Online pre-hardening cooling device for 1.2311 plastic mold steel

Abstract

This invention discloses an online pre-hardening cooling device for 1.2311 plastic mold steel, comprising a cooling bed, an upper fan unit, a lower fan unit, and an annular water mist nozzle. The upper and lower fan units are respectively arranged above and below the cooling bed. The air outlets of the upper fan units are inclined downwards towards the steel plate surface, and the air outlets of the lower fan units are inclined upwards towards the steel plate surface. The air outlets of both the upper and lower fan units form a 30° angle with the steel plate surface. An annular water mist nozzle is installed in the air outlet area of ​​each fan, and the annular water mist nozzles are arranged circumferentially along the air outlet of the fan. The nozzle spray direction is consistent with or perpendicular to the air outlet direction of the fan, forming a uniform cooling air field combining air cooling and mist cooling. This invention can achieve precise adjustment of the cooling rate after rolling, keeping the tempering temperature of steel plates of different thicknesses consistent, meeting the requirements of continuous industrial production; at the same time, it ensures uniform air field, controlling the hardness difference of the steel plate cross section within 2 HRC, and avoiding cracking caused by excessive cooling rate.

Description

Technical Field

[0001] This invention relates to the field of medium and heavy plate production technology, specifically to an online pre-hardening cooling device for 1.2311 plastic mold steel. Background Technology

[0002] 1.2311 plastic mold steel is widely used in mold manufacturing. This steel has a high alloy content, and the traditional post-rolling ACC rapid cooling system has an excessively high cooling rate, which can easily lead to internal stress and cracking in the steel plate. According to CCT curve simulation, 1.2311 steel can obtain a stable bainitic + martensite structure by cooling it at a rate of 0.1–1℃ / s after rolling, which meets the requirements for online pre-hardening. Subsequent tempering can achieve a delivery hardness of 28–30HRC or 32–34HRC.

[0003] If only natural air cooling is used, the cooling process is significantly affected by ambient temperature and radiant heat from the cooling bed, resulting in large fluctuations in hardness in the rolled state and poor uniformity of hardness across the entire cross-section after tempering, failing to meet standard requirements. Furthermore, uncontrollable cooling necessitates matching different tempering temperatures to steel plates of varying thicknesses, which is detrimental to continuous industrial production, leading to low production efficiency and poor quality stability. Therefore, a cooling method that achieves adjustable cooling rate, uniform airflow, and adaptability to multiple thickness specifications would be of great significance for the continuous operation of the entire production process. Summary of the Invention

[0004] To meet the above technical requirements, the present invention aims to provide an online pre-hardening cooling device for 1.2311 plastic mold steel, which enables precise adjustment of the cooling rate after rolling, keeps the tempering temperature of steel plates of different thicknesses consistent, and meets the requirements of continuous industrial production; at the same time, it ensures uniform airflow and controls the hardness difference of the steel plate cross section within 2HRC, avoiding cracking caused by excessive cooling rate.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: an online pre-hardening cooling device for 1.2311 plastic mold steel, comprising a cooling bed, an upper fan unit, a lower fan unit, and an annular water mist nozzle; the upper fan unit and the lower fan unit are respectively arranged above and below the cooling bed, the air outlet of the upper fan unit is inclined downward toward the steel plate surface, and the air outlet of the lower fan unit is inclined upward toward the steel plate surface, and the air outlets of the upper fan and the lower fan are both at a 30° angle to the steel plate surface; an annular water mist nozzle is provided in the air outlet area of ​​each fan, the annular water mist nozzle is arranged circumferentially along the air outlet of the fan, and the nozzle spray direction is consistent with or perpendicular to the air outlet direction of the fan, forming a uniform cooling air field combining air cooling and mist cooling.

[0006] Furthermore, both the upper and lower fan units consist of multiple axial flow fans, with the upper and lower fans arranged in a one-to-one correspondence, totaling 40 sets, which together cover the entire length and width of the cooling bed.

[0007] The annular water mist nozzle is a circular tube with multiple spray holes evenly opened along the circumference of the tube wall. The circular tube is coaxially installed on the outside or inside of the fan outlet.

[0008] The annular water mist nozzle is connected to a high-pressure water supply system and can be turned on or off independently, enabling switching between three cooling modes: pure air cooling, pure mist cooling, and air cooling + mist cooling.

[0009] The upper and lower fan units are controlled in groups, which can adjust the number of fans and the air volume according to the thickness and temperature of the steel plate, so as to achieve adjustable cooling speed of the steel plate.

[0010] The above-mentioned device is suitable for 1.2311 plastic mold steel with a thickness of 100-400mm; for 100-150mm 1.2311 plastic mold steel, pure air cooling is used, with 10 sets of fans turned on at intervals; for 151-250mm 1.2311 plastic mold steel, mist cooling is used, with 20 sets of fans turned on at intervals; for 251-400mm 1.2311 plastic mold steel, mist cooling is used, with all 40 sets of fans turned on; the steel plate is cooled to below 500℃ and then tempered, with a tempering temperature of 555–565℃.

[0011] The beneficial effects of this invention are: significantly improved cooling uniformity. The use of double-layer fans at the top and bottom, with the air outlets blowing at a 30° angle to the surface of the steel plate, forms a uniform opposing airflow field that can fully cover the upper and lower surfaces of the steel plate, avoiding uneven local cooling and making the temperature and hardness distribution of the entire cross-section of the steel plate more consistent.

[0012] With high cooling efficiency and controllable speed, it is based on air cooling and enhanced by water mist heat exchange. The number and air volume of fans can be flexibly adjusted according to the thickness and temperature of the steel plate to achieve precise cooling control of steel plates of different specifications and meet the requirements of online continuous production.

[0013] The cooling mode is flexible and adaptable. The annular water mist nozzle can be opened and closed independently, and can freely switch between three modes: pure air cooling, mist cooling, and air cooling + mist cooling, to meet the cooling process requirements of different steel grades and steel plates of different thicknesses.

[0014] With a stable structure and smooth airflow, the annular water mist nozzles are arranged around the fan outlet, ensuring uniform water mist distribution and thorough mixing with the airflow. This does not interfere with the main airflow flow line, resulting in stable operation and a low failure rate.

[0015] With a wide range of applications and a high degree of industrialization, the upper and lower fans are arranged to fully cover the cooling bed, which can be adapted to the simultaneous cooling of multiple specifications and quantities of steel plates, and facilitates online automated control and large-scale production. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the present invention.

[0017] Figure 2 yes Figure 1 Top view.

[0018] Figure 3 This is a schematic diagram of the structure of the annular water mist nozzle in this invention.

[0019] The markings in the diagram are: 1. Upper fan unit; 2. Lower fan unit; 4. Steel plate; 7. Fan direction diagram; 8. Upper and lower fan units; 10. Cooling bed; 12. Circular tube; 13. Nozzle. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to specific embodiments.

[0021] See appendix Figure 1 and 2 This is an embodiment of the present invention, disclosing an online pre-hardening cooling device for 1.2311 plastic mold steel, including a cooling bed 10, an upper fan unit 1, a lower fan unit 2, and an annular water mist nozzle 13; the upper fan unit 1 and the lower fan unit 2 are respectively arranged above and below the cooling bed 10, the air outlet of the upper fan unit 1 is inclined downward toward the surface of the steel plate 4, and the air outlet of the lower fan unit 2 is inclined upward toward the surface of the steel plate 4, and the air outlets of the upper fan and the lower fan are both at a 30° angle to the surface of the steel plate 4; an annular water mist nozzle 13 is provided in the air outlet area of ​​each fan, the annular water mist nozzle 13 is arranged circumferentially along the air outlet of the fan, and the spray direction of the nozzle 13 is consistent with or perpendicular to the air outlet direction of the fan, forming a uniform cooling air field combining air cooling and mist cooling. The upper fan is inclined downward to blow, and the lower fan is inclined upward to blow, ensuring that the upper and lower surfaces of the steel plate 4 are simultaneously covered by a uniform and stable airflow.

[0022] An annular water mist nozzle 13 is coaxially installed in the air outlet area of ​​each fan. The nozzle 13 adopts a circular tube body 12 structure, with multiple small water spray holes evenly opened along the circumference of the tube body. The annular tube body is fixed on the outside or inside of the fan outlet, and the water spray direction is perpendicular to or consistent with the fan outlet direction, so that the water mist is evenly dispersed under the airflow and fully mixed with the air field to form a combined air cooling and mist cooling environment. The annular water mist nozzle 13 is connected to an external high-pressure water supply system, and the water supply circuit can be turned on or off independently. Depending on the fan operating status, it can freely switch between three cooling modes: pure air cooling, mist cooling, and air cooling + mist cooling.

[0023] Both the upper fan unit 1 and the lower fan unit 2 consist of multiple axial flow fans, with the upper and lower fans arranged one-to-one, totaling 40 sets, which together cover the entire length and width of the cooling bed 10. They are controlled independently in groups, and the number of fans and the operating air volume can be flexibly adjusted according to the thickness of the steel plate 4, the rolling temperature and the target cooling rate.

[0024] The annular water mist nozzle 13 is a circular annular tube 12 with multiple spray holes evenly opened along the circumference of the tube wall. The circular annular tube 12 is coaxially installed on the outside or inside of the fan outlet.

[0025] The annular water mist nozzle 13 is connected to the high-pressure water supply system and can be turned on or off independently to achieve switching between three cooling modes: pure air cooling, pure mist cooling, and air cooling + mist cooling.

[0026] In actual operation, the rolled steel plate 4 is fed into the cooling zone of the cooling bed 10, and the corresponding cooling method is selected according to the thickness of the steel plate 4: The thinner steel plate 4 adopts a pure air-cooling mode, turns on the corresponding number of upper and lower layer fans, turns off the water mist nozzles 13 to supply water, and relies on airflow to achieve gentle and uniform cooling. The medium-thickness steel plate 4 adopts a combined air-cooling and mist-cooling mode, with the fan and water mist nozzle 13 turned on at the same time to improve cooling efficiency. The thicker steel plate 4 adopts a strong cooling mode, turning on all the upper and lower layer fans and fully opening the annular water mist nozzles 13 to achieve rapid and uniform cooling with maximum cooling capacity.

[0027] This device combines a 30° oblique airflow field with a uniform annular water mist, resulting in a stable and dead-angle-free cooling airflow. The overall temperature of the steel plate 4 drops evenly, effectively avoiding stress, deformation, and cracking problems caused by uneven cooling. At the same time, the cooling speed can be flexibly adjusted to meet the online continuous production needs of steel plates 4 of different specifications.

[0028] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. All modifications and equivalent substitutions made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An on-line pre-hardening cooling device for 1.2311 plastic mold steel, characterized in that: It includes a cooling bed, an upper fan unit, a lower fan unit, and annular water mist nozzles. The upper and lower fan units are respectively arranged above and below the cooling bed. The air outlets of the upper fan units are tilted downwards towards the steel plate surface, and the air outlets of the lower fan units are tilted upwards towards the steel plate surface. The air outlets of both the upper and lower fans form a 30° angle with the steel plate surface. Each fan's air outlet area is equipped with annular water mist nozzles, which are arranged circumferentially along the fan's air outlet. The nozzle spray direction is consistent with or perpendicular to the fan's air outlet direction, forming a uniform cooling air field that combines air cooling and mist cooling.

2. The online pre-hardening cooling device for 1.2311 plastic mold steel according to claim 1, characterized in that: Both the upper and lower fan units consist of multiple axial flow fans, with the upper and lower fans arranged one-to-one, totaling 40 units, which together cover the entire length and width of the cooling bed.

3. The online pre-hardening cooling device for 1.2311 plastic mold steel according to claim 1, characterized in that: The annular water mist nozzle is a circular tube with multiple spray holes evenly opened along the circumference of the tube wall. The circular tube is coaxially installed on the outside or inside of the fan outlet.

4. The online pre-hardening cooling device for 1.2311 plastic mold steel according to claim 1, characterized in that: The annular water mist nozzle is connected to a high-pressure water supply system and can be turned on or off independently, enabling switching between three cooling modes: pure air cooling, pure mist cooling, and air cooling + mist cooling.

5. The online pre-hardening and cooling device for 1.2311 plastic mold steel according to claim 1, characterized in that: The upper and lower fan units are controlled in groups, which can adjust the number of fans and the air volume according to the thickness and temperature of the steel plate, so as to achieve adjustable cooling speed of the steel plate.

6. The online pre-hardening cooling device for 1.2311 plastic mold steel according to claim 1, characterized in that: The above-mentioned device is suitable for 1.2311 plastic mold steel with a thickness of 100-400mm; for 100-150mm 1.2311 plastic mold steel, pure air cooling is used, with 10 sets of fans turned on at intervals; for 151-250mm 1.2311 plastic mold steel, mist cooling is used, with 20 sets of fans turned on at intervals; for 251-400mm 1.2311 plastic mold steel, mist cooling is used, with all 40 sets of fans turned on. The steel plate is cooled to below 500℃ and then tempered at a temperature of 555–565℃.

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