Rolling method of thin-gauge 9Cr heat-resistant steel single-stand steckel mill
By employing a nine-pass rolling method, combined with appropriate rolling tonnage and heating conditions, the problems of thickness accuracy and shape control when rolling SA1017Gr92 steel on a single-stand hot roll mill were solved, achieving high tolerance requirements and efficient production.
Patent Information
- Application Number
- CN202511205769.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-27
- Publication Date
- 2025-11-11
AI Technical Summary
When rolling SA1017Gr92 steel on a single-stand hot roll mill, the thickness accuracy is difficult to control, making it difficult to meet high tolerance requirements, and the shape control is not perfect.
A nine-pass rolling method is adopted, combined with reasonable rolling tonnage, heating conditions and coiling furnace insulation, the coiling furnace temperature is controlled above 850℃, the reduction rate of the last pass is ≤15%, and the bending roll force of each pass is 700KN-800KN to ensure the plate shape.
It has achieved thickness accuracy and shape control during single-stand hot roll mill rolling, improving production efficiency and product quality.
Smart Images
Figure CN120920501A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of iron and steel metallurgy technology, and in particular to a rolling method for thin-gauge 9Cr heat-resistant steel single-stand furnace coil rolling mill. Background Technology
[0002] SA1017Gr92 steel, with its excellent high-temperature strength, oxidation resistance, and creep resistance, is widely used in many key fields such as energy and chemical industry. Especially thin-gauge SA1017Gr92 steel plates are in high demand in the manufacture of certain key components for supercritical power plant boilers, as they can effectively reduce equipment weight and improve energy efficiency. While single-stand hot-rolling mills are suitable for thin-gauge rolling, the thickness accuracy is difficult to control when rolling this steel, making it difficult to meet high tolerance requirements; furthermore, the coupling control of various factors in plate shape control is not perfect. Summary of the Invention
[0003] The purpose of this application is to provide a rolling method for thin-gauge 9Cr heat-resistant steel using a single-stand furnace coil mill, which solves the problems in related technologies where the thickness accuracy is difficult to control and high tolerance requirements are difficult to meet when rolling this steel using a single-stand furnace coil mill; and the coupling control of various factors in the shape control is not perfect.
[0004] To solve the above-mentioned technical problems, this application adopts the following technical solution:
[0005] This application provides a method for rolling thin-gauge 9Cr heat-resistant steel using a single-stand furnace coil mill, including the following steps:
[0006] (1) Raw material preparation: Select billets that meet the requirements and inspect and clean the billets;
[0007] (2) Planning and scheduling: Scheduling shall be carried out during the rolling period of 300-1000 rolling tons;
[0008] (3) Heating: The billet is sent into a heating furnace for heating at a temperature of 1240℃-1260℃ for a time of 150min-300min;
[0009] (4) Descaling: Descaling is performed on the surface of the heated billet using a coarse descaling box;
[0010] (5) Rolling: The billet is rolled in 9 passes to obtain 9Cr heat-resistant steel;
[0011] In particular, the coiling process is kept warm in the coiling furnace from the 5th to the 8th pass, with the temperature of the coiling furnace being ≥850℃. The reduction rate of the last pass is ≤15%, and the bending force of each pass is 700KN-800KN.
[0012] This scheme achieves the production of 9Cr heat-resistant steel using a single-stand hot run mill through raw material preparation, planning, heating, descaling, and rolling steps. By rationally selecting materials, rolling tonnage, and heating conditions, the thickness accuracy during rolling on the single-stand hot run mill is ensured to meet high tolerance requirements. This scheme employs a 9-pass rolling process without controlled rolling. Passes 5-8 involve heat preservation in the coiling furnace, with the furnace temperature controlled above 850℃ to guarantee the shape of the rolled sheet at both ends. Furthermore, the reduction rate in the final pass is ≤15%, and the bending roll force in each pass is 700KN-800KN, further ensuring the rolled sheet shape.
[0013] Optionally, in the raw material preparation step, a blank with a thickness of 150mm, a width of 2000mm-2100mm, and a length of 5900mm-8800mm is selected.
[0014] Optionally, in the heating step, the temperature at the beginning and end of the billet is 10°C-15°C higher than the temperature in the middle.
[0015] In this scheme, by heating the billet to a higher temperature at the beginning and end than in the middle, the heat loss during rolling is compensated, and the uniformity of performance is enhanced.
[0016] Optionally, in the rolling step, the billet is descaled 1-3 times with a descaling pressure ≥20MPa.
[0017] Optionally, in the planning and scheduling steps, before rolling, 1-2 rows of transition billets are loaded first. The thickness of the transition billets is greater than the thickness of the billets, and the difference is no more than 2 mm. The difference between the width of the transition billets and the width of the billets is within 400 mm.
[0018] Optionally, after the raw material preparation step and before the planning and scheduling step, the method further includes: preheating the billet to a preheating temperature ≥200℃.
[0019] Optionally, in the rolling step, the billet length is controlled to be ≤220m.
[0020] Optionally, after rolling, the process further includes: segmenting the 9Cr heat-resistant steel using a flying shear.
[0021] Optionally, the 9Cr heat-resistant steel can be segmented using flying shears, and air cooling can also be performed on a cooling bed.
[0022] Optionally, in the descaling step, the coarse descaling box descales the heated billet surface once.
[0023] Compared with existing technologies, the beneficial effects achieved by this application are as follows: This application realizes the production of 9Cr heat-resistant steel using a single-stand furnace coil mill through raw material preparation, planning, heating, descaling, and rolling steps. By rationally selecting materials, rolling tonnage, and heating conditions, the thickness accuracy during rolling using the single-stand furnace coil mill is ensured to meet high tolerance requirements. This application employs a 9-pass rolling process; among which, the 5th to 8th passes are held in a coiling furnace at a temperature controlled above 850℃ to guarantee the shape of the rolled sheet at both ends. Furthermore, with a reduction rate ≤15% in the final pass and bending roll forces of 700KN-800KN in each pass, the rolled sheet shape is further ensured, thereby improving production efficiency and guaranteeing product quality. Attached Figure Description
[0024] To more clearly illustrate the technical solutions in the embodiments or related technologies of this disclosure, the accompanying drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0025] Figure 1 This is the rolling pass parameter table of Embodiment 1 provided in this application. Detailed Implementation
[0026] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure / application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use.
[0027] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention, as well as the prior art known to those skilled in the art and the description of the invention, may be implemented using any prior art methods, devices, and materials similar to or equivalent to the methods, devices, and materials in the embodiments of the present invention.
[0028] This invention provides a method for rolling thin-gauge 9Cr heat-resistant steel using a single-stand furnace coil mill, comprising:
[0029] (1) Raw material preparation: Select billets that meet the requirements and inspect and clean them;
[0030] The selected billets have a thickness of 150mm, a width of 2000mm-2100mm, and a length of 5900mm-8800mm. Before loading the billets into the furnace, the surface of the billets is inspected and cleaned to ensure that there are no defects such as scabs, inclusions, burrs, or indentations. Special attention is paid to checking whether there are cracks on the edges of the billets to prevent tearing of the rolled pieces during the rolling process.
[0031] In some embodiments, after ensuring that the billet meets the requirements, the billet is preheated at a preheating temperature ≥200°C.
[0032] (2) Planning and scheduling: Scheduling shall be carried out during the rolling period of 300-1000 rolling tons;
[0033] (3) Heating: The billet is sent into a heating furnace for heating at a temperature of 1240℃-1260℃ and for a time of 150min-300min.
[0034] The billet is fed into a heating furnace for heating at a temperature of 1240℃-1260℃, for example: 1240℃, 1250℃, 1260℃. The furnace time is 150min-300min, for example: 150min, 160min, 170min, 180min, 190min, 200min, 210min, 220min, 230min, 240min, 250min, 260min, 270min, 280min, 290min, 300min. During heating, the temperature at the beginning and end of the billet is kept 10℃-15℃ higher than the temperature in the middle to compensate for heat loss during subsequent rolling.
[0035] (4) Descaling: Descaling is performed on the surface of the heated billet using a coarse descaling box;
[0036] In some embodiments, a coarse descaling box is used to descale the surface of the heated billet in one pass.
[0037] (5) Rolling: The billet is rolled in 9 passes to obtain 9Cr heat-resistant steel;
[0038] The winding process involves heat preservation in a coiling furnace during passes 5-8, with the furnace temperature ≥850℃. The final pass has a reduction rate ≤15%, and the bending roller force for each pass is 700KN-800KN.
[0039] Nine rolling passes are employed, with no controlled rolling during the process. Passes 5-8 involve heat treatment in a coiling furnace, with the furnace temperature controlled above 850℃ to ensure the shape of the rolled sheet at both ends. Furthermore, the reduction rate in the final pass is ≤15%, and the bending roll force in each pass is 700KN-800KN, further ensuring the rolled sheet shape.
[0040] In some embodiments, during the rolling process, descaling is performed 1-3 times depending on the shape of the sheet at each rolling stage, with a descaling pressure ≥20MPa. During the rolling process, the billet length is controlled to ≤220m.
[0041] In some embodiments, 1-2 rows of transition billets are loaded before rolling. The thickness of the transition billets is greater than the thickness of the 9Cr heat-resistant steel, but the difference is not more than 2 mm. The difference between the width of the transition billets and the width of the 9Cr heat-resistant steel is within 400 mm.
[0042] After rolling, the 9Cr heat-resistant steel is segmented using a flying shear and then air-cooled on a cooling bed.
[0043] To facilitate a further understanding of the present invention by those skilled in the art, the following examples are provided:
[0044] Example 1
[0045] This embodiment describes a rolling method for thin-gauge 9Cr heat-resistant steel using a single-stand furnace coil rolling mill, including the following steps:
[0046] (1) Raw material preparation: Select a billet with a thickness of 150mm, a width of 2024mm, and a length of 6985mm, and inspect and clean the billet.
[0047] (2) Planning and arrangement: Before rolling, arrange the finished product with a thickness of 6mm-7mm and a width of 2000mm-2400mm in the heating furnace to ensure the shape of the rolled plate. The rolled product will be produced in the later stage of the working roll at 958t.
[0048] (3) Heating: The billet is sent into a heating furnace for heating at a temperature of 1246℃ for 181 min.
[0049] (4) Descaling: The surface of the heated billet is descaled once using a coarse descaling box;
[0050] (5) Rolling, see reference Figure 1 The billet was rolled in 9 passes to obtain 9Cr heat-resistant steel. In the first pass, the rolled piece was descaled at a pressure of 22.4 MPa. Passes 5-8 were held in a coiling furnace at 850℃. The final pass had a reduction rate of 11.22%, and the bending force of each pass was 700-800 kN.
[0051] Example 2
[0052] This embodiment describes a rolling method for thin-gauge 9Cr heat-resistant steel using a single-stand furnace coil rolling mill, including the following steps:
[0053] (1) Raw material preparation: Select a billet with a thickness of 150mm, a width of 2000mm, and a length of 5900mm; inspect and clean the billet. After the raw material preparation is completed, preheat the billet to 200℃.
[0054] (2) Planning and arrangement: Before rolling, arrange the finished product with a thickness of 6mm and a width of 2000mm in the heating furnace to ensure the shape of the rolled plate. The rolled product will be produced in the later stage of the working roll 300t.
[0055] Heating: The billet is sent into a heating furnace for heating at a temperature of 1240℃ for 150 minutes.
[0056] Descaling is performed by using a coarse descaling box to descale the surface of the heated billet in one pass.
[0057] The billet is rolled in 9 passes to obtain 9Cr heat-resistant steel. In the first pass, the workpiece is descaled at a pressure of 20 MPa. The workpiece is then held in a coiling furnace at a temperature of 850°C in passes 5-8. The reduction rate in the last pass is 11%, and the bending force of each pass is 700-800 kN.
[0058] Example 3
[0059] This embodiment describes a rolling method for thin-gauge 9Cr heat-resistant steel using a single-stand furnace coil rolling mill, including the following steps:
[0060] (1) Raw material preparation: Select a billet with a thickness of 150mm, a width of 2100mm, and a length of 8800mm; inspect and clean the billet. After the raw material preparation is completed, preheat the billet to 250℃.
[0061] (2) Planning and arrangement: Before rolling, arrange the finished product with a thickness of 6mm and a width of 2100mm in the heating furnace to ensure the shape of the rolled plate. The rolled product will be produced in the later stage of 1000t of the working roll.
[0062] (3) Heating: The billet is sent into a heating furnace for heating at a temperature of 1260℃ for 300 min.
[0063] (4) Descaling: The surface of the heated billet is descaled once using a coarse descaling box;
[0064] (5) Rolling: The billet is rolled in 9 passes to obtain 9Cr heat-resistant steel. In the first to third passes of rolling, the workpiece is descaled at a pressure of 25 MPa. In the fifth to eighth passes, the workpiece is held in a coiling furnace at a temperature of 1000℃. The reduction rate in the last pass is 13%, and the bending force of each pass is 700KN-800KN.
[0065] Example 4
[0066] This embodiment describes a rolling method for thin-gauge 9Cr heat-resistant steel using a single-stand furnace coil rolling mill, including the following steps:
[0067] (1) Raw material preparation: Select a billet with a thickness of 150mm, a width of 2050mm, and a length of 6500mm. Inspect and clean the billet. After the raw material preparation is completed, preheat the billet to 250℃.
[0068] (2) Planning and arrangement: Before rolling, arrange the finished product with a thickness of 7mm and a width of 2050mm in the heating furnace to ensure the shape of the rolled plate. The rolled product will be produced in the later stage of the working roll at 800t.
[0069] (3) Heating: The billet is sent into a heating furnace for heating at a temperature of 1250°C for 230 minutes.
[0070] (4) Descaling: The surface of the heated billet is descaled once using a coarse descaling box;
[0071] (5) Rolling: The billet is rolled in 9 passes to obtain 9Cr heat-resistant steel. In the first and second passes of rolling, the workpiece is descaled at a pressure of 22 MPa. In the 5th to 8th passes, the workpiece is kept warm in a coiling furnace at a temperature of 900℃. The reduction rate in the last pass is 14%, and the bending force of each pass is 700KN-800KN.
[0072] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this disclosure / application, and these improvements and modifications should also be considered within the protection scope of this disclosure / application.
Claims
1. A method for rolling thin-gauge 9Cr heat-resistant steel using a single-stand furnace coil rolling mill, characterized in that, Including the following steps: (1) Raw material preparation: Select billets that meet the requirements and inspect and clean the billets; (2) Planning and scheduling: Scheduling shall be carried out during the rolling tonnage of 300-1000 rolls in the working roll period; (3) Heating: The billet is sent into a heating furnace for heating at a temperature of 1240℃-1260℃ for a time of 150min-300min; (4) Descaling: Descaling is performed on the surface of the heated billet using a coarse descaling box; (5) Rolling: The billet is rolled in 9 passes to obtain 9Cr heat-resistant steel; In particular, the coiling process is kept warm in the coiling furnace from the 5th to the 8th pass, with the temperature of the coiling furnace being ≥850℃. The reduction rate of the last pass is ≤15%, and the bending force of each pass is 700KN-800KN.
2. The rolling method for thin-gauge 9Cr heat-resistant steel single-stand hot-roll mill according to claim 1, characterized in that, In the raw material preparation step, a blank with a thickness of 150mm, a width of 2000mm-2100mm, and a length of 5900mm-8800mm is selected.
3. The rolling method for thin-gauge 9Cr heat-resistant steel single-stand furnace coil according to claim 1, characterized in that, After the raw material preparation step and before the planning and scheduling step, the method further includes: preheating the billet to a preheating temperature ≥200℃.
4. The rolling method for thin-gauge 9Cr heat-resistant steel single-stand hot runner coils according to claim 1, characterized in that, In the heating step, the temperature at the beginning and end of the billet is 10°C-15°C higher than the temperature in the middle.
5. The rolling method for thin-gauge 9Cr heat-resistant steel single-stand furnace coil according to claim 1, characterized in that, In the descaling step, the coarse descaling box descales the surface of the heated billet in one pass.
6. The rolling method for thin-gauge 9Cr heat-resistant steel single-stand hot-roll mill according to claim 1, characterized in that, In the planning and arrangement steps, before rolling, 1-2 rows of transition billets are loaded first. The thickness of the transition billets is greater than that of the 9Cr heat-resistant steel, but the excess is not more than 2mm. The difference between the rolling width of the 9Cr heat-resistant steel and the width of the billets is within 400mm.
7. The rolling method for thin-gauge 9Cr heat-resistant steel single-stand furnace coil according to claim 1, characterized in that, In the rolling step, the billet is descaled 1-3 times with a descaling pressure ≥20MPa.
8. The rolling method for thin-gauge 9Cr heat-resistant steel single-stand furnace coil mill according to claim 1, characterized in that, In the rolling process, the billet length is controlled to be ≤220m.
9. The rolling method for thin-gauge 9Cr heat-resistant steel single-stand furnace coil mill according to claim 1, characterized in that, After rolling, the process also includes: segmenting the 9Cr heat-resistant steel using a flying shear.
10. The rolling method for thin-gauge 9Cr heat-resistant steel single-stand hot-roll mill according to claim 1, characterized in that, After segmenting 9Cr heat-resistant steel using flying shears, the process also includes air cooling on a cooling bed.