The need for making connections between the engineering contours of the pipeline arises when performing the first installation, and during repair operations. A feature of pipe welding in communication systems is the mandatory provision of tightness. Only in rare cases does this aspect have no special significance, and it can be neglected. In search of an answer to the question of how to weld a pipe to a pipe, one cannot do without a description of modern technologies. First of all, this refers to plastic materials, which have recently become widespread in the market and quite quickly introduced a new soldering method into installation work. But traditional metal pipes are welded at a modern and more technological level than 10-15 years ago.
What types of pipes can be welded?
The entire range of pipe material used in water, gas and heating systems can be divided into two types of material - these are metal and plastic products. In both cases, the pipes are weldable, otherwise installation work with them would be impossible. Of course, as an alternative, we can recall the threaded connection method, which used to be applied to steel structures difficult to process, but this technique has long been outdated and is not used. Nowadays, welding of steel pipes is carried out by means of electric arc devices, which allow for durable joints. The technology of working with plastic pipes is somewhat different. In this case, the problem of using classical welding is determined by the softness and viscosity of the material structure. Therefore, soldering and melting methods are used, which are also included in the general group of welding technologies. At the same time, the technical means for implementing these types of joints are noticeably different from traditional welding equipment.
Welding equipment
The most popular apparatus for carrying out electric arc welding of metal pipes is an inverter type semiautomatic device. In the process, to ensure protection of the working area from external influences, a special gas is used, which allows to achieve a high degree of accuracy and tightness in the seam. The popularity of MMA manual arc welding machines is declining. This is an affordable and easy way to obtain a seam with high mobility of the equipment, but it has significant disadvantages, including low productivity and the formation of slag on the surface of the seam, which must be removed. As for the technique for welding plastic materials, the most commonly used are press brazing complexes. Both modern polypropylene pipes and models made of polyvinyl chloride are soldered in a machine that has a cutter in its design, a gripping vice, a cutting plate (heating element) and a device for sealing joints.
Preparation of metal pipes for welding
Pipes are carefully cleaned to maximize fit to each other. Both connecting sides must have a bevel located at a 45-degree angle relative to the axis of the pipe. At the same time, a flat end must remain at least 2 mm wide. However, specific parameters may vary depending on pipe diameters. Equally important in the matter of how to weld the pipe to the pipe, the correct alignment. Immediately before the operation, it is necessary to assemble - so as to ensure maximum accuracy in reducing the edges of the two components to be welded. In some cases, a tack is performed, that is, a short seam is formed, which during the assembly process acts as an overlay in the structure.
Electric welding of metal pipes
First of all, you should make the "ground" clamp. The cable must be insulated and fixed in a special holder. The welding machine sets the optimal current power indicator required for a particular material - average values are required for mild alloys, and higher values are suitable for alloy steels. Then the arc is clamped, and the electrode is installed at a 60-degree angle relative to the workpiece. From this moment, by touching the arc of the working surfaces, welding of metal pipes begins, which may be accompanied by the formation of sparks. The electrode should move slowly, but so that no sticking occurs. With a delay in one place, there is also a risk of excessive deformation. Avoid this will allow uniform arc over the entire surface. As a result, a strong wavy seam should form.
Preparation of plastic pipes for welding
First, the pipes are cut to size in accordance with the sufficient length of the planned structure. That is, it is desirable to organize the overall installation process in such a way that welding is the final touch. This is far from always possible, but if possible all technical work with the pipeline should be carried out before welding operations. It will also be good to leave a small margin so that part of the product can be incorporated into the fitting. Then, as in the case of metal analogues, the polyvinyl chloride and polypropylene pipes are cleaned. The main task at this stage is to get smooth, clean and neat edges. The reliability of the future weld depends on the quality of the edges of the pipe. This is especially true for plastic products, because in the soft structure the smallest burrs and irregularities are of great importance in the soldering process.
Plastic pipe joint
Large complexes for welding plastic pipes usually have a stationary installation and allow in-line formation of joints. A little more complicated are the processes of one-time soldering operations. For such purposes, manual devices are used that work with heating elements in the form of nozzles. Before work, it is necessary to install the device on a flat surface, as well as set the optimal temperature regime. For example, welding of PVC pipes is usually carried out at 260 ° C. After 10-15 minutes after switching on, the device will pick up the optimal temperature regime, it will be possible to start the operation.
Workpieces for connection are installed on the nozzles - the fitting is fixed on the mandrel, and a pipe is installed on the sleeve. The operation itself takes several minutes, as the plastic melts quickly. Therefore, after turning on the device, you should prepare to complete the process. Direct welding of PVC pipes with subsequent connection is made the first time in one step. In the first seconds, the joint cannot be turned and attempted to be corrected, since any changes after welding will affect the strength for the worse.
How long does it take to cool the material?
In the case of metal pipes, the process takes longer and, as a rule, the formation of the joint is performed in layers. Therefore, the structure is gaining strength already in the course of work activities. After work, it is enough to wait until the junction has cooled naturally. Wait a few minutes if welding of pipe joints made of plastic was performed. Depending on the thickness of the product and the depth of welding, this interval can vary from 3 to 20 minutes. It is important to note that in working with metal, and when soldering plastic elements, you can not use tools that accelerate the cooling process.
How to weld a pipe to a pipe at different sections?
Sometimes, for certain reasons, due to the non-standard structural design of the pipeline, it is necessary to deal with different sections. For example, there may be a need to connect a classic round pipe and a workpiece with an expanded section. In this case, a corner is welded to a regular pipe, in which the width of the shelf corresponds to the radius of the circle. An operation is performed on only one shelf. Further, the technology of welding pipes with different sections provides for ignition of the arc on a thicker material. By redistributing the formed deposited metal , the joint should be made over the entire joint area - it is obvious that in this case it will be larger than in standard welding.
Conclusion
New technologies made it possible to simplify the welding processes of various materials, significantly expanding the possibilities of installation. Today, in matters of how to weld a pipe to a pipe, there are practically no technical limitations. Electric arc welding, for example, allows you to work with all materials that are used not only in the household, but also in the industrial sector. There are no barriers for the installation of plastic pipes that are easily connected by soldering apparatus.