CN112090958B - Rolling process for controlling actual grain size of low-carbon deep-drawing steel - Google Patents
Rolling process for controlling actual grain size of low-carbon deep-drawing steel Download PDFInfo
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- CN112090958B CN112090958B CN202010766925.2A CN202010766925A CN112090958B CN 112090958 B CN112090958 B CN 112090958B CN 202010766925 A CN202010766925 A CN 202010766925A CN 112090958 B CN112090958 B CN 112090958B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/22—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
- B21B37/74—Temperature control, e.g. by cooling or heating the rolls or the product
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
- B21B45/02—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for lubricating, cooling, or cleaning
- B21B45/0203—Cooling
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/22—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length
- B21B2001/225—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length by hot-rolling
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Abstract
The invention discloses a rolling process for controlling the actual grain size of low-carbon deep-drawing steel, which comprises the following steps of: heating, rolling and cooling; the heating comprises low-temperature zone heating and high-temperature zone heating, wherein the heat preservation temperature of the high-temperature zone heating is 1201-1260 ℃, and the heat preservation time is 2-4 hours; in the rolling procedure, the initial rolling temperature is 1150-1200 ℃, the final rolling temperature is 930-960 ℃, the final rolling temperature is controlled by speed-up production, and the rolling speed is 5-10 m/s; the cooling procedure sequentially comprises the steps of preheating the cooling bed, cooling the cooled workpiece on the preheated cooling bed in the heat-preservation cover for 600-900 s, and naturally cooling the rolled workpiece on the cooling bed after the rolled workpiece is taken out of the heat-preservation cover when the temperature is less than or equal to 550 ℃. According to the invention, the grain size of the low-carbon deep-drawing steel is controlled to be 5-8 grade by controlling the heating temperature of the casting blank, the heat preservation time of a high-temperature area, the rolling temperature, the rolling speed and the cooling process after rolling, so that the requirement of customers on the grain size of the low-carbon deep-drawing steel is met.
Description
Technical Field
The invention belongs to the technical field of metallurgy, and relates to a rolling process for controlling the actual grain size of low-carbon deep-drawing steel.
Background
Low carbon deep drawing steel generally requires good drawing properties. At present, the domestic production process flow of low-carbon deep drawing steel comprises billet heating, rolling and cooling, wherein the heating temperature is 1150-1200 ℃, the rolling temperature is more than or equal to 850 ℃, and the cooling mode adopts air cooling. Taking 18A low-carbon deep drawing steel as an example, the material specification is generally phi 23 mm-40 mm, and the chemical components (mass percent) are as follows: c: 0.12 to 0.24%, Si: less than or equal to 0.15 percent, Mn: 0.20-0.70%, P: less than or equal to 0.025%, S: less than or equal to 0.020%, Cr: less than or equal to 0.30 percent, Ni: not more than 0.30%, not more than 0.20% of Cu, Al: less than or equal to 0.03-0.10 percent, and the balance of matrix Fe and inevitable impurities. In order to achieve the best deep drawing performance, users require the actual grain size of steel to be 5-8 grades.
However, the material has a small rolling specification (phi 23-40 mm), a rolled piece is cooled quickly after rolling, the rolled piece is rolled according to a conventional process, the rolling compression ratio is large, the conventional rolling process is adopted, the actual grain size reaches 9-10 levels, and the requirement of the standard 5-8 levels cannot be met.
Therefore, developing a rolling process capable of controlling the actual grain size of the low-carbon deep drawing steel is very important for realizing the deep drawing performance of the low-carbon deep drawing steel.
Disclosure of Invention
In order to enable the grain size of the low-carbon deep drawing steel to reach 5-8 levels and achieve the best deep drawing performance, the invention provides a rolling process for controlling the actual grain size of the low-carbon deep drawing steel, and the grain size of the low-carbon deep drawing steel is controlled to be 5-8 levels by controlling the heating temperature of a casting blank, the heat preservation time of a high-temperature region, the rolling temperature, the rolling speed and the cooling process after rolling, so that the requirement of customers on the grain size of the low-carbon deep drawing steel is met.
In order to achieve the purpose, the invention adopts the following technical scheme:
a rolling process for controlling the actual grain size of low-carbon deep-drawing steel comprises the following steps: heating, rolling and cooling; the heating includes low temperature zone heating and high temperature zone heating.
In the rolling process, the low-carbon deep-drawing steel is of any grade in the field for deep-drawing, and as a preferred embodiment, the specification of the low-carbon deep-drawing steel is phi 23-40 mm.
In the rolling process, as a preferred embodiment, in the heating step, the low-temperature zone is heated at a holding temperature of 1140 to 1190 ℃ for 1.5 to 3 hours.
In the above rolling process, as a preferred embodiment, in the heating step, the holding temperature of the high-temperature zone is 1201 to 1260 ℃ (e.g., 1210 ℃, 1220 ℃, 1230 ℃, 1240 ℃ and 1250 ℃), the holding time of the high-temperature zone is 2 to 4 hours (e.g., 2.5 hours, 3 hours, and 3.5 hours), and the high-temperature zone is heated for coarsening the grain size of the billet and provides an advantageous condition for controlling the actual grain size of the steel product during rolling.
In the rolling process, the rolling includes rough rolling, intermediate rolling and finish rolling, and as a preferred embodiment, in the rolling process, the initial rolling temperature (i.e., the rough rolling start temperature) is 1150 to 1200 ℃ (for example, 1160 ℃, 1170 ℃, 1180 ℃ and 1190 ℃), and the specific initial rolling temperature is determined according to the heating temperature of the billet and the temperature drop of the billet from the heating furnace to the initial rolling.
In the rolling process, as a preferred embodiment, in the rolling step, the finishing temperature (i.e., finishing temperature) is 930 to 960 ℃ (e.g., 935 ℃, 940 ℃, 945 ℃, 950 ℃, 955 ℃). In order to ensure that the low-carbon deep drawing steel achieves the best deep drawing performance, the method adopts higher finish rolling temperature to ensure that the crystal grains after rolling become as coarse as possible and ensure that the crystal grain size after rolling reaches 5-8 grades of the actual crystal grain size of steel required by a user.
In the rolling process, as a preferred embodiment, in order to reduce the thermal temperature drop, i.e. the thermal loss, of the rolled piece on the conveying roller way in the rolling procedure, the heat-insulating covers of the roller ways along the middle rolling and the finish rolling are put down in the middle rolling and finish rolling processes, so that the temperature of the rolled piece is ensured to be slowly reduced in the rolling process.
In the rolling process, in the rolling procedure, in the equipment capacity range, the speed is increased by increasing the rolling speed so as to control the final rolling temperature, so that the final rolling temperature is increased; as the rolling speed is higher, the deformation and temperature rise of the rolled piece are increased, and the rolling time is shorter, the temperature drop of the rolled piece is less. Therefore, the speed-up production can reduce the rolling time on one hand and increase the temperature rise generated by the deformation of the rolled piece on the other hand, and the speed-up production can increase the final rolling temperature under the combined action of the reduction of the rolling time and the deformation temperature rise of the rolled piece.
In the above rolling process, as a preferred embodiment, the rolling speed in the rolling step is 5 to 10m/s (e.g., 6m/s, 7m/s, 8m/s, 9m/s), and the rolling speed varies depending on the specifications of the low carbon deep drawing steel, and for example, the rolling speed is 8.5 to 10m/s (e.g., 8.7m/s, 9m/s, 9.2m/s, 9.5m/s, 9.8m/s) for the rolling production of a deep drawing steel having a phi 26mm specification, and the rolling speed is 6 to 7.5m/s (e.g., 6.3m/s, 6.5m/s, 6.8m/s, 7.0m/s, 7.2m/s) for the rolling production of a deep drawing steel having a phi 32mm specification.
In the rolling process, as a preferred embodiment, the cooling process sequentially comprises cold bed preheating, in-cover cooling in a heat preservation cover and natural cooling on the cold bed.
In the above rolling process, as a preferred embodiment, in the cooling step, before the rolled material after the final rolling is cooled on the cooling bed, the cooling bed is preheated to raise the temperature in the space between the rack of the cooling bed and the heat retaining cover and the rack, so as to prepare for controlling the cooling rate during the production of the low-carbon deep drawing steel. By adopting the treatment mode, the grain size of the product is reduced, and simultaneously, the other properties of the low-carbon deep drawing steel cannot be reduced.
In the rolling process, as a preferred embodiment, in the cooling step, the cold bed is preheated after the cold bed is put down with the heat-insulating cover. In order to reduce the cost, the rolled piece which does not need to control the grain size below 8 grade can be placed on the cooling bed before the cooling bed is preheated, but the rolled piece which needs to control the grain size below 8 grade needs to be placed on the cooling bed after the cooling bed is preheated.
In the rolling process, as a preferred embodiment, in the cooling step, the temperature in the heat-retaining cover after the cold bed is preheated is 560 to 900 ℃ (for example, 600 ℃, 650 ℃, 700 ℃, 750 ℃, 800 ℃, 850 ℃).
In the above rolling process, as a preferred embodiment, in the cooling step, the cooling in the heat-insulating cover means that, in order to reduce the cooling rate of the rolled piece after final rolling, crystal grains of the rolled piece grow up in the slow cooling process, and after the rolled piece is placed on a preheated cooling bed, the heat-insulating cover of the cooling bed is put down to cool the rolled piece in the heat-insulating cover.
In the rolling process, as a preferred embodiment, in the cooling step, the natural cooling on the cooling bed means that the rolled piece is naturally cooled on the cooling bed after being taken out of the heat-insulating cover; at this time, the cooling rate of the rolled material cannot be artificially controlled, and therefore the cooling rate does not affect the grain size of the rolled material.
In the above rolling process, as a preferred embodiment, in the cooling process, after the rolled piece is loaded on a preheated cooling bed, the residence time of the rolled piece under the heat-insulating cover is ensured, and the residence time is 600-900 s (for example, 630s, 660s, 720s, 780s, 840 s). In the heat-insulating cover, the steel stays for a long time, and the cooling speed of the steel is slow, so that the growth of crystal grains of the steel is facilitated, and the crystal grains of the steel are coarsened.
In the rolling process, as a preferred embodiment, in the cooling process, the temperature of the rolled piece exiting from the heat-preserving cover must be strictly controlled; the temperature of the rolled piece taken out of the heat preservation cover is less than or equal to 550 ℃, and at the moment, the steel finishes the structure transformation and transforms from austenite to ferrite and pearlite.
The steps and processes not described in detail in the process of the present invention are conventional in the art.
Compared with the prior art, the invention has the beneficial effects that:
1. according to the invention, the initial grain size of the steel billet is coarsened by increasing the heating temperature of the casting blank and the heat preservation time of the high-temperature area, and meanwhile, the start rolling temperature and the finish rolling temperature are increased as the tapping temperature of the steel billet is higher.
2. The control of the grain size of the rolled piece after final rolling is realized by controlling the rolling temperature; by controlling the cooling process after rolling and the cooling speed of the steel after final rolling, the crystal grains of the rolled piece grow up in the slow cooling process, so that the actual grain size of the steel is controlled to be 5-8 grade, the steel obtains the best deep drawing performance, and the quality requirement of the steel for deep drawing is met.
Drawings
FIG. 1 is a microstructure diagram of a low carbon deep drawing steel obtained in example 1 of the present invention.
FIG. 2 is a microstructure diagram of a low carbon deep drawing steel obtained in a comparative example of the present invention.
Detailed Description
The present invention will be described in detail with reference to examples. The various examples are provided by way of explanation of the invention, and not limitation of the invention. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope or spirit thereof. For instance, features illustrated or described as part of one embodiment, can be used with another embodiment to yield a still further embodiment. It is therefore intended that the present invention encompass such modifications and variations as fall within the scope of the appended claims and equivalents thereof.
According to the embodiment of the invention, the rolling process for controlling the actual grain size of the low-carbon deep drawing steel is provided, and the low-carbon deep drawing steel can be low-carbon steel for deep drawing of any brands in the field, such as 18A, 15A, 20A, 25A and the like; the specification of the low-carbon deep-drawing steel is phi 23-40 mm.
A rolling process for controlling the actual grain size of low-carbon deep-drawing steel comprises the following steps: heating, rolling and cooling; wherein the content of the first and second substances,
in the heating process, the heating process comprises low-temperature region heating and high-temperature region heating; the temperature of the low-temperature zone is 1140-1190 ℃, and the heat preservation time is 1.5-3 h; the temperature of the high-temperature area is 1201-1260 ℃, the heating time of the high-temperature area is 2-4 hours, the heating of the high-temperature area aims at coarsening the grain size of the steel billet, and favorable conditions are created for controlling the actual grain size of the steel during rolling and forming.
In the rolling procedure, the initial rolling temperature is 1150-1200 ℃, and the final rolling temperature is 930-960 ℃; in order to reduce the thermal temperature drop, namely the thermal loss, of the rolled piece on the conveying roller way, the heat-insulating covers of the roller way along the middle rolling and the finish rolling are put down in the middle rolling and finish rolling processes, so that the temperature of the rolled piece is ensured to be slowly reduced in the rolling process; during rolling, within the range of equipment capacity, the speed is increased by increasing the rolling speed so as to control the finish rolling temperature and increase the finish rolling temperature; according to different specifications of low-carbon deep drawing steel, the rolling speed is different.
In the rolling step, the initial rolling temperature is determined based on the heating temperature of the billet and the temperature drop from tapping to initial rolling of the billet. In order to ensure that the low-carbon deep drawing steel achieves the optimal deep drawing performance, the method adopts higher finish rolling temperature to ensure that the crystal grains after rolling become as coarse as possible and ensure that the crystal grain size after rolling reaches 5-8 grades of the actual crystal grain size of steel required by a user; meanwhile, in order to improve the final rolling temperature as much as possible, the invention adopts the speed-up production to control the final rolling temperature, because the higher the rolling speed is, the higher the deformation temperature rise of the rolled piece is, the shorter the rolling time is, and the less the temperature drop of the rolled piece is. Therefore, the speed-up production can reduce the rolling time on one hand and increase the temperature rise generated by the deformation of the rolled piece on the other hand, and the speed-up production can increase the final rolling temperature under the combined action of the reduction of the rolling time and the deformation temperature rise of the rolled piece.
In the cooling process, the cooling process sequentially comprises the steps of preheating of a cooling bed, cooling in a heat-preservation cover and natural cooling on the cooling bed.
(1) Preheating a cooling bed: preheating a cooling bed before a rolled piece after final rolling is cooled on the cooling bed so as to improve the temperature in the space between a rack and a heat-insulating cover of the cooling bed and the rack and prepare for controlling the cooling speed during the production of low-carbon deep-drawing steel; the cold bed is preheated by a method of putting a rolled piece which does not require to control the grain size on the cold bed and putting down the heat-insulating cover. After the cooling bed is preheated, the temperature in the heat-insulating cover is 560-900 ℃.
(2) Cooling in a heat preservation cover: after the preheated cooling bed is arranged on the rolled piece, the cooling bed heat-insulating cover is put down to cool the rolled piece in the heat-insulating cover, so that the cooling speed of the rolled piece after final rolling can be reduced, and crystal grains of the rolled piece grow up in the slow cooling process; after the rolled piece is placed on a preheated cooling bed, ensuring the retention time of the rolled piece under a heat-preservation cover, wherein the retention time is 600-900 s; in the heat-insulating cover, the steel stays for a long time, and the cooling speed of the steel is slow, so that the growth of the crystal grains of the steel is facilitated, and the crystal grains of the steel are coarsened.
(3) Naturally cooling on a cooling bed: and after the rolled piece is taken out of the heat preservation cover, naturally cooling the rolled piece on a cooling bed. The temperature of the rolled piece out of the heat-preservation cover must be strictly controlled in the cooling process; the temperature of the rolled piece leaving the heat preservation cover is less than or equal to 550 ℃. In this case, the cooling rate of the steel material cannot be artificially controlled, and therefore the cooling rate does not affect the grain size of the steel material.
The steps and processes not described in detail in the process of the present invention are conventional in the art.
Examples 1 to 9
In the embodiment, 18A steel billets are used as raw materials, 3 batches of low-carbon deep drawing steel with the specification of phi 26mm and 6 batches of low-carbon deep drawing steel with the specification of phi 32mm are designed and rolled by adopting the technical scheme in the embodiment of the invention, and the low-carbon deep drawing steel with the required specification is finally obtained by heating, rough rolling, roller way heat preservation, intermediate rolling, roller way heat preservation, finish rolling, cooling (cold bed heat preservation cover heat preservation), shearing, collecting and bundling. Wherein the content of the first and second substances,
in the heating process, the heating process comprises low-temperature region heating and high-temperature region heating; the temperature of the low-temperature zone is 1140-1190 ℃, and the heating time is 1.5-3 h; the temperature of the high-temperature zone is 1201-1260 ℃, and the heating time of the high-temperature zone is 2-4 h;
in the rolling procedure, the initial rolling temperature is 1150-1200 ℃, and the final rolling temperature is 930-960 ℃; in the middle rolling and finish rolling processes, putting down a heat preservation cover of a roller way along the middle rolling and finish rolling; during rolling, within the range of equipment capacity, the speed is increased by increasing the rolling speed so as to control the finish rolling temperature and increase the finish rolling temperature; the rolling speed is different according to different specifications of the low-carbon deep drawing steel;
in the cooling procedure, the cooling bed needs to be preheated before the rolled piece after final rolling is cooled on the cooling bed; the cold bed preheating is carried out by putting other billet rolled pieces which do not require grain size control, such as 6 billets before 18A production, on a cold upper bed and putting down a heat preservation cover. Because there is the heat preservation cover above the rack of cold bed on the steel, through using the heat preservation cover, reduce the cooling rate of steel on the cold bed. 6 billets (i.e., billets without grain size reduction) before 18A were produced were loaded onto the cooling bed and the heat-retaining cap was lowered in order to increase the temperature in the space between the cooling bed rack and the heat-retaining cap and rack in preparation for controlling the cooling rate in the cooling bed for 18A production.
After the cooling bed is preheated, putting the rolled piece with the grain size level needing to be reduced on the cooling bed, putting down the cooling bed heat-insulating cover to cool the rolled piece in the heat-insulating cover, and ensuring that the retention time of the rolled piece under the heat-insulating cover is 600-900 s; strictly controlling the temperature of the rolled piece out of the heat-insulating cover to be less than or equal to 550 ℃; and after the rolled piece is taken out of the heat preservation cover, naturally cooling the rolled piece on a cooling bed.
Table 1 shows the main parameters of the actual rolling process for producing 18A deep-drawing steel by rolling in examples 1 to 9, wherein the finish rolling speed is the speed of the finish rolling process in the finish rolling process. Table 2 shows the actual grain sizes and the mechanical properties of the deep-drawing steels obtained in examples 1 to 9. Fig. 1 shows a microstructure diagram of the deep drawing steel obtained in example 1.
As can be seen from FIG. 1, the 18A deep drawing steel obtained by rolling production according to the technical scheme of the invention has very uniform actual grain size and relatively coarse grains. As can be seen from Table 2, the low-carbon deep-drawing steel produced by the rolling process of the technical scheme of the invention has the actual grain size meeting the standard 5-8 grade requirement, and the mechanical property also meets the mechanical property standard requirement required by the low-carbon deep-drawing steel and meets the requirement required by users.
TABLE 1 EXAMPLES 1-9 main parameters of practical rolling process of low-carbon deep-drawing steel
TABLE 2 actual grain size and mechanical properties of the deep-drawing steels obtained in examples 1 to 9
Comparative example 1
The comparative example is that 18A steel is used as a raw material, and the conventional rolling process is adopted to produce the deep drawing steel, so that the low-carbon deep drawing steel with the specification of 26mm is obtained. The specific rolling process is as follows:
heating, rough rolling, medium rolling, finish rolling, cooling, shearing, collecting and bundling.
Wherein the heating temperature is 1140-1190 ℃; the initial rolling temperature is 1000-1150 ℃; the finishing temperature is 830-880 ℃; and (4) air-cooling the rolled steel on a cooling bed.
The microstructure of the low carbon deep drawing steel obtained in the present comparative example is shown in FIG. 2. As can be seen from FIG. 2, the actual grain size of the low carbon deep drawing steel obtained in this comparative example was 10 grades, and the deep drawing property of the low carbon deep drawing steel was not good because the grains were very fine.
Therefore, the conventional rolling process is adopted to produce the deep drawing steel, the actual grain size of the obtained low-carbon deep drawing steel cannot meet the standard requirement (5-8 level) of the user on the actual grain size of the deep drawing steel, and the deep drawing performance of the steel is poor as the grain size is finer and the deep drawing performance of the steel is poor as the deep drawing performance of the steel is related to the actual grain size of the steel, so that the low-carbon deep drawing steel produced by the conventional rolling process cannot meet the requirement of the user on the deep drawing performance of the steel.
In summary, according to the rolling process for controlling the actual grain size of the low-carbon deep-drawing steel disclosed by the application, the grain size of the low-carbon deep-drawing steel is controlled to be 5-8 grade by controlling the heating temperature of the casting blank, the heat preservation time of the high-temperature area, the rolling speed and the cooling process after rolling, so that the grain size requirement of customers on the low-carbon deep-drawing steel is met.
The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Variations and modifications to these embodiments may occur to those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.
Claims (3)
1. A rolling process for controlling the actual grain size of low-carbon deep-drawing steel comprises the following steps: heating, rolling and cooling; the method is characterized in that the heating comprises low-temperature area heating and high-temperature area heating;
in the heating procedure, the heat preservation temperature of the low-temperature zone is 1140-1190 ℃, and the heat preservation time is 1.5-3 h; the heat preservation temperature of the high-temperature zone is 1201-1260 ℃, and the heat preservation time of the high-temperature zone is 2-4 hours;
in the rolling procedure, the initial rolling temperature is 1150-1200 ℃, and the final rolling temperature is 930-960 ℃;
in the rolling procedure, the rolling speed in the finish rolling process is 5-10 m/s;
the cooling process sequentially comprises the steps of cold bed preheating, heat preservation cover internal cooling and cold bed natural cooling; after the cooling bed is preheated, the temperature in the heat-insulating cover is 560-900 ℃;
the internal cooling of the heat-preservation cover means that after the rolled piece is placed on the preheated cooling bed, the cooling bed heat-preservation cover is put down to cool the rolled piece in the heat-preservation cover, and the retention time of the rolled piece under the heat-preservation cover is ensured, wherein the retention time is 600-900 s;
in the cooling procedure, the temperature of the rolled piece taken out of the heat-preservation cover is less than or equal to 550 ℃;
the specification of the low-carbon deep-drawing steel is phi 23-40 mm.
2. The rolling process according to claim 1, wherein in the rolling process, a heat-insulating cover of a roller bed along the middle rolling and the finish rolling is put down in the middle rolling and the finish rolling.
3. The rolling process according to claim 1, wherein the cold bed is preheated after the cold bed is put down with a heat preservation cover.
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| JP2597986B2 (en) * | 1985-12-28 | 1997-04-09 | 新日本製鐵株式会社 | Manufacturing method of hot rolled steel |
| JP4635525B2 (en) * | 2003-09-26 | 2011-02-23 | Ｊｆｅスチール株式会社 | High-strength steel sheet excellent in deep drawability and manufacturing method thereof |
| JP4507867B2 (en) * | 2004-12-08 | 2010-07-21 | 住友金属工業株式会社 | Manufacturing method and manufacturing apparatus for hot-rolled steel sheet |
| CN1978689A (en) * | 2005-11-30 | 2007-06-13 | 宝山钢铁股份有限公司 | Low-carbon hot-rolled deep-drawing steel sheet |
| CN100436632C (en) * | 2006-11-10 | 2008-11-26 | 武汉钢铁(集团)公司 | Vanadium treated bake hardening type deep drew steel plates of saloon sedan, and preparation method |
| CN102581008A (en) * | 2012-03-01 | 2012-07-18 | 河北钢铁股份有限公司唐山分公司 | Processing method for producing low-cost high-formability IF (interstitial-free) steel |
| CN103320689A (en) * | 2012-03-22 | 2013-09-25 | 上海梅山钢铁股份有限公司 | Aluminum-zinc hot plating deep drawing steel with thick gauge of more than 1.2 mm, and manufacturing method thereof |
| CN106216391B (en) * | 2016-08-09 | 2018-10-23 | 大冶特殊钢股份有限公司 | A kind of rolling production method reducing 42CrMo hardness |
| CN107597844A (en) * | 2017-10-16 | 2018-01-19 | 北京科技大学 | The ferrite rolling method and apparatus that endless casting rolling deep-draw is rolled up with humble carbon steel |
| CN108906884B (en) * | 2018-06-22 | 2020-08-14 | 大冶特殊钢有限公司 | Low-temperature rolling production method of high-performance 20CrMnTi gear steel |
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