Method for improving grain size of M6
By improving the heating uniformity, rolling temperature stability, and air cooling uniformity of M6 steel, the problem of grain size inhomogeneity in the existing rolling process was solved, and the overall grain size consistency and process stability of M6 steel were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-15
- Publication Date
- 2026-03-20
AI Technical Summary
The existing rolling process has problems such as temperature difference imbalance during the heating stage, uncontrolled temperature fluctuation during rolling, uneven cooling in the air-cooling line, and insufficient precision of the control system, which makes it difficult to control the non-uniformity of grain size in M6 steel.
By employing a combination of cross-arrangement of steel billets, temperature control of the heating furnace soaking section, precise adjustment of rolling temperature, optimization of the Stellmore air-cooling line, and multi-dimensional temperature detection and central control system, heating uniformity, rolling stability, and cooling uniformity are ensured.
Significant improvement in grain size uniformity of M6 steel was achieved. By optimizing heating uniformity, rolling temperature stability and air cooling uniformity, human error was reduced, ensuring overall grain size consistency.
Abstract
Description
Technical Field
[0001] This invention relates to the field of steel rolling technology, specifically to a method for improving the grain size of M6 steel. Background Technology
[0002] Ultra-low carbon M6 steel, due to its excellent plasticity and cold working properties, is widely used in the production of fine wires. It requires subsequent drawing to extremely small diameters, demanding extremely high uniformity of the material's grain size. However, existing rolling processes suffer from multiple technical bottlenecks, making grain size control difficult. Specific problems are as follows: Temperature imbalance during heating: In traditional heating furnaces, steel billets are often arranged in a concentrated manner on one side, resulting in a significant difference in the heating area between the head and tail of the billet, which easily leads to a head-tail temperature difference of more than 15°C. In addition, the temperature control accuracy of the soaking zone is low, often resulting in high temperatures exceeding 1120°C or side temperature differences exceeding 18°C. Coupled with excessively long heating times of more than 160 minutes, this causes abnormal grain growth in some areas, creating a hidden danger for subsequent grain size inhomogeneity.
[0003] Uncontrolled temperature fluctuations during rolling: The lack of stable control over the rolling line temperature during the rolling process often results in temperature fluctuations below 940℃ or above 990℃, and the wire drawing temperature deviation exceeds ±15℃; Improper adjustment of the water cooling system can easily cause a rapid temperature drop on the surface of the rolled piece, forming a temperature difference of more than 50℃ between the inside and outside of the steel, leading to differences in grain growth rate in different areas and exacerbating grain size inhomogeneity.
[0004] Uneven cooling in the air-cooled line: In the traditional process of the Stellmore air-cooled line, the timing of the fan start-up is not matched with the switching rhythm of the insulation cover. Often, the workpiece enters slow cooling before it reaches the phase transformation point (830-870℃), resulting in insufficient phase transformation and the formation of mixed crystals. In addition, there is no incremental design of the roller speed, the overlap point of the workpiece coil is concentrated, and the cooling conditions of the inner and outer rings and the upper and lower layers are significantly different, which further amplifies the grain size deviation.
[0005] Insufficient accuracy of the control system: Existing temperature detection systems typically only have 1-2 sets of infrared thermometers, resulting in missing temperature data at key nodes (such as the inlet of the slow cooling and insulation unit). Insufficient thermocouple arrangement leads to incomplete temperature monitoring of the heating furnace's soaking zone. Poor linkage between the central control unit and the execution module prevents dynamic adjustment of water pressure and heating power based on real-time temperature data, causing process parameters to easily deviate from the optimal range and making it difficult to stably control grain size. Summary of the Invention
[0006] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a method for improving the grain size of M6, which has advantages such as significantly improved heating uniformity and solves problems such as temperature imbalance during the heating stage.
[0007] (II) Technical Solution To achieve the above-mentioned goal of significantly improving heating uniformity, the present invention provides the following technical solution: a method for improving M6 grain size, including S1 heating control, S2 rolling temperature control, S3 Steyrmo air-cooling line cooling control and S4 application of a matching control system, wherein S1 heating control includes S101 billet arrangement and S102 temperature and time control. Among them, the S2 rolling temperature control includes the S201 rolling line and wire drawing temperature; Among them, the S3 Stellmore air-cooled line cooling control includes S301 cooling speed regulation and S302 roller speed control. The S4 supporting control system includes S401 temperature detection and S402 central control and execution.
[0008] Preferably, the S101 billet arrangement is as follows: the billets in the heating furnace are changed from a single-sided arrangement to a cross arrangement, which reduces the temperature difference caused by the difference in heating area at the head and tail of the billet and ensures that the billet is heated evenly as a whole.
[0009] Preferably, the temperature and time control in S102 is as follows: the temperature of the upper section of the heating furnace, both the rolling side and the non-rolling side, is controlled at 1070-1120℃, and the temperature difference between the two sides does not exceed 12-18℃; the total heating time of the billet is controlled at 100-160 minutes. By using low heating temperature and reasonable furnace time, abnormal growth of some grains due to long-term high-temperature heating is avoided.
[0010] Preferably, the S201 rolling line and wire drawing temperatures are as follows: during the rolling process, the rolling line temperature is controlled at 940-990℃ to ensure the temperature of the rolled piece is stable during the rolling stage; the wire drawing temperature is controlled at 910-945℃ to avoid the surface temperature of the rolled piece dropping too quickly due to water cooling, reduce the temperature unevenness inside and outside the steel, and prevent differences in grain growth.
[0011] Preferably, the S301 cooling rate adjustment is as follows: after rolling, the fan is turned on to accelerate the cooling rate. After the temperature of the rolled piece drops to 830-870℃ (phase transformation point range), it is then sent into the heat preservation cover for slow cooling. The rapid phase transformation avoids the phenomenon of mixed crystals and ensures the uniformity of grain growth.
[0012] Preferably, the speed control of the S302 roller conveyor is as follows: the speed of the air-cooled line roller conveyor increases sequentially in segments, with the speed of each segment controlled at 0.15-0.55 m / s. By staggering the overlap points of the rolled pieces, the difference in cooling conditions between the inner and outer coils and between the upper and lower layers is reduced, promoting uniform cooling of the rolled pieces as a whole.
[0013] Preferably, the S401 temperature detection involves: setting up 3-5 sets of non-contact infrared thermometers, which are respectively installed at the finishing mill inlet, the wire drawing machine inlet, and the slow cooling and heat preservation unit inlet to monitor the temperature of key nodes of the rolled piece in real time; and arranging 2-3 sets of thermocouples to detect the temperature of the rolling side and non-rolling side of the upper section of the heating furnace to ensure accurate temperature data acquisition.
[0014] Preferably, the S402 central control and execution: the central control unit is connected to the temperature detection module, water tank cooling unit, slow cooling and heat preservation unit and heating unit by signal, and sends instructions to the execution module according to the detection data; the execution module adjusts the water pressure (0.3-0.8MPa) and water volume of each cooling unit, as well as the power of the heating unit and the on / off status of the heat preservation unit, to realize dynamic optimization of process parameters.
[0015] (III) Beneficial Effects Compared with the prior art, the present invention provides a method for improving the grain size of M6, which has the following beneficial effects: 1. The method for improving the grain size of M6 steel billets significantly improves heating uniformity: the cross-arrangement design of the billets completely solves the problem of head-to-tail temperature difference in single-sided arrangement. Combined with the temperature control of the soaking zone at 1070-1120℃ and the side temperature difference limitation of 12-18℃, and the reasonable heating time of 100-160 minutes, it effectively avoids abnormal grain growth caused by high-temperature long-term heating, laying the foundation for the subsequent formation of uniform grains.
[0016] 2. The method for improving M6 grain size achieves enhanced rolling temperature stability: precise control of the rolling line temperature of 940-990℃ and the wire drawing temperature of 910-945℃ reduces the temperature difference between the inside and outside of the rolled piece caused by water cooling and avoids the difference in grain growth rate caused by temperature fluctuations, ensuring the uniformity of grain growth during the rolling stage.
[0017] 3. The method for improving the grain size of M6 achieves optimized air-cooling uniformity: the post-rolling fan is turned on in time to achieve rapid cooling, and the design of slow cooling after the rolled piece drops to the phase transformation point of 830-870℃ effectively avoids mixed crystal phenomenon; the segmented incremental roller speed of 0.15-0.55m / s and the staggered coil overlap point of the rolled piece eliminate the cooling difference between the inner and outer rings and the upper and lower layers, further ensuring the uniformity of grain size along the entire length.
[0018] 4. The method for improving M6 grain size achieves enhanced control precision and process stability: a multi-dimensional detection system of 3-5 sets of infrared thermometers and 2-3 sets of thermocouples enables comprehensive monitoring of the temperatures at key nodes such as the finishing mill inlet and the wire drawing mill inlet; real-time linkage between the central control unit and the execution module can dynamically adjust the cooling water pressure, heating power, and insulation unit status within the range of 0.3-0.8MPa, ensuring that process parameters are always within the optimal range and significantly reducing human error. Detailed Implementation
[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0020] This solution provides a technical solution, specifically, a method for improving the grain size of M6, including the following method: S1 heating control; S101 billet arrangement: The billet arrangement in the heating furnace is changed from a single-sided arrangement to a cross arrangement to reduce the temperature difference caused by the difference in heating area at the head and tail of the billet, and to ensure that the billet is heated evenly as a whole. S102 Temperature and Time Control: The temperature of the upper section of the heating furnace, both the rolling and non-rolling sides, is controlled at 1070-1120℃, and the temperature difference between the two sides does not exceed 12-18℃; the total heating time of the billet is controlled at 100-160 minutes. By using low heating temperature and reasonable furnace time, abnormal growth of some grains due to high temperature and long heating time is avoided. S2 rolling temperature control; S201 Rolling Line and Wire Spinning Temperature: During the rolling process, the rolling line temperature is controlled at 940-990℃ to ensure the temperature of the rolled workpiece is stable during the rolling stage; the wire spinning temperature is controlled at 910-945℃ to avoid the surface temperature of the rolled workpiece dropping too quickly due to water cooling, reduce the temperature difference between the inside and outside of the steel, and prevent differences in grain growth. S3 Stellmore air-cooled line cooling control; S301 Cooling rate adjustment: After rolling, turn on the fan to accelerate the cooling rate. After the temperature of the rolled piece drops to 830-870℃ (phase transformation point range), send it into the heat preservation cover for slow cooling. Avoid mixed crystal phenomenon through rapid phase transformation and ensure uniform grain growth. S302 Roller Speed Control: The speed of the air-cooled line rollers increases sequentially in sections, with each section's speed controlled between 0.15-0.55 m / s. By staggering the overlap points of the rolled pieces, the difference in cooling conditions between the inner and outer coils and between the upper and lower layers is reduced, promoting uniform cooling of the rolled pieces as a whole. Application of S4 supporting control system; S401 Temperature Detection: Set up 3-5 sets of non-contact infrared thermometers, respectively installed at the entry of the finishing mill, the entry of the wire drawing machine, and the entry of the slow cooling and heat preservation unit, to monitor the temperature of key nodes of the rolled piece in real time; arrange 2-3 sets of thermocouples to detect the temperature of the rolling side and non-rolling side of the upper section of the heating furnace to ensure accurate temperature data acquisition; S402 Central Control and Execution: The central control unit is connected to the temperature detection module, water tank cooling unit, slow cooling and heat preservation unit, and heating unit. It sends instructions to the execution module based on the detection data. The execution module adjusts the water pressure (0.3-0.8MPa) and water volume of each cooling unit, as well as the power of the heating unit and the on / off status of the heat preservation unit, to achieve dynamic optimization of process parameters. Furthermore, this method significantly improves heating uniformity: the cross-arrangement design of steel billets completely solves the problem of head-to-tail temperature difference in single-sided arrangement. Combined with the temperature control of the soaking zone at 1070-1120℃ and the lateral temperature difference limit of 12-18℃, plus a reasonable heating time of 100-160 minutes, it effectively avoids abnormal grain growth caused by high-temperature long-term heating, laying the foundation for the subsequent formation of uniform grains. Furthermore, this method achieves enhanced rolling temperature stability: precise control of the rolling line temperature of 940-990℃ and the wire drawing temperature of 910-945℃ reduces the temperature difference between the inside and outside of the rolled piece caused by water cooling and rapid cooling, avoids the difference in grain growth rate caused by temperature fluctuations, and ensures the uniformity of grain growth during the rolling stage. Furthermore, this method optimizes the uniformity of air cooling: the timely activation of the post-rolling fan enables rapid cooling, while the design of slow cooling after the rolled piece reaches the phase transformation point of 830-870℃ effectively avoids mixed crystal phenomenon; the segmented incremental roller speed of 0.15-0.55m / s and the staggered coil overlap points of the rolled piece eliminate the cooling differences between the inner and outer rings and the upper and lower layers, further ensuring the uniformity of grain size along the entire length. Furthermore, this method improves control precision and process stability: a multi-dimensional detection system of 3-5 sets of infrared thermometers and 2-3 sets of thermocouples enables comprehensive monitoring of the temperatures at key nodes such as the finishing mill inlet and the wire drawing mill inlet; the real-time linkage between the central control unit and the execution module can dynamically adjust the cooling water pressure, heating power, and insulation unit status within the range of 0.3-0.8MPa, ensuring that process parameters are always within the optimal range and significantly reducing human error.
[0021] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A method for improving the grain size of M6, comprising S1 heating control, S2 rolling temperature control, S3 Steyrmo air-cooled line cooling control, and S4 application of a matching control system, characterized in that: The heating control in S1 includes billet arrangement in S101 and temperature and time control in S102. Among them, the S2 rolling temperature control includes the S201 rolling line and wire drawing temperature; Among them, the S3 Stellmore air-cooled line cooling control includes S301 cooling speed regulation and S302 roller speed control. The S4 supporting control system includes S401 temperature detection and S402 central control and execution.
2. The method for improving the grain size of M6 according to claim 1, characterized in that: The S101 billet arrangement: The billets in the heating furnace are changed from a single-sided arrangement to a cross arrangement to reduce the temperature difference caused by the difference in heating area at the head and tail of the billet, and to ensure that the billet is heated evenly as a whole.
3. The method for improving the grain size of M6 according to claim 1, characterized in that: The temperature and time control of S102: The temperature of the upper section of the heating furnace, both the rolling side and the non-rolling side, is controlled at 1070-1120℃, and the temperature difference between the two sides does not exceed 12-18℃; the total heating time of the billet is controlled at 100-160 minutes. By using low heating temperature and reasonable furnace time, abnormal growth of some grains due to high temperature and long heating time is avoided.
4. The method for improving the grain size of M6 according to claim 1, characterized in that: The S201 rolling line and wire drawing temperatures are as follows: During the rolling process, the rolling line temperature is controlled at 940-990℃ to ensure the temperature of the rolled piece is stable during the rolling stage; the wire drawing temperature is controlled at 910-945℃ to avoid the surface temperature of the rolled piece dropping too quickly due to water cooling, reduce the temperature unevenness between the inside and outside of the steel, and prevent differences in grain growth.
5. The method for improving the grain size of M6 according to claim 1, characterized in that: The S301 cooling rate adjustment: After rolling, the fan is turned on to accelerate the cooling rate. After the temperature of the rolled piece drops to 830-870℃ (phase transformation point range), it is sent into the heat preservation cover for slow cooling. The rapid phase transformation avoids the phenomenon of mixed crystals and ensures the uniformity of grain growth.
6. The method for improving the grain size of M6 according to claim 1, characterized in that: The speed control of the S302 roller conveyor: the speed of the air-cooled line roller conveyor increases sequentially in segments, with the speed of each segment controlled at 0.15-0.55m / s. By staggering the overlap points of the rolled pieces, the difference in cooling conditions between the inner and outer coils and between the upper and lower layers is reduced, promoting uniform cooling of the rolled pieces as a whole.
7. The method for improving the grain size of M6 according to claim 1, characterized in that: The S401 temperature detection involves setting up 3-5 sets of non-contact infrared thermometers, which are installed at the entry point of the finishing mill, the entry point of the wire drawing machine, and the entry point of the slow cooling and heat preservation unit, respectively, to monitor the temperature of key nodes of the rolled piece in real time; and arranging 2-3 sets of thermocouples to detect the temperature of the rolling side and non-rolling side of the upper section of the heating furnace to ensure accurate temperature data acquisition.
8. The method for improving the grain size of M6 according to claim 1, characterized in that: The S402 central control and execution: The central control unit is connected to the temperature detection module, water tank cooling unit, slow cooling and heat preservation unit and heating unit. It sends instructions to the execution module according to the detection data. The execution module adjusts the water pressure (0.3-0.8MPa) and water volume of each cooling unit, as well as the power of the heating unit and the on / off status of the heat preservation unit, to achieve dynamic optimization of process parameters.