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Main Equipment of High Frequency Welded Pipe Production Line

Date:2021-07-05    keywords:high frequency welded pipe, production line equipment
Main equipment of high frequency straight seam welded pipe (ERW welded pipe) production line:

1. Uncoiler

The hot-rolled steel strip is disassembled and sent to the strip leveling machine. There are two types of unwinding: upper unwinding and lower unwinding. The decoiler is the front-end equipment of the high-frequency welded pipe production line.

2. Steel strip leveling machine

The strip steel is leveled before the welded pipe unit is formed. Generally, it consists of an upper base, a lower base, and a transmission device. There are five rollers, seven rollers, etc. In the high-frequency welded pipe production line, there is usually a pinch roller before the leveling machine.

3. Shearing butt welding machine

In order to ensure the continuous production of the high-frequency welded pipe production line, the irregular head and tail ends of the front and rear strips need to be cut neatly by a shear butt welding machine, clamped in the center, and welded to form a strip that can be continuously produced.

4. Storage looper

In order to meet the continuous production of high-frequency welded pipe units, a looper storage device is set in front of the strip head and tail shearing butt welding station, so that the strip is uncoiled during feeding and the head and tail are cut off during the preparation work for butt welding. The stored strip steel is continuously delivered to ensure continuous operation of the high-frequency welded pipe production line.


PMC High frequency welded pipe unit


5. Horizontal looper

The horizontal spiral looper is suitable for the strip steel thickness range of 0.4-16mm, and the production specification of the adapted high-frequency welded pipe is Ф14-Ф610mm. The horizontal looper is mainly composed of an inlet guide device, a filling and transmission system, an inner and outer roller cage, a center roller system, and an outlet guide device. The main advantages are that it can be filled at any time, the strip deformation is small, and the maintenance is convenient. The filling provides a guarantee for the continuous and stable production of the high-frequency welded pipe production line.

6. Disc cutter

Both sides of the strip are cut and trimmed to meet the requirements of the strip width and straightness of the high-frequency welded pipe unit forming machine. Its main components include cutting blade, cutting blade shaft, width adjustment mechanism, adjustment of overlap and gap mechanism, upper and lower guide rollers, transmission mechanism, etc. It is prepared for the regularity of the welded pipe after the welded pipe is formed on the high frequency welded pipe production line.

7. High-frequency welded pipe production line milling machine

For steel strips larger than 10mm, in order to ensure the quality of high-frequency welding, it is necessary to mill the edges of the steel strips to obtain strip edges of geometric shapes and sizes, which is beneficial to high-frequency welding. The milling machine equipment is mainly composed of two sets of milling cutter heads arranged horizontally up and down on both sides of the strip, an automatic control system, an AC speed regulation or a DC speed regulation transmission system, etc. It can greatly improve the quality of high-frequency welding and reduce material consumption.

8. Forming machine

It can be divided into two categories: spiral line forming machine and straight seam welded pipe forming machine. The spiral forming machine is based on the principle of three-roll bending, and it is divided into two types: external control and internal control; the longitudinal welded pipe forming machine is divided into longitudinal resistance roll forming and longitudinal submerged arc welding molding. The forming machine is an important equipment component in the high-frequency welded pipe production line.

9. Welded pipe mould

Welded pipe molds are the main molds for high-frequency welded pipe production lines and cold-formed steel production lines, and are the main consumable parts. The types of molds are divided into casting molds and forging molds according to the manufacturing method; according to the process method, they are divided into integral mold rolls and combined molds. Its quality directly affects the quality, output and cost of the product. A good mold should include three aspects: ①The mold pass is designed according to the strip steel deformation law to ensure the quality of welded pipe forming; ②The mold material has high strength, high hardness, high wear resistance and toughness to ensure a long life. ③Choose the corresponding mold material and manufacturing method and manufacturing process according to the performance of the product to achieve practicability and economy.

10. High frequency welding equipment

The skin effect and proximity effect of the high-frequency current are used to quickly heat the metal of the welded pipe to a molten state, and the welding can be realized by extrusion. The current frequency range usually used in high frequency welding is 300-450KHZ, and the power is 100-1000KW. Currently, the use of solid-state high-frequency welding machines is advocated. High frequency welding equipment is one of the core equipment of high frequency welded pipe production line.

11. Sizing machine

In the high-frequency welded pipe production line, the sizing unit usually consists of several transmission horizontal racks, passive vertical roll racks, and correcting devices to ensure the accuracy of the outer diameter and cross-sectional shape of the steel pipe, and also improve the forming and high frequency Stress concentration and residual stress in welding production. The sizing machine is also one of the main components of the high-frequency welded pipe production line.

12. Burr machine in high frequency welded pipe production line

In the ERW welded pipe process, it is used for the weld burr device in the welded pipe. Commonly used is the shaft diameter bidirectional hydraulic internal burr device. It is mainly composed of shaft, neck hydraulic cylinder, linkage mechanism and tool height adjustment mechanism. The tool is preferably a ring knife.

13. High-frequency welded pipe production line-weld heat treatment

In the ERW welded pipe process, normalizing the weld including the heat-affected zone, or performing quenching + tempering and normalizing + tempering on the weld. Make the metallographic structure and mechanical properties of the weld be consistent with the metallographic structure and mechanical properties of the base metal to eliminate welding stress and improve weld performance. The medium frequency heat treatment machine is widely used.

14. Fixed-length flying saw

The fixed-length flying saw is an important equipment for the high-frequency welded pipe production line. High-precision cut-to-length cutting is achieved in the online operation of high frequency welded pipes. The cutting forms include sawing, rotary cutting and punching. According to the different driving modes, they are divided into AC computer flying saw, DC computer flying saw and servo-controlled computer flying saw, which automatically control cut to length.

15. Straightening machine for high frequency welded pipe production line

Although the sizing device for high-frequency welded pipes is shaped in the radial direction, there is still some curvature in the length direction. For this reason, high-frequency welded pipes are straightened, and the straightening machines are generally divided into pressure straightening machines and roller straightening machines. The working principle of the roller straightening machine is: the high-frequency welded pipe moves in a straight line between the oblique hyperboloid straightening rollers while rotating. The high-frequency welded pipe undergoes repeated elastic-plastic bending in the straightening roller to make the high frequency The welded pipe achieves the purpose of correction.

16. High frequency welded pipe production line flat head machine

The ends of high-frequency welded pipes cut by a computer flying saw generally have some cut defects and burrs. In order to meet the follow-up process and the user's requirements for grooves, the burrs and inner and outer edges of the high-frequency welded pipe ends need to be trimmed. The flat-head machine is a device used for milling both ends of high-frequency welded pipes to flatten and chamfer them. It is composed of high-frequency welded pipe feeding device, high-frequency welded pipe clamping device, tool holder, follow-up device, speed regulating device, frame body and other parts. The working process of the flat head machine can realize automatic continuous circulation and automatic control.

17. High-frequency welded pipe production line hydraulic testing machine

Water pressure test is the main equipment for the production of high-frequency welded pipes. At present, the working process of the hydraulic testing machine used in the production of high-frequency welded pipes is: feeding, clamping, water filling, pressurizing, maintaining pressure, depressurizing, and discharging. This process also constitutes the basic action cycle of the test tube hydraulic press. Modern hydraulic testing machines are all controlled by PLC, so that each work process is automatically completed in sequence, and has the function of automatically recording test results and parameters. According to the sealing form, it can be divided into radial seal and end face seal. The radial seal adopts a sealing ring matched with the inner diameter or outer diameter of the high-frequency welded pipe. The sealing ring is compressed and expanded to achieve the purpose of sealing the pipe wall. Its advantage is that the high-frequency welded pipe is easy to clamp and withdraw, and the sealing is reliable. High-frequency welded pipe has small axial force and is not easy to bend, but the structure of the sealing head is more complicated, with many specifications, and there is a test blind zone at the end of the pipe; end face sealing is to rely on the sealing material and the end face of the nozzle to achieve the purpose of sealing the nozzle. Its advantages are simple test structure and good versatility, but higher requirements for sealing material performance, oil-water pressure difference ratio and servo control system.

18. Ultrasonic flaw detection of high frequency welded pipe production line

A non-destructive inspection method for detecting internal defects of high-frequency welded pipes using the principle that the interface of different density media will be diffracted during the propagation of ultrasonic waves.

19. Eddy current flaw detection of high frequency welded pipe production line

It is mostly used for on-line inspection of small diameter ERW high-frequency welded pipes. Because the probe does not touch the pipe surface, it can realize high-speed flaw detection. It is more sensitive to the detection of defects on the surface of high-frequency welded pipes, but is not ideal for detecting layer defects and inner surface defects. It can detect defects in the body of high-frequency welded pipes and welds of high-frequency welded pipes, and can use impedance plane technology to analyze the location and depth of the defects.

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