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Pipe Bending

pipe bending

What Is Pipe Bending?

Bending is a processing process that allows materials such as plates, pipes, and bars to be bent at a certain angle and shape, used to make various components, such as machine parts, automotive body parts, building components, etc. Bending can make materials more flexible, increase their application range, meet the needs of different shapes and sizes, and also make manufacturing costs more affordable. Bending is an indispensable process in modern industrial manufacturing.
bending steel pipe
bending pipe


how to bend square tube without bender?
This method requires skills and patience.
How to straighten a curved square tube?
1、 Heating straightening method
Heating straightening method is a common straightening method. The basic principle is to use the principle of thermal expansion and contraction to deform the square tube under heating, then straighten it with a hydraulic press, and finally return it to its normal state.
The advantage of this method is that it is easy to operate and implement, while the disadvantage is that it requires heating equipment and has a significant impact on the production line.
2、 Cold straightening method
Cold straightening method refers to straightening square tubes at room temperature. This method is mainly operated by a hydraulic press or mechanical straightening machine, which places the square tube into the machine fixture, then straightens it, and finally returns it to its normal state.
The advantage of this method is that it does not require heating equipment and has little impact on the production line. The disadvantage is that precise operational control is required during the process, otherwise it may lead to straightening failure.
3、 Hydraulic straightening method
Hydraulic straightening method refers to the use of equipment such as hydraulic presses or hydraulic cylinders for straightening square pipes. The principle of this method is to use the pressure of the liquid to perform standard straightening on the square tube.
The advantages of this method are high accuracy and efficiency, while the disadvantages are high cost, high operational requirements, and high requirements for hydraulic systems.
4、 Swing straightening method
The swing straightening method refers to fixing a square tube on a bracket, and then using a motor or reducer to drive the rocker arm to straighten the square tube. The advantage of this method is that it is easy to operate and does not require equipment such as a hydraulic press, while the disadvantage is that it is difficult to straighten pipes with larger bends solely relying on the force of the rocker arm.
5、 Tool straightening method
The tool straightening method refers to the use of manual straightening tools to straighten the square tube. The advantages of this method are low cost and simple operation, while the disadvantage is that it requires high technical level of straightening tools and operators, and the effect is sometimes not ideal.
In short, there are many methods for bending and straightening square tubes, and the method to be adopted should be selected based on the specific situation. At the same time, regardless of the method used, it is necessary to strictly follow the operating procedures to ensure the quality and safety of straightening.
How to polish the inner wall of bent steel pipes?
If the bend used is not suitable, such as being too thick or having surface defects, it can be polished to make it a more suitable pipe. How to polish it?
1. Check for irreparable defects such as leaking welds, weld penetration, solder joints, and scratches, and if so, correct them.
2. Eliminate defects such as welding spots and scratches on the surface of bent pipes, and preliminarily form rounded corners of welded joints. Grind back and forth with sandtape, and there are basically no large collisions or scratches on the horizontal and vertical planes.
3. Grind the joints and marks with abrasive tape to ensure that the surface of the bent pipe is free of scratches and basically bright.
4. In order to eliminate the weld seam between the ground part and the unpolished part, sand tape is used to correct the fine lines of the bend in the previous process, so as to further brighten the surface of the workpiece.
When polishing the bend, the system must be controlled and not pushed forcefully. In addition, during grinding, the entire surface of the pipeline must be kept uniform and bright.
When selecting a bend, it is generally evident from its surface whether the pipeline is good or bad. In order to ensure good surface quality, it is usually subjected to heat treatment, quenching, and high-temperature tempering to achieve its quenching and tempering:
1. The surface of the bent pipe must withstand high stress or wear resistance, so it is necessary to strengthen the surface of the workpiece, and different quenching methods can be used.
2. The thin rod hardening layer of the piston has a large thickness, making it difficult for the bent pipe to decarburize after quenching. The heating speed is fast, the operation is convenient, the hardening layer depth is large, and it is easy to achieve mechanization, automation, etc.
Surface conditioning of bent pipes is a surface treatment method, where the contact between the pipeline and the outside is greater than the internal contact. Therefore, in order to not affect the use of the entire pipeline, surface conditioning must be done well.
The hot melt connection between intermediate frequency bends and pipe fittings is a task that many manufacturers need to do during construction, and it needs to be carried out in a high-temperature environment. The work required for hot melt docking is as follows:
After heating, the components to be connected should be quickly separated from the heating tool to check the uniformity and degree of damage of the melting surface of the connected parts.
2. The connecting ends of the connecting parts at both ends should extend a certain free length of the welding fixture, and the two corresponding connectors should be straightened so that the staggered edges should not be greater than 5% of the wall thickness of the rotating joint of the intermediate frequency bend on the same axis.
3. The joint has a smooth and symmetrical flange along the circumference of the pipe joint, and the depth of the lower flange is not lower than the depth of the outer surface of the pipe joint.
4. The connection surface of the intermediate frequency elbow rotary joint is fully in contact with uniform external force, and the flange flange forms a flange. The flange shape is uniform and consistent, without pores, blisters, and cracks.
There are various connection methods for medium frequency bends, among which hot melt docking utilizes certain heating conditions to achieve the connection between the two, solving the problem of insufficient pipeline length.
The above has introduced the polishing of bent pipes, surface quenching and tempering of bent pipes, as well as the hot melt docking of medium frequency bent pipes, hoping to be helpful to everyone.
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