In the production of high frequency welded pipe, the removal of inner burr is always a difficult problem to solve, especially for small diameter welded pipe. The larger and medium diameter welded pipe is prone to inner burr scraping deviation, excessive or small, and unclean scraping, which seriously affects the scraping quality of inner burr and the quality of welded pipe. By introducing the type of inner burr cutter rod and the structure of small diameter HFW cutter rod, the common problems and solutions of burr removal in small diameter HFW welded pipe are put forward according to production practice.
Types of cutter rod for inner burr removal
There are three types of inner burr removal cutter rod: mechanical inner burr removal cutter rod, pneumatic inner burr removal cutter rod and hydraulic inner burr removal cutter rod.
Mechanical inner burr removal cutter rod
The lower roll of this type of cutter rod has adjustable top wire fixing height, in which the mechanical cutter rod and buffer spring are needed to remove burrs in 76-114 mm steel pipe.
The advantages of this type of cutter rod are fixed size, simple structure and convenient maintenance. Disadvantage: Inside burr removal is unstable and compatibility is poor. The product with low precision of inner burr removal has low strength of steel tube after removal.
Pneumatic inner burr removal cutter rod
The lower roll of this type of cutter rod is controlled by adjustable air pressure, which is stable in the process of inner burr removal, simple in structure and convenient in maintenance. It is suitable for products with high precision of inner burr removal. But it has the disadvantage of poor compatibility, and because of the limitation of air pressure, it can not remove the burr of high strength steel pipe.
Hydraulic inner burr removal cutter rod
The lower roll of this type of cutter rod is controlled by adjustable oil pressure, so its working stability is good. It is suitable for steel pipes with high inner burr clearance accuracy, high precision pipes and high strength pipes. However, its structure is complex and the requirement of cutter rod processing and fabrication is high.
Structure of Hydraulic inner Burr Removal Device for Small Diameter HFW Welded Pipe
Composition of inner burr clearing cutter rod
The inner burr removal cutter rod is composed of adjustable upper roll, tool head, tool holder, lower roll, cylinder, impedance, connecting shaft and fixing plate. Its structure is shown in the following figure.
Diagram of Burr Scraping Mechanism in Small Diameter HFW Longitudinal Welded Pipe
Working Process of Inner Burr cutter rod：
Adjusting the relative position between the tool head and the upper roll can determine how much inner burr is removed. The adjusted cutter rod is put into the steel pipe, and the end fixing plate of the cutter rod is fixed on the adjustment device. The inner burr ring cutter is located near the inner and outer burr planer. The pressure oil supplied by the hydraulic station enters the vertical lifting cylinder through the tubing, ejects the cylinder, and ejects the lower roll rack. When the tool holder is raised, the inner burr ring blade cuts into the continuous moving inner weld bar of high temperature steel pipe and cuts off the inner weld bar.
Cutter rod fixing adjustment device
The function of this part is to firmly fix the fixing plate at the end of the fixed cutter rod on the frame to prevent the fixing plate from loosening in production. The device consists of two parts: rotation and lifting. The rotating part rotates through the handle, so that the tool rod can rotate around the center of the pipe (+15 degrees) and align with the welding seam to cut burrs. The lifting part can make the cutter rod in a reasonable height position to suit the position of steel pipes of various sizes.
The function of hydraulic station is to provide stable and lasting working pressure for cutter rod. The working pressure of the cutter rod varies according to the material used to produce the steel pipe. The range of oil pressure adjustment is 4-12.5 MPa. The pressure of oil is adjusted according to the wall thickness and strength of steel pipe and the size of inner burr to make the cleared inner weld within the standard range.
Pressure range required for burr removal of steel pipes of different materials
The function of this part integrates the tool holder and the fixing device. Including impedance, connecting pipe (rod), cooling shunt and eccentric coupling sleeve, the tool holder is also in normal working position.
Post time: Apr-09-2019