CN110369519B - Plate type control method for 500 MPa-level low-alloy high-strength steel plate in rolling process - Google Patents
Plate type control method for 500 MPa-level low-alloy high-strength steel plate in rolling process Download PDFInfo
- Publication number
- CN110369519B CN110369519B CN201910666476.1A CN201910666476A CN110369519B CN 110369519 B CN110369519 B CN 110369519B CN 201910666476 A CN201910666476 A CN 201910666476A CN 110369519 B CN110369519 B CN 110369519B
- Authority
- CN
- China
- Prior art keywords
- rolling
- steel plate
- alloy high
- strength steel
- mpa
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000005096 rolling process Methods 0.000 title claims abstract description 195
- 238000000034 method Methods 0.000 title claims abstract description 119
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 90
- 239000010959 steel Substances 0.000 title claims abstract description 90
- 239000000956 alloy Substances 0.000 title claims abstract description 44
- 229910045601 alloy Inorganic materials 0.000 title claims abstract description 44
- 238000001816 cooling Methods 0.000 claims abstract description 77
- 238000010438 heat treatment Methods 0.000 claims abstract description 57
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 53
- 230000009467 reduction Effects 0.000 claims description 40
- 230000008569 process Effects 0.000 claims description 38
- 238000007664 blowing Methods 0.000 claims description 12
- 238000002791 soaking Methods 0.000 claims description 10
- 238000005266 casting Methods 0.000 abstract description 4
- 230000008859 change Effects 0.000 abstract description 4
- 238000010926 purge Methods 0.000 description 11
- 238000009749 continuous casting Methods 0.000 description 8
- 238000007689 inspection Methods 0.000 description 8
- 239000002184 metal Substances 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000005728 strengthening Methods 0.000 description 3
- 238000001514 detection method Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005098 hot rolling Methods 0.000 description 2
- 230000001788 irregular Effects 0.000 description 2
- 230000008520 organization Effects 0.000 description 2
- 238000004321 preservation Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005272 metallurgy Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000011946 reduction process Methods 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Images
Classifications
-
- 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
- B21B37/28—Control of flatness or profile during rolling of strip, sheets or plates
-
- 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
- B21B37/28—Control of flatness or profile during rolling of strip, sheets or plates
- B21B37/44—Control of flatness or profile during rolling of strip, sheets or plates using heating, lubricating or water-spray cooling of the product
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Metal Rolling (AREA)
Abstract
The invention discloses a plate type control method for a 500 MPa-level low-alloy high-strength steel plate in a rolling process, which comprises the working procedures of heating, rough rolling, finish rolling, controlled cooling and thermal straightening. The invention fully considers the integral temperature uniformity of the casting blank and the intermediate blank and the uniformity of the structure state after phase change in the heating and rolling processes, and solves the problems of uneven stress caused by the technical reason and the stress caused by uneven temperature and structure difference in the rolling process of medium plate steel. According to the plate type control method disclosed by the invention, the thickness of the steel plate is 12-50 mm, and the performance of the steel plate is as follows: the yield strength is more than or equal to 500 MPa; the surface unevenness of the steel plate is less than or equal to 8mm/2 m.
Description
Technical Field
The invention belongs to the technical field of metallurgy, and particularly relates to a method for controlling a plate shape in a rolling process of a 500 MPa-level low-alloy high-strength steel plate.
Background
With the continuous development of various industries such as domestic construction industry, engineering machinery, pressure vessels and the like, the strength requirement on steel grades is continuously increased, particularly, foreign manufacturing technologies are continuously introduced in nearly twenty years, and the state that the industrial steel in China mainly comprises Q235 and Q345 low-grade steel gradually cannot meet the social requirement. At present, many grades of high strength steels have been developed, and the highest strength is required to be more than 1000MPa, and the steel grade of more than 500MPa accounts for more than 10% of the total portion. The high-strength steel not only improves the strength performance index to a new height, but also strictly complies with the requirements of the national standard GB/T709-2006 in the aspect of plate type.
In order to obtain higher strength index, the solid solution strengthening effect is continuously used, and the steel plate strength is increased by more depending on the fine grain strengthening and precipitation strengthening effects, so that the rolling processing with large deformation and the controlled cooling measure after rolling are adopted when the high-strength medium and heavy plates are produced by rolling. The plate is deformed due to uneven metal rheological in the rolling deformation process and uneven stress in the width direction and the length direction of the plate in the cooling control process, the deformation resistance is increased in the temperature reduction process of the formed plate, the plate is difficult to straighten in the cold state subsequent straightening process, the plate type requirement in the national standard is difficult to meet, a high-power cold straightening machine and a flattening machine are required to flatten when necessary or the plate type straightening is carried out after stress is removed through heat treatment, so that the cost is increased, the logistics burden is caused, and meanwhile, the plate type deterioration directly influences the technical requirement in engineering projects. The waste rate of the high-strength steel plate in enterprises in the same industry in China is up to more than 21% due to plate shape.
Therefore, it is urgently needed to develop a rolling production method of thin medium and thick plate steel with good plate shape in a hot rolling state.
Disclosure of Invention
The invention aims to provide a method for controlling the plate shape of a 500 MPa-level low-alloy high-strength steel plate in the rolling process. The invention fully considers the integral temperature uniformity of the casting blank and the intermediate blank and the uniformity of the structure state after phase change in the heating and rolling processes, and solves the problems of uneven stress caused by the technical reason and the stress caused by uneven temperature and structure difference in the rolling process of medium plate steel.
In order to solve the technical problems, the invention adopts the technical scheme that: a plate type control method for a 500 MPa-level low-alloy high-strength steel plate in a rolling process comprises the following specific process steps of heating, rough rolling, finish rolling, controlled cooling and hot straightening:
(1) a heating procedure: the heating temperature of the blank is 1100-1250 ℃, the heating time is 7-12 cm/min, and the soaking time of the blank is 1.6-2.5 cm/min; after heating, the temperature difference of each point of the blank is less than or equal to 30 ℃;
(2) rough rolling procedure: the initial rolling temperature is 980-1080 ℃, MAS (Multi-media sheet) is used for rolling in rough rolling widening passes, the ratio of the delta h height of a wedge-shaped section to the blank thickness is 1: 50-1: 150, the length of a horizontal section L1 is 400mm, the length of a wedge-shaped section L2 is 200-600 mm, and the widening passes are carried out in 2-6 passes; 4-8 passes of longitudinal rolling are divided, the single-pass reduction rate is 12-25%, and the total reduction rate is 50-70%;
(3) a finish rolling procedure: the single-pass reduction rate is 5-20%, and the total reduction rate is 30-50%; the linear velocity of the last three secondary working rolls of the finish rolling is less than or equal to 1.5m/s, and the deformation rate is less than or equal to 1s-1The relaxation time after finish rolling is 10-50 s;
(4) a controlled cooling process: adopting a laminar cooling process, wherein the final cooling temperature is 450-650 ℃, and the cooling rate is less than or equal to 10 ℃/s;
(5) a thermal straightening process: the straightening temperature is higher than 400 ℃, the roller speed is 0.24-1.2 m/s, and the setting of the roller gap of the straightening machine ensures that the plastic deformation depth of the rolled piece in the thickness direction is larger than or equal to 70%.
In the step (2), the rough rolling working roll has a positive convexity of 0.05-0.20 mm.
In the step (3) of the present invention, a flat roll is used as the finish rolling work roll.
In the step (3), before rolling the low-alloy high-strength steel, the number of kilometers used by a finishing mill in a finishing rolling procedure is controlled to be 6-12 ㎞.
In the step (4), the plate enters a cooling system for cooling, a head and tail shielding function is adopted, and the shielding length is 0.3-1.0 m, so that the temperature difference between the head and the tail of the plate and the middle of the plate is reduced.
In the step (2), water beams are used for purging after rough rolling; and (3) blowing by using a water beam before finish rolling.
In the step (4), the speed of the roller way is 0.35-1.0 m/s, and the ratio of the upper water amount to the lower water amount is controlled to be 1.6-2.4.
In the step (5) of the invention, the roll gap of the straightener is controlled to be 11.5-50 mm.
The thickness of the steel plate produced by the plate type control method is 12-50 mm, and the performance of the steel plate is as follows: the yield strength is more than or equal to 500 MPa.
The surface unevenness of the steel plate produced by the plate type control method is less than or equal to 8mm/2 m.
The design idea of the invention is as follows:
in order to reduce the irregular deformation of a plate type caused by the uneven stress generated by the process in the rolling process of medium and heavy plate steel, the reason that the irregular deformation of a casting blank is mainly caused by the uneven temperature and the stress generated by the structure difference is considered, so that the integral temperature uniformity of the casting blank and an intermediate blank and the uniformity of the structure state after the phase transformation are fully considered in the heating and rolling production process.
The blank heating adopts longer heating coefficient and heat preservation time, mainly aims to reduce the temperature difference of each direction of the blank, realize the uniformity of metal flowing in the thermal deformation process as much as possible, and simultaneously prevent the temperature of a plate area from being reduced by water stored on the plate surface in the hot rolling process, so a post-machine purging device is arranged behind a double-stand rolling mill, and water beams are used for purging behind a roughing mill and before a finishing mill so as to reduce the water residue on the plate surface.
MAS rolling is adopted in the rough rolling process, so that the allowance of metal at the edge of the plate can compensate for the uneven deformation caused by the free widening of the edge of the plate.
The lower deformation rate is adopted in the finish rolling process, so that the deformation energy of the crystal grain deformation can be accumulated on the plate, the phase change generation process is more sufficient, and a finer and more uniform organization structure can be obtained.
In order to prevent the thicker plate from having larger structure and performance difference in the thickness direction when the temperature of the plate is higher, the difference in the aspect can be reduced by adopting smaller cooling rate and lower final cooling temperature, and meanwhile, the difference between the head and the tail of the plate and the difference between the head and the tail of the plate are prevented by adopting a head and tail shielding technology.
The standard of the performance detection method of the low-alloy high-strength steel plate is referred to GB/T1591-2018; the standard of the detection method of the unevenness of the surface of the steel plate refers to GB/T709-2006.
Adopt the produced beneficial effect of above-mentioned technical scheme to lie in: 1. the blank heating of the invention adopts longer heating coefficient and heat preservation time, reduces the temperature difference of the blank in each direction, and realizes the uniformity of metal flow in the thermal deformation process. 2. In the rough rolling process, MAS rolling is adopted, so that the allowance of metal at the edge of the plate can compensate for the uneven deformation caused by the free widening of the edge of the plate. 3. In the finish rolling process, the lower deformation rate is adopted, so that the plate can accumulate the distortion energy of the grain deformation, the phase change generation process is more sufficient, and a finer and more uniform organization structure is obtained. 4. The invention adopts lower cooling rate and lower final cooling temperature, reduces larger structure and performance difference of the plate in the width and length directions, and simultaneously adopts a head-tail shielding technology to prevent the head-tail and middle difference of the plate. 5. The surface unevenness of the low-alloy high-strength steel plate produced by the control method is less than or equal to 8mm/2 m.
Drawings
Fig. 1 is a schematic cross-sectional view of the MAS rolled in the width direction, Δ h =1.5mm, L1=350mm, and L2=400 mm.
Detailed Description
The invention is described in further detail below with reference to the figures and specific examples.
Example 1
The thickness of the low-alloy high-strength steel plate is 20mm, the specification of the continuous casting billet is 280 x 1800 x 2800mm, the plate shape control method in the rolling process of the low-alloy high-strength steel plate comprises the working procedures of heating, rough rolling, finish rolling, controlled cooling and hot straightening, and the specific process steps are as follows:
(1) a heating procedure: the heating temperature of the blank is 1210 ℃, the heating time is 7.5cm/min, the soaking time of the blank is 1.8cm/min, and the temperature difference of each point of the blank is 25 ℃ after the heating is finished;
(2) rough rolling procedure: the initial rolling temperature is 1063 ℃, MAS rolling is used for widening passes in rough rolling, the ratio of the height of a wedge-shaped section delta h to the thickness of a blank is 1:90, the length of a horizontal section L1 is 400mm, the length of a wedge-shaped section L2 is 320mm, the widening passes are carried out in 4 passes, and the steel turning passes are carried out in one direction; longitudinal rolling is divided into 6 passes after the widening pass, the roll gap value of the pass is set to be 180mm, 152mm, 125mm, 99mm, 81mm and 70mm, the single-pass reduction rate is 15 percent, and the total reduction rate is 69.75 percent; the rough rolling working roll has positive convexity of 0.05 mm; the thickness of the intermediate blank is 3 times of that of the finished product, namely 60 mm; blowing by using a water beam after rough rolling;
(3) a finish rolling procedure: before finish rolling, water beam purging is used, the single-pass reduction rate is 11%, and the total reduction rate is 31.25%; the linear speed of the last three working rolls of the finish rolling is 1.25m/s, and the deformation rate is 0.8s-1(ii) a Extract of Chinese medicinal materials
The rolling working roll adopts a flat roll, and the finish rolling machine adopts a kilometer number of 6 ㎞; blowing and cleaning residual water on the surface of the plate after the rolling mill is used; the relaxation time after finish rolling is 20 s;
(4) a controlled cooling process: adopting a laminar cooling process, wherein the final cooling temperature is 480 ℃, the speed of a roller way is 1m/s, the water quantity ratio of the upper water to the lower water is controlled to be 1.9, and the cooling speed is 5 ℃/s; the plate enters a cooling system for cooling, a head and tail shielding function is adopted, and the shielding length is 1m, so that the temperature difference between the head and the tail of the plate and the middle of the plate is reduced;
(5) a thermal straightening process: the straightening temperature is 410 ℃, the roll gap of the straightening machine is controlled to be 18.9mm, the roll speed is 0.25m/s, and the setting of the roll gap of the straightening machine ensures that the plastic deformation depth in the thickness direction of a rolled piece is 73 percent.
The specification of the low-alloy high-strength finished steel plate rolled in the embodiment is 20 × 2200 × 12000mm, and the steel plate performance: yield strength 560 MPa; the maximum unevenness of the steel plate is 5mm/2m after surface inspection, and completely meets the requirements of national standards.
Example 2
The thickness of the low-alloy high-strength steel plate is 16mm, the specification of the continuous casting billet is 250 × 2100 × 280mm, the plate shape control method in the rolling process of the low-alloy high-strength steel plate comprises the working procedures of heating, rough rolling, finish rolling, controlled cooling and hot straightening, and the specific process steps are as follows:
(1) a heating procedure: the heating temperature of the blank is 1210 ℃, the heating time is 8.4cm/min, the soaking time of the blank is 2.5cm/min, and the temperature difference of each point of the blank is 21 ℃ after the heating is finished;
(2) rough rolling procedure: the initial rolling temperature is 1060 ℃, the rough rolling widening pass is rolled by using MAS, the ratio of the height of the wedge-shaped section delta h to the blank thickness is 1:70, the length of the horizontal section L1 is 400mm, the length of the wedge-shaped section L2 is 430mm, the widening pass is carried out in 4 passes, and the steel turning pass is carried out in a single direction; longitudinal rolling is divided into 6 passes after the widening pass, the roll gap value of the pass is set to be 170mm, 142mm, 115mm, 99mm, 78mm and 56mm, the single-pass reduction rate is 22 percent, and the total reduction rate is 67 percent; the rough rolling working roll has positive convexity of 0.05 mm; the thickness of the intermediate blank is 3.5 times of the thickness of the finished product, namely 56 mm; blowing by using a water beam after rough rolling;
(3) a finish rolling procedure: before finish rolling, water beam purging is used, the single-pass reduction rate is 10%, and the total reduction rate is 33%; the linear speed of the last three working rolls of the finish rolling is 1.25m/s, and the deformation rate is 0.6s-1(ii) a The finish rolling working roll adopts a flat roll, and the finish rolling machine adopts a kilometer number of 6 ㎞; the relaxation time after finish rolling is 15 s;
(4) a controlled cooling process: adopting a laminar cooling process, wherein the final cooling temperature is 510 ℃, the speed of a roller way is 1m/s, the water quantity ratio of the upper water to the lower water is controlled to be 1.9, and the cooling speed is 5 ℃/s; the plate enters a cooling system for cooling, a head and tail shielding function is adopted, and the shielding length is 1m, so that the temperature difference between the head and the tail of the plate and the middle of the plate is reduced;
(5) a thermal straightening process: the straightening temperature is 420 ℃, the roll gap of the straightening machine is controlled to be 14.7mm, the roll speed is 0.25m/s, and the setting of the roll gap of the straightening machine ensures that the plastic deformation depth in the thickness direction of a rolled piece is 71 percent.
The specification of the low-alloy high-strength finished steel plate rolled in the embodiment is 16 × 2500 × 12000mm, and the steel plate performance: yield strength 523 MPa; the maximum unevenness of the steel plate is 6mm/2m after surface inspection, and completely meets the requirements of national standards.
Example 3
The thickness of the low-alloy high-strength steel plate is 22mm, the specification of the continuous casting billet is 250 x 1800 x 2500mm, the plate shape control method in the rolling process of the low-alloy high-strength steel plate comprises the working procedures of heating, rough rolling, finish rolling, controlled cooling and hot straightening, and the specific process steps are as follows:
(1) a heating procedure: the heating temperature of the blank is 1130 ℃, the heating time is 10cm/min, the soaking time of the blank is 1.9cm/min, and the temperature difference of each point of the blank is 28 ℃ after the heating is finished;
(2) rough rolling procedure: the initial rolling temperature is 1023 ℃, MAS rolling is used for rough rolling widening passes, the ratio of the height of a wedge-shaped section delta h to the blank thickness is 1:110, the length of a horizontal section L1 is 400mm, the length of a wedge-shaped section L2 is 370mm, the widening passes are carried out in 2 passes, and the steel turning passes are carried out in one direction; 4 passes of longitudinal rolling are divided after widening passes, the roll gap values of the passes are set to be 180mm, 152mm, 125mm and 99mm, the single-pass reduction rate is 13 percent, and the total reduction rate is 52 percent; the rough rolling working roll has positive convexity of 0.08 mm; the thickness of the intermediate blank is 3.5 times of the thickness of the finished product, namely 77 mm; blowing by using a water beam after rough rolling;
(3) a finish rolling procedure: before finish rolling, water beam purging is used, the single-pass reduction rate is 7%, and the total reduction rate is 33%; the linear speed of the last three working rolls of the finish rolling is 1.15m/s, and the deformation rate is 0.9s-1(ii) a The finish rolling working roll adopts a flat roll, and the kilometer number of the finish rolling machine is 10 ㎞; the relaxation time after finish rolling is 30 s;
(4) a controlled cooling process: adopting a laminar cooling process, wherein the final cooling temperature is 550 ℃, the roller speed is 0.6m/s, the water quantity ratio of the upper water to the lower water is controlled at 1.7, and the cooling rate is 6 ℃/s; the plate enters a cooling system for cooling, a head and tail shielding function is adopted, and the shielding length is 0.5m, so that the temperature difference between the head and the tail of the plate and the middle of the plate is reduced;
(5) a thermal straightening process: the straightening temperature is 405 ℃, the roll gap of the straightening machine is controlled to be 15.8mm, the roll speed is 0.30m/s, and the setting of the roll gap of the straightening machine ensures that the plastic deformation depth in the thickness direction of a rolled piece is 72 percent.
The specification of the low-alloy high-strength finished steel plate rolled in the embodiment is 22 × 2500 × 27000mm, and the steel plate performance: yield strength 523 MPa; the maximum unevenness of the steel plate is 5mm/2m after surface inspection, and completely meets the requirements of national standards.
Example 4
The thickness of the low-alloy high-strength steel plate is 30mm, the specification of the continuous casting billet is 360 x 2100 x 2700mm, the plate shape control method in the rolling process of the low-alloy high-strength steel plate comprises the working procedures of heating, rough rolling, finish rolling, controlled cooling and hot straightening, and the specific process steps are as follows:
(1) a heating procedure: the heating temperature of the blank is 1170 ℃, the heating time is 9.5cm/min, the soaking time of the blank is 2.2cm/min, and the temperature difference of each point of the blank is 23 ℃ after the heating is finished;
(2) rough rolling procedure: the initial rolling temperature is 1045 ℃, the rough rolling widening pass is rolled by using MAS, the ratio of the height of the wedge-shaped section delta h to the blank thickness is 1:70, the length of the horizontal section L1 is 400mm, the length of the wedge-shaped section L2 is 510mm, the widening pass is carried out in 5 passes, and the steel turning pass is carried out in a single direction; the longitudinal rolling is divided into 7 passes after the widening pass, the roll gap value of the pass is set to be 180mm, 152mm, 125mm, 112mm, 99mm, 81mm and 70mm, the single-pass reduction rate is 15 percent, and the total reduction rate is 65 percent; the rough rolling working roll has positive convexity of 0.10 mm; the thickness of the intermediate blank is 3 times of that of the finished product and is 90 mm; blowing by using a water beam after rough rolling;
(3) a finish rolling procedure: before finish rolling, water beam purging is used, the single-pass reduction rate is 11%, and the total reduction rate is 43%; the linear speed of the last three working rolls of the finish rolling is 1.45m/s, and the deformation rate is 0.5s-1(ii) a The finish rolling working roll adopts a flat roll, and the finish rolling machine adopts a kilometer number of 9 ㎞; the relaxation time after finish rolling is 35 s;
(4) a controlled cooling process: adopting a laminar cooling process, wherein the final cooling temperature is 580 ℃, the roller speed is 0.5m/s, the water quantity ratio of the upper water to the lower water is controlled at 2.3, and the cooling rate is 8 ℃/s; the plate enters a cooling system for cooling, a head and tail shielding function is adopted, and the shielding length is 0.5m, so that the temperature difference between the head and the tail of the plate and the middle of the plate is reduced;
(5) a thermal straightening process: the straightening temperature is 425 ℃, the roll gap of the straightening machine is controlled to be 29.5mm, the roll speed is 0.4m/s, and the setting of the roll gap of the straightening machine ensures that the plastic deformation depth of the rolled piece in the thickness direction is 75 percent.
The specification of the low-alloy high-strength finished steel plate rolled in the embodiment is 30 × 2400 × 18000mm, and the steel plate performance is as follows: yield strength 533 MPa; the maximum unevenness of the steel plate is 6mm/2m after surface inspection, and completely meets the requirements of national standards.
Example 5
The thickness of the low-alloy high-strength steel plate is 14mm, the specification of the continuous casting billet is 250 × 1800 × 2400mm, the plate shape control method in the rolling process of the low-alloy high-strength steel plate comprises the working procedures of heating, rough rolling, finish rolling, controlled cooling and hot straightening, and the specific process steps are as follows:
(1) a heating procedure: heating the blank at 1195 deg.C for 11.5cm/min, soaking the blank at 2.4cm/min, and maintaining the temperature difference between each point of the blank at 13 deg.C;
(2) rough rolling procedure: the initial rolling temperature is 1044 ℃, the rough rolling widening pass is rolled by using MAS, the ratio of the height of the wedge-shaped section delta h to the blank thickness is 1:125, the length of the horizontal section L1 is 400mm, the length of the wedge-shaped section L2 is 535mm, the widening pass is carried out in 3 passes, and the steel turning pass is carried out in a single direction; longitudinally rolling for 8 passes after widening passes, setting the roll gap values of the passes to be 180mm, 152mm, 142mm, 135mm, 125mm, 99mm, 81mm and 70mm, setting the single-pass reduction rate to be 17 percent and setting the total reduction rate to be 66 percent; the rough rolling working roll has positive convexity of 0.12 mm; the thickness of the intermediate blank is 4 times of the thickness of the finished product, namely 56 mm; blowing by using a water beam after rough rolling;
(3) a finish rolling procedure: before finish rolling, water beam purging is used, the single-pass reduction rate is 16%, and the total reduction rate is 34%; the linear speed of the last three working rolls of the finish rolling is 1.05m/s, and the deformation rate is 0.7s-1(ii) a The finish rolling working roll adopts a flat roll, and the finish rolling machine adopts a kilometer number of 7 ㎞; the relaxation time after finish rolling is 25 s;
(4) a controlled cooling process: adopting a laminar cooling process, wherein the final cooling temperature is 620 ℃, the roller speed is 0.8m/s, the water quantity ratio of the upper water to the lower water is controlled at 2.1, and the cooling rate is 8 ℃/s; the plate enters a cooling system for cooling, a head and tail shielding function is adopted, and the shielding length is 0.7m, so that the temperature difference between the head and the tail of the plate and the middle of the plate is reduced;
(5) a thermal straightening process: the straightening temperature is 422 ℃, the roll gap of the straightening machine is controlled to be 13.7mm, the roll speed is 0.5m/s, and the setting of the roll gap of the straightening machine ensures that the plastic deformation depth of the rolled piece in the thickness direction is 76%.
The specification of the low alloy high strength finished steel plate after rolling in the embodiment is 14 × 2400 × 30500mm, and the steel plate performance: the yield strength is 545 MPa; the maximum unevenness of the steel plate is 7mm/2m after surface inspection, and completely meets the requirements of national standards.
Example 6
The thickness of the low-alloy high-strength steel plate is 12mm, the specification of the continuous casting billet is 220 x 1600 x 2700mm, the plate type control method in the rolling process of the low-alloy high-strength steel plate comprises the working procedures of heating, rough rolling, finish rolling, controlled cooling and hot straightening, and the specific process steps are as follows:
(1) a heating procedure: the heating temperature of the blank is 1235 ℃, the heating time is 11.5cm/min, the soaking time of the blank is 2.1cm/min, and the temperature difference of each point of the blank is 22 ℃ after the heating is finished;
(2) rough rolling procedure: the initial rolling temperature is 1039 ℃, MAS rolling is used for rough rolling widening passes, the ratio of the height of the delta h of the wedge-shaped section to the thickness of the blank is 1:100, the length of the horizontal section L1 is 400mm, the length of the wedge-shaped section L2 is 230mm, the widening passes are carried out in 5 passes, and the steel turning passes are carried out in one direction; longitudinally rolling 8 passes after widening passes, setting the roll gap values of the passes to be 180mm, 152mm, 142mm, 135mm, 1125mm, 99mm, 81mm and 70mm, setting the single-pass reduction rate to be 17 percent and setting the total reduction rate to be 60 percent; the rough rolling working roll has positive convexity of 0.05 mm; the thickness of the intermediate blank is 4 times of the thickness of the finished product, namely 60 mm; blowing by using a water beam after rough rolling;
(3) a finish rolling procedure: before finish rolling, water beam purging is used, the single-pass reduction rate is 8%, and the total reduction rate is 40%; the linear velocity of the last three working rolls of the finish rolling is 0.85m/s, and the deformation rate is 0.5s-1(ii) a The finish rolling working roll adopts a flat roll, and the finish rolling machine adopts a kilometer number of 7 ㎞; the relaxation time after finish rolling is 40 s;
(4) a controlled cooling process: adopting a laminar cooling process, wherein the final cooling temperature is 525 ℃, the roller speed is 0.8m/s, the water quantity ratio of the upper water to the lower water is controlled to be 1.8, and the cooling speed is 4 ℃/s; the plate enters a cooling system for cooling, a head and tail shielding function is adopted, and the shielding length is 0.7m, so that the temperature difference between the head and the tail of the plate and the middle of the plate is reduced;
(5) a thermal straightening process: the straightening temperature is 435 ℃, the roll gap of the straightening machine is controlled to be 14.7mm, the roll speed is 0.6m/s, and the setting of the roll gap of the straightening machine ensures that the plastic deformation depth of the rolled piece in the thickness direction is 78%.
The specification of the low-alloy high-strength finished steel plate rolled in the embodiment is 12 × 2200 × 25000mm, and the steel plate performance: the yield strength is 549 MPa; the maximum unevenness of the steel plate is 3mm/2m after surface inspection, and completely meets the requirements of national standards.
Example 7
The thickness of the low-alloy high-strength steel plate is 40mm, the specification of the continuous casting billet is 480 x 1800 x 2700mm, the plate type control method in the rolling process of the low-alloy high-strength steel plate comprises the working procedures of heating, rough rolling, finish rolling, controlled cooling and hot straightening, and the specific process steps are as follows:
(1) a heating procedure: the heating temperature of the blank is 1250 ℃, the heating time is 7cm/min, the soaking time of the blank is 2.5cm/min, and the temperature difference of each point of the blank is 10 ℃ after the heating is finished;
(2) rough rolling procedure: the initial rolling temperature is 1080 ℃, MAS rolling is used for widening passes in rough rolling, the ratio of the height of a wedge-shaped section delta h to the thickness of a blank is 1:50, the length of a horizontal section L1 is 400mm, the length of a wedge-shaped section L2 is 200mm, the widening passes are performed in 6 passes, and the steel turning passes are performed in a single direction; longitudinal rolling is divided into 6 passes after the widening pass, the roll gap value of the pass is set to be 180mm, 152mm, 125mm, 99mm, 81mm and 70mm, the single-pass reduction rate is 25 percent, and the total reduction rate is 70 percent; the rough rolling working roll has positive convexity of 0.15 mm; the thickness of the intermediate blank is 2.5 times of the thickness of the finished product, namely 100 mm; blowing by using a water beam after rough rolling;
(3) a finish rolling procedure: before finish rolling, water beam purging is used, the single-pass reduction rate is 20%, and the total reduction rate is 50%; the linear speed of the last three working rolls of the finish rolling is 1.50m/s, and the deformation rate is 0.4s-1(ii) a The finish rolling working roll adopts a flat roll, and the finish rolling machine adopts a kilometer number of 12 ㎞; the relaxation time after finish rolling is 10 s;
(4) a controlled cooling process: adopting a laminar cooling process, wherein the final cooling temperature is 450 ℃, the speed of a roller way is 0.7m/s, the water quantity ratio of the upper water to the lower water is controlled to be 1.6, and the cooling speed is 10 ℃/s; the plate enters a cooling system for cooling, a head and tail shielding function is adopted, and the shielding length is 0.4m, so that the temperature difference between the head and the tail of the plate and the middle of the plate is reduced;
(5) a thermal straightening process: the straightening temperature is 405 ℃, the roll gap of the straightening machine is controlled to be 50mm, the roll speed is 0.24m/s, and the setting of the roll gap of the straightening machine ensures that the plastic deformation depth of a rolled piece in the thickness direction is 72.5 percent.
The specification of the low-alloy high-strength finished steel plate rolled in the embodiment is 40 × 2400 × 14000mm, and the yield strength of the steel plate is 528 MPa; the maximum unevenness of the steel plate is 3mm/2m after surface inspection, and completely meets the requirements of national standards.
Example 8
The thickness of the low-alloy high-strength steel plate is 50mm, the specification of the continuous casting billet is 580 × 1800 × 2800mm, the plate shape control method in the rolling process of the low-alloy high-strength steel plate comprises the working procedures of heating, rough rolling, finish rolling, controlled cooling and hot straightening, and the specific process steps are as follows:
(1) a heating procedure: the heating temperature of the blank is 1100 ℃, the heating time is 12cm/min, the soaking time of the blank is 1.6cm/min, and the temperature difference of each point of the blank is 30 ℃ after the heating is finished;
(2) rough rolling procedure: the initial rolling temperature is 980 ℃, MAS rolling is used for rough rolling widening passes, the ratio of the height of a wedge-shaped section delta h to the thickness of a blank is 1:150, the length of a horizontal section L1 is 400mm, the length of a wedge-shaped section L2 is 600mm, the widening passes are carried out in 4 passes, and the steel turning passes are carried out in a single direction; longitudinal rolling is divided into 6 passes after widening passes, the roll gap values of the passes are set to be 180mm, 152mm, 142mm, 135mm, 1125mm and 99mm, the single-pass reduction rate is 12 percent, and the total reduction rate is 50 percent; the rough rolling working roll has positive convexity of 0.20 mm; the thickness of the intermediate blank is 3 times of the thickness of the finished product, namely 150 mm; blowing by using a water beam after rough rolling;
(3) a finish rolling procedure: before finish rolling, water beam purging is used, the single-pass reduction rate is 5%, and the total reduction rate is 30%; the linear velocity of the last three working rolls of the finish rolling is 1.0m/s, and the deformation rate is 1.0s-1(ii) a The finish rolling working roll adopts a flat roll, and the finish rolling machine adopts a kilometer number of 6 ㎞; the relaxation time after finish rolling is 50 s;
(4) a controlled cooling process: adopting a laminar cooling process, wherein the final cooling temperature is 650 ℃, the roller speed is 0.35m/s, the water quantity ratio of the upper water to the lower water is controlled at 2.4, and the cooling speed is 4 ℃/s; the plate enters a cooling system for cooling, a head and tail shielding function is adopted, and the shielding length is 0.3m, so that the temperature difference between the head and the tail of the plate and the middle of the plate is reduced;
(5) a thermal straightening process: the straightening temperature is 418 ℃, the roll gap of the straightening machine is controlled to be 11.5mm, the roll speed is 1.2m/s, and the setting of the roll gap of the straightening machine ensures that the plastic deformation depth in the thickness direction of the rolled piece is 70 percent.
The specification of the low-alloy high-strength finished steel plate after rolling in the embodiment is 50 × 2200 × 20000mm, and the steel plate performance: yield strength 502 MPa; the maximum unevenness of the steel plate is 6mm/2m after surface inspection, and completely meets the requirements of national standards.
Although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that: modifications and equivalents may be made thereto without departing from the spirit and scope of the invention and it is intended to cover in the claims the invention as defined in the appended claims.
Claims (10)
- The method for controlling the plate shape in the rolling process of the 1.500 MPa-level low-alloy high-strength steel plate is characterized by comprising the working procedures of heating, rough rolling, finish rolling, controlled cooling and thermal straightening, and comprises the following specific process steps:(1) a heating procedure: the heating temperature of the blank is 1100-1250 ℃, the heating time is 7-12 cm/min, and the soaking time of the blank is 1.6-2.5 cm/min; after heating, the temperature difference of each point of the blank is less than or equal to 30 ℃;(2) rough rolling procedure: the initial rolling temperature is 980-1080 ℃, MAS (Multi-media sheet) is used for rolling in rough rolling widening passes, the ratio of the delta h height of a wedge-shaped section to the blank thickness is 1: 50-1: 150, the length of a horizontal section L1 is 400mm, the length of a wedge-shaped section L2 is 200-600 mm, and the widening passes are carried out in 2-6 passes; 4-8 passes of longitudinal rolling are divided, the single-pass reduction rate is 12-25%, and the total reduction rate is 50-70%;(3) a finish rolling procedure: the single-pass reduction rate is 5-20%, and the total reduction rate is 30-50%; the linear velocity of the last three secondary working rolls of the finish rolling is less than or equal to 1.5m/s, and the deformation rate is less than or equal to 1s-1The relaxation time after finish rolling is 10-50 s;(4) a controlled cooling process: adopting a laminar cooling process, wherein the final cooling temperature is 450-650 ℃, and the cooling rate is less than or equal to 10 ℃/s;(5) a thermal straightening process: the straightening temperature is higher than 400 ℃, the roller speed is 0.24-1.2 m/s, and the setting of the roller gap of the straightening machine ensures that the plastic deformation depth of the rolled piece in the thickness direction is larger than or equal to 70%.
- 2. The method for controlling the plate shape in the rolling process of the 500 MPa-level low-alloy high-strength steel plate according to claim 1, wherein in the step (2), the rough rolling working roll has a positive convexity of 0.05-0.20 mm.
- 3. The method for controlling the plate shape in the rolling process of the 500MPa grade low-alloy high-strength steel plate according to claim 1, wherein in the step (3), the finish rolling work rolls use flat rolls.
- 4. The method for controlling the plate shape in the rolling process of the 500MPa grade low-alloy high-strength steel plate according to any one of claims 1 to 3, wherein in the step (3), before the low-alloy high-strength steel grade is rolled, the number of kilometers used by a finishing mill in a finishing rolling process is controlled to be 6 to 12 ㎞.
- 5. The method for controlling the plate shape in the rolling process of the 500MPa grade low-alloy high-strength steel plate according to any one of claims 1 to 3, wherein in the step (4), the plate enters a cooling system for cooling, and a head-to-tail shielding function is adopted, and the shielding length is 0.3-1.0 m.
- 6. The method for controlling the plate shape in the rolling process of the 500 MPa-level low-alloy high-strength steel plate according to any one of claims 1 to 3, wherein in the step (2), water beam blowing is used after rough rolling; and (3) blowing by using a water beam before finish rolling.
- 7. The method for controlling the plate shape in the rolling process of the 500 MPa-grade low-alloy high-strength steel plate according to any one of claims 1 to 3, wherein in the step (4), the roller speed is 0.35 to 1.0m/s, and the water ratio between the upper water and the lower water is controlled to be 1.6 to 2.4.
- 8. The method for controlling the plate shape in the rolling process of the 500MPa grade low-alloy high-strength steel plate according to any one of claims 1 to 3, wherein in the step (5), the roll gap of the straightener is controlled to be 11.5-50 mm.
- 9. The method for controlling the plate shape in the rolling process of the 500 MPa-grade low-alloy high-strength steel plate according to any one of claims 1 to 3, wherein the thickness of the steel plate produced by the method for controlling the plate shape is 12-50 mm, and the properties of the steel plate are as follows: the yield strength is more than or equal to 500 MPa.
- 10. The method for controlling the plate shape in the rolling process of the 500 MPa-grade low-alloy high-strength steel plate according to any one of claims 1 to 3, wherein the surface unevenness of the steel plate produced by the method for controlling the plate shape is less than or equal to 8mm/2 m.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910666476.1A CN110369519B (en) | 2019-07-23 | 2019-07-23 | Plate type control method for 500 MPa-level low-alloy high-strength steel plate in rolling process |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910666476.1A CN110369519B (en) | 2019-07-23 | 2019-07-23 | Plate type control method for 500 MPa-level low-alloy high-strength steel plate in rolling process |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110369519A CN110369519A (en) | 2019-10-25 |
| CN110369519B true CN110369519B (en) | 2020-10-02 |
Family
ID=68255192
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910666476.1A Active CN110369519B (en) | 2019-07-23 | 2019-07-23 | Plate type control method for 500 MPa-level low-alloy high-strength steel plate in rolling process |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110369519B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114888083B (en) * | 2022-06-25 | 2024-06-21 | 湖南华菱湘潭钢铁有限公司 | Method for rolling wide sheet by medium plate mill |
| CN115305330B (en) * | 2022-07-28 | 2024-05-14 | 鞍钢股份有限公司 | Plate shape control method for 460 MPa-level thick steel plate with thickness of more than 50mm |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2201972C2 (en) * | 2001-04-23 | 2003-04-10 | Открытое акционерное общество "Северсталь" | Method for making strips of low-alloy steel |
| KR100832970B1 (en) * | 2001-12-22 | 2008-05-27 | 주식회사 포스코 | Widthwide rolling method for prevention of camber of steel plate |
| CN102330023A (en) * | 2010-07-12 | 2012-01-25 | 马鞍山钢铁股份有限公司 | Steel for H steels at 500MPa level of yield strength and thermomechanical control process thereof |
| CN103866204B (en) * | 2014-02-27 | 2016-02-17 | 济钢集团有限公司 | The large sstrain X80 dual phase sheet steel that the large soft reduction process of a kind of low temperature is produced |
| CN104148384B (en) * | 2014-08-21 | 2016-04-20 | 柳州钢铁股份有限公司 | The rolling mill practice method of ultra-thin ultra-wide steel plate |
| CN104962812B (en) * | 2015-07-16 | 2017-03-08 | 武汉钢铁(集团)公司 | Hot continuous rolling axle housing steel and its manufacture method with good profile |
| CN109821903A (en) * | 2019-02-20 | 2019-05-31 | 攀钢集团攀枝花钢铁研究院有限公司 | The control method of high-strength steel hot rolled plate shape |
-
2019
- 2019-07-23 CN CN201910666476.1A patent/CN110369519B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN110369519A (en) | 2019-10-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105665443B (en) | A kind of rolling mill practice of wide and heavy plate mill production Limit specifications pipe line steel | |
| CN102699028A (en) | Method for eliminating linear edge defects of hot-rolled low-carbon steel | |
| CN103710507B (en) | A kind of preparation method of low nickel duplex stainless steel hot-rolled sheet coil | |
| CN108067507B (en) | Control method for rough rolling warping of hot-rolled variety steel | |
| CN102101124B (en) | Production method for eliminating edge defects of hot-rolled strip steel | |
| CN111069282B (en) | High-precision multi-segmentation hot-rolled steel bar grading and controlled cooling process method | |
| CN103173598B (en) | Annealing-free medium-high carbon steel plate making technology | |
| CN111676355B (en) | Online solution treatment process for austenitic stainless steel plate | |
| CN102717233B (en) | Method for manufacturing 304 precision stainless steel band of precision needle head | |
| CN104525560A (en) | Effective control method for pitted surface of plain carbon steel/Nb-containing steel plate of 20-30 mm thickness | |
| CN111889512B (en) | Method for producing thin steel plate by single-stand rolling mill | |
| CN105032958A (en) | Instant cooling system and cooling method for controlling rolling through interpass cooling technology | |
| CN110369519B (en) | Plate type control method for 500 MPa-level low-alloy high-strength steel plate in rolling process | |
| CN106311745A (en) | Hot rolling method for reducing red rust on surface of hot-rolled strip steel | |
| CN105689408A (en) | Hot rolling control method for iron scale on edge of low-carbon aluminum killed steel | |
| CN104438326B (en) | Rolling technology for high-carbon steel in thin slab casting and rolling | |
| CN110170528B (en) | Control method for white spot defect on surface of cold-rolled low-carbon steel | |
| CN111635986B (en) | Head and tail temperature control method for hectometer heat-treated steel rail | |
| JP2022549653A (en) | Thick and medium plate production line and production method directly connected to an efficient two-stand double cutting line | |
| CN103008361B (en) | Method for controlling bending of steel plate head | |
| CN109365527B (en) | Rolling method of wide and thick steel plate with large spreading ratio | |
| CN104588418A (en) | Method for overcoming defect of pocks on surface of ultra-low carbon steel | |
| CN113560343A (en) | Method for controlling grain size of low-carbon austenitic stainless steel extra-thick plate | |
| CN110860577B (en) | Short-process preparation method of TA5 titanium alloy wide medium plate | |
| CN108188175A (en) | A kind of CrMnTiH Series Gears steel and its milling method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| PE01 | Entry into force of the registration of the contract for pledge of patent right |
Denomination of invention: Method for controlling the shape of 500MPa low alloy high-strength steel plate during rolling process Granted publication date: 20201002 Pledgee: Bank of Cangzhou Limited by Share Ltd. Yutian branch Pledgor: TANGSHAN HEAVY PLATE CO.,LTD.|TANGSHAN IRON&STEEL GROUP Co.,Ltd.|HBIS COMPANY LIMITED TANGSHAN BRANCH Registration number: Y2024980001649 |
|
| PE01 | Entry into force of the registration of the contract for pledge of patent right |