Cold rolling, galvanizing and continuous annealing dual-purpose annealing furnace and process

Abstract

A preheating section, a heating section, a soaking section, a rapid cooling section, an overaging section, a final cooling section, a hot tensioning roller chamber, an outlet zinc nose, a zinc pot, an ascending cooler, a descending cooler, a water quenching tank and a squeezing and hot air dryer are sequentially arranged in the furnace in the advancing direction of strip steel. According to the heat treatment process furnace profile, common cold plate coils and coated plate coils can be produced, the processing capacity of a unit is improved, the use cost of the unit is reduced, rapid switching in the production process of the common cold plate coils and the coated plate coils is achieved, and the requirements of the market for different products are rapidly responded.

Description

Technical Field

[0001] The invention relates to the technical field of cold-rolled carbon steel annealing furnaces, and in particular to a cold-rolled galvanized and annealed dual-purpose annealing furnace and a process thereof. Background Art

[0002] At present, ordinary cold rolled coils and coated coils account for the largest proportion of cold rolled ordinary carbon steel production. Currently, carbon steel continuous annealing units and continuous hot dip galvanizing units are commonly used to produce ordinary cold rolled coils and coated coils respectively. The investment and use costs of the units are high and they occupy a large area. Therefore, how to achieve efficient production of carbon steel ordinary cold rolled coils and coated coils, improve the processing capacity of the units, and reduce the use cost of the units is a problem that needs to be solved urgently.

[0003] Conventional continuous galvanizing machine annealing furnace includes the following processes: preheating → heating → soaking → cooling → equalization → galvanizing → air cooling → water quenching; conventional continuous annealing furnace includes the following processes: preheating → heating → soaking → primary cooling → aging → secondary cooling → water quenching. Comparing the processes of the two annealing furnaces, it is found that the first half of the annealing furnace is the same.

[0004] At present, many dual-purpose units have been built in China, but their process routes all add bypass pipes in the galvanizing section. In the galvanizing mode, production is carried out directly through the galvanizing section; in the continuous annealing mode, it is necessary to bypass the galvanizing section to enter the aging section and final cooling section for production. The switching procedure between the two modes of this process is relatively complicated, and the switching time is very long, estimated to be between 72h-96h, which makes it difficult to respond quickly to market changes.

[0005] Chinese patent CN101532119B discloses a device and process for dual-use production of hot-dip galvanizing and continuous annealing. An over-aging section and a secondary cooling section are added to the existing continuous vertical furnace hot-dip galvanizing unit, while retaining the complete existing continuous hot-dip galvanizing unit inlet section equipment, vertical annealing furnace and subsequent galvanizing and post-galvanizing cooling equipment, and outlet section equipment, so that the modified unit can produce both hot-dip galvanized sheets and annealed general sheets. However, there is a switching channel between the galvanizing process and the continuous annealing process, which requires more than three days of switching time. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a cold-rolled galvanized continuous annealing furnace and process for the above-mentioned problems, reasonably arrange the furnace sections after cooling, and complete the co-line of the two processes.

[0007] The embodiment of the present application is implemented as follows:

[0008] The embodiment of the present application provides a cold-rolling, galvanizing and annealing dual-purpose annealing furnace, characterized in that a preheating section, a heating section, a soaking section, a rapid cooling section, an aging section, a final cooling section, a hot tensioning roller chamber, an outlet zinc nose, a zinc pot, an upward cooler, a downward cooler, a water quenching tank, a squeezer and a hot air dryer are arranged in sequence along the traveling direction of the strip in the furnace.

[0009] In some optional embodiments, a slow cooling section is provided between the soaking section and the fast cooling section.

[0010] In some optional embodiments, an inlet sealing chamber and an outlet sealing chamber are respectively provided at the inlet of the preheating section and the outlet of the final cooling section. The inlet sealing chamber and the outlet sealing chamber are both provided with sealing rollers, and nitrogen is introduced to isolate the atmosphere inside and outside the furnace.

[0011] A method for using a cold-rolling, galvanizing and annealing annealing furnace, characterized in that it comprises the following steps:

[0012] Step 1, continuous retreat mode:

[0013] The strip enters the annealing furnace through the entrance sealing chamber, is preheated in the preheating section, and then enters the heating section and the soaking section to heat the strip to the annealing temperature and keep it warm for a period of time to complete the recrystallization annealing; then the strip enters the slow cooling section and the fast cooling section to cool the strip to the over-aging temperature according to the annealing curve requirements, and then enters the over-aging section for the corresponding aging reaction, and then enters the final cooling section to cool the strip to the furnace discharge temperature, and then the strip passes through the exit sealing chamber to discharge. In the case of continuous annealing mode, the exit sealing roller is closed, and sealed nitrogen is introduced to isolate the atmosphere inside and outside the furnace; the strip after discharge passes through the hot tension roller chamber and the exit zinc nose, and enters the post-plating cooling tower. At this time, the zinc pot is lowered and withdraws from the working position. The strip passes through the upward cooler and the downward cooler in the cooling tower to be cooled to an appropriate temperature. In the case of continuous annealing mode, the water quenching tank, squeeze dryer and hot air dryer are not put into use;

[0014] Step 2, galvanizing mode:

[0015] The strip enters the annealing furnace through the entrance sealing chamber, is preheated in the preheating section, and then enters the heating section and the soaking section to heat the strip to the annealing temperature and keep it warm for a period of time to complete the recrystallization annealing; then the strip enters the slow cooling section and the fast cooling section to cool the strip to the zinc pot temperature according to the annealing curve requirements, and then enters the over-aging section. In the galvanizing mode, the electric heating set in this section is fully turned on to balance the strip, and then enters the final cooling section. In the galvanizing mode, all the circulating cooling fans in this section are turned off, and the electric radiation tube or the corresponding electric heating is turned on for further balancing, and then the strip The steel passes through the outlet sealing chamber and exits the furnace; in the galvanizing mode, the outlet sealing roller is opened and the nitrogen is stopped, and then the strip passes through the hot tension roller chamber and the outlet zinc nose to enter the zinc pot to complete the coating, and then enters the post-galvanizing cooling tower. In the galvanizing mode, the zinc pot rises and reaches the working position to complete the coating of the strip. Then the strip passes through the upward cooler and the downward cooler in the post-galvanizing cooling tower to cool to a certain temperature according to the process curve. In the galvanizing mode, the water quenching tank, the squeezer and the hot air dryer are put into use, the strip is further cooled in the water quenching tank, and then the moisture on the surface of the strip is removed through the squeezer and the hot air dryer.

[0016] In some optional implementation schemes, the preheating temperature of the strip in the preheating section in the continuous annealing mode and the galvanizing mode is 150°C to 180°C.

[0017] In some optional embodiments, the duration of the aging reaction in the over-aging section in the continuous aging mode is greater than or equal to 60 seconds.

[0018] In some optional embodiments, the furnace exit temperature in the continuous retreat mode is less than or equal to 190°C.

[0019] In some optional embodiments, the temperature of the strip steel in the continuous annealing mode after being cooled in a cooling tower is less than or equal to 45°C.

[0020] In some optional embodiments, the temperature of the strip steel in the galvanized mode after being cooled by an upper cooler and a lower cooler in a cooling tower is less than or equal to 170°C.

[0021] In some optional embodiments, the temperature of the strip steel in the galvanizing mode after cooling in the water quenching tank is less than or equal to 45°C.

[0022] The beneficial effects of the present application are as follows: the present application provides a cold-rolled galvanized continuous annealing dual-purpose annealing furnace and process, which can realize the heat treatment process furnace type for producing both ordinary cold-rolled coils and coated coils, improve the processing capacity of the unit, reduce the use cost of the unit, realize rapid switching between the production process of ordinary cold-rolled coils and coated coils, and quickly respond to market demand for different products. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 This is a schematic diagram of the layout of the annealing furnace of an embodiment of the present application. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0027] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0028] The features and performance of the present application are further described in detail below in conjunction with the embodiments.

[0029] like Figure 1 As shown, an embodiment of the present invention provides a cold-rolling, galvanizing and annealing dual-purpose annealing furnace, in which a preheating section 1, a heating section 2, a soaking section 3, a quick cooling section 4, an aging section 5, a final cooling section 6, a hot tensioning roller chamber 7, an outlet zinc nose 8, a zinc pot 9, an upward cooler 10, a downward cooler 11, a water quenching tank 12 and a squeeze and hot air dryer 13 are arranged in sequence along the traveling direction of the strip.

[0030] In some optional embodiments, a slow cooling section 14 may or may not be provided between the soaking section and the fast cooling section.

[0031] An inlet sealing chamber 15 and an outlet sealing chamber 16 are respectively provided at the inlet of the preheating section and the outlet of the final cooling section. Sealing rollers are provided in the inlet sealing chamber and the outlet sealing chamber, and nitrogen is introduced to isolate the atmosphere inside and outside the furnace. The closing and opening of the sealing rollers are controlled by a cylinder to clamp and seal the strip, and the atmosphere inside and outside the annealing furnace is isolated by controlling the introduction of nitrogen.

[0032] Conventional continuous galvanizing machine annealing furnace includes the following processes: preheating → heating → soaking → cooling → equalization → galvanizing → air cooling → water quenching; conventional continuous annealing furnace includes the following processes: preheating → heating → soaking → primary cooling → aging → secondary cooling → water quenching. Comparing the processes of the two annealing furnaces, it is found that the first half of the annealing furnace is the same. As long as the cooling sections are reasonably arranged, the two processes can be realized in the same line.

[0033] The co-production of the two processes is achieved through the following scheme:

[0034] 1. Continuous retreat mode:

[0035] The strip enters the annealing furnace through the entrance sealing chamber, is preheated in the preheating section, and then enters the heating section and the soaking section to heat the strip to the annealing temperature and keep it warm for a period of time to complete the recrystallization annealing; then the strip enters the slow cooling section and the fast cooling section to cool the strip to the over-aging temperature according to the annealing curve requirements, and then enters the over-aging section for the corresponding aging reaction, and then enters the final cooling section to cool the strip to the furnace discharge temperature, and then the strip passes through the exit sealing chamber to discharge. In the case of continuous annealing mode, the exit sealing roller is closed, and sealed nitrogen is introduced to isolate the atmosphere inside and outside the furnace; the strip after discharge passes through the hot tensioning roller chamber and the exit zinc nose, and enters the post-plating cooling tower. At this time, the zinc pot is lowered and exits the working position. The strip is cooled to an appropriate temperature through the ascending cooler and the descending cooler in the cooling tower. In the continuous annealing mode, the water quenching tank, the squeeze dryer and the hot air dryer are not put into use.

[0036] 2. Galvanizing mode:

[0037] The strip enters the annealing furnace through the entrance sealing chamber, is preheated in the preheating section, and then enters the heating section and the soaking section to heat the strip to the annealing temperature and keep it warm for a period of time to complete the recrystallization annealing; then the strip enters the slow cooling section and the fast cooling section to cool the strip to the zinc pot temperature according to the annealing curve requirements, and then enters the over-aging section. In the galvanizing mode, the electric heating set in this section is fully turned on to balance the strip, and then enters the final cooling section. In the galvanizing mode, all the circulating cooling fans in this section are turned off, and the electric radiation tube or the corresponding electric heating is turned on for further balancing, and then the strip The steel passes through the outlet sealing chamber and exits the furnace; in the galvanizing mode, the outlet sealing roller is opened and the nitrogen is stopped, and then the strip passes through the hot tension roller chamber and the outlet zinc nose to enter the zinc pot to complete the coating, and then enters the post-galvanizing cooling tower. In the galvanizing mode, the zinc pot rises and reaches the working position to complete the coating of the strip. Then the strip passes through the upward cooler and the downward cooler in the post-galvanizing cooling tower to cool to a certain temperature according to the process curve. In the galvanizing mode, the water quenching tank, the squeezer and the hot air dryer are put into use, the strip is further cooled in the water quenching tank, and then the moisture on the surface of the strip is removed through the squeezer and the hot air dryer.

[0038] Example 1

[0039] Continuous annealing mode: The strip enters the annealing furnace through the entrance sealing chamber, and the entrance seal is used to isolate the atmosphere inside and outside the furnace. After the strip enters the furnace, it is preheated to 150℃~180℃ in the preheating section, and then enters the heating section and the soaking section to heat the strip to the annealing temperature and keep it warm for a period of time to complete the recrystallization annealing; then the strip enters the slow cooling section and the fast cooling section to cool the strip to the over-aging temperature according to the annealing curve requirements. Then it enters the over-aging section for the corresponding aging reaction, and the aging time is generally controlled at ≥60s. Then it enters the final cooling section to cool the strip to a temperature that can be discharged from the furnace, generally ≤190℃. Then the strip passes through the exit sealing chamber and exits the furnace. In the case of the continuous annealing mode, the exit sealing roller is closed by the cylinder, and sealed nitrogen is introduced to isolate the atmosphere inside and outside the furnace. After leaving the furnace, the strip passes through the hot tension roller chamber and the exit zinc nose and enters the post-plating cooling tower.

[0040] In the continuous withdrawal mode, the zinc pot (with lifting function) is lowered and withdrawn from the working position. The strip is cooled to ≤45℃ in the cooling tower through the upward cooler and the downward cooler.

[0041] In the continuous retreat mode, the water quenching tank, squeezer and hot air dryer are not put into use.

[0042] Galvanizing mode: The strip enters the annealing furnace through the entrance sealing chamber. The entrance sealing is used to isolate the atmosphere inside and outside the furnace. After the strip enters the furnace, it is preheated to 150℃~180℃ in the preheating section, and then enters the heating section and the soaking section to heat the strip to the annealing temperature and keep it warm for a period of time to complete the recrystallization annealing; then the strip enters the slow cooling section and the fast cooling section to cool the strip to the zinc pot temperature according to the annealing curve. Then it enters the over-aging section. In the galvanizing mode, the electric heating set in this section is fully turned on to balance the strip. Then it enters the final cooling section. In the galvanizing mode, all the circulating cooling fans in this section are turned off, and the electric radiation tube or the corresponding electric heating is turned on for further balancing. Then the strip passes through the exit sealing chamber and leaves the furnace. In the galvanizing mode, the exit sealing roller is opened by the cylinder, and the sealing nitrogen is stopped. Then the strip passes through the hot tension roller chamber and the exit zinc nose and enters the post-galvanizing cooling tower. In the galvanizing mode, the zinc pot (with lifting function) rises to the working position to complete the coating of the strip. Then the strip is cooled in the post-galvanizing cooling tower through the upward cooler and the downward cooler according to the process curve, generally cooled to a temperature of ≤170℃ before entering the water quenching tank.

[0043] In the galvanizing mode, the water quenching tank, squeezer and hot air dryer are put into use. The strip is further cooled in the water quenching tank to ≤45°C, and then the moisture on the strip surface is removed by squeezing and hot air drying.

Claims

1. A cold rolling and galvanizing annealing furnace, characterized in that: In the furnace, the preheating section, heating section, soaking section, quick cooling section, aging section, final cooling section, hot tensioning roller room, outlet zinc nose, zinc pot, upward cooler, downward cooler, water quenching tank, squeezer and hot air dryer are arranged in sequence along the direction of strip travel.

2. The cold-rolling, galvanizing and annealing annealing furnace according to claim 1, characterized in that: A slow cooling section is provided between the soaking section and the fast cooling section.

3. A cold rolling and galvanizing annealing furnace according to claim 1 or 2, characterized in that: An inlet sealing chamber and an outlet sealing chamber are respectively provided at the inlet of the preheating section and the outlet of the final cooling section. The inlet sealing chamber and the outlet sealing chamber are both provided with sealing rollers and nitrogen is introduced to isolate the atmosphere inside and outside the furnace.

4. A method for using the cold-rolling, galvanizing and annealing annealing furnace according to claim 3, characterized in that: The steps include: Step 1, continuous retreat mode: The strip enters the annealing furnace through the entrance sealing chamber, is preheated in the preheating section, and then enters the heating section and the soaking section to heat the strip to the annealing temperature and keep it warm for a period of time to complete the recrystallization annealing; then the strip enters the slow cooling section and the fast cooling section to cool the strip to the over-aging temperature according to the annealing curve requirements, and then enters the over-aging section for the corresponding aging reaction, and then enters the final cooling section to cool the strip to the furnace discharge temperature, and then the strip passes through the exit sealing chamber to discharge. In the case of continuous annealing mode, the exit sealing roller is closed, and sealed nitrogen is introduced to isolate the atmosphere inside and outside the furnace; the strip after discharge passes through the hot tension roller chamber and the exit zinc nose, and enters the post-plating cooling tower. At this time, the zinc pot is lowered and withdraws from the working position. The strip passes through the upward cooler and the downward cooler in the cooling tower to be cooled to an appropriate temperature. In the case of continuous annealing mode, the water quenching tank, squeeze dryer and hot air dryer are not put into use; Step 2, galvanizing mode: The strip enters the annealing furnace through the entrance sealing chamber, is preheated in the preheating section, and then enters the heating section and the soaking section to heat the strip to the annealing temperature and keep it warm for a period of time to complete the recrystallization annealing; then the strip enters the slow cooling section and the fast cooling section to cool the strip to the zinc pot temperature according to the annealing curve requirements, and then enters the over-aging section. In the galvanizing mode, the electric heating set in this section is fully turned on to balance the strip, and then enters the final cooling section. In the galvanizing mode, all the circulating cooling fans in this section are turned off, and the electric radiation tube or the corresponding electric heating is turned on for further balancing, and then the strip The steel passes through the outlet sealing chamber and exits the furnace; in the galvanizing mode, the outlet sealing roller is opened and the nitrogen is stopped, and then the strip passes through the hot tension roller chamber and the outlet zinc nose to enter the zinc pot to complete the coating, and then enters the post-galvanizing cooling tower. In the galvanizing mode, the zinc pot rises and reaches the working position to complete the coating of the strip. Then the strip passes through the upward cooler and the downward cooler in the post-galvanizing cooling tower to cool to a certain temperature according to the process curve. In the galvanizing mode, the water quenching tank, the squeezer and the hot air dryer are put into use, the strip is further cooled in the water quenching tank, and then the moisture on the surface of the strip is removed through the squeezer and the hot air dryer.

5. The method for using a cold-rolling, galvanizing and annealing annealing furnace according to claim 3, characterized in that: The preheating temperature of the strip steel in the preheating section in the continuous annealing mode and the galvanizing mode is both 150°C to 180°C.

6. A cold rolling and galvanizing annealing furnace according to claim 3 or 4, characterized in that: The duration of the aging reaction in the over-aging stage in the continuous retreat mode is greater than or equal to 60 seconds.

7. The cold rolling and galvanizing annealing furnace according to claim 6, characterized in that: The furnace exit temperature in the continuous retreat mode is less than or equal to 190°C.

8. The cold-rolling, galvanizing and annealing annealing furnace according to claim 7, characterized in that: The temperature of the strip steel in the continuous annealing mode after being cooled in the cooling tower is less than or equal to 45°C.

9. The cold-rolling, galvanizing and annealing annealing furnace according to claim 8, characterized in that: The temperature of the strip steel in the galvanizing mode after being cooled by the ascending cooler and the descending cooler in the cooling tower is less than or equal to 170°C.

10. The cold rolling and galvanizing annealing furnace according to claim 9, characterized in that: The temperature of the strip steel in the galvanizing mode after cooling in the water quenching tank is less than or equal to 45°C.

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