For the transport of oil or gas, require pre-bending of pipes. Without this procedure will not be able to do construction or industrial field of activity. To organize a strong rotation, used in practice reliable connection elements in the form of fittings.
However, this technology is not suitable for every system and depends on the material. If the bend pipe, can maintain a decent appearance, without disturbing the integrity of the structure.
Technology and features
Creating any pipeline system, experts select products from different metals. This is due to the fact that each has different characteristics. To change the shape of the structure is carried out by the impact of the radial and tangential forces. The first section required for deformation, and due to the formation of the second folds. It is important that after the completion of all procedures, the range has remained the same, and inside walls should be no corrugation.
During the manufacture of metal structures using solid material, is used instead of welding alternative - bending. There are several main reasons for this choice:
- Consumption of materials is reduced due to the lack of cooking elements.
- Compared to systems where there are welding or threaded connections, in this case the complexity index is much less.
- Improved hydroaerodynamics created passage.
- Comparing with carrying out welding work, when bent pipes no negative impact on the structure.
- Creating a sealing and high reliability.
Classification
Selection method for bending pipes depends on several factors:
- The material from which the pipe is manufactured;
- The thickness of the tubes;
- What is the profile;
- The cross section diameter and height;
- Radius foldable surface;
- With what accuracy you need to bend the pipe;
- What is the size of deformation is allowed in accordance with the standards established by state standards;
- How is a solid structure in the fold areas.
There are 4 main types of flexible pipes:
- Hot.
- It's cold.
- By means of portable benders.
- Machining.
Each method has its own tools for bending.
Using hot bending
This method is relevant when there is no specialist equipment required to use the cold method. This is a laborious process, wherein preheating is carried out using special fillers. In this situation, the use of topical sifted river sand. It is important that it does not contain organic additions and milled fractions. Otherwise, at high temperatures will burn the sand to the walls of the structure. It is also important to prevent the damp raw material, as it will increase the pressure and steam.
A flexible pipe with induction heating or hot should be carried out at temperature in the range of 900 degrees. It is important to make sure that did not happen burnout, and use only a single heating, otherwise the design quality may deteriorate. Once all the procedures are implemented, it is necessary to remove the sand and clean the cavity from residual contamination. Plugs are also eliminated.
Features cold bending
There are a lot of advantages compared to hot bending. This method has a high efficiency, thereby reducing the material costs of the holding. Cold bending optimally suited not only for blacks, but also non-ferrous materials with high plasticity. For example, to bend a pipe of copper or aluminum can be in a spiral without exposure to high temperatures.
Bending adversely affects the quality and characteristics of the metal. As a result, there are following defects, among which are:
- The wall thickness of the outside of the bend is reduced.
- There are folds of the corrugations on the inside of the bend.
- passage form begins to change and becomes an oval appearance.
Deformations of the most susceptible structures made from soft metal with thin walls.
To properly organize the process and not to cause mechanical damage, be sure to use a mechanical stabilizer, which acts as a mandrel. This special tool, located in the cavity at the future site of the bend. The main purpose is to prevent the occurrence of deformation. In practice, apply soft and hard structures.
Hard type involves an element of the form guide. It is made of a hard metal type. The end face rounded by the working surface. Refilling is carried out with a bending point. At the heart of the flexible structure is a special rod. At the end of one side is somewhat greater flexibility segments. Visually presented hemispheres. Their use is necessary in order to avoid deformation of the passage.
Once the process is coming to an end, it is pushed out of the folding seats and special balls are placed on the inner surface. The second option involves the mandrel a number of difficulties in the process, therefore, used the automatic control system.
Based on the specific characteristics of the device, mandrels are used only in stationary mode. Their production is necessary for semi-automatic or automatic mode. To ensure uninterrupted control of CNC system is used. It is intended for monitoring the implementation of all processes.
Work portable bending tool
If necessary bending pipes in place of creating structures, the portable operation of the instrument is the best one. Allocate only a few types of tools:
- Lever. Due to the small shoulder and will need to apply a small amount of physical effort. When using the metal structure (typically, stainless steel up to ¾ inch), it is possible to make a bend of 180 degrees.
Figure 5. lever - Crossbow. The structure must be located on both edges of the bearings, which rotate around its own axis. The shoe has a direct connection with the rod. It occurs pressure pipe portion which is located between the supports. Thanks to its light weight, it is possible to bend the pipe diameter in the range 100 mm to 90 angle degrees.
stem through pressurized pipes. It can be a hydraulic manual or electrically powered mechanical screw.
- Electric. Bending of the pipe is carried radially by removable segments. To bend the pipe at a certain angle, the rotary mandrel.
The tool has a number of positive qualities:
- The design is versatile in use, as provided in the kit removable segments;
- It is possible to achieve a bend of 180 degrees;
- The work is automated, which reduces the cost of manual labor;
- Have reversed, the device can operate in a smooth operation;
- No deformation occurs where the dynamics and coordinate snap feed;
- The high level of productivity.
If there is no electricity grid, you can use a replaceable battery, and continue to operate the equipment.
Machining flexible
It is considered the most common method of bending pipes. Used construction with three roller Roller benders. It used a method which involves the cold deformation of the metal. Alternative title - rolling. A distinctive feature is the fact that it can be used even for bending titanium tubing. It should be noted that it may be used in the construction of any type of products: oval or circular, capable of quickly coping with chrome pipe. Able to bend the elements prepared with square, rectangular or triangular cross-sections.
Also permitted from any flexible metal pipes of large diameter. Universal rolling work property is provided, involving deformation in a specific direction. To provide a certain type and size of the bend, a special gauge is selected.
The distinctive advantage of this type is the ability to bend the pipe length of 5 m. In the construction sector are often required to carry out such manipulations. The blank may be bent at an angle of 360 degrees (in the ring). If you intend to work with large-diameter pipes, all manipulations are carried out by means of electrical machines. The first end of the workpiece is set in a special capture, then there is a wound to the required radius.
Machine tools allow you to create the exact angle of the bend. Providing performs classical mechanical work, or when installing certain tasks on the controller. It uses highly automated systems.
Own hands to carry out such an operation without adequate skills will be extremely difficult. It is therefore recommended to entrust work even professionals in the case where the planned fold pipe. In the case of errors in the calculations, it is possible the rapid deformation of the entire system, the occurrence of leaks and in some cases the creation of an emergency.
