A method to avoid the front end of continuous rolling from biting into the rough pipe
By adjusting the hole shape of the air rolling mill, the height of the pinched roller under the inlet and optimizing the roller lifting process, the problem of no bite in the horn pipe at the continuous rolling front is solved, the yield rate and production efficiency are improved, the scrap and downtime are significantly reduced, and the economy is achieved Improved efficiency.
Patent Information
- Application Number
- CN202210833095.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-07-14
- Publication Date
- 2024-12-20
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
During the continuous rolling mill, the problem of continuous rolling front hood tubes frequently occur, resulting in an increase in the volume of rolled scrap, a decrease in the yield and output, resulting in serious economic losses and production downtime.
By adjusting the hole shape of the air rolling mill, the height of the under-inlet pinch rollers, cleaning the alignment forks and optimizing the lifting process of the front rollers, specific measures include reducing the disengagement angle, increasing the length of the long shaft and eccentric distance, and ensuring that the height of the No. 1 roller is higher than that of other rollers High, online slag cleaning alignment forks and adjust support roller lift logic to achieve effective capillary clamping.
It effectively avoids the capillary tube not biting, improves the yield rate, simplifies the rolling process, facilitates quality control, minimizes interference from human factors, significantly reduces waste and downtime, and creates a benefit of about 2.671 million yuan.
Smart Images
Figure CN115301744B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to metal processing, in particular to a method for preventing a rough pipe from being bitten into the front end of continuous rolling. Background Art
[0002] The continuous rolling unit is installed after the piercing machine. It is used to send the punched rough pipe to the front desk of continuous rolling to complete the process actions such as mandrel pre-piercing and limited rolling. The rough pipe with the mandrel is sent to the tube rolling mill to complete the deformation process of reducing the diameter and wall, and the rough pipe that meets the required diameter and wall thickness is rolled out, and the quality of the inner and outer surfaces of the steel pipe is improved.
[0003] During the production process of seamless steel pipe units, the front rough pipe of the continuous rolling mill frequently fails to bite, which not only causes a significant increase in the amount of rolling scraps, reduces the yield rate, but also causes a decrease in the unit's operating rate and output. According to statistics, the unit had 71 cases of front rough pipe failure in the continuous rolling mill in 2018, resulting in a total of 215 waste losses and 32.5 hours of cumulative downtime; in 2019, the front rough pipe of the continuous rolling mill failed to bite 63 times throughout the year, resulting in a total of 197 waste losses and 27.8 hours of cumulative downtime, which seriously affected the unit's yield rate and steel pipe output and other indicators. Summary of the invention
[0004] In order to overcome the shortcomings of the prior art, one of the purposes of the present invention is to provide a method for preventing the rough pipe from being bitten into the front end of continuous rolling, which is simple and easy to control and reduces the scrap rate.
[0005] One of the purposes of the present invention is achieved by the following technical solution:
[0006] A method for preventing a rough pipe from being bitten into the front end of a continuous rolling mill comprises the following steps:
[0007] Adjust the hole shape of the air rolling mill: reduce the disengagement angle of the air rolling mill hole, increase the major axis length and eccentric distance of the air rolling mill hole, so as to increase the contact area between the raw tube and the bottom of the air rolling mill groove, reduce the overfilling of steel at the roll gap, and play a role in increasing friction;
[0008] Adjust the lower pinch roller at the entrance: Check the height of the lower pinch roller at the front of the continuous rolling mill to ensure that the height of the No. 1 roller is higher than that of other rollers before continuous production;
[0009] Clean the alignment fork: clean the area under the alignment fork so that the alignment fork can be lowered from the high position to the low position normally, ensuring the normal passage of the capillary tube;
[0010] Optimize the front roller lifting process: adjust the lifting control logic of the front rough support roller of the continuous rolling mill, so that the rear support roller is lifted first, and then the front support roller is lifted. In this way, the rough tube has a tendency to "slide forward" after lifting, so that the rough tube stays within the effective clamping range of the upper pinch roller.
[0011] Furthermore, in the step of adjusting the hole shape of the air rolling mill, the disengagement angle of the hole of the air rolling mill is adjusted to 47°-49°.
[0012] Furthermore, in the step of adjusting the hole shape of the air rolling mill, the major axis length of the hole of the air rolling mill is 115mm-120mm.
[0013] Furthermore, in the step of adjusting the hole shape of the air rolling mill, the eccentric distance is 15mm-20mm.
[0014] Furthermore, in the step of adjusting the hole shape of the air rolling mill, the minor axis length of the hole of the air rolling mill is 105mm-107mm, and the ellipticity is 1.01-1.15.
[0015] Furthermore, in the step of adjusting the pinch rollers at the entrance, the height of roller No. 1 is 5 mm-8 mm higher than that of other rollers.
[0016] Furthermore, in the step of cleaning the alignment fork, the cleaning of the alignment fork specifically includes: adding a slag flushing water pipe under the alignment fork to achieve online slag flushing.
[0017] Furthermore, in the step of cleaning the alignment fork, cleaning the alignment fork specifically includes: using downtime to clean the alignment fork.
[0018] Furthermore, in the step of optimizing the front roller lifting process, a delay of 0.5s is provided between the rear support roller and the front support roller.
[0019] Further, in the step of optimizing the front roller table lifting process, the number of the rear support rollers is the same as the number of the front support rollers.
[0020] Compared with the prior art, the method of the present invention for avoiding the non-biting of the rough pipe at the front end of continuous rolling effectively avoids the non-biting of the rough pipe and improves the yield rate by adjusting the hole shape of the empty rolling mill, adjusting the clamping rollers under the entrance, cleaning the alignment fork and optimizing the lifting process of the front end roller. The complex rolling process is simplified into quality control points, which is convenient for workers to judge and handle. The main improvement measures are implemented by optimizing the automatic control program or tools to minimize the interference of human factors. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 A flow chart of the method for preventing the rough pipe from not biting into the front end of continuous rolling according to the present invention;
[0022] Figure 2 It is a schematic diagram of an empty rolling mill hole in the prior art;
[0023] Figure 3 A schematic diagram of the empty rolling mill hole after adjustment using a method to avoid the front end of the continuous rolling mill from biting into the raw pipe for this application. DETAILED DESCRIPTION
[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0025] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may be another intermediate component through which it is fixed. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may be another intermediate component at the same time. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be another intermediate component at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.
[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.
[0027] Figure 1 This is a flow chart of the method for preventing the front-end rough pipe of the continuous rolling mill from not biting into the continuous rolling mill according to the present invention. The method for preventing the front-end rough pipe of the continuous rolling mill from not biting into the continuous rolling mill according to the present invention comprises the following steps:
[0028] Adjust the hole shape of the air rolling mill: reduce the disengagement angle of the air rolling mill hole, increase the major axis length and eccentric distance of the air rolling mill hole to increase the contact area between the raw tube and the bottom of the air rolling mill groove and improve the friction;
[0029] Adjust the lower pinch roller at the entrance: Check the height of the lower pinch roller at the front of the continuous rolling mill to ensure that the height of the No. 1 roller is higher than that of other rollers before continuous production;
[0030] Clean the alignment fork: clean the area under the alignment fork so that the alignment fork can be lowered from the high position to the low position normally, ensuring the normal passage of the capillary tube;
[0031] Optimize the front roller lifting process: adjust the lifting control logic of the front rough support roller of the continuous rolling mill, so that the rear support roller is lifted first, and then the front support roller is lifted. In this way, the rough tube has a tendency to "slide forward" after lifting, so that the rough tube stays within the effective clamping range of the upper pinch roller.
[0032] Adjust the hole shape of the air rolling mill as follows:
[0033] Low rolling force is one of the main problems that cause poor bite effect of rough pipe. The fundamental reason is that the continuous rolling hole is not perfect. By checking the hole notification, it is found that the VRS hole (empty rolling mill hole) has a small breakaway angle and ovality, which will cause too little contact between the steel and the bottom of the groove during the air reduction process, and there is an overfilling situation at the roll gap, resulting in low forward rolling force. Therefore, it is necessary to optimize the VRS hole.
[0034] Existing VRS hole types are as follows Figure 2 As shown, the breakaway angle is 50.21°, the major axis a is 111.58 mm, the minor axis b is 106.7 mm, the ellipticity is 1.046, and the eccentricity is 6.92 mm. In order to increase the friction of VRS on the capillary tube, the present application designs the VRS hole type as follows Figure 3 As shown, the disengagement angle of the air mill hole is adjusted to 47°-49°, the major axis length of the air mill hole is 115mm-120mm, the eccentric distance is 15mm-20mm, the minor axis length of the air mill hole is 105mm-107mm, and the ellipticity is 1.01-1.15. Specifically, the disengagement angle is designed to be 48°, the major axis a is designed to be 117.40mm, the minor axis b is designed to be 106.7mm, the ellipticity is 1.10, and the eccentricity is 18.7mm. In this way, the steel is reduced from being squeezed into the VRS roll gap during steel rolling, the contact area between the rough pipe and the bottom of the VRS groove is increased, and the friction is improved.
[0035] Adjust the pinch roller at the entrance as follows:
[0036] The 1#~3# support rollers at the front of the continuous rolling mill are beam-type integrated structures. The lower pinch rollers often fail to clamp the raw pipes and cannot be adjusted by the extension and contraction of the hydraulic cylinder. The lower pinch rollers need to be padded or replaced separately. To solve this problem, after a long period of exploration, a special inspection plan and standard were formulated for the lower pinch rollers at the front of the continuous rolling mill. The height of the rollers is regularly checked to ensure that the height of the 1# roller before continuous production is 5~8mm higher than that of other rollers.
[0037] Cleaning the alignment fork is as follows:
[0038] Through long-term tracking, we found that due to the descaling process before continuous rolling, the iron sheet under the alignment fork is seriously accumulated. If it is not cleaned in time, the alignment fork will not be able to be lowered normally from the high position, causing the rough pipe to be unable to pass. Therefore, in order to ensure the normal operation of the alignment fork, we added a slag flushing water pipe under the alignment fork to achieve online slag flushing; in addition, the team is required to use more than 20 minutes of downtime to clean the alignment fork.
[0039] The optimization of the front roller lifting process is as follows:
[0040] The logic of the lifting action of the front-end support rollers of the continuous rolling mill is that after the tube is screwed onto the support rollers, the 1#~6# tube support rollers are lifted at the same time. Since the roller adjustment test is in a climbing trend, the tube is very likely to "slip backward" after it is lifted, causing the upper pinch roller to be unable to clamp the tube head after the tube is lifted, which in turn causes the continuous rolling to fail to bite in. To solve this problem, the lifting control logic of the front-end support rollers of the continuous rolling mill was slightly adjusted, that is, the 4#~6# tube support rollers were lifted first, and the 1#~3# support rollers were lifted later, and a 0.5s delay was designed between the two, so that the tube has a tendency to "slip forward" after it is lifted, so that the tube stays within the effective clamping range of the upper pinch rollers.
[0041] Through the above steps, the complex rolling process is simplified into quality control points, which is convenient for workers to judge and handle. The main improvement measures are realized by optimizing the automatic control program or tool, which minimizes the interference of human factors and has a high degree of automation. It effectively reduces the scrap and accident time caused by the failure of the rough pipe to bite into the rolling process. The scrap caused by the failure to bite into the rough pipe has dropped from an average of 206 pieces in 2019 / 20 to 19 pieces in 2021; the downtime has dropped from an average of 30.15 hours in 2019 / 20 to 1.40 hours in 2021. In the past two years, it has created benefits of about 2.671 million yuan, with significant benefits.
[0042] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which are equivalent modifications and improvements made to the above embodiments based on the essential technology of the present invention, and all of them belong to the protection scope of the present invention.
Claims
1. A method for preventing the rough pipe from not biting into the front end of continuous rolling, characterized in that: The following steps are involved: Adjust the hole shape of the air rolling mill: reduce the disengagement angle of the air rolling mill hole, the disengagement angle of the air rolling mill hole is adjusted to 47°-49°, increase the major axis length and eccentric distance of the air rolling mill hole to enhance the contact area between the raw tube and the bottom of the air rolling mill groove and improve the friction. The major axis length of the air rolling mill hole is 115mm-120mm, the eccentric distance is 15mm-20mm, the minor axis length of the air rolling mill hole is 105mm-107mm, and the ellipticity is 1.01-1.15; Adjust the lower pinch roller at the entrance: Check the height of the lower pinch roller before continuous rolling to ensure that the height of No. 1 roller is higher than other rollers before continuous production. The height of No. 1 roller is 5mm-8mm higher than other rollers; Clean the alignment fork: clean the area under the alignment fork so that the alignment fork can be lowered from the high position to the low position normally, ensuring the normal passage of the capillary tube; Optimize the lifting process of the front roller: adjust the lifting control logic of the front rough support roller of the continuous rolling mill, so that the rear support roller is lifted first, and then the front support roller is lifted. There is a delay of 0.5s between the rear support roller and the front support roller. In this way, the rough tube has a tendency to "slide forward" after lifting, so that the rough tube stays within the effective clamping range of the upper pinch roller.
2. The method for preventing the rough pipe from being bitten into the front end of continuous rolling according to claim 1, characterized in that: In the step of cleaning the alignment fork, the cleaning of the alignment fork specifically includes: adding a slag flushing water pipe under the alignment fork to achieve online slag flushing.
3. The method for preventing the rough pipe from being bitten into the front end of continuous rolling according to claim 1, characterized in that: In the step of cleaning the alignment fork, cleaning the alignment fork specifically includes: using downtime to clean the alignment fork.
4. The method for preventing the rough pipe from being bitten into the front end of continuous rolling according to claim 1, characterized in that: In the process of optimizing the front roller lifting process, the delay between the rear support roller and the front support roller is 0.5s.
5. The method for preventing the rough pipe from being bitten into the front end of continuous rolling according to claim 1, characterized in that: In the process step of optimizing the front roller table lifting, the number of rear support rollers is the same as the number of front support rollers.