats nitrogen-hydrogen mixed gas in the bellows body, high Wen Danqing mixed gas is blown to two sides of the strip steel through high-speed nozzles opposite to two sides of the strip steel, the strip steel is rapidly heated, the ejected high Wen Danqing mixed gas exchanges heat with low-temperature strip steel, the mixed gas is subjected to heat exchange again from circulating fans which are arranged close to two sides of the strip steel after the temperature of the mixed gas is reduced, the temperature of the nitrogen-hydrogen mixed gas is raised again, and then the nitrogen-hydrogen mixed gas is sprayed to two sides of the strip steel from the inside of the air injection bellows unit again, and the strip steel is circulated and reciprocated in this way.
In the preheating device of the invention:
the preheating device is characterized in that a heat exchange and air injection bellows unit and a direct-fire combustion waste gas secondary combustion chamber are arranged, the heat exchange and air injection bellows unit adopts a heat exchange pipeline (the heat exchanger is not arranged outside the furnace), the waste gas which is combusted again in the direct-fire combustion waste gas secondary combustion chamber heats nitrogen and hydrogen protective gas circularly utilized in the bellows, and the heated nitrogen and hydrogen protective gas is sprayed to the upper surface and the lower surface of the strip steel at a high speed under the action of a circulating fan for forced convection heat exchange, so that the strip steel is preheated rapidly and efficiently.
And an open flame burner is further arranged in the direct-fire combustion waste gas secondary combustion chamber and is used for carrying out oxygen-enriched secondary combustion on insufficiently combusted fuel gas in the direct-fire combustion waste gas secondary combustion chamber, and the burning flame cannot contact strip steel.
An exhaust gas secondary mixing chamber communicated with the heat exchange tube is arranged between the upper and lower bellows bodies, and the exhaust gas temperature is homogenized in the exhaust gas secondary mixing chamber and then enters the downstream bellows body.
The sealing device is of a nitrogen sealing structure and is provided with a nitrogen sealing chamber, a nitrogen injection pipeline opening is arranged in the nitrogen sealing chamber, sealing nitrogen is introduced into the nitrogen sealing chamber to maintain relatively high pressure, a large amount of direct-fire combustion waste gas is prevented from entering a strip penetrating channel in the furnace for heat exchange and the air injection bellows unit, and accordingly the surface of strip steel can be prevented from being excessively oxidized by the direct-fire combustion waste gas.
The strip steel inlet of the preheating furnace is provided with a sealing device, and the inside of the sealing device is also provided with a gas injection port for injecting a small amount of sealing nitrogen or air, so that the sealing device has the function of preventing the direct-fired combustion waste gas from overflowing out of the furnace.
The invention also provides a jet-radiation composite heating/soaking device, which comprises:
the furnace body is internally provided with a composite heating body along the height direction; the composite heating body comprises an insulation box body, wherein an insulation material is arranged on the inner wall of the shell; a mounting hole is arranged in the center of one side surface of the heat preservation box body;
the circulating fan is arranged at the mounting hole of the heat insulation box body, the air suction inlet of the circulating fan corresponds to the axis of the mounting hole, and the air outlet is arranged on the side surface of the shell;
the buffer cavity is arranged in the insulation box body at a position corresponding to the air suction opening of the circulating fan, the back surface of the buffer cavity is provided with a hot air outlet corresponding to the air suction opening of the circulating fan, and the front surface of the buffer cavity is provided with a hot air inlet; preferably, the buffer cavity and the high-temperature air injection bellows are of an integrated structure;
the two high-temperature air jet bellows are vertically and symmetrically arranged at two sides of a hot air inlet at the front side of the buffer cavity in the heat insulation box body to form a strip penetrating channel for strip steel to pass through; a plurality of rows of jet nozzles are arranged on one side surface of the two high-temperature jet bellows at two sides of the threading channel at intervals along the height direction, a gap is arranged between n rows of jet nozzles, and when n is more than or equal to 1 and n=1, the radiation pipes are arranged above or below one row of jet nozzles in parallel; preferably, the diameter of the jet nozzle is 1/10-1/5 of the distance from the jet nozzle to the strip steel; more preferably, the jet nozzle adopts a round hole structure;
The radiant tubes are symmetrically arranged in the two high-temperature air injection bellows and comprise a connecting tube section for connecting a burner, a radiant tube section bent and extended from one end of the connecting tube section and a heat exchange tube section formed by extending and bending from one end of the radiant tube section; the radiant tube section corresponds to gaps arranged between n rows of jet nozzles in the high-temperature jet bellows, so as to form a jet-radiation alternating structure; preferably, the radiant tube section, the connecting tube section and the heat exchange tube section of the radiant tube are arranged in parallel.
The jet-radiation composite heating/soaking device adopts a composite heating technology, can organically combine a high-speed high-temperature jet-heating technology with a radiant tube heating technology, and fully plays technical advantages of the high-speed high-temperature jet-heating technology and the radiant tube heating technology. The structure of the radiant tube is optimally designed, the radiant tube is arranged in the high-speed high-temperature jet air box, heat generated by burning gas of the radiant tube is rapidly transferred to the strip steel through two modes of high-speed high-temperature jet and radiation, the rapid heating of the strip steel is realized, the highest average heating speed of the strip steel of 1mm is not lower than 40 ℃/s, the length of a heating furnace can be greatly shortened, the heating section of a unit with 30 ten thousand tons per year output is about 2 pass, and the thermal inertia of a furnace body is reduced;
Second, heat generated by the fuel gas is transferred to the circulating gas (N 2 +H 2 ) The heat-conducting material is taken away, so that the exhaust temperature of the radiant tube can be reduced, the exhaust temperature of the radiant tube can be reduced by about 100 ℃ under the same condition, the heat efficiency of the radiant tube is improved by about 5%, the average working temperature of the radiant tube can be reduced, and the service life of the radiant tube is prolonged;
and the temperature of the heated circulating gas is uniform, so that the temperature distribution of the strip steel in the width direction in the heating process is uniform, and the temperature distribution of the strip steel in the width direction in the actual heating process is controlled to be +/-5 ℃ according to the uniformity of the strip steel in the width direction, thereby realizing the stable operation of the unit. The high-speed air injection and radiation composite heating technology can obviously improve the productivity of the existing unit and solve the problem of insufficient heating capacity on the production line.
The radiant tube of the jet-radiation composite heating/soaking device has the functions of combustion radiation (namely, a high-temperature section of the radiant tube between two rows of nozzles) and a heat exchanger, and is used for heating circulating gas, so that the heat of the combustion gas in the radiant tube can be rapidly transferred to strip steel through forced heat exchange, the rapid heating of the strip steel is realized, the length of a heating furnace can be greatly shortened, and the thermal inertia of a large vertical continuous annealing furnace body is reduced.
The invention is different from the traditional process in that:
1) The invention has at least three or more than three selectable process paths;
2) The invention can realize the production of five different types of high-strength steel, especially super-high-strength steel, including cold rolling annealing, acid washing, flash plating, hot plating pure zinc and alloying hot galvanizing;
3) The invention can carry out surface post-treatment such as withdrawal straightening or/and passivation or fingerprint resistance on five different types of ultra-high strength steel including cold rolling annealing, acid washing, flash plating, hot plating pure zinc and alloying hot galvanizing;
4) The invention is provided with the secondary reheating section equipment, thereby realizing the twice lifting of the temperature of the strip steel before hot galvanizing or overaging treatment, being capable of realizing the rapid cooling of third-generation high-strength steel (QP steel) products to lower temperature, then rapidly heating to higher temperature on the horse for long-time carbon redistribution treatment, and rapidly reheating to the temperature of a hot galvanizing zinc-entering pot for the second time after the treatment is finished, and performing galvanization treatment;
5) The invention changes the common preheating section into the injection direct fire preheating section, more precisely the high-temperature nitrogen-hydrogen protective gas injection direct fire preheating section, which is one of the novelty and creativity of the invention, and the remarkable characteristics of the invention are that the invention is different from the common preheating section: (1) the method has the advantages that compared with the traditional preheating method, the heat loss of a furnace shell and a protective gas channel is obviously reduced, the waste heat utilization of combustion waste gas is more complete, the heating efficiency is higher, and the heating rate is faster; (2) in the preheating section, the direct-fired combustion waste gas passes through a heat exchanger chamber of the preheating section, and in the passing process, the direct-fired combustion waste gas and a heat exchanger in the heat exchanger chamber perform sufficient heat exchange to heat the nitrogen-hydrogen protective gas, so that the direct-fired combustion waste gas is not always in direct contact with strip steel in the preheating section (only in a short time in a high-temperature section and the waste gas belongs to a reducing atmosphere or a micro-oxidizing atmosphere at the moment), thereby avoiding peroxidation on the surface of the strip steel; (3) the insufficiently combusted fuel gas in the directly-fired waste gas is subjected to oxygen-enriched secondary combustion in a semi-sealing unit at the top of the jet preheating section, but the burning flame does not contact strip steel, so that the surface peroxidation of the strip steel is effectively avoided; (4) the preheating temperature of the strip steel is higher, and the high-temperature nitrogen-hydrogen protective gas injection direct-fire preheating heat exchange coefficient is high, so that the temperature of the preheated strip steel at least reaches 350 ℃ and above, and is at least 100 ℃ higher than that of the common preheating strip steel; (5) the preheating section adopts the design of a jet direct fire preheating section, the temperature of the direct fire combustion waste gas from the preheating section is usually far lower than 750 ℃ (if the number of the high-speed jet preheating units is enough, the direct discharge can be even lower than 200 ℃), and the secondary utilization outside the furnace or the secondary utilization at all is not required by the cold air.
6) According to the invention, the transverse magnetic induction heating section and the muffle furnace section are arranged between the radiant tube heating section and the radiant tube soaking section, and are arranged in parallel, and the switching between the transverse magnetic induction heating section and the muffle furnace section is realized by cutting off strip steel and re-threading. The jet-radiation composite soaking section adopts a mode of combining forced convection and radiation to soak the strip steel, so that the uniformity of the strip steel temperature is improved, and the quick adjustment of the soaking temperature of the strip steel is realized; the muffle furnace section equipment is provided with sealing devices from front to back, and is also provided with an atmosphere adjusting device, and the hydrogen content, the oxygen content and the dew point in the muffle furnace section equipment can be independently adjusted and controlled.
7) The radiation tube is adopted to jet and radiate the composite soaking section before the slow cooling section, and the forced convection and radiation are adopted to soak the strip steel in a combined mode, so that the temperature uniformity of the strip steel can be improved, the quick adjustment of the soaking temperature of the strip steel can be realized, and the fluctuation quantity of the actual temperature of the strip steel in the soaking section can be reduced.
The novel and creative embodiment of the invention is realized by simultaneously using the high-efficiency high-speed jet preheating section and the transverse magnetic induction heating section between the radiant tube heating section and the radiant tube soaking section. The transverse magnetic induction heating section is arranged between the radiant tube heating section and the radiant tube soaking section, and has the beneficial effects that:
(1) The rapid adjustment of the temperature of the strip steel can be realized, which is very critical to the production of high-strength steel, especially ultra-high-strength steel, and the loss of the strip steel can be reduced;
(2) the strip steel can be heated to a higher temperature, and the prior engineering realizes the heat treatment of heating to about 880 ℃ through radiant tube heating and transverse magnetic induction heater;
(3) the soaking is matched with a radiant tube, the temperature uniformity of the strip steel after soaking is good, and the temperature uniformity along the width direction of the strip steel can be controlled within +/-5 ℃;
(4) the improvement of the heating rate can refine the grain structure to improve the strong plasticity of the material, and is particularly beneficial to the performance improvement and the cost reduction of high-strength steel and ultra-high-strength steel products.
The invention has the beneficial effects that:
1) The same production line can be used for producing continuous annealing cold rolled DP steel, MS steel, TRIP steel, QP steel, hot galvanized DP steel, TRIP steel, QP steel and other super-high-strength steel, and various high-strength steel products produced by adopting the rapid heat treatment process have better performance and lower cost;
2) The invention can realize the production of five different types of high-strength steel, especially super-high-strength steel, including cold rolling annealing, acid washing, flash plating, hot plating pure zinc and alloying hot galvanizing;
3) The primary utilization rate of the waste heat of the directly heated combustion waste gas is high, and the temperature of the strip steel can be preheated to at least 350 ℃;
4) The direct-fired combustion waste gas is prevented from directly contacting the strip steel in the preheating section for a long time, and an excessively thick oxide layer can be prevented from being generated on the surface of the strip steel;
5) The secondary ignition combustion flame of excessive fuel gas in the direct-fired waste gas can not contact the strip steel, and the generation of an excessively thick oxide layer on the surface of the strip steel can be avoided;
6) The strip steel can be economically and rapidly heated to above 870 ℃ when transverse magnetic induction heating is used, so that high-temperature annealing can be realized;
7) The strip steel after the jet-air radiation composite soaking has good temperature uniformity, and the temperature uniformity along the width direction of the strip steel can be controlled within +/-5 ℃;
8) The rapid adjustment of the strip steel heating and soaking temperature can be realized, and the fluctuation of the actual strip steel soaking temperature is small;
9) The martensitic ultra-high-strength steel with the strength up to 1500MPa can be produced by adopting water mist cooling, acid washing or acid washing and nickel plating, and the steel strip has high surface quality and plate shape quality, good platability and excellent plating quality during hot galvanizing;
10 According to the invention, through the adjustment of the air-fuel ratio of the direct-fired furnace, a pre-oxidation reduction process can be realized, and the platability of the ultra-high-strength steel is better.
Drawings
FIG. 1 is a schematic diagram of a station arrangement of a conventional continuous annealing production line;
FIG. 2 is a station layout of a conventional hot dip pure zinc (GI) production line;
FIG. 3 is a station layout of a conventional Galvannealed (GA) production line;
FIG. 4 is a layout of the production line of embodiment 1 of the present invention;
FIG. 5 is a layout of the production line in accordance with embodiment 2 of the present invention;
FIG. 6 is a station layout of the production line of example 3 of the present invention;
FIG. 7 is a station layout of the production line of example 4 of the present invention;
FIG. 8 is a layout of the production line of embodiment 5 of the present invention;
FIG. 9 is a layout of the production line of embodiment 6 of the present invention;
FIG. 10 is a schematic view of an embodiment of a jet direct-fire preheating device according to the present invention;
FIG. 11 is a schematic diagram of the structure of a preheating furnace in the jet direct-fire preheating device according to the present invention;
FIG. 12 is a schematic view of an embodiment of a jet-propelled radiant composite heating/soaking device according to the present invention 1;
FIG. 13 is a schematic view of an embodiment of a jet-propelled radiant composite heating/soaking device according to the present invention in FIG. 2;
fig. 14 is a schematic structural diagram of a composite heating body in an embodiment of the air jet radiation composite heating/soaking device according to the present invention;
FIG. 15 is a partial perspective view of a high temperature jet bellows in an embodiment of a jet radiant composite heating/soaking apparatus according to the present invention;
fig. 16 is a perspective view of a radiant tube in an embodiment of the jet radiant composite heating/soaking device according to the present invention.
Detailed Description
The invention is further illustrated by the following examples and figures: it should be noted that, by applying the inventive concept, various production lines can be simplified and combined, only one embodiment is given in this example, and other embodiments are given in the present invention, even though all the group patent examples are given only in some embodiments, various combinations generated by selecting and not selecting the optional stations according to the inventive concept are within the scope of the present invention, and various production lines derived according to the inventive concept are also within the scope of the present invention. In addition, for conventional stations, such as cleaning stations comprising an alkali liquor spraying section, an alkali liquor brushing section, an electrolytic cleaning section, a hot water brushing or cold water abrasive particle roller brushing section and a hot water rinsing section, even the cleaning new technical equipment which is simplified and combined by adopting a high-pressure water jet brushing section, an ultrasonic cleaning section, a high-pressure cleaning section and the like is considered to be the production line of the invention, and the production line is also within the protection scope of the invention. As another example, finishing stations including trimming, oiling, etc., are also within the scope of the present invention.
Referring to fig. 4, in embodiment 1 of the present invention, the post-treatment line for a flexible cold-rolled steel strip suitable for producing various high-strength steels sequentially comprises the following stations: uncoiling, welding, inlet looping, cleaning, central continuous post-treatment, intermediate looping, flattening, outlet looping, finishing and coiling; wherein,
The central continuous post-treatment station sequentially comprises a jet direct-fire preheating section, a direct-fire heating section, a radiant tube heating section, a parallel-arranged selectable transverse magnetic induction heating section or muffle furnace section, a jet radiation composite soaking section, a slow cooling section, a high-hydrogen cooling or aerosol cooling or/and water quenching cooling section, a reheating section, a parallel-arranged (furnace nose section, a zinc pot section, an air knife section, an alloying heating section, an alloying soaking section and a post-plating cooling section), a final water cooling section, a selectable pickling section and a selectable flash plating section, wherein strip steel can be selected to be subjected to pickling and flash plating without the pickling section and the flash plating section;
an optional withdrawal straightening station and/or a surface post-treatment station such as passivation or fingerprint resistance are arranged between the flattening station and the outlet looper station;
the production line has more than three selectable process paths, and can realize the production of five different types of high-strength steel including cold rolling annealing, pickling, flash plating, hot plating pure zinc and alloying hot galvanizing.
Preferably, the muffle furnace section is provided with sealing devices at the front and back, and is also provided with an atmosphere regulating device which can independently regulate and control the hydrogen content, the oxygen content and the dew point in the muffle furnace section.
Referring to fig. 5, in embodiment 2 of the present invention, on the basis of embodiment 1, an equalizing heat-preserving section is provided between the reheating section and the furnace nose section, and the equalizing heat-preserving section is connected with the furnace nose section and the moving channel section.
Referring to fig. 6, in embodiment 3 of the present invention, on the basis of embodiment 3, a mobile post-plating quick cooling section is provided between the air knife section and the post-plating cooling section, and the mobile post-plating quick cooling section and the alloying heating section are arranged in parallel; preferably, a mobile plating post-fast cooling section is arranged within a range of 10 meters above the air knife section.
Referring to fig. 7, which shows embodiment 4 of the present invention, in embodiment 4, a secondary reheating section is disposed after the equalizing insulation section, and the secondary reheating section is reconnected to the furnace nose section and the moving walkway section.
Referring to fig. 8, which shows embodiment 5 of the present invention, in embodiment 5, an acid washing stage including an acid washing unit, a hot water brushing unit, a hot water rinsing unit, and a hot air drying unit is disposed between the rapid cooling stage and the reheating stage.
Referring to fig. 9, which shows embodiment 6 of the present invention, in embodiment 6, a flash iron or nickel plating stage is disposed before a reheating stage after an acid washing stage, and then the reheating stage is connected.
Preferably, the radiant tube heating section adopts a jet-jet radiant composite heating section.
Referring to fig. 10 and 11, the injection direct-fire preheating device according to the present invention includes: a direct burner 1 and a preheating furnace 2; wherein,
the direct burner 1 comprises:
a furnace shell 11, the upper and lower ends of which are respectively provided with a furnace top roller chamber 101 and a furnace bottom roller chamber 102; the furnace top roller chamber 101 and the furnace bottom roller chamber 102 are respectively provided with steering rollers 12 and 12'; a plurality of direct-fire heating areas 111 are arranged in the furnace shell 11 along the height direction, and a plurality of direct-fire burners 13 are arranged in the direct-fire heating areas 111; the side wall of the upper part of the furnace shell 11 is provided with two through holes which are symmetrically arranged left and right;
the preheating furnace 2 includes:
the furnace body 21 is provided with two connecting holes on the side wall of the upper part, is symmetrically arranged left and right, and is respectively connected with the through holes on the upper part of the furnace shell 11 of the direct-fired furnace 1 through the communicating pipe 22; the top end of the furnace body 21 is provided with a furnace throat 211 which corresponds to the furnace top roller chamber 101 of the direct furnace 1 and is used for the strip steel to pass through; the bottom of the furnace body 21 is provided with a strip steel inlet and a corresponding sealing device 212 and a steering roller 23; an upper partition plate 213 with a through hole is arranged at the upper part in the furnace body 21 to form a direct-fire waste gas upper gas collection chamber 201; a direct-fire combustion waste gas secondary combustion chamber 202 is arranged below the direct-fire waste gas upper gas collection chamber 201, and at least one open-fire burner 24 is arranged in the direct-fire combustion waste gas secondary combustion chamber 202; a lower partition plate 214 with a penetrating hole is arranged at the lower part in the furnace body 21 to form a lower straight fire waste gas collecting chamber 203 and is connected with a waste gas fan 25 through a waste gas discharge pipeline 215;
A plurality of heat exchange and air injection bellows units 26 which are arranged at two sides below the direct-fire combustion waste gas secondary combustion chamber 202 in the furnace body 21 along the height direction of the furnace body 21, and a penetrating channel 204 for the strip steel to pass through is formed in the middle; each heat exchange and air injection bellows unit 26 includes,
a bellows body 261, in which a plurality of heat exchange tubes 262 are vertically arranged, and a plurality of nozzles 263 are arranged on one side surface of the bellows body 261 opposite to the threading channel 204; an exhaust gas secondary mixing chamber 205 communicated with the heat exchange tube 262 is arranged between the upper and lower bellows bodies 261; introducing nitrogen and hydrogen protective gas into the bellows 261;
a circulating fan 264, the inlet of which is arranged in the threading channel 204, and the outlet of which is arranged in the bellows 261;
a plurality of sealing devices 27, 27', 27″ for the strip steel to pass through are respectively arranged at the upper and lower ports of the strip passing channel 204 and at the strip passing holes of the upper and lower partition plates 213, 214.
Preferably, a combustion exhaust gas thermometer 28 is also disposed in the direct-fired combustion exhaust gas secondary combustion chamber 202.
Preferably, the sealing devices 27, 27', 27″ are nitrogen sealing structures, and nitrogen sealing chambers are adopted, on which nitrogen injection pipelines are arranged.
Preferably, a control valve 216 is provided on the exhaust gas discharge pipe 215.
The strip steel 100 is turned to upwards run by a turning roll in front of the direct fire furnace, enters the preheating furnace 2 for preheating after being sealed by a preheating furnace inlet sealing device, then enters a furnace top roll chamber of the direct fire furnace 1 for direct fire heating after being turned by the turning roll, then enters a furnace bottom roll chamber of the direct fire furnace 1 for continuous running after being turned by the turning roll.
The temperature of the waste gas is reduced after the nitrogen-hydrogen protective gas is heated by the direct-fire combustion waste gas through the heat exchange pipeline (the nitrogen-hydrogen protective gas is blown to the upper surface and the lower surface of the strip steel to preheat the strip steel under the action of the circulating fan), and the nitrogen-hydrogen protective gas after the temperature reduction is sucked into the bellows by the circulating fan 264 on the two sides of the working side (WS side) and the driving side (DS side) of the preheating furnace to exchange heat with the heat exchange pipeline; the direct-fired combustion waste gas sequentially passes through the heat exchange and air injection bellows unit from top to bottom, is subjected to secondary utilization of the waste heat of the combustion waste gas outside the furnace through the waste heat boiler 400 under the suction of the variable-frequency waste gas fan 25 and enters the chimney 500 for final discharge.
Referring to fig. 12 to 16, the jet-radiation composite heating/soaking device according to the present invention includes:
a furnace body 4 in which a composite heating body 5 is arranged in the height direction; the composite heating body 5 comprises a metal sheet and a metal sheet,
A heat-insulating box 51, the inner wall of which is provided with a heat-insulating material; a mounting hole is arranged in the center of one side surface of the heat preservation box body 51;
the circulating fan 52 is arranged at the mounting hole of the heat insulation box body 51, the air suction inlet 521 of the circulating fan corresponds to the axis of the mounting hole, and the air outlet 522 is arranged on the side surface of the casing;
the buffer cavity 53 is arranged in the insulation box 51 at a position corresponding to the air suction opening of the circulating fan 52, the back surface of the buffer cavity 53 is provided with a hot air outlet corresponding to the air suction opening of the circulating fan 52, and the front surface of the buffer cavity is provided with a hot air inlet;
the two high-temperature air jet bellows 54, 54' are vertically and symmetrically arranged at two sides of the hot air inlet at the front side of the buffer cavity 53 in the heat insulation box body 51 to form a strip penetrating channel 200 for the strip 100 to penetrate through; a plurality of rows of jet nozzles 55, 55 'are arranged on one side surface of the two high-temperature jet bellows 54, 54' positioned on two sides of the threading channel 100 at intervals along the height direction, and a gap 300 is arranged between n rows of jet nozzles, wherein n is more than or equal to 1;
the plurality of radiant tubes 56, 56 'are symmetrically arranged in the two high-temperature jet bellows 54, 54', and the radiant tubes 56 (radiant tubes 56 are exemplified by the same below) comprise a connecting tube section 561 for connecting with a burner, a radiant tube section 562 which is bent and extended from one end of the connecting tube section 561, and a heat exchange tube section 563 which is formed by extending and bending from one end of the radiant tube section 562; the radiant tube sections 562 correspond to the gaps 300 provided between the n rows of jet nozzles in the high temperature jet bellows 54 to form an alternating jet and radiant configuration.
Preferably, the buffer cavity and the high-temperature air injection bellows are of an integrated structure.
Preferably, the diameter of the jet nozzle is 1/10-1/5 of the distance from the jet nozzle to the strip steel.
Preferably, the jet nozzle adopts a round hole structure.
Preferably, the radiant tube adopts a space four-stroke structure to form four sections of tube sections which are arranged in parallel, wherein one of the tube sections is a radiant tube section, and the rest is a connecting tube section and a heat exchange tube section.
Example 1
A process for preparing high-strength steel strip includes such steps as unwinding the strip steel whose main chemical component (mass%) is 0.165-0.39-2.4% Mn, welding, passing through entrance loop, washing, spraying straight fire, preheating to 365 deg.C, heating to 665 deg.C, heating radiant tube to 820 deg.C, passing through muffle furnace, air-jet radiating for composite soaking at 820 deg.C for 60 seconds, slow cooling to 756 deg.C, water quenching to room temp., heating to 220 deg.C by reheating section, passing through moving channel section, passing through overageing section at about 220 deg.C, air-jet cooling to 140 deg.C, water cooling to room temp., passing through intermediate loop, strong tension straightening, passing through exit loop, finishing and coiling. The yield strength of the final product is 1298MPa, the tensile strength is 1513MPa, and the breaking elongation is 4%.
Example 2
The preparation of the high-strength steel strip steel has the production line arrangement shown in fig. 5, and the main chemical components (mass%) of the substrate are: uncoiling, welding, passing an inlet loop through strip steel with 0.08% of C-0.19% of Si-2.0% of Mn, cleaning, spraying direct fire, preheating to 366 ℃, heating to 665 ℃ by direct fire, heating to 825 ℃ by a radiant tube, heating to 865 ℃ by transverse magnetic induction, carrying out air jet radiation composite soaking for 60 seconds at 865 ℃, slowly cooling to 730 ℃, cooling aerosol to 280 ℃, carrying out balanced heat preservation at 280 ℃ through a reheating section (without investment of a reheating function), entering an overaging section through a moving channel, carrying out overaging treatment at 280 ℃, finally carrying out air jet cooling to about 140 ℃, carrying out final water cooling to room temperature, carrying out pickling treatment, then carrying out flash galvanization, entering an intermediate loop, flattening, entering an outlet loop, carrying out coiling after finishing, and completing production. The yield strength of the final product strip steel is 923MPa, the tensile strength is 1102MPa, and the breaking elongation is 14%.
Example 3
A process for preparing high-strength steel strip includes such steps as uncoiling the strip steel whose main chemical component (mass%) is 0.15-1.8% Si-2.3% Mn, welding, passing through entrance loop, washing, spraying straight fire to 360 deg.C, heating to 710 deg.C, heating radiant tube to 810 deg.C, transverse magnetic induction heating to 875 deg.C, air-jet radiating to 875 deg.C for 80 seconds, slow cooling to 675 deg.C, high-hydrogen cooling to 230 deg.C, heating to 410 deg.C, heat preserving at 410 deg.C, heating to 460 deg.C again, immersing in zinc pot for hot galvanizing, alloying to 515 deg.C at 510 deg.C for 20 seconds, cooling to room temperature, cooling to intermediate loop, levelling and surface of plated layer, and winding. The yield strength of the final product strip steel is 712MPa, the tensile strength is 1010MPa, and the breaking elongation is 21%.
Example 4
A process for preparing high-strength steel strip includes such steps as uncoiling the strip steel whose main chemical component (mass%) is 0.10-0.18% Si-1.90% Mn, welding, passing through entrance loop, washing, spraying straight fire, preheating to 353 deg.C, heating to 665 deg.C, heating to 800 deg.C, transverse magnetic induction heating to 830 deg.C, air-jet radiating for composite soaking at 830 deg.C for 60 seconds, slow cooling to 755 deg.C, water quenching to room temp., pickling, reheating to 220 deg.C, passing through balanced heat-insulating segment, secondary reheating segment (no need of heating), moving channel, passing through overageing segment, air-jet cooling to 140 deg.C, cooling to room temp., passing through intermediate loop, levelling, pulling and straightening, passing through exit loop, and coiling. The yield strength of the final product strip steel is 985MPa, the tensile strength is 1207MPa, and the elongation at break is 12%.
Example 5
A process for preparing high-strength steel strip includes such steps as uncoiling the strip steel whose main chemical component (mass%) is 0.15-0.38-2.2-0% Mn, welding, passing through entrance loop, washing, spraying direct fire, preheating to 373 deg.C, heating to 665 deg.C, heating radiant tube to 820 deg.C, passing through muffle furnace, spraying air, immersing in heat for 60 seconds, slow cooling to 675 deg.C, cooling to room temp. by aerial fog, pickling, plating nickel, heating to 380 deg.C, balancing heat-insulating segment at 380 deg.C, immersing in zinc pot at 460 deg.C for hot galvanizing, controlling the weight of plated layer by air knife, alloying at about 500 deg.C for 20 seconds, cooling to 140 deg.C, cooling to room temp. finally, entering in intermediate loop, levelling, entering in exit loop, finishing and coiling. The yield strength of the final product is 1078MPa, the tensile strength is 1287MPa, and the breaking elongation is 5%.
The invention has realized the industrial application, and the production line that the invention gives can produce many kinds of, multi-grade ultra-high strength steel, have superior market suitability, under the situation that the demand of ultra-high strength steel increases day by day, can meet the steel factory and develop and produce the demand of many ultra-high strength steel fast, therefore, have very broad market application prospect.
Claims (10)
1. A flexible cold-rolled strip steel post-treatment line suitable for producing various high-strength steels is characterized by sequentially comprising the following stations: uncoiling, welding, inlet looping, cleaning, central continuous post-treatment, intermediate looping, flattening, outlet looping, finishing and coiling; wherein,
the central continuous post-treatment station sequentially comprises a jet direct-fire preheating section, a direct-fire heating section, a radiant tube heating section or a jet-radiation composite heating section, a selectable transverse magnetic induction heating section or a muffle section, a jet-radiation composite soaking section, a slow cooling section, a quick cooling section, a reheating section, a (furnace nose section+zinc pot section+air knife section+alloying heating section+alloying soaking section+post-plating cooling section) and (moving channel section+overaging section+final jet cooling section), a final water cooling section, and a selectable pickling section and flash plating section;
The rapid cooling section comprises a high hydrogen cooling section and/or an aerosol cooling section and/or a water quenching cooling section.
2. The post-treatment line for flexible cold-rolled steel strip suitable for producing various high-strength steels according to claim 1, wherein optional withdrawal and straightening stations and/or surface post-treatment stations such as passivation or fingerprint resistance are arranged between the flattening station and the outlet looper station.
3. The post-treatment line for flexible cold-rolled steel strip suitable for producing various high-strength steels according to claim 1 or 2, wherein the muffle section is provided with sealing devices at the front and back, and is further provided with an atmosphere adjusting device capable of independently adjusting and controlling the hydrogen content, the oxygen content and the dew point in the muffle section.
4. A flexible cold-rolled strip steel post-treatment line suitable for producing a plurality of high-strength steels according to claim 1, 2 or 3, wherein an equalizing heat-preserving section is arranged between the reheating section and the furnace nose section, and the equalizing heat-preserving section is connected with the furnace nose section and the moving channel section.
5. The post-treatment line for flexible cold-rolled steel strip suitable for producing various high-strength steels according to claim 1, 2, 3 or 4, wherein a mobile post-plating quick cooling section is arranged between the air knife section and the post-plating cooling section, and the mobile post-plating quick cooling section and the alloying heating section are arranged in parallel; preferably, a mobile plating post-quick cooling section is arranged within a range of 10 meters above the air knife section; more preferably, the mobile post-plating rapid cooling section adopts a mobile jet rapid cooling section or a mobile aerosol cooling section.
6. The flexible cold rolling post-treatment production line suitable for producing various high-strength strip steels according to claim 4 or 5, wherein a secondary reheating section is arranged after the equalizing heat-preserving section, and the secondary reheating section is connected with the furnace nose section and the moving channel section.
7. The flexible cold rolling post-treatment production line suitable for producing various high-strength strip steels according to any one of claims 1 to 6, wherein an acid washing section is arranged between the rapid cooling section and the reheating section, and the acid washing section equipment comprises an acid washing unit, a hot water scrubbing unit, a hot water rinsing unit and a hot air drying unit.
8. The flexible cold rolling finishing line suitable for producing various high strength steel strips according to any one of claims 1 to 7, characterized in that a flash iron or nickel plating stage is arranged after the pickling stage and before the reheating stage.
9. Injection direct fire preheating device for a flexible cold rolling post-treatment line suitable for producing a plurality of high-strength strip steels according to any one of claims 1 to 8, characterized by comprising: a direct fire furnace and a preheating furnace; wherein,
the direct fire includes:
a furnace shell, the upper end and the lower end of which are respectively provided with a furnace top roller chamber and a furnace bottom roller chamber; steering rollers are respectively arranged in the furnace top roller chamber and the furnace bottom roller chamber; a plurality of direct-fire heating areas are arranged in the furnace shell along the height direction, and a plurality of direct-fire burners are arranged in the direct-fire heating areas; the side wall of the upper part of the furnace shell is provided with at least two through holes which are symmetrically arranged left and right;
The preheating furnace comprises:
the side wall of the upper part of the furnace body is provided with at least two connecting holes which are symmetrically arranged left and right and are respectively connected with the through holes on the upper part of the furnace shell of the direct-fired furnace through communicating pipes; the top end of the furnace body is provided with a furnace throat which corresponds to the furnace top roller chamber of the direct furnace and is used for the strip steel to pass through; the bottom of the furnace body is provided with a strip steel inlet, a corresponding sealing device and a corresponding steering roller; an upper partition plate with a through hole is arranged at the upper part in the furnace body to form an upper gas collection chamber of the direct-fire waste gas; a direct-fire combustion waste gas secondary combustion chamber is arranged below the upper gas collection chamber of the direct-fire waste gas, and at least one open-fire burner is arranged in the direct-fire combustion waste gas secondary combustion chamber; preferably, a combustion waste gas thermometer is further arranged in the direct-fired combustion waste gas secondary combustion chamber; a lower partition plate with a penetrating hole is arranged at the lower part in the furnace body to form a lower straight fire waste gas collecting chamber, and the lower straight fire waste gas collecting chamber is connected with a waste gas fan through a waste gas discharge pipeline; a control valve is arranged on the waste gas discharge pipeline;
the heat exchange and air injection bellows units are arranged on two sides below the direct-fired combustion waste gas secondary combustion chamber in the furnace body along the height direction of the furnace body, and a strip penetrating channel for strip steel to pass through is formed in the middle of the heat exchange and air injection bellows units; each heat exchange and air injection bellows unit comprises,
the air box body is vertically provided with a plurality of heat exchange tubes, and a plurality of nozzles are arranged on one side surface of the air box body, which is opposite to the threading channel; an exhaust gas secondary mixing chamber communicated with the heat exchange tube is arranged between the upper and lower bellows bodies; introducing nitrogen and hydrogen protective gas into the bellows body;
The port of the inlet pipeline of the circulating fan is arranged in the threading channel, and the port of the outlet pipeline of the circulating fan is positioned in the bellows body;
the sealing devices are respectively arranged at the upper and lower ports of the threading channel and the threading holes of the upper and lower partition plates; preferably, the sealing device is of a nitrogen sealing structure, a nitrogen sealing chamber is adopted, and a nitrogen injection pipeline is arranged on the sealing device.
10. A jet-radiation composite heating/soaking apparatus for a flexible cold rolling post-treatment line suitable for producing a plurality of high-strength strip steels according to any one of claims 1 to 8, characterized by comprising:
the furnace body is internally provided with a composite heating body along the height direction; the composite heating body comprises a plurality of heating elements,
the inner wall of the shell of the heat preservation box body is provided with a heat preservation material; a mounting hole is arranged in the center of one side surface of the heat preservation box body;
the circulating fan is arranged at the mounting hole of the heat insulation box body, the air suction inlet of the circulating fan corresponds to the axis of the mounting hole, and the air outlet is arranged on the side surface of the shell;
the buffer cavity is arranged in the insulation box body at a position corresponding to the air suction opening of the circulating fan, the back surface of the buffer cavity is provided with a hot air outlet corresponding to the air suction opening of the circulating fan, and the front surface of the buffer cavity is provided with a hot air inlet; preferably, the buffer cavity and the high-temperature air injection bellows are of an integrated structure;
The two high-temperature air jet bellows are vertically and symmetrically arranged at two sides of a hot air inlet at the front side of the buffer cavity in the heat insulation box body to form a strip penetrating channel for strip steel to pass through; a plurality of rows of jet nozzles are arranged on one side surface of the two high-temperature jet bellows at two sides of the threading channel at intervals along the height direction, and a gap is arranged between n rows of jet nozzles, wherein n is more than or equal to 1; preferably, the diameter of the jet nozzle is 1/10-1/5 of the distance from the jet nozzle to the strip steel; more preferably, the jet nozzle adopts a round hole structure;
the radiant tubes are symmetrically arranged in the two high-temperature air injection bellows and comprise a connecting tube section for connecting a burner, a radiant tube section bent and extended from one end of the connecting tube section and a heat exchange tube section formed by extending and bending from one end of the radiant tube section; the radiant tube section corresponds to gaps arranged between n rows of jet nozzles in the high-temperature jet bellows, so as to form a jet-radiation alternating structure; preferably, the radiant tube section, the connecting tube section and the heat exchange tube section of the radiant tube are arranged in parallel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211122669.9A CN117737635A (en) | 2022-09-15 | 2022-09-15 | Flexible cold-rolled strip steel post-treatment line suitable for producing various high-strength steel |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211122669.9A CN117737635A (en) | 2022-09-15 | 2022-09-15 | Flexible cold-rolled strip steel post-treatment line suitable for producing various high-strength steel |
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