Main Equipment of High-Frequency Welded Pipe Production Line

　　1. Coil Winding Machine

　　Unwinds and feeds hot-rolled steel strip into the strip leveling machine. There are two types of unwinding methods: upper unwinding and lower unwinding. The coil winding machine is the front-end equipment of the high-frequency welded pipe production line.

　　2. Steel Strip Leveling Machine

　　Levels the steel strip before forming in the welding pipe machine. Generally, it consists of an upper machine seat, a lower machine seat, and a transmission device, including five-roll and seven-roll types. In the high-frequency welded pipe production line, a feeding roller is usually installed in front of the leveling machine.

　　3. Shearing and Welding Machine

　　To ensure continuous production of the high-frequency welded pipe production line, the irregular head and tail ends of the steel strips are trimmed and aligned, clamped, and welded by a shearing and welding machine to form a continuously producible steel strip.

　　4. Material Storage Loop

　　In order to meet the continuous production of the high-frequency welded pipe unit, a loop storage device is set before the head and tail shearing and welding station of the steel strip, so that when the steel strip is loaded and unwound, and the head and tail are cut and welded, the loop can continuously deliver the pre-stored steel strip to ensure that the high-frequency welded pipe production line can operate continuously.

　　5. Horizontal Loop

　　The horizontal spiral loop is suitable for steel strips with a thickness range of 0.4-16mm, and the matching high-frequency welded pipe production Specification is Ф14-Ф610mm. The horizontal loop mainly consists of an inlet guiding device, a filling and its transmission system, inner and outer roller cages, a central roller system, and an outlet guiding device. The main advantages are that it can be filled at any time, the steel strip deformation is small, and the maintenance is convenient. Filling provides a guarantee for the continuous and stable production of the high-frequency welded pipe production line.

　　6. Rotary Shear

　　The edges of the steel strip are sheared and trimmed to meet the requirements of the high-frequency welded pipe forming machine for the width and straightness of the steel strip. Its main components include cutting blades, cutting blade shafts, width adjusting mechanism, coincidence and gap adjusting mechanism, upper and lower guide rollers, and transmission mechanism. It is used to prepare for the regularity of the welded pipe after forming on the high-frequency welded pipe production line.

　　7. High-Frequency Welded Pipe Production Line Edging Machine

　　For steel strips above 10mm, in order to ensure the quality of high-frequency welding, the edges of the steel strip need to be milled to obtain steel strip edges with geometric shape and Size, which is conducive to high-frequency welding. The edging machine mainly consists of two sets of milling cutter plates arranged horizontally up and down on both sides of the steel strip, an automatic control system, and an AC or DC speed regulation transmission system. 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 forming machine and straight seam welded pipe forming machine. The spiral forming machine is based on the principle of three-roll bending plate and is divided into two types: external control type and internal control type; the straight seam welded pipe forming machine is divided into straight seam resistance roller forming and straight seam submerged arc

　　Welding and molding. The forming machine is an important equipment component in the high-frequency welded pipe production line.

　　9. Welded Pipe Mold

　　Welded pipe molds are the main molds of high-frequency welded pipe production lines and cold-bent steel production lines, and are major consumable parts. According to the manufacturing method, molds are divided into cast molds and forged molds; according to the process method, they are divided into integral mold rolls and combined molds. Their quality directly affects the quality, output, and cost of the products. A good mold should include three aspects: ①Design the mold profile according to the deformation law of the steel strip to ensure the quality of the welded pipe forming; ②The mold material has high strength, high hardness, high wear resistance, and toughness to ensure a longer service life; ③Select the appropriate mold material, manufacturing method, and manufacturing process according to the product performance to achieve practicality and economy.

　　10. High-Frequency Welding Equipment

　　Using the skin effect and proximity effect of high-frequency current, the metal at the welding part of the welded pipe is quickly heated to a molten state, and welding is achieved through extrusion. The current frequency range commonly used in high-frequency welding is 300-450KHZ, and the power is 100-1000KW. At present, it is advocated to use solid-state high-frequency welding machines. High-frequency welding equipment is one of the core equipment of the high-frequency welded pipe production line.

　　11. Sizing Machine

　　In the high-frequency welded pipe production line, the sizing unit usually consists of several driven horizontal machine frames and passive vertical roll machine frames, as well as a correction device, finally ensuring the accuracy of the outer diameter and cross-sectional shape of the steel pipe, and also improving the stress concentration and residual stress of the forming and high-frequency welding production. The sizing machine is also one of the main components of the high-frequency welded pipe production line.

　　12. High-Frequency Welded Pipe Production Line Internal Burr Removal Machine

　　In ERW welded pipe technology, it is used for welded pipe internal weld seam burr removal device. Commonly used is the axial bidirectional hydraulic internal burr removal device. It mainly consists of an axis, a neck hydraulic cylinder, a connecting rod mechanism, and a tool height adjustment mechanism. The annular knife is preferred as the tool.

　　13. High-Frequency Welded Pipe Production Line-Weld Heat Treatment

　　In ERW welded pipe technology, the weld seam, including the heat affected zone, is normalized, or the weld seam is quenched + tempered and normalized + tempered. The microstructure and mechanical properties of the weld seam are consistent with those of the base metal to eliminate welding stress and improve the performance of the weld seam. The widely used is the medium frequency heat treatment machine.

　　14. Fixed-Length Flying Saw

　　The fixed-length flying saw is an important equipment of the high-frequency welded pipe production line. It realizes high-precision fixed-length cutting under the online operation of the high-frequency welded pipe. The cutting forms include sawing, rotary cutting, and punching. According to different drive forms, it is divided into AC computer flying saw, DC computer flying saw, and servo-controlled computer flying saw, which automatically control the fixed-length cutting.

　　15. High-Frequency Welded Pipe Production Line Straightening Machine

　　Although the sizing device of high-frequency welded pipes performs radial shaping, there is still some curvature in the length direction. Therefore, the 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 that the high-frequency welded pipe performs linear forward movement while rotating between obliquely manufactured double-curved straightening rollers, and the repeated elastic-plastic bending of the high-frequency welded pipe in the straightening roller achieves the purpose of straightening.

　　16. High-Frequency Welded Pipe Production Line End Facing Machine

　　The ends of high-frequency welded pipes cut by computer flying saws generally leave some cutting defects and burrs. To meet the requirements of subsequent processes and users for bevels, the burrs and inner and outer edges of the ends of the high-frequency welded pipes need to be trimmed. The end facing machine is a device used to mill both ends of high-frequency welded pipes to make them flat and chamfered. It consists of high-frequency welded pipe feeding device, high-frequency welded pipe clamping device, knife holder, following device, speed regulating device, machine frame, etc. The end facing machine working process can be automatically continuous cyclic, automatically controlled.

　　17. High-Frequency Welded Pipe Production Line Hydraulic Test Machine

　　Hydraulic testing is the main equipment in high-frequency welded pipe production. At present, the hydraulic test machine used in the production of high-frequency welded pipes has the following working process: feeding, clamping, water filling, pressurization, pressure holding, depressurization, and discharging. This process also constitutes the basic movement cycle of the test tube hydraulic press. Modern hydraulic test machines use PLC control to automatically complete each working process in sequence and automatically record the test result parameters. According to the sealing form, it can be divided into radial sealing and end face sealing. Radial sealing uses a sealing ring that matches the inner diameter or outer diameter of the high-frequency welded pipe, and the sealing ring is pressurized and expanded to achieve the purpose of sealing the pipe wall. Its advantages are that the high-frequency welded pipe is easy to clamp and pull out, the sealing is reliable, the axial force of the high-frequency welded pipe is small, and it is not easy to bend, but the sealing head structure is more complex, there are many specifications, and there is a blind area for testing at the pipe end; end face sealing relies on the pressure of the sealing material and the end face of the pipe mouth to achieve the purpose of sealing the pipe mouth. Its advantages are simple test structure and good universality, but the requirements for the performance of sealing materials, the ratio of oil and water pressure difference, and the servo control system are higher.

　　18. High-Frequency Welded Pipe Production Line Ultrasonic Flaw Detection

　　A non-destructive testing method that uses the principle that ultrasonic waves will diffract when encountering different density medium interfaces during propagation to detect internal defects in high-frequency welded pipes.

　　19. High-Frequency Welded Pipe Production Line Eddy Current Flaw Detection

　　It is mostly used for online detection of small-diameter ERW high-frequency welded pipes. Because the probe does not contact the pipe surface, high-speed flaw detection can be achieved. It is more sensitive to surface defects of high-frequency welded pipes, but not ideal for detecting layered defects and internal surface defects. It can detect defects in the pipe body and weld seam of high-frequency welded pipes, and can use impedance plane technology to analyze the location and depth of defects.