3 ways to fold Stainless steel rectangular tube

Source:    Time:17 May 2022

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Stainless steel pipes are widely used in modern life. As people's demand increases, stainless steel pipes of different shapes have also been invented. This requires this certain folding technology. The first contact will be full of confusion. Let's take a look at 3 ways to fold stainless steel rectangular tubes.


Here is the content list:

  • Folding using a bending machine

  • Cold bending

  • Hot bending


Folding using a bending machine

1. Hold the forming handle of the pipe bender or fix the pipe bender on a vise.

2. Loosen the hook and raise the slider handle.

3. Place the stainless steel rectangular tube in the groove of the forming disc and fix it in the forming disc with a hook.

4. Lower the slider handle until the 0 scale line on the hook is aligned with the 0° position on the forming plate.

5. Rotate the slider handle around the forming disc until the 0 scale line on the slider is aligned with the required scale on the forming disc.


Cold bending

Because the high-pressure pipe wall of stainless steel rectangular tube fittings is very thick, it is usually not possible to fill with sand during incubation. For high-pressure pipes of stainless steel rectangular tube fittings used for bending, pipes with acceptable flaw detection and normal thickness should be selected. Pipes that have been inspected, repaired, and polished shall not be used for bending. If there is no stainless steel rectangular tube with positive wall thickness, it can be checked. Bend the pipe to obtain a negative tolerance. During the bending process, the thread of the pipe end must be protected. A cast-iron protective sleeve with internal threads is placed on the pipe end thread and wrapped with asbestos and asbestos. The protective sleeve should not be made of steel to prevent the protective sleeve and pipe threads from jamming after heating.

The bending of high-pressure pipes of stainless steel rectangular tube fittings should be as cold as possible. The bending radius should not be less than 5 times the pipe diameter. The minimum straight side length should not be less than 1.3 times the pipe diameter and should not be less than 60 mm. Mechanical cold bending can also be used for large-diameter stainless steel rectangular tubes and high-pressure pipes, but heat treatment is required after bending to eliminate residual stress. Due to the limitation of the bending radius of the bent tire, the wall thickness after bending is reduced, and the allowable value is 9%-15% of the nominal wall thickness. For high-pressure elbows larger than 45 mm, the thickness of the bent part needs to be measured, and the wall thickness of the thinned part should not be lower than the safe range.


Hot bending

If cold bending cannot be performed due to the limitations of bending equipment, hot bending can be used. In the case of thermal bending, the mechanical properties of the pipe will change due to the need to heat the pipe. Therefore, the high-pressure pipes of stainless steel rectangular tube fittings of different materials should be controlled in different heating temperature ranges, and different post-bending heat treatment methods should be adopted.

To more accurately control the heating temperature, a thermocouple or optical pyrometer can be used to measure the heating temperature. When heating, the tube should be rotated frequently, and the heating speed should be slow and uniform. It is necessary to ensure the heat penetration of the tube and prevent excessive combustion. In addition, appropriate measures must be taken to prevent the partial pressure of the pipe during thermal bending. When performing thermal bending in high-pressure pipes of stainless steel rectangular tube fittings, coal or coke should not be used as fuel to prevent carburization. To ensure the bending quality, it is preferable to heat the casting elbow by high-frequency or medium-frequency heating or partial heating flame.


After reading it, I believe you have a deeper understanding of the folding method of stainless steel rectangular tubes. Our company conducts many tests on stainless steel rectangular tubes before they leave the factory, and the quality qualification rate is guaranteed. If you are in the stainless steel rectangular tube business, you can consider our cost-effective products.