Large-thickness ultra-wide 20Mn23AlV steel plate and heating and rolling method
By using a phased heating and high-pressure water descaling method, the problems of center segregation and surface oxidation in the hot rolling process of thick and wide 20Mn23AlV steel plates were solved, and high-performance and high-yield steel plate production was achieved.
Patent Information
- Application Number
- CN202510915469.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-03
- Publication Date
- 2025-11-04
AI Technical Summary
Thick and wide 20Mn23AlV steel plates are prone to central segregation, banded structure, surface iron oxide scale and cracks during the hot rolling process, resulting in substandard performance and low yield.
A staged heating method is adopted, including heating in a homogenizing furnace under slightly positive pressure and weak oxidizing conditions, combined with high-pressure water descaling and rolling with a small number of passes and a large reduction, to ensure heating uniformity and microstructure uniformity and prevent surface oxidation.
It improved the flaw detection pass rate and yield of steel plates, resulting in good plate shape, clean and tidy surface, and excellent performance, meeting the needs of subsequent processing. The flaw detection pass rate increased from 80% to over 98%, and the yield increased from 85% to over 97%.
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of metal material processing, and particularly relates to a large-thickness and super-wide 20Mn23AlV steel plate, and further relates to a heating and rolling method of the large-thickness and super-wide 20Mn23AlV steel plate. BACKGROUND
[0002] 20Mn23AlV is a kind of high-manganese and high-aluminum non-magnetic austenitic steel plate, with a Mn content of 21.5-25% and an Al content of 1.5-2.5%. It has a low magnetic permeability and a high resistivity. In addition, since the steel is an austenitic steel, its electromagnetic performance is stable, and the eddy current loss in the magnetic field is extremely small. It also has good magnetic isolation performance, mechanical properties, and easy cutting performance, and is widely used in high-end transformers, large nuclear fusion devices, superconducting power generation, power transmission, special ships, national defense and military industry, and many other fields, and has a broad application prospect.
[0003] Since the Mn content of the steel is high, it is well known that the Mn content is prone to central segregation and banded structure, which leads to the fact that the yield strength, tensile strength and other performance indicators of the steel plate cannot meet the standard requirements, and the thicker and wider the steel plate is, the more difficult it is to guarantee its performance. At the same time, since manganese is easy to oxidize, if the heating and rolling process is not properly controlled, a large amount of iron oxide scale and cracks will appear on the surface of the steel plate. At present, the flaw detection qualified rate of 20Mn23AlV steel plate with a thickness of more than 50 mm and a width of more than 3000 mm is only 80%, and the yield rate is only 85%. SUMMARY
[0004] The purpose of the present application is to provide a heating and rolling method of a large-thickness and super-wide 20Mn23AlV steel plate, which eliminates the surface cracks of the steel plate and improves the flaw detection qualified rate and yield rate of the steel plate.
[0005] Another purpose of the present application is to provide a large-thickness and super-wide 20Mn23AlV steel plate.
[0006] The technical solution adopted by the present application is a large-thickness and super-wide 20Mn23AlV steel plate and a heating and rolling method, which comprises the following steps: Step 1, placing the 20Mn23AlV steel billet in the soaking furnace under the conditions of micro-positive pressure and weak oxidizing property, and performing first heat preservation; Step 2, heating the soaking furnace in step 1 to slowly raise the temperature of the soaking furnace for the first time; Step 3, heating the soaking furnace in step 2 to slowly raise the temperature of the soaking furnace for the second time, and performing second heat preservation; Step 4, heating the soaking furnace in step 3 to slowly raise the temperature of the soaking furnace for the third time, and performing third heat preservation; Step 5, taking out the steel billet in step 4, removing phosphorus from the steel billet, and performing rough rolling on the steel billet after the phosphorus removal; Step 6, the rough rolling completed billet is finished, and is cooled to room temperature to obtain the large-thickness super-wide 20Mn23AlV steel plate.
[0007] The application also has the characteristics that: The pressure of the micro-positive pressure in step 1 is 5 Pa-10 Pa, and the oxygen content of the weak oxidizing condition is 2%-5%.
[0008] The furnace entry temperature of the step 1 put into the soaking furnace is 300-400 DEG C, and the holding time of the first holding is 1-2 h.
[0009] The time of the first slow heating in step 2 is 2-2.5 h, and the temperature reached by the first slow heating is 780-800 DEG C.
[0010] The time of the second slow heating in step 3 is 1-1.5 h, the temperature reached by the second slow heating is 1000-1100 DEG C, and the holding time of the second holding is 6-8 h.
[0011] The time of the third slow heating in step 4 is 1.5-2.5 h, the temperature reached by the third slow heating is 1280-1300 DEG C, and the holding time of the third holding is 1-3 h.
[0012] The phosphorus removal in step 5 is specifically: high-pressure water is used for phosphorus removal, and the pressure of the high-pressure water is not less than 22 MPa.
[0013] The billet temperature when the first pass of the rough rolling in step 5 is not less than 1100 DEG C, the rolling reduction of each pass of the first five passes of the rough rolling is 30-40 mm, the rolling reduction of each pass of the subsequent passes of the rough rolling is 20-30 mm, and the node of the rough rolling is rolling to 2 times the thickness of the finished steel plate.
[0014] The rolling reduction of each pass of the finish rolling in step 6 is 0-20 mm, the billet temperature when the last pass of the finish rolling is not higher than 900 DEG C, and the rolling thickness of the cold rolling is the thickness of the finished steel plate.
[0015] Another technical solution adopted by the application is that the large-thickness super-wide 20Mn23AlV steel plate has a thickness of not less than 50 mm, a width of not less than 3000 mm, a flatness of not more than 3 mm / m, a yield strength of 400-500 MPa, a tensile strength of 600-700 MPa, an elongation of 35%-45%, and a magnetic permeability of not more than 1.003 Gs.
[0016] The beneficial effects of the present application are: The large-thickness super-wide 20Mn23AlV steel plate and the heating rolling method provided by the present application can make the blank heating uniform through the staged heating of the heating step, make the internal structure uniform, eliminate the center segregation, banded structure and rolling process edge phenomenon caused by uneven blank heating, and make the steel plate after rolling have good shape, clean and neat surface and excellent performance, thereby improving the yield rate and production efficiency, meeting the needs of subsequent part processing, preventing the anisotropy and surface oxidation of the blank through the setting of appropriate staged heating and soaking process, greatly improving the yield rate, and improving the flaw detection qualified rate of the super-thick super-wide 20Mn23AlV steel plate obtained through the heating rolling of the present application from 80% to more than 98%, improving the yield rate from 85% to more than 97%, and making the internal quality flaw detection meet the GB I level. DETAILED DESCRIPTION
[0017] The present application will be described in detail below in combination with specific embodiments.
[0018] Embodiment 1 The large-thickness super-wide 20Mn23AlV steel plate and the heating rolling method provided by the present embodiment include the following steps: Step 1, placing the 20Mn23AlV steel blank in the soaking furnace under the conditions of micro positive pressure and weak oxidizing property, and performing first heat preservation; Step 2, heating the soaking furnace in step 1 to make the soaking furnace slowly heat up for the first time; Step 3, heating the soaking furnace in step 2 to make the soaking furnace slowly heat up for the second time and perform second heat preservation; Step 4, heating the soaking furnace in step 3 to make the soaking furnace slowly heat up for the third time and perform third heat preservation; Step 5, taking out the steel blank in step 4, removing phosphorus from the steel blank, and performing rough rolling on the steel blank after the removal of phosphorus; Step 6, performing finish rolling on the steel blank after the rough rolling, cooling to room temperature, and obtaining a large-thickness super-wide 20Mn23AlV steel plate.
[0019] Embodiment 2 The large-thickness super-wide 20Mn23AlV steel plate and the heating rolling method provided by the present embodiment include the following steps: Step 1, placing the 20Mn23AlV steel blank in the soaking furnace under the conditions of micro positive pressure and weak oxidizing property, and performing first heat preservation; The pressure of the micro positive pressure is 5 Pa to 10 Pa, and the oxygen content of the weak oxidizing property is 2% to 5%; The blank temperature when placed in the soaking furnace is 300℃ to 400℃, and the heat preservation time of the first heat preservation is 1 h to 2 h; Step 2, heat the soaking furnace in step 1 to make the soaking furnace slowly rise in temperature for the first time; The time for the first slow temperature rise is 2-2.5 h, and the temperature reached by the first slow temperature rise is 780-800℃; Step 3, heat the soaking furnace in step 2 to make the soaking furnace slowly rise in temperature for the second time and perform second-time temperature holding; Step 4, heat the soaking furnace in step 3 to make the soaking furnace slowly rise in temperature for the third time and perform third-time temperature holding; Step 5, take out the billet in step 4, remove phosphorus from the billet, and perform rough rolling on the phosphorus-removed billet; Step 6, perform finish rolling on the rough-rolled billet, cool it to room temperature, and obtain the large-thickness and super-wide 20Mn23AlV steel plate.
[0020] Example 3 The large-thickness and super-wide 20Mn23AlV steel plate and the heating and rolling method proposed in this example include the following steps: Step 1, place the 20Mn23AlV billet in the soaking furnace under micro-positive pressure and weak oxidizing conditions to perform first-time temperature holding; The micro-positive pressure is 5-10 Pa, and the oxygen content in the weak oxidizing conditions is 2-5%; The temperature at which the billet is placed in the soaking furnace is 300-400℃, and the first-time temperature holding time is 1-2 h; Step 2, heat the soaking furnace in step 1 to make the soaking furnace slowly rise in temperature for the first time; The time for the first slow temperature rise is 2-2.5 h, and the temperature reached by the first slow temperature rise is 780-800℃; Step 3, heat the soaking furnace in step 2 to make the soaking furnace slowly rise in temperature for the second time and perform second-time temperature holding; The time for the second slow temperature rise is 1-1.5 h, the temperature reached by the second slow temperature rise is 1000-1100℃, and the second-time temperature holding time is 6-8 h; Step 4, heat the soaking furnace in step 3 to make the soaking furnace slowly rise in temperature for the third time and perform third-time temperature holding; Step 5, take out the billet in step 4, remove phosphorus from the billet, and perform rough rolling on the phosphorus-removed billet; Step 6, perform finish rolling on the rough-rolled billet, cool it to room temperature, and obtain the large-thickness and super-wide 20Mn23AlV steel plate.
[0021] Example 4 The large-thickness super-wide 20Mn23AlV steel plate and the heating rolling method proposed in the embodiment include the following steps. Step 1, put the 20Mn23AlV steel blank in the soaking furnace under the conditions of micro-positive pressure and weak oxidizing, and perform first heat preservation; The pressure of the micro-positive pressure is 5 Pa-10 Pa, and the oxygen content of the weak oxidizing condition is 2%-5%; The furnace temperature for putting into the soaking furnace is 300-400 DEG C, and the heat preservation time of the first heat preservation is 1-2 h; Step 2, heat the soaking furnace in step 1 to make the soaking furnace first slowly heat up; The time of the first slow heating is 2-2.5 h, and the temperature reached by the first slow heating is 780-800 DEG C; Step 3, heat the soaking furnace in step 2 to make the soaking furnace second slowly heat up and perform second heat preservation; The time of the second slow heating is 1-1.5 h, the temperature reached by the second slow heating is 1000-1100 DEG C, and the heat preservation time of the second heat preservation is 6-8 h; Step 4, heat the soaking furnace in step 3 to make the soaking furnace third slowly heat up and perform third heat preservation; The time of the third slow heating is 1.5-2.5 h, the temperature reached by the third slow heating is 1280-1300 DEG C, and the heat preservation time of the third heat preservation is 1-3 h; Step 5, take out the steel blank in step 4, remove phosphorus from the steel blank, and perform rough rolling on the steel blank after the phosphorus removal; Step 6, perform finish rolling on the steel blank after the rough rolling, cool to room temperature, and obtain a large-thickness super-wide 20Mn23AlV steel plate.
[0022] Embodiment 5 The large-thickness super-wide 20Mn23AlV steel plate and the heating rolling method proposed in the embodiment include the following steps. Step 1, put the 20Mn23AlV steel blank in the soaking furnace under the conditions of micro-positive pressure and weak oxidizing, and perform first heat preservation; The pressure of the micro-positive pressure is 5 Pa-10 Pa, and the oxygen content of the weak oxidizing condition is 2%-5%; The furnace temperature for putting into the soaking furnace is 300-400 DEG C, and the heat preservation time of the first heat preservation is 1-2 h; Step 2, heat the soaking furnace in step 1 to make the soaking furnace first slowly heat up; The time of the first slow heating is 2-2.5 h, and the temperature reached by the first slow heating is 780-800 DEG C; Step 3: Heat the homogenizing furnace from Step 2, allowing it to heat up slowly for the second time, and then hold it at that temperature for the second time. The second slow heating time is 1 h to 1.5 h, the temperature reached by the second slow heating is 1000℃ to 1100℃, and the holding time for the second heat preservation is 6 h to 8 h. Step 4: Heat the homogenizing furnace from Step 3, causing it to heat up slowly for the third time, and then hold it at that temperature for the third time. The third slow heating period lasts 1.5 to 2.5 hours, the temperature reached during the third slow heating period is 1280℃ to 1300℃, and the holding time for the third heating period is 1 to 3 hours. Step 5: Take out the steel billet from Step 4, descal the steel billet, and then rough roll the descaled steel billet. Phosphorus removal specifically involves using high-pressure water for phosphorus removal, with a pressure of not less than 22 MPa. The billet temperature during the first pass of rough rolling shall not be lower than 1100℃. The rolling reduction of each of the first five passes of rough rolling shall be 30 mm to 40 mm. The rolling reduction of each of the subsequent passes of rough rolling shall be 20 mm to 30 mm. The node of rough rolling shall be rolled to twice the thickness of the finished steel plate. Step 6: Finish rolling the rough-rolled steel billet and cooling it to room temperature to obtain a thick and wide 20Mn23AlV steel plate. The reduction in each pass of finishing rolling is 0 mm to 20 mm. The billet temperature during the final pass of finishing rolling is not higher than 900℃. The rolling thickness of static rolling is the thickness of the finished steel plate.
[0023] Example 6 The thick and wide 20Mn23AlV steel plate is prepared according to the above method. The thickness of the 20Mn23AlV steel plate is not less than 50 mm, the width is not less than 3000 mm, the flatness is not greater than 3 mm / m, the yield strength is 400 MPa ~ 500 MPa, the tensile strength is 600 MPa ~ 700 MPa, the elongation is 35% ~ 45%, and the magnetic permeability is not greater than 1.003 Gs.
[0024] Example 7 The hot rolling production method of 20Mn23AlV in this embodiment includes billet heating and rolling processes, and the specific steps are as follows: 1. Steel billet heating process: Select furnace temperature of 300℃ and hold for 1 hour; then slowly raise the temperature to 780℃ for 2 hours; then raise the temperature to 1000℃ for 1 hour and hold for 6 hours; finally raise the temperature to 1280℃ for 1.5 hours and hold for 2 hours. 2. Rolling process: High-pressure water is used to descal the steel billet, with a pressure of 22MPa; the rolling process is carried out with fewer passes and larger reductions, with reductions of 30mm, 32mm, 35mm, 38mm and 40mm for the first five passes, respectively, and a final rolling temperature of 900℃, followed by air cooling. 3. The finished steel plate is 50mm thick and 3000mm wide; The hot-rolled 20Mn23AlV plate has a good shape, a clean and neat surface, no edge folds or foreign objects pressed in, and excellent performance; it meets the requirements of subsequent processing, and the steel plate can meet the GBI grade for flaw detection.
[0025] Example 8 The heating and rolling production method of 20Mn23AlV steel billet in this embodiment includes billet heating and rolling processes, and the specific steps are as follows: 1. Steel billet heating process: Select furnace temperature of 350℃ and hold for 1.5 hours; then slowly raise the temperature to 790℃ for 2.5 hours; then raise the temperature to 1050℃ for 1.5 hours and hold for 7 hours; finally raise the temperature to 1290℃ for 2 hours and hold for 2.5 hours. 2. Rolling process: High-pressure water is used to descal the steel billet, with a pressure of 23MPa; the rolling process is carried out with fewer passes and larger reductions, with reductions of 33mm, 34mm, 35mm, 35mm and 40mm for the first five passes, respectively, and a final rolling temperature of 850℃, followed by air cooling. 3. The finished steel plate is 60mm thick and 3200mm wide; The hot-rolled 20Mn23AlV plate has a good shape, a clean and neat surface, no edge folds or foreign objects pressed in, and excellent performance; it meets the requirements of subsequent processing, and the steel plate can meet the GBI grade for flaw detection.
[0026] Example 9 The heating and rolling production method of 20Mn23AlV steel billet in this embodiment includes billet heating and rolling processes, and the specific steps are as follows: 1. Steel billet heating process: Select furnace temperature of 400℃ and hold for 2 hours; then slowly raise the temperature to 800℃ for 2.5 hours; then raise the temperature to 1100℃ for 1.5 hours and hold for 7.5 hours; finally raise the temperature to 1270℃ for 2.5 hours and hold for 3 hours. 2. Rolling process: High-pressure water is used to descal the steel billet, with a pressure of 22.5 MPa; the rolling process is carried out with fewer passes and larger reductions, with the reductions of the first five passes being 34 mm, 36 mm, 38 mm, 39 mm, and 36 mm, respectively, and the final rolling temperature being 830℃, followed by air cooling. 3. The finished steel plate is 70mm thick and 3300mm wide; The hot-rolled 20Mn23AlV plate has a good shape, a clean and neat surface, no edge folds or foreign objects pressed in, and excellent performance; it meets the requirements of subsequent processing, and the steel plate can meet the GBI grade for flaw detection.
[0027] Example 10 The heating and rolling production method of 20Mn23AlV steel billet in this embodiment includes billet heating and rolling processes, and the specific steps are as follows: 1. Steel billet heating process: Select furnace temperature of 400℃ and hold for 2 hours; then slowly raise the temperature to 800℃ for 2.5 hours; then raise the temperature to 1100℃ for 1.5 hours and hold for 8 hours; finally raise the temperature to 1300℃ for 2.5 hours and hold for 2.5 hours. 2. Rolling process: High-pressure water is used to descal the steel billet, with a pressure of 20.5 MPa; the rolling process is carried out with fewer passes and larger reductions, with the reductions of the first five passes being 36 mm, 38 mm, 40 mm, 36 mm, and 35 mm, respectively, and the final rolling temperature being 840℃, followed by air cooling. 3. The finished steel plate is 80mm thick and 3500mm wide; The hot-rolled 20Mn23AlV plate has a good shape, a clean and neat surface, no edge folds or foreign objects pressed in, and excellent performance; it meets the requirements of subsequent processing, and the steel plate can meet the GBI grade for flaw detection.
Claims
1. A method for hot rolling of thick, ultra-wide 20Mn23AlV steel plates, characterized in that, Includes the following steps: Step 1: Place the 20Mn23AlV steel billet into a soaking furnace under slightly positive pressure and weak oxidation conditions for the first heat preservation. Step 2: Heat the soaking furnace from Step 1 to allow it to heat up slowly for the first time. Step 3: Heat the homogenizing furnace from Step 2, allowing it to heat up slowly for the second time, and then hold it at that temperature for the second time. Step 4: Heat the homogenizing furnace from Step 3, causing it to heat up slowly for the third time, and then hold it at that temperature for the third time. Step 5: Take out the steel billet from Step 4, descal the steel billet, and then rough roll the descaled steel billet. Step 6: The rough-rolled steel billet is finished by finishing rolling and cooled to room temperature to obtain a thick and wide 20Mn23AlV steel plate.
2. The method for hot rolling of thick, ultra-wide 20Mn23AlV steel plates according to claim 1, characterized in that, The pressure of the micro-positive pressure mentioned in step 1 is 5 Pa to 10 Pa, and the oxygen content of the weak oxidizing conditions is 2% to 5%.
3. The method for hot rolling of thick, ultra-wide 20Mn23AlV steel plates according to claim 1, characterized in that, The temperature of the sample placed in the homogenizing furnace in step 1 is 300℃~400℃, and the holding time for the first heat preservation is 1 h~2 h.
4. The method for hot rolling of thick, ultra-wide 20Mn23AlV steel plates according to claim 1, characterized in that, The time for the first slow heating in step 2 is 2 h to 2.5 h, and the temperature reached by the first slow heating is 780℃ to 800℃.
5. The method for hot rolling of thick, ultra-wide 20Mn23AlV steel plates according to claim 1, characterized in that, The second slow heating time in step 3 is 1 h to 1.5 h, the temperature reached by the second slow heating is 1000℃ to 1100℃, and the holding time of the second heat preservation is 6 h to 8 h.
6. The method for hot rolling of thick, ultra-wide 20Mn23AlV steel plates according to claim 1, characterized in that, The third slow heating in step 4 takes 1.5 to 2.5 hours, reaches a temperature of 1280°C to 1300°C, and is held for 1 to 3 hours.
7. The method for hot rolling of thick, ultra-wide 20Mn23AlV steel plates according to claim 1, characterized in that, The phosphorus removal process in step 5 specifically involves using high-pressure water for phosphorus removal, with the pressure of the high-pressure water not less than 22 MPa.
8. The method for hot rolling of thick, ultra-wide 20Mn23AlV steel plates according to claim 1, characterized in that, In step 5, the billet temperature during the first pass of rough rolling shall not be lower than 1100℃. The rolling reduction of each of the first five passes of rough rolling shall be 30 mm to 40 mm. The rolling reduction of each of the subsequent passes of rough rolling shall be 20 mm to 30 mm. The node of rough rolling shall be rolled to twice the thickness of the finished steel plate.
9. The method for hot rolling of thick, ultra-wide 20Mn23AlV steel plates according to claim 1, characterized in that, In step 6, the rolling reduction of each pass of the finishing rolling is 0 mm to 20 mm, the billet temperature during the last pass of the finishing rolling is not higher than 900℃, and the rolling thickness of the static rolling is the thickness of the finished steel plate.
10. A thick, ultra-wide 20Mn23AlV steel plate, manufactured by the hot rolling method according to any one of claims 1 to 9, characterized in that, The thickness of the 20Mn23AlV steel plate is not less than 50mm, the width of the 20Mn23AlV steel plate is not less than 3000mm, the flatness of the 20Mn23AlV steel plate is not greater than 3mm / m, the yield strength of the 20Mn23AlV steel plate is 400 MPa ~ 500MPa, the tensile strength of the 20Mn23AlV steel plate is 600 MPa ~ 700MPa, the elongation of the 20Mn23AlV steel plate is 35% ~ 45%, and the magnetic permeability of the 20Mn23AlV steel plate is not greater than 1.003Gs.