WO2010097042A1

WO2010097042A1 - Flexible strip steel processing line suitable for producing various kinds of high-strength steels

Info

Publication number: WO2010097042A1
Application number: PCT/CN2010/070741
Authority: WO
Inventors: 李俊; 粱轩; 胡广魁; 王劲; 向顺华; 朱晓东; 刘华飞; 熊伟; 刘益民
Original assignee: 宝山钢铁股份有限公司
Priority date: 2009-02-25
Filing date: 2010-02-25
Publication date: 2010-09-02
Also published as: JP5670920B2; KR101395047B1; BRPI1008466B1; JP2012518720A; RU2519458C2; CN101812579B; CN101812579A; KR20110117253A; BRPI1008466A2; RU2011139833A

Abstract

Flexible strip steel processing line suitable for producing various kinds of high-strength steels, includes decoiling and cleaning, heating, soaking and slowly cooling stations in turn，and then arranging high hydrogen jet cooling station and water quenching station in parallel; the high hydrogen jet cooling station is followed by reheating, overaging, final cooling, leveling up, finishing station, oil coating and batching station; the water quenching station is followed in turn by pickling station, electroplating station；the hot galvanizing station is arranged behind the reheating station；the galvannealing station is arranged behind the hot galvanizing station, and is connected with the final cooling station by setting connection pipeline；the pickling station and electroplating station separately connect with reheating station by connection pipeline；the electroplating station directly connects with decoiling and cleaning station by connection pipeline；the water quenching station connects with slowly cooling station by fixed bypass line; reheating station connects with overaging station by movable bypass line. The processing line realizes flexible production by production of various high strength steels to form an assembling unit.

Description

Flexible strip processing line suitable for producing various high strength steels

Technical field

The invention relates to strip heat treatment and surface treatment technology, in particular to a flexible strip processing line suitable for producing various high-strength steels. Background technique

Protecting the environment and achieving sustainable development have become the consensus of humanity in the 21st century. With the development of the modern automobile industry, weight reduction and energy conservation have become the trend of the times. The results of automotive lightweight research show that in order to achieve the goal of “weight reduction, energy saving, and emission reduction”, the automotive industry must use high-strength steel in large quantities to reduce the thickness of the steel used. Therefore, the demand for high-strength cold-rolled sheets and hot-dip galvanized sheets has been greatly increased.

The high-strength cold-rolled sheet is produced by a continuous annealing unit with a rapid cooling device. To achieve a strength of 980 MPa class or higher and excellent subsequent processing performance, the continuous annealing unit must be equipped with water quenching, aerosol cooling or high-hydrogen jet cooling. For rapid cooling devices, the main processes for continuous annealing are:

Unwinding, cleaning, heating, heating, soaking, cooling, cooling, one (sour washing), one (reheating), one-time aging (tempering), one cooling, one leveling, one finishing, one high-strength cold-rolled sheet

The continuous annealing process is to heat the unrolled cleaned cold-rolled steel strip to a certain temperature for a period of time, and after cooling to a certain temperature, it is cooled to a room temperature or an overaging temperature in a rapid cooling device at a rapid cooling rate.

Water quenching is the fastest cooling method at present, and it is also a cheaper method for producing high-strength steel. It can also produce high-strength two-phase, multi-phase and martensitic high strength by adding a small amount of alloying elements. Steel, when the method is water-cooled, an oxide film is formed on the surface of the strip, which requires additional pickling. When water quenching is used, it is difficult to terminate the cooling at the overaging temperature, so the strip has to be cooled below locrc. Therefore, it is necessary to reheat to the tempering temperature for tempering to ensure the anti-aging stability of the steel strip.

When the continuous annealing process adopts the high hydrogen jet cooling method, the cooling end temperature is controllable, the strip steel does not need to be cooled to room temperature, and does not oxidize, so the strip does not need to be acid washed and directly enters overaging or reheating. After entering the aging effect, the cooling rate of the high-hydrogen jet cooling method is slower than that of the water quenching. Therefore, under the premise of adding the same alloying elements, the cold-rolled sheet produced by high-hydrogen jet cooling has a higher strength grade than water quenching. It's much lower.

High-strength hot-dip galvanized sheet is produced by continuous hot-dip galvanizing unit with rapid cooling device. In order to maximize the strength of the substrate and ensure the hot-dip galvanizing, the continuous hot-dip galvanizing unit must be equipped with a high-hydrogen rapid cooling device. Water quenching or aerosol cooling and pickling equipment, the main process of continuous hot-dip galvanizing is: Unwinding, cleaning, heating, heating, soaking, cooling, rapid cooling, one (sour washing), one (reheating), one hot-dip galvanizing (or including alloying annealing furnace), one cooling, one smoothing, one finishing, one high-strength hot-dip galvanizing board

The continuous hot-dip galvanizing process is to heat the unrolled cleaned cold-rolled strip steel to a soaking temperature, keep it for a certain period of time, and slowly cool to a certain temperature and then cool to the zinc pot temperature in a fast cooling device at a rapid cooling rate. Near or at room temperature, the water-quenched strip is also subjected to acid washing to remove the oxide film on the surface of the strip, and then reheated into the zinc pot for hot-dip galvanizing or alloying annealing, and finally cooled to the leveling and other post-treatment steps.

Since the hot-dip galvanizing of the strip must be completed at around 46 CTC, the alloying annealing treatment after hot-dip galvanizing must be completed at about 50 CTC. If a high-strength grade hot-dip galvanized sheet is produced on a conventional continuous hot-dip galvanizing line, it must be A large amount of alloying elements are added to the substrate, but this leads to the enrichment of alloying elements such as Mn and Si on the surface of the steel sheet before galvanizing, and it is impossible to obtain hot-dip galvanizing and hot-dip galvanized sheet with good surface quality. Therefore, the process of quenching water + pickling + reheating + hot-dip galvanizing (or including alloying annealing) can greatly improve the strength grade of the steel plate. On the other hand, pickling can also wash away the surface of the strip. The alloying elements ensure high-strength hot-dip galvanizing with good surface quality and its alloyed hot-dip galvanized sheet.

When using the high-hydrogen rapid cooling process, the strip steel can be directly galvanized (or include alloying annealing treatment) or reheated into the zinc pot by hot-dip galvanizing (or including plating alloying) without acid pickling. Annealing), and then cooling into a post-processing process such as leveling, but when this process is used, in order to ensure platability, too many alloying elements cannot be added, and the strength level of the finished product is low under the same chemical composition conditions. Compared with water quenching, high-hydrogen rapid cooling produces hot-dip galvanized sheets and their coated alloyed hot-dip galvanized sheets with lower strength levels.

It can be seen from the above that the production process of high-strength cold-rolled sheets and hot-dip galvanized sheets, the inlet cleaning equipment of the original board, the heating and soaking equipment for annealing, the rapid cooling and related equipment (such as water quenching and pickling) And the refining equipment, etc., the flattening of the outlet and the composition of the oiling and coiling equipment are basically the same, so that the production of the high-strength cold-rolled sheet and the hot-dip galvanized sheet can be integrated on one unit. More importantly, the market demand for high-strength cold-rolled sheets and hot-dip galvanized sheets is not very large. If the production lines for producing high-strength cold-rolled sheets and high-strength hot-dip galvanized sheets are separately constructed, Will greatly increase the investment cost, on the other hand, the production of the two units will be in an unsaturated state. At the same time, the production of high-strength steel, especially ultra-high-strength steel units, is not suitable for the production of high-quality soft steel products, but only Production of ordinary low-grade mild steel products with poor surface quality, resulting in serious waste of resources. Therefore, how to rationally arrange the equipment of each section of the unit and research and develop the switching equipment for the plate-passing plate, and integrate the production of high-strength and ultra-high-strength cold-rolled sheets and hot-dip galvanized sheets with many specifications and few quantities in the same unit. Has become more and more caused by the steel industry Highly valued.

Japanese Patent Application Laid-Open No. 2003-253413 provides a high-strength cold-rolled steel sheet and a galvanized steel sheet manufacturing apparatus and a combined manufacturing method, which can be an annealing furnace equipped with a heating section, a soaking section, and a jet cooling section. The steel plate is supplied for galvanizing equipment to produce galvanized steel sheet, that is, the galvanizing passage path. In addition, the steel sheet coming out of the annealing furnace can be supplied to the water quenching tank without passing through a galvanizing device to produce high strength. Cold-rolled steel sheet, that is, the cold-rolled bare plate channel path.

This patent is a dual-purpose manufacturing method of a galvanized sheet and a high-strength cold-rolled steel sheet characterized by two process path switching devices. In order to realize the dual-purpose manufacturing of galvanized sheet and high-strength cold-rolled sheet, the process adopted by the method includes three types: 1. The switching device between the zinc pot and the water quenching tank is directly disposed after the jet cooling section; The zinc pan and the sinking roller in the water quenching tank are lifted and lowered to realize the switching; 3. The switching is realized by injecting zinc liquid or water into the common bath of galvanizing/water quenching.

However, the main disadvantages of this patent are:

First, because the high-hydrogen jet cooling and water quenching and pickling processes with rapid cooling capacity are not used, the patented combined manufacturing method can not only produce high-strength grade cold-rolled sheets, hot-dip galvanized sheets and alloyed hot-dip galvanized sheets. Even low-strength phase-change strengthened cold-rolled sheets, hot-dip galvanized sheets and alloyed hot-dip galvanized sheets with good surface quality cannot be produced;

Secondly, since the pickling process after water quenching and the reheating and tempering process are not used, the high-strength cold-rolled sheet produced by the combined manufacturing method of the patent not only has a poor surface quality, but also has a plasticity and anti-aging stability. The process realization method of the patented dual-purpose manufacturing method is difficult to operate in actual production. When switching between the galvanized sheet and the cold-rolled sheet, the residual zinc on the roll surface will seriously affect the surface quality of the cold-rolled sheet and the unit. Normal operation, and the sharing of the zinc pot and the water quenching tank will bring many difficult technical problems and expensive switching costs such as bursting of the zinc pot. Summary of the invention

The object of the present invention is to provide a flexible strip processing line suitable for producing various high-strength steels, which can use cold-rolled hardened rolled hard materials and hot-rolled pickled sheets to produce high-strength cold-rolled sheets and heat. Plating pure zinc plate, plated alloyed hot-dip galvanized sheet and electro-galvanized and nickel plate, which can effectively utilize resources and save investment, integrate cold-rolled sheet and hot-dip galvanized sheet and alloyed hot-dip galvanized sheet on one unit And by using the connecting channel, it is also possible to produce electroplated Zn, Ni plates; it is also possible to produce ultra-high strength grade cold-rolled sheets and hot-dip galvanized sheets and alloyed hot-dip galvanized sheets; and, by using acid before hot-dip galvanizing Washing process or electroplating Fe, Ni process, The production process and equipment completely eliminate the shortcomings of high-strength steel, especially ultra-high-strength steel hot-dip galvanizing, so as to ensure good surface quality of high-strength hot-dip galvanizing and its alloyed hot-dip galvanizing products.

In order to achieve the above object, the technical solution of the present invention is

A flexible strip processing line suitable for producing various high-strength steels, the settings are as follows: in turn, unwinding cleaning, heating, soaking, slow cooling station, and then setting a high-hydrogen jet cooling station and a water quenching cooling station in parallel After the high-hydrogen jet cooling station, reheating, overaging, final cooling, leveling, finishing station and oiling, coiling station are set in turn; pickling station and plating station are set in sequence after the water quenching cooling station In addition, there is also: a hot-dip galvanizing station, connected to the reheating station; a plating alloying annealing treatment station, connected to the hot-dip galvanizing station; and connecting the final cooling device through a connecting channel The pickling station and the plating station are respectively connected to the reheating station through the connecting passage; the plating station is also directly connected to the unwinding cleaning station through the connecting passage; the water quenching cooling station The fixed bypass passage is connected to the slow cooling station; the reheating station is further connected to the overage station by providing a movable bypass passage, and the movable bypass passage is produced when the continuous product is produced. When the hot-dip galvanizing and its alloyed hot-dip galvanizing products are produced, the movable bypass passage is withdrawn, and the two interfaces exiting are sealed.

Further, the processing line is further provided with a passivation and other post-processing stations, which are respectively connected to the plating station, the leveling station, and the finishing station by connecting the connecting channels.

Moreover, the bypass passage is different from the connecting passage, and the bypass passage is a sealed passage. The atmosphere in the passage is substantially the same as the atmosphere in the annealing furnace, and is usually a nitrogen-hydrogen mixed shielding gas containing 2% to 7% of hydrogen. In addition, the high-hydrogen jet cooling section is equipped with a high-power induction heater. Preferably, the induction heater has a frequency of 1000 Hz or higher. Compared with other patents, the processing line of the present invention can control the heating rate after rapid cooling. Moreover, it does not require pickling, and can fully meet the equipment requirements of the high-strength board manufacturing process.

Further, the high-hydrogen jet-cooled gas of the present invention is a nitrogen-hydrogen mixed gas containing hydrogen of 20% by volume or more.

The flexible production process of a strip processing line suitable for producing various high-strength steels includes: stripping, cleaning, heating, soaking, slow cooling, high-hydrogen jet cooling, and part of the cooled strip It can be processed into cold-rolled high-strength steel after over-aging into cooling and leveling, and the other part can be reheated into zinc pot and plate alloying annealing furnace to produce high-strength hot-dip galvanized sheet or plated alloy hot-dip plating. Zinc plate.

Moreover, the flexible strip processing line suitable for producing various high-strength steels of the invention is subjected to unwinding, cleaning, heating, soaking, slow cooling, water quenching, and then pickling after cooling. After Heating into the zinc pot to produce hot-dip galvanized high-strength steel; also can directly enter the over-aging section to produce ultra-high-strength steel cold-rolled sheet; It can also be directly treated by electroplating Zn and Ni into passivation to produce ultra-high-strength electro-galvanized sheet; Or after electroplating extremely thin Ni, Fe, then improve the platability and then into the reheating, zinc pot and coating alloy annealing furnace and other post-process equipment to produce ultra-high strength hot-dip pure zinc and coated alloy hot-dip galvanized sheet.

In the current cold-rolled continuous heat treatment unit, high-strength plates and high-surface-quality plates (such as automobile outer plates) are usually produced at the same time, while high-strength steels, especially ultra-high-strength steels and high-surface-quality plates, have completely different surface quality requirements. . High-strength steel is generally used for automotive structural parts, so the surface quality is not high, and the outer surface of the car is extremely demanding. When a large continuous heat treatment unit produces a small amount of high-strength steel, especially ultra-high-strength steel, due to the high strength of the steel plate and the poor shape of the plate, the furnace roll is easy to be nodulated or partially scratched, so that the unit can produce high-strength steel after the production. It is not possible to produce high surface quality plates, so it is necessary to stop the replacement of the damaged furnace rolls, and the loss of the large continuous heat treatment furnace to replace the furnace rolls is very large, so high strength steel, especially ultra high strength steel and high surface quality plate The production organization of the same unit caused great difficulties.

In terms of specifications, high surface quality plates represented by automobile outer panels are generally wider, but thinner in thickness, while high-strength steels, especially ultra-high-strength steels, are generally thicker but narrower. When designing a continuous heat treatment unit with both products in mind, the technical difficulty is high, the unit is complex and large, and the investment is inevitably large.

There are also different requirements for the cooling technology of the furnace. The unit for producing high surface quality plates does not require high cooling rate of the furnace, but it has high requirements for the high-speed stable plate technology for preventing buckling and broken belts at high temperatures. The tension required for each furnace section is low and stable. The unit that produces high-strength steel has high requirements on the cooling rate of the fast cooling section of the furnace, and the high-strength steel with thick and narrow specifications is easy to run off. The strip shape is worse and the deviation is more serious after the strip cold-phase transformation. Therefore, the tension of each furnace section of the unit is required to be large and the requirements for correcting the deviation are high.

The requirements for the leveling machine are also different. For products with high surface quality requirements, in addition to the control of material properties and the improvement of the shape of the plate, the improvement and improvement of the surface quality is extremely important, so it is required to have a larger Flat work roll diameter and large rolling force. However, the high yield strength of high-strength steel products, the excessively large roll diameter of the smoothing work rolls will greatly increase the rolling force of the leveling machine, increase the power consumption and investment of the leveling machine, so generally use a smaller diameter flat work roll, which is larger. The flat rolling force and tension are used to improve the shape of the high-strength steel.

In terms of specification and variety switching, high-strength steel, especially ultra-high-strength steel, due to the small amount of each type of specification, but the total variety of specifications, the continuous heat treatment unit production switching, increased transition time, which seriously affected the large Stable operation and production efficiency of continuous heat treatment units. The flexible strip processing line suitable for producing various high-strength steels has unique advantages, and has obvious outstanding features and advantages compared with existing heat treatment units:

1. The product of the invention is rich in variety.

The most common continuous annealing units can only produce popular cold products. The most common continuous hot dip galvanizing units can only produce hot-dip pure zinc and coated alloy hot-dip galvanized products. Even the recently developed de-hot galvanizing dual-purpose unit can only produce both cold and hot-dip galvanized products; and this continuous de-hot galvanizing dual-purpose unit is not targeted at high-strength steel, especially ultra-high-strength steel. Therefore, the advantages of multiple varieties are not obvious.

The flexible high-strength thin strip steel processing line of the invention is equipped with a high-hydrogen high-speed jet cooling device and a water quenching device, and is particularly suitable for the production of high-strength steel and ultra-high-strength steel with a large variety of specifications, and can not only produce Cold-rolled high-strength steel and ultra-high-strength steel of various strength grades (strength up to 1470MPa), and can produce various hot-dip galvanized high-strength steels with the highest strength grade of 980MPa, in addition to various strength grades. Electroplated zinc, electroplated nickel and its electroplated zinc-nickel alloy products. In short, the multi-functional processing line has the characteristics of multi-function and multi-variety compared with other cold-rolled strip processing lines, and can obtain a variety of high-strength steel products including hot-dip, cold-plated and electroplated with minimum investment. To meet the needs of the current automotive industry for a variety of high-strength steel varieties.

2. Low production costs.

First of all, in terms of raw materials, not only rolling hard materials are used as raw materials, but also hot-rolled pickling plates can be directly used as raw materials. Since the invention adopts a novel high-hydrogen high-speed jet cooling device and a new water quenching device, high-strength steel of the same strength grade can be used with a lower alloy content, saving alloying elements and reducing production costs, and at the same time, for steel making, hot rolling, pickling And the production requirements of the cold rolling process are reduced, the production is more stable and straightforward, and the cost is correspondingly reduced. In addition, since the flexible processing line can specifically produce various high-strength steels, the connection and transition of various high-strength steels are more convenient, while others The unit does not need to increase the investment for the production of a small amount of ultra-high-strength steel, thus liberating other units, which greatly reduces the overall production cost of the entire company;

3. The quality of the products! 3⁄4.

Since the processing line of the present invention is specifically used for processing various high-strength steel products, more effective measures can be taken for the production process requirements of high-strength steel to improve the quality of the products. For example, for the problem of low cooling rate of ordinary continuous heat treatment units, the unit adopts new high-hydrogen high-speed jet cooling and new water quenching technology to greatly increase the cooling rate, so that the alloy content of high-strength steel chemical components of the same strength grade is greatly reduced. , not only reduces the production cost but also significantly improves the splicing performance and platability of high-strength steel products. In addition, as the technique of the present invention adopts a new process of water-quenching and acid-washing and even hot-plating after electroplating, the platability of the high-strength steel is further fundamentally improved, so that the surface quality and corrosion resistance of the hot-dip galvanized high-strength steel are obtained. Significantly increased. BRIEF abstract

1 is a block diagram of a process route according to a first embodiment of the present invention;

2 is a block diagram of a process route according to a second embodiment of the present invention;

Figure 3 is a block diagram of a process route according to a third embodiment of the present invention;

Figure 4 is a block diagram of a process route according to a fourth embodiment of the present invention;

Figure 5 is a block diagram of a process route according to a fifth embodiment of the present invention;

Figure 6 is a block diagram showing a process route of a sixth embodiment of the present invention;

Figure 7 is a block diagram of a process route of a seventh embodiment of the present invention;

Figure 8 is a block diagram of a process route of an eighth embodiment of the present invention;

Figure 9 is a block diagram of a process route of a ninth embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the flexible strip processing line suitable for producing various high-strength steels according to the present invention will be specifically described by way of embodiments with reference to the accompanying drawings (in the figure, the solid arrow is the process path adopted in the embodiment, and the dotted arrow is optional for other embodiments. Process path).

Example 1

Referring to Figure 1, the process route of this embodiment is: raw material 1 unwinding cleaning 2 - heating 3 - soaking 4 - slow cooling 5 - high hydrogen jet cooling 6 - overaging 10 - final cooling 11 - leveling 12 - finishing 13 - Oiling and post-treatment 14 rolls 15 - finished 16 .

The process of the embodiment of the invention can produce a general cold-rolled sheet and a phase-strengthened high-strength steel cold-rolled sheet, and is particularly suitable for producing cold-rolled TRIP steel and DP steel of 80 kg class and below, and producing cold-rolled 80 kg-grade TRIP steel and The process parameters of the 80 kg class DP steel are shown in Table 1. It can be seen from Table 1 that for 80 kg class TRIP steel, it is important to control the soaking temperature, aging temperature and time of continuous annealing, which is not required for rapid cooling rate; and for 80 kg class DP steel. The key process control parameters of continuous annealing are soaking temperature and rapid cooling rate, especially for rapid cooling rate. As for aging, it is required to have low temperature and short time to avoid decomposition of martensite.

The process of this embodiment does not require an acid washing and reheating process, and the heat treatment process has a low production cost and an excellent surface quality.

Table 1 Process parameters of cold rolled 80 kg TRIP steel and 80 kg DP steel Heating soaking, soaking, slow cooling, slow cooling, fast cooling, aging, mouth speed, temperature, time, speed, temperature, temperature

Wide mouth

V0 T1 tl VI T2 V2 T3 °C/s V s °C/s V °C/s V

120-50

80K-TRIP 3-15 700-820 30-150 3-30 500-700 20-60 300-500

0

80K-DP 3-15 750-850 30-150 3-30 500-700 50-150 200-300 80-300

Example 2

Referring to Fig. 2, the process route of this embodiment is: raw material 1 unwinding cleaning 2 - heating 3 - soaking 4 - slow cooling 5 high hydrogen jet cooling 6 reheating 9 overaging 10 - final cooling 11 flattening 12 - finishing 13 - Oiling and post-treatment 14 One roll 15 - Finished product 16.

Compared with the embodiment 1, the process of the embodiment of the invention can realize the over-aging process after the low temperature and the high temperature, and the process can produce the soft steel product with excellent anti-aging property by using the low carbon aluminum killed steel, and the production of the anti-aging property is low. The process parameters of carbon-aluminum-stable soft steel products are shown in Table 2. It can be seen from Table 2 that in order to produce low-carbon aluminum killed steel with excellent anti-aging properties, it is important to control the soaking temperature and aging process of continuous annealing. Among them, in order to analyze the solid solution carbon in the steel, it must be achieved after the low temperature. The high temperature overaging process, the treatment line of the present invention satisfies the process requirements by reheating after rapid cooling.

Compared with other patents, the present invention is equipped with a high-power induction heater after processing the high-hydrogen jet cooling section on the line, which can control the heating speed after rapid cooling, and does not require pickling, and can fully satisfy the equipment of the high-strength plate manufacturing process. Claim.

Table 2 Process parameters of low carbon aluminum killed steel and martensitic steel

More importantly, the process of the embodiment of the present invention can first cool the strip to below the martensite transformation point, and then perform tempering after martensite transformation to achieve quenching and tempering, and obtain tempered martensite structure. Adjusting the overall performance of the steel sheet to produce a high strength steel that is better than the strength and plasticity of the duplex steel product of Example 1. Plates can also produce martensitic steels with lower strength grades but better plasticity. The process parameters for the production of martensitic steel products are also shown in Table 2. It can be seen from Table 2 that in order to produce high-strength martensitic steel, the key is to control the soaking temperature and rapid cooling rate of continuous annealing, in which, in order to obtain sufficient martensite to ensure strength, fast cooling rate and fast cooling end point Temperature is the main factor.

Compared with the usual rapid cooling and reheating, since the high-hydrogen jet cooling section of the treatment line of the present invention is equipped with a high-power induction heater, the heating speed and temperature after rapid cooling can be controlled, and no pickling is required. Fully meet the equipment requirements for high-strength steel plate manufacturing processes. The ability to implement the process is also one of the features of the present invention. Example 3

Referring to Figure 3, the process route of this embodiment is: raw material 1 unwinding cleaning 2 - electroplating 17 (electroplating Fe or Ni) and then heating 9 hot-dip galvanizing 18 (or including plating alloying annealing 19) - final cooling 11 - flat 12 - Passivation 20 - Finishing 13 (or including oiling) 14 Rolling 15 - Finished product 16.

In the embodiment of the present invention, high-strength or ultra-high-strength hot-rolled pickling plates (such as hot-rolled martensitic steel) are used as raw materials, and high-strength steel hot-dip galvanizing is improved by plating a layer of extremely thin elements such as Ni and Fe on the surface. Platinum, then heated to 45 (T550 ° C, hot-dip galvanizing in the zinc pot (or alloying annealing treatment), and then cooled into the flat after the process. Because of the shorter time for reheating galvanizing (one minute) Internal), can greatly reduce or even avoid martensite decomposition, so that can obtain good surface quality of ultra-high strength hot-rolled hot-dip galvanized sheet, greatly reducing production costs. Production of ultra-high-strength hot-rolled hot-dip galvanized martensitic steel products The process parameters are shown in Table 3. The treatment line of the present invention can produce ultra high strength hot rolled hot-dip galvanized sheet, which is also a feature of the present invention.

Example 4

Referring to Fig. 4, the process route of this embodiment is: raw material 1 unwinding cleaning 2 - heating 3 - soaking 4 - slow cooling 5 - water quenching cooling 7 - pickling 8 reheating 9 overaging 10 - final cooling 11 flattening 12 - Finishing 13 - oiling 14 and post-processing one coil 15 - finished product 16. The process of the embodiment of the invention adopts a water quenching and tempering process, and can produce an ultra-high strength steel cold-rolled plate with good surface quality. Due to the water quenching process which is faster than the high hydrogen jet cooling rate, the strength grade of the cold rolled sheet can be greatly improved under the same chemical composition conditions, or the high strength steel alloy content of the same strength grade can be significantly reduced, and the product splicing performance can be significantly improved. Significantly improved, in addition, after the water quenching, the acid washing process can be used to wash away the oxide film on the surface of the strip steel, thereby ensuring a good surface quality of the steel sheet. Example 5

Referring to Figure 5, the process route of this embodiment is: raw material 1 unwinding cleaning 2 - heating 3 - soaking 4 - slow cooling 5 high hydrogen jet cooling 6 hot galvanizing 18 (or including plating alloying annealing 19) a final cooling 11 A flat 12-passivation 20 (or including finishing 13 and oiling 14) and the like, a post-processing one roll 15 - finished product 16.

The process of the embodiment of the invention can produce high-strength hot-dip galvanizing and alloyed hot-dip galvanized steel sheets with high strength grade, and is particularly suitable for producing hot-dip galvanized TRIP steel and DP steel with lower strength grade, and the operating cost of the unit is simple due to the simple production process. Lower. Example 6

Referring to Figure 6, the process route of this embodiment is: raw material 1 unwinding cleaning 2 - heating 3 - soaking 4 - slow cooling 5 high hydrogen jet cooling 6 reheating 9 hot galvanizing 18 (or including plating alloying annealing 19) Final cooling 11 flattening 12 post-treatment (pre-phosphorization, passivation 20, finishing 13, oiling 14, etc.) One coil 15 - finished product 16.

The process of the embodiment of the invention can produce a hot-dip galvanized high-strength steel plate with a high strength grade and good surface quality. The process of the invention adopts high-hydrogen jet cooling to rapidly cool the strip steel to below the phase transformation point to complete the martensite transformation, and then heat to about 46 CTC to complete the hot-dip galvanizing, thereby reducing the demand for hardenability of the steel sheet, partially eliminating the current The shortcoming of the process, that is, adding more alloying elements in the steel (in order to improve the hardenability of the steel sheet to complete the martensitic transformation after hot-dip galvanizing), the alloying elements such as Mn and Si on the surface of the steel sheet affect the hot-dip plating. Zinc platability. While improving the strength of the steel sheet, the process of the invention can reduce the content of the alloying elements of the substrate, and at the same time, because the alloying elements in the steel are small, the platability and the splicing performance can be ensured, and the hot galvanizing high strength which finally obtains good surface quality and user performance is obtained. Steel plate. 5倍和, The cooling capacity of the conventional hot-dip galvanizing unit after the plating is 1.5 times and the cooling capacity of the conventional hot-dip galvanizing unit is 1. 5 times and The above is to reduce the decomposition of the strengthening phase. Example 7 Referring to Fig. 7, the process route of the embodiment is: raw material 1 unwinding cleaning 2 - heating 3 - soaking 4 - slow cooling 5 - water quenching cooling 7 - pickling 8 reheating 9 hot galvanizing 18 (or including plating alloying) Annealing 19) A final cooling 1 1 flattening 12 post-treatment (pre-phosphorization, passivation 20, finishing 13, oiling 14, etc.) coiling 15 - finished product 16.

The process of the embodiment of the present invention can produce a hot-dip galvanized high-strength steel sheet having a higher surface quality than that of the embodiment 6. The process of the invention adopts water quenching with faster cooling rate instead of high-hydrogen jet cooling, which can greatly improve the strength of the steel plate under the same substrate chemical composition condition, and the oxidation of the steel strip surface due to water quenching can be washed off by the pickling process. The film, at the same time, can also wash away the surface-enriched alloy elements such as Mn and Si, which can ensure the subsequent hot-dip galvanizing platability and obtain a hot-dip galvanized high-strength steel plate with good surface quality. Example 8

Referring to Fig. 8, the process route of this embodiment is: raw material 1 unwinding cleaning 2 - heating 3 - soaking 4 - slow cooling 5 - water quenching cooling 7 - pickling 8 - electroplating 17 (electroplating Fe or Ni) reheating 9 heat Galvanized 18 (or including plating alloying annealing 19) - Final cooling 1 1 - Leveling 12 Post-treatment (pre-phosphorization, passivation 20, finishing 13, oiling 14, etc.) One coil 15 - finished product 16.

The process of the embodiment of the present invention is similar to the process of Embodiment 7, except that after the pickling, a process of plating Fe or m is added, and a layer of Fe or Ni is plated on the surface of the steel plate, which changes the surface condition of the steel plate before hot-dip galvanizing, thereby completely solving the problem. Some ultra-high strength steel hot-dip galvanizing can not be plated. The process of the embodiment of the present invention can produce a double-plated ultra-high-strength hot-dip galvanized sheet having high corrosion resistance and high surface quality, which is also one of the features of the present invention. Example 9

Referring to Fig. 9, the process route of the embodiment is: raw material 1 unwinding cleaning 2 - heating 3 - soaking 4 - slow cooling 5 - water quenching cooling 7 - pickling 8 - electroplating 17 (electroplating Ni, Zn) post treatment (pre Phosphating, passivation 20, finishing 13, oiling 14, etc.) One coil 15 - finished product 16.

The process of the present invention combines the continuous annealing and electroplating processes for producing cold-rolled electroplated Zn and Ni steel plates into one, and can produce annealed electroplated Zn and Ni steel plates on one unit, which not only reduces the investment cost, The production efficiency is improved, and the amount of head-to-tail removal can be reduced, and the yield can be improved. On the other hand, due to the slow cooling and water quenching process, high-strength cold-rolled electroplated Zn and Ni steel sheets can be produced by using lower alloying elements. .

Claims

Rights request

1. A flexible strip processing line suitable for the production of various high-strength steels. The settings are as follows:

In turn, it is an unwinding cleaning, heating, soaking, slow cooling station, and then a high-hydrogen jet cooling station and a water quenching cooling station are arranged in parallel;

After the high-hydrogen jet cooling station, reheating, overaging, final cooling, leveling, finishing station and oiling, coiling station are set in sequence;

After the water quenching and cooling station, the pickling station and the plating station are set in sequence;

In addition, there are also:

Galvanizing station, connected to the reheating station;

Plating alloying annealing station galvannealing), connected to the hot-dip galvanizing station; and connecting the final cooling station through a connecting passage;

The pickling station and the plating station are respectively connected to the reheating station through the connecting passage; the plating station is also directly connected to the unwinding cleaning station through the connecting passage; the water quenching cooling station is fixed by The bypass passage is connected to the slow cooling station; after the reheating station, the movable bypass passage is connected with the overage station, and the movable bypass passage is put into production when the product is retired and produced. The hot-dip galvanizing and its alloyed hot-dip galvanized product exit when the movable bypass channel exits and the two interfaces exiting are sealed.

2. The flexible strip processing line suitable for producing various high-strength steels according to claim 1, wherein the processing line is further provided with a passivation and other post-processing stations, which are respectively plated by connecting channels. After leveling and before finishing the station.

3. The flexible strip processing line suitable for producing various high strength steels according to claim 1, wherein the reheating station after the high hydrogen jet cooling station is equipped with an induction heater.

4. A flexible strip processing line suitable for producing various high strength steels according to claim 3, wherein said induction heater has a frequency of 1000 Hz or more.

5. The flexible strip processing line suitable for producing various high strength steels according to claim 1, wherein the bypass passage is a sealed passage, and the atmosphere in the passage is 2% by volume. ~7% hydrogen nitrogen and hydrogen mixed with protective gas.

6. The flexible strip processing line suitable for producing various high-strength steels according to claim 1, wherein the high-hydrogen jet-cooled gas is a nitrogen-hydrogen mixture containing 20% by volume or more of hydrogen. gas.