With the continuous advancement of industrialization, the demand for various types of mechanical equipment in the market is growing. As an important industrial equipment, used spiral pipe mill has gradually become the first choice of many companies due to its high cost performance and wide application range.
1. What is a spiral steel pipe machine
Spiral welding pipe machine is mainly used to produce spiral welded pipes of various specifications and models, and is widely used in construction, petroleum, chemical and other fields. Used spiral pipe mill is a used equipment that has been put into the market for sale and use again after professional inspection, maintenance and repair. Compared with the new spiral welding pipe machine, second-hand equipment has the advantages of low cost and high return on investment, especially suitable for small and medium-sized enterprises and start-ups.
The equipment of the common used spiral pipe mill brand JINYUJIE in the market is favored by users because of its reliable quality and stable performance.
2. Unit characteristics
This machine consists of single machines such as unwinding, feeding, straightening, shearing, splicing, trimming, delivery, input guide plate, forming, internal and external welding of steel pipes, pipe cutting, output and pipe turning. This machine is the first in China to use new technologies and equipment such as adjustable outer rollers, pulling and shearing, pulling and kneading transmission, and resistance shaping method.
3. Forming method
In view of the fact that this product has a variety of specifications, large diameter and thin wall, and the amplitude modulation reaches 1600ram, an outer roller cantilever forming machine frame is selected.
① Forming roller adjustment and quantity selection
When the forming rollers are evenly distributed at an angle of 45° to the outer circle of the steel pipe, the adjustment track A, B, and C of the pipe diameter change is a terminal straight line with an angle of 30° to the horizontal line. However, considering the best force surface, it should be 4.
If the base is formed into two, each with an angle of 30° to the corresponding bottom surface, it will form a forming roller regulator that meets the above two requirements. In order to minimize the output resistance of the forming roller to the welded pipe, the forming roller I should be rotated around the axis on the small base with the change of the spiral angle. When the specifications change, the axial position of the spiral line will change, so the forming roller regulator is required to be able to make lateral adjustments along the slide rail. In order to keep the bottom elevation unchanged and its position constant, the upper and side forming rollers should be adjusted up and down and left and right when the pipe diameter changes. The above five adjustment factors are the basic elements of adjustable forming.
② Design features of forming machine
(1) In order to make the outer roller adjustable, the cantilever forming machine adapts to the 1600ram amplitude modulation requirements, and the frame extension arm is adjusted up and down along the square guide column by the transmission mechanism.
(2) In order to solve the problem of easy burn-through when welding thin-walled pipes inside and outside, internal and external flux pads are provided.
(3) The internal welding point should be as close as possible to the forming meshing point and the chassis rotation center to prevent the strip rebound from misalignment and facilitate the adjustment and tracking of the internal welding head.
3. Equipment structure
Working principle of flying milling pipe cutting In order to solve the problem of flying cutting and sizing of ultra-large diameter thin-walled spiral welded pipes, gas cutting, milling cutting and sawing were tested successively. Among them, milling cutting is better. Vertical roller 2 and flat roller 1 are close to the running pipe end and the outer pipe wall, and are connected to the tie rod 4 through connecting rod 3. The pull rod 4 is connected to the pipe cutting machine head 7 and guided by the pressure roller 5. The tracking and synchronization of the cutting process can be achieved.
The steel pipe becomes oval after the output guide frame loses its bearing. When the rear axle is fine-tuned, the pipe vibrates, and the weld reinforcement height and diameter changes all give the pipe cutting tool a variable impact force and damage the tool.
Disc scissors disc structure
Usually, there are two types of disc shears: cantilever type and through-axis type. The latter has better rigidity than the former, but it is time-consuming and laborious to replace the cutter disc. For this reason, we use a split structure. It has the characteristics of through-axis rigidity and cantilever type easy maintenance. In order to improve its service life and solve the blade scarring phenomenon, we use 5CrMnMo village material after isothermal spheroidizing annealing to obtain satisfactory results.
Rear axle flexural transmission mechanism
The rear axle transmission commonly uses two methods: the forming rotary center gear transmission method and the rear axle far-end fan-shaped rack transmission method. Its disadvantage is that it brings inconvenience to processing, installation and maintenance. This machine adopts the steel rope drive method. The steel rope 1 is wound on the drivable drum 2. The two ends are connected to the rear axle 4 through the adjustable lock 3 to realize the rear axle drive. Years of production practice have proved that the flexible transmission method has the advantages of simple structure, flexible operation, reliable use and low investment.
4. Adjustment technology
The change of pipe diameter must be accompanied by the phenomenon of "strip shearing off". Relying on pushing steel coils or adjusting vertical rollers to prevent "strip shearing off" will result in either thickening of the strip edge (in severe cases, twice the thickness of the strip), or alternating wavy "ridges" on one side or the other side of the conveyor strip. In severe cases, the vertical rollers are squeezed off or the strip is stuck in the input guide plate and cannot be pushed. This shows that in addition to the three elements of forming, there are other factors, such as strip crescent bend, yield limit, steel pipe output resistance, equipment installation accuracy, welding and forming process, etc. In order to control the pipe diameter within the given deviation range, we take the following adjustment measures accordingly.
① Strip crescent bend
According to actual measurements, some steel coils have a double-sided tower shape of more than 100ram, and the strip crescent bend is increased every 10m Up to 120ram. Most of the crescent can be eliminated by trimming, but when the forced limit of the strip by the vertical roller, delivery roller, etc. is released, the strip will rebound so that a small part of the crescent will still appear during forming. The existence of this residual crescent will change the input direction of the strip (forming angle) and the width B of the strip, thereby causing a change in the tube diameter D.
According to regulations, such steel coils are prohibited. But when they must be used, we adopt the following adjustment methods:
(1) Increase the trimming amount, but the increase is limited to avoid wasting steel.
(2) Improve the installation accuracy of the equipment. In order to prevent the strip from being deviated, the non-parallelism error between any two single machines of the feeding equipment shall not exceed ±0.5ram, and the roller gap error at both ends of each feeding straightening roller shall not exceed ±0.1mm.
(3) Depending on the size of the crescent, the unwinder is moved back 30~50m Or make the unwinder transversely movable to buffer or eliminate the "bulge" of the strip caused by factors such as the crescent bend, but it cannot eliminate the crescent bend.
(4) Use the knife to borrow material method. The larger the crescent bend, the easier it is to shear off. Once the shear is off, it is a shutdown accident. It is more difficult to handle.
Cut in advance at the B-B surface of the minimum allowable trimming amount, move the lower strip to the left to the non-shearing position and then dock it with the upper strip. Use the material borrowed by the transverse shift to compensate for the insufficient trimming amount. Although it can prevent shearing off, it will affect the production if the machine is shut down. In serious cases, it needs to be cut 2 to 3 times. It may even be necessary to cut off a section before docking, which increases the loss of steel.
② Adjustment of the three-roll plate bending machine
Control the pipe diameter deviation through the pre-bending curvature of the Zhengtang strip. Roller 1 can be lowered or rollers 2 and 3 can be raised to reduce the pipe diameter, while the pipe diameter becomes larger. It can also be raised or lowered at one end of rollers 1, 2, and 3 at the same time to make the initial bent pipe flare-shaped. If the outer end is "closed", the pipe diameter becomes larger; if it is "expanded", the pipe diameter becomes smaller.
Due to the change in the position of roller 1, the bottom elevation of the output pipe is changed, which not only increases the output resistance, but also brings disadvantages to welding. Therefore, the best adjustment scheme should be that rollers 1 and 2 are stationary and roller 3 is lifted and lowered.
③ Adjustment of steel pipe output resistance
For steel pipes that have been removed from the output guide, as the length of the pipe increases, the ovality and weight of the pipe also increase continuously. As a result, the output resistance of the steel pipe continues to increase. Reflected on the inner welding point, a speed difference is generated at the meshing point with the input strip steel. The strip steel with a relatively high speed will inevitably increase the outer diameter of the welded pipe during the forming process, and it will be expressed in the form of misalignment, which destroys the forming and weldability conditions. The larger the difference, the greater the change in pipe diameter. As long as the rotation speed of the output roller can be increased proportionally with the increase in output resistance, the increased output resistance can be offset to achieve the purpose of controlling the pipe diameter deviation.
In addition to the factors mentioned above, the factors that affect the change of pipe diameter include the mechanical properties of strip steel (such as yield limit), the initial bending and rebound of steel pipe forming, the manufacturing and installation accuracy of equipment, the maintenance and operation level of workers, etc. Therefore, changing the output resistance to control the pipe diameter deviation reflects the comprehensive effect of many influencing factors.
According to the above working principle, when the pipe diameter becomes larger, the output roller speed is increased to "twist" the pipe diameter down and make the pipe diameter smaller; when the pipe diameter becomes smaller, the active output roller speed is reduced to "hold" the pipe diameter up and make the pipe diameter larger. Years of production practice have proved that the output resistance adjustment method to control the pipe diameter deviation is successful and effective.
5. Market status
According to the latest data, the used spiral pipe mill market presents a situation of strong supply and demand. On the one hand, many companies will choose to sell existing second-hand equipment when expanding production scale or updating equipment; on the other hand, due to the cost-effectiveness of second-hand equipment, more and more companies tend to purchase second-hand equipment to meet production needs.
From the price trend, the price of used spiral pipe mill is affected by many factors, including but not limited to brand, model, service life, maintenance and so on. For example, the second-hand spiral welded pipe production line provided by Foshan Shunde Jinyujie Electromechanical Equipment Co., Ltd. has attracted wide attention from the market due to its advanced control method and stable performance.
With the increasingly stringent environmental protection policies, some old equipment has been eliminated due to non-compliance with environmental protection standards, which has also injected new vitality into the used spiral pipe mill market. By purchasing second-hand equipment and carrying out technical transformation, enterprises can meet environmental protection requirements to a certain extent and reduce production costs at the same time.
6. Key points for purchase
When purchasing a used spiral pipe mill, users need to pay attention to the following aspects:
Equipment condition: First of all, a comprehensive inspection of the appearance and internal structure of the equipment should be carried out to ensure that there is no obvious wear and damage. At the same time, attention should be paid to the service life and maintenance records of the equipment to understand its past use.
Performance test: Before purchasing, field tests should be carried out as much as possible to test whether the various performance indicators of the equipment meet the production requirements. This includes welding speed, weld quality, stability and other aspects.
Brand selection: Equipment from well-known brands usually has better quality and after-sales service, but the price is also relatively high. Therefore, users should make reasonable choices based on their actual needs and budget when choosing.
After-sales service: When purchasing second-hand equipment, you must pay attention to the seller's after-sales service capabilities. Good after-sales service can provide strong guarantees for the later use and maintenance of the equipment.
Technical support: For some equipment with high technical content, users also need to pay attention to whether the seller provides technical support and training services. This helps users better master the use and maintenance skills of the equipment.
7. Development direction
With the continuous advancement of science and technology and changes in market demand, the development direction of used spiral pipe mill is mainly reflected in the following aspects:
Technology upgrade: By introducing advanced manufacturing technology and intelligent control systems, the production efficiency and automation level of the equipment can be improved. At the same time, it can also reduce energy consumption and emissions, which is in line with the development trend of green production.
Intelligence: Use technical means such as the Internet of Things and big data to achieve remote monitoring and intelligent management of equipment. This can not only improve the operating efficiency and safety of the equipment, but also save labor costs and management expenses for enterprises.
Environmental protection and energy saving: With the increasingly stringent environmental protection policies, enterprises have put forward higher requirements for the environmental protection performance of equipment. Therefore, the future used spiral pipe mill will pay more attention to the technological innovation and application of environmental protection and energy saving.
Diversification of market demand: With the continuous changes and segmentation of market demand, the types and specifications of used spiral pipe mill will also be more diverse. This will help meet the special needs of different industries and enterprises.
As an efficient and economical production tool, used spiral pipe mill plays an increasingly important role in industrial production. With the continuous advancement of technology and the continuous development of the market, it is believed that used spiral pipe mill will be widely used and promoted in more fields in the future.
