ENDLESS HOT-ROLLED STRIP PRODUCTION DEVICE AND METHOD FOR FERRITE ROLLING

Abstract

The device has a short production line, and all components are reasonably configured. A multifunctional cooling control device is adopted to integrate high-pressure water descaling and intermediate billet cooling functions, which is simpler and more efficient. Layout of a 4R+(3−4)F rolling mill, four thermos-detectors and short-distance underground coilers are use. The method includes the steps: carrying out continuous casting to manufacture a slab, high-pressure water rotating descaling, rough rolling by a four-stand high reduction rough rolling unit, machining by a drum shear, cooling after high-pressure water descaling in the multifunctional cooling control device, finish rolling by a three-stand or four-stand finish rolling unit, air cooling, dividing coils by a high-speed flying shear, and coiling by underground coilers, wherein temperature monitoring is respectively carried out after rough rolling, before finish rolling, after finish rolling, and before coiling by the underground coiler.

Claims

1. An endless hot-rolled strip production device for ferrite rolling, comprising a continuous casting machine, a high-pressure water rotating descaling device, a four-stand high reduction rough rolling unit, a drum shear, thermo-detectors, a multifunctional cooling control device, a three-stand or four-stand finish rolling unit, a high-speed flying shear, and underground coilers, wherein, the number of the thermo-detectors is four, and the thermo-detectors are respectively arranged behind the four-stand high reduction rough rolling unit, in front of and behind the three-stand or four-stand finish rolling unit, and in front of the underground coilers; and all components are connected in sequence.

2. The endless hot-rolled strip production device for ferrite rolling according to claim 1, wherein the multifunctional cooling control device has a length of 5 m-10 m and is divided into two sections, the front section being a high-pressure water descaling device and the rear section being a water-cooling or mist cooling device.

3. The endless hot-rolled strip production device for ferrite rolling according to claim 1, wherein the underground coilers are two conventional underground coilers, wherein a distance from a last finish rolling stand to the first coiler is 10 m-45 m, and a distance from the last finish rolling stand to the second coiler is 15 m-50 m; and the underground coilers can also adopt one rotating two-reel coiler, and a distance from the underground coiler to the last finish rolling stand is 10 m-50 m.

4. The endless hot-rolled strip production device for ferrite rolling according to claim 3, wherein the underground coilers are two conventional underground coilers, wherein the distance from the last finish rolling stand to the first coiler is 15 m-30 m, and the distance from the last finish rolling stand to the second coiler is 20 m-35 m; and the underground coilers can also adopt one rotating two-reel coiler, and the distance from the underground coiler to the last finish rolling stand is 15 m-30 m.

5. An endless hot-rolled strip production method for ferrite rolling using the device according to claim 1, wherein the production process comprises the steps of carrying out continuous casting to manufacture a slab, high-pressure water rotating descaling, rough rolling by the four-stand high reduction rough rolling unit, machining by the drum shear, cooling after high-pressure water descaling in the multifunctional cooling control device, finish rolling by the three-stand or four-stand finish rolling unit, air cooling, dividing coils by the high-speed flying shear, and coiling by the underground coilers, wherein temperature monitoring is respectively carried out after rough rolling, before finish rolling, after finish rolling, and before coiling by the underground coilers.

6. The endless hot-rolled strip production method for ferrite rolling according to claim 5, wherein a temperature at an entrance of rough rolling of a continuously casting slab is 1050° C.-1250° C. and a temperature at an exit of rough rolling is 950° C.-1000° C., an intermediate billet after rough rolling is cooled by the multifunctional cooling control device at a cooling speed of 20° C./s-50° C./s, a temperature at an entrance of finish rolling is 780° C.-880° C., a temperature at an exit of finish rolling is 700° C.-800° C., and after air cooling, a coiling temperature is 650° C.-750° C.; and after being unloaded from the coilers, steel coils are thermally insulated with an on-line thermal insulation cover, or quickly sent to a thermal insulation pit until the temperature drops below 550° C.

7. The endless hot-rolled strip production method for ferrite rolling according to claim 5, wherein a reduction rate of each stand of the rough rolling unit is 40%-60% and a speed at the exit of rough rolling is 0.5 m/s-2.0 m/s; a reduction rate of the first two stands of the three-stand or four-stand finish rolling unit is 40%-60% and a reduction rate of the last stand is 10%-25%, wherein a reduction rate of the third stand is 20%-45% when the finish rolling unit is a four-stand finish rolling unit; and the finish rolling unit adopts lubrication rolling.

8. The endless hot-rolled strip production method for ferrite rolling according to claim 5, wherein a descaling pressure for the high-pressure water rotating descaling before rough rolling and a descaling pressure for the high-pressure water descaling in the multifunctional cooling control device before finish rolling are both 20 MPa-40 MPa.

9. The endless hot-rolled strip production method for ferrite rolling according to claim 5, wherein a thickness range of the continuously casting slab is 70 mm-130 mm, and a drawing speed of the continuous casting is 4.5 m/min-7.0 m/min; a thickness of the intermediate billet at the exit of rough rolling is 5 mm-15 mm; and a thickness of a finished product is 0.6 mm-3.0 mm.

10. The endless hot-rolled strip production method for ferrite rolling according to claim 5, wherein applicable strip is low carbon with C≤0.05%, Si≤0.10% and Mn≤0.20% in terms of percentage content or ultra-low carbon steel.

11. An endless hot-rolled strip production method for ferrite rolling using the device according to claim 2, wherein the production process comprises the steps of carrying out continuous casting to manufacture a slab, high-pressure water rotating descaling, rough rolling by the four-stand high reduction rough rolling unit, machining by the drum shear, cooling after high-pressure water descaling in the multifunctional cooling control device, finish rolling by the three-stand or four-stand finish rolling unit, air cooling, dividing coils by the high-speed flying shear, and coiling by the underground coilers, wherein temperature monitoring is respectively carried out after rough rolling, before finish rolling, after finish rolling, and before coiling by the underground coilers.

12. An endless hot-rolled strip production method for ferrite rolling using the device according to claim 3, wherein the production process comprises the steps of carrying out continuous casting to manufacture a slab, high-pressure water rotating descaling, rough rolling by the four-stand high reduction rough rolling unit, machining by the drum shear, cooling after high-pressure water descaling in the multifunctional cooling control device, finish rolling by the three-stand or four-stand finish rolling unit, air cooling, dividing coils by the high-speed flying shear, and coiling by the underground coilers, wherein temperature monitoring is respectively carried out after rough rolling, before finish rolling, after finish rolling, and before coiling by the underground coilers.

13. An endless hot-rolled strip production method for ferrite rolling using the device according to claim 4, wherein the production process comprises the steps of carrying out continuous casting to manufacture a slab, high-pressure water rotating descaling, rough rolling by the four-stand high reduction rough rolling unit, machining by the drum shear, cooling after high-pressure water descaling in the multifunctional cooling control device, finish rolling by the three-stand or four-stand finish rolling unit, air cooling, dividing coils by the high-speed flying shear, and coiling by the underground coilers, wherein temperature monitoring is respectively carried out after rough rolling, before finish rolling, after finish rolling, and before coiling by the underground coilers.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 is an endless hot-rolled strip production device for ferrite rolling according to an embodiment of the present disclosure, wherein the reference sign “1” represents a continuous casting machine, “2” represents a high-pressure water rotating descaling device, “3” represents a four-stand high reduction rough rolling unit, “4” represents a drum shear, “5a”, “5b”, “5c” and “5d” represent thermo-detectors, “6” represents a multifunctional cooling control device, “7” represents a three-stand or four-stand finish rolling unit, “8” represents a high-speed flying shear, “9a” and “9b” represent underground coilers, L1 is a distance from the last finish rolling stand to the first coiler, and L2 is a distance from the last finish rolling stand to the second coiler

[0027] FIG. 2 is a schematic diagram of key process points of an endless hot-rolled strip production method for ferrite rolling according to an embodiment of the present disclosure.

DESCRIPTION OF THE EMBODIMENTS

[0028] The present disclosure will be further described in detail below with reference to specific embodiments.

Embodiment 1

[0029] The following chemical components and mass percent of low carbon steel are adopted: C: 0.05%, Si: 0.10%, Mn: 0.20%, P: 0.010%, S: 0.005%, N: 0.0040%, and the balance being Fe. A thickness of a continuously casting slab is 130 mm, a drawing speed is 4.5 m/min, a slab exits a continuous casting machine and then is subjected to high-pressure water rotating descaling at a descaling pressure of 20 MPa, and then directly enters a four-stand high reduction rough rolling unit for rolling (a reduction rate is 50%, 50%, 40% and 40%, respectively), a temperature of the slab before rough rolling is 1080° C., an intermediate billet after rough rolling has a thickness of 11.7 mm, an exit speed of 0.83 m/s and an exit temperature of 950° C., the intermediate billet enters a multifunctional cooling control device for high-pressure water descaling and controlled cooling, a length of the multifunctional cooling control device is 7 m, a high-pressure water descaling pressure is 35 MPa, and a cooling speed of a cooling section is 30° C. Is, a temperature of the intermediate billet before entering the finish rolling mill is 810° C., and then finish rolling by four stands is carried out (a reduction rate is 50%, 40%, 30% and 15%, respectively). Each stand of the finish rolling adopts lubrication rolling. The thickness of the strip at the exit is 2.0 mm, the final rolling temperature is 740° C., and an air cooling mode is adopted after the strip exits the finish rolling. The underground coilers are two conventional underground coilers, a distance L1 from the last finish rolling stand to the first coiler is 15 m, and the strip enters the first underground coiler to be coiled after delivering for 15 m on a runout table, and the coiling temperature is 710° C. A high-speed flying shear shears the steel coils according to requirements for weight of the strip coils, the sheared coils are unloaded and then thermally insulated with a thermal insulation cover, and when the temperature slowly drops 550° C. or below, the coils are naturally air cooled. By using the above process, the material performance meets standard requirements.

Embodiment 2

[0030] The following chemical components and mass percent of low carbon steel are adopted: C: 0.025%, Si: 0.07%, Mn: 0.10%, P: 0.010%, S: 0.004%, N: 0.0045%, and the balance being Fe. A thickness of a continuously casting slab is 70 mm, a drawing speed is 7 m/min, a slab exits a continuous casting machine and then is subjected to high-pressure water rotating descaling at a descaling pressure of 40 MPa, and then directly enters a four-stand high reduction rough rolling unit for rolling, a temperature of the slab before rough rolling is 1150° C., an intermediate billet after rough rolling has a thickness of 5 mm (a reduction rate is 60%, 50%, 40% and 40%, respectively), an exit speed of 1.6 m/s and an exit temperature of 980° C., the intermediate billet enters a multifunctional cooling control device for high-pressure water descaling and controlled cooling, a length of the multifunctional cooling control device is 5 m, a high-pressure water descaling pressure is 36 MPa, and a cooling speed of a cooling section is 35° C./s, a temperature of the intermediate billet before entering the finish rolling mill is 820° C., and then finish rolling by three stands is carried out (a reduction rate is 53%, 48% and 15%, respectively). Each stand of the finish rolling adopts lubrication rolling. The thickness of the strip at the exit is 1.0 mm, the final rolling temperature is 750° C., and an air cooling mode is adopted after the strip exits the finish rolling. The underground coilers are two conventional underground coilers, a distance L2 from the last finish rolling stand to the second coiler is 30 m, and the strip enters the second underground coiler to be coiled after delivering for 30 m on a runout table, and the coiling temperature is 700° C. A high-speed flying shear shears the coils according to requirements for weight of the strip coils, the sheared coils are unloaded and then sent to a thermal insulation pit for thermal insulation, and when the temperature slowly drops 450° C. or below, the coils are naturally air cooled.

Embodiment 3

[0031] The following chemical conponents and mass percent of ultra-low carbon steel are adopted: C: 0.0035%, Si: 0.03%, Mn: 0.08%, P: 0.009%, S: 0.003%, N: 0.0040%, and the balance being Fe. A thickness of a continuously casting slab is 110 mm, a drawing speed is 5.5 m/min, a slab exits a continuous casting machine and then is subjected to high-pressure water rotating descaling at a descaling pressure of 25 MPa, and then directly enters a four-stand high reduction rough rolling unit for rolling (a reduction rate is 55%, 50%, 46% and 40%, respectively), a temperature of the slab before rough rolling is 1200° C., an intermediate billet after rough rolling has a thickness of 8 mm, an exit speed of 1.26 m/s and an exit temperature of 970° C., the intermediate billet enters a multifunctional cooling control device for high-pressure water descaling and controlled cooling, a length of the multifunctional cooling control device is 7 m, a high-pressure water descaling pressure is 32 MPa, and a cooling speed of a cooling section is 30° C./s, a temperature of the intermediate billet before entering the finish rolling mill is 860° C., and then finish rolling by four stands is carried out (a reduction rate is 55%, 50%, 45% and 15%, respectively). Each stand of the finish rolling adopts lubrication rolling. The thickness of the strip at the exit is 0.8 mm, the final rolling temperature is 780° C., and an air cooling mode is adopted after the strip exits the finish rolling. The underground coilers are one rotating two-reel coiler, a distance from the last finish rolling stand to the coiler is 20 m, and the strip enters the rotating two-reel coiler to be coiled after delivering for 20 m on a runout table, and the coiling temperature is 730° C. A high-speed flying shear shears the coils according to requirements for weight of the strip coils, the sheared coils are unloaded and then sent to a thermal insulation cover for thermal insulation, and when the temperature slowly drops 350° C. or below, the coils are naturally air cooled.

Embodiment 4

[0032] The following chemical components and mass percent of ultra-low carbon steel are adopted: C: 0.0015%, Si: 0.05%, Mn: 0.10%, P: 0.008%, S: 0.004%, N: 0.0035%, and the balance being Fe. A thickness of a continuously casting slab is 100 mm, a drawing speed is 6.0 m/min, a slab exits a continuous casting machine and then is subjected to high-pressure water rotating descaling at a descaling pressure of 35 MPa, and then directly enters a four-stand high reduction rough rolling unit for rolling (a reduction rate is 55%, 50%, 48% and 40%, respectively), a temperature of the slab before rough rolling is 1250° C., an intermediate billet after rough rolling has a thickness of 7 mm, an exit speed of 1.43 m/s and an exit temperature of 1000° C., the intermediate billet enters a multifunctional cooling control device for high-pressure water descaling and controlled cooling, a length of the multifunctional cooling control device is 7 m, a high-pressure water descaling pressure is 34 MPa, and a cooling speed of a cooling section is 30° C./s, a temperature of the intermediate billet before entering the finish rolling mill is 870° C., and then finish rolling by three stands is carried out (a reduction rate is 55%, 45% and 13%, respectively). Each stand of the finish rolling adopts lubrication rolling. The thickness of the strip at the exit is 1.5 mm, the final rolling temperature is 800° C., and an air cooling mode is adopted after the strip exits the finish rolling. The underground coilers are two conventional underground coilers, a distance L1 from the last finish rolling stand to the first coiler is 30 m, and the strip enters the first underground coiler to be coiled after delivering for 30m on a runout table, and the coiling temperature is 720° C. A high-speed flying shear shears the coils according to requirements for weight of the strip coils, the sheared coils are unloaded and then sent to a thermal insulation cover for thermal insulation, and when the temperature slowly drops 400° C. or below, the coils are naturally air cooled.

Embodiment 5

[0033] The following chemical components and mass percent of ultra-low carbon steel are adopted: C: 0.0010%, Si: 0.035%, Mn: 0.08%, P: 0.008%, S: 0.004%, N: 0.0035%, and the balance being Fe. A thickness of a continuously casting slab is 120 mm, a drawing speed is 5.0 m/min, a slab exits a continuous casting machine and then is subjected to high-pressure water rotating descaling at a descaling pressure of 25 MPa, and then directly enters a four-stand high reduction rough rolling unit for rolling (a reduction rate is 50%, 50%, 45% and 40%, respectively), a temperature of the slab before rough rolling is 1130° C., an intermediate billet after rough rolling has a thickness of 10 mm, an exit speed of 1 m/s and an exit temperature of 980° C., the intermediate billet enters a multifunctional cooling control device for high-pressure water descaling and controlled cooling, a length of the multifunctional cooling control device is 7 m, a high-pressure water descaling pressure is 36 MPa, and a cooling speed of a cooling section is 25° C./s, a temperature of the intermediate billet before entering the finish rolling mill is 880° C., and then finish rolling by four stands is carried out (a reduction rate is 55%, 45%, 25% and 13%, respectively). Each stand of the finish rolling adopts lubrication rolling. The thickness of the strip at the exit is 1.6 mm, the final rolling temperature is 790° C., and an air cooling mode is adopted after the strip exits the finish rolling. The underground coilers are two conventional underground coilers, a distance L2 from the last finish rolling stand to the second coiler is 35 m, and the strip enters the second underground coiler to be coiled after delivering for 35 m on a runout table, and the coiling temperature is 720° C. A high-speed flying shear shears the coils according to requirements for weight of the strip coils, the sheared coils are unloaded and then sent to a thermal insulation cover for thermal insulation, and when the temperature slowly drops 450° C. or below, the coils are naturally air cooled.