Welding is the connection of parts using electric current. In order to avoid the need to contact specialists, a home craftsman needs to master the science of welding. It is useful in everyday life. Training begins with the simplest - welding two pipes, mastering various types of seams. Having grasped the basics and principles of technology, you can move on to more complex processes.
When working with a welding machine, you need to protect your face with a special mask.
Required material and tools for welding metal pipes:
- welding machine;
- set of electrodes;
- steel brush;
- hammer with a pointed end.
There are three types of connection of electric welding pipes:
- Thermomechanical (using a magnetically controlled arc).
Before you weld two pipes, you need to prepare their surface. They must be the same diameter and cleaned of traces of dirt and rust. In the case of home welding, as a rule, the thermomechanical method is used. It requires electrodes.
How to choose electrodes: recommendations
Welded pipe joints.
The electrode is a metal rod with a coating for welding. Electrodes are of two types: with a melting base and non-melting.
- With cellulose (organic) coating - for pipes of large diameter, they create vertical and circular seams.
- With rutile coating - allow you to create seams on the outer surface, for carbon steel.
- With rutile-cellulose coating - you can perform any seams.
- With rutile acid coating - they are distinguished by a special structure of slag, which is easily removed upon completion of work.
Electrodes with a basic coating allow you to create excellent seams without cracking for pipes with a large wall thickness. The main coating is applied only to those pipes that will be used at low temperatures.
The larger the diameter of the pipe, the larger the diameter of the electrode.Back to table of contents
Types of welding connections
Types of pipe connections.
To weld two pipes, you need to familiarize yourself with the types of welding joints:
- Butt joint - two components opposite each other.
- Corner joints.
- Brand connections - pipes are perpendicular
Types of seams are horizontal, vertical, ceiling and bottom. The most familiar is the bottom seam. The most difficult joint is the ceiling seam.Back to table of contents
Phased welding process description
Welding is a time consuming process.
For its implementation, the arc is held from the electrode to the products that need to be connected. Under this influence, the base and the electrode core are melted. Formed the so-called welding bath. The workpieces are fixed carefully and firmly; no displacement should occur during operation.
Use a welding electrode.
The first step is to attach the clip "ground", the cable must be well insulated and filled into the holder.
The second step - on the welding machine is set the power of the current corresponding to the diameter of the electrode.
The third step - the arc ignites. The electrode is installed at an angle to the product. If you slowly hold them on the surface, sparks will appear. A gap of 5 mm is maintained throughout the entire welding process.
Remember that with proper welding, the electrode will start to burn out. It should be slightly pressed to the metal. If the arc does not ignite, try increasing the amperage.
The fourth step is to weld the roller. The arc smoothly and quietly moves horizontally across the electrode. Molten metal "crawls" to the center of the arc. As a result, you get a strong seam.
The fifth step - the seam needs time to cool completely. After this has happened, it is necessary to carefully clean it of slag by tapping it with a hammer. All the excess will fly away from the pipe, and you will see a clean seam. Care must be taken to avoid damage to the pipes.Back to table of contents
What should be the seams?
Seams after welding should not have deviations in height and width.
To eliminate the defects of the seams, you need to understand exactly how they look, as well as what are the main mistakes novice masters can make.
External defects are deviations in width and height. Occur due to uneven movement of the electrode. Such seams have an unsatisfactory appearance and can cause deformations. Improper heating can lead to cracks, which will change the structure of the metal. Nodules are formed due to too fast melting of the electrode. Nodules must be cut.
Internal defects are pores that may appear due to improper adjustment of the flame of the burner or moisture of the coating, as well as due to rust on the surfaces being welded. Pores make the seam unprotected. And liquid or gases can penetrate it. You can see them with a magnifying glass.
Poor penetration of the root of the seam will reduce its strength. The seam becomes unreliable, its resistance to harmful external influences is sharply reduced. The reasons for this, as a rule, are insufficient current flow, too fast and abrupt movement of the electrode or poor edge stripping. The defect area is corrected by re-welding. When overheated metal becomes coarse. This reduces grip and strength. This trouble is eliminated by heat treatment. Pressed weld areas are completely removed and re-welded.Back to table of contents
How to weld plastic pipes?
Scheme of the device of the welding machine.
When laying plumbing, arranging the sewage system and heating very often use plastic pipes. They are durable and easy to install. If you have not done this before, then there is no need to worry, this process is much easier than welding metal products.
To weld pipes by electric welding, you will need:
- electric welding apparatus (soldering iron for pipes);
- pipe cutting scissors;
- building level;
First, prepare everything you need. Make all measurements. Cut the pipes and arrange them in the order in which they will be joined.
Secondly, the soldering iron is heated. It will automatically shut off when it reaches the set temperature.
Third, in order for the circuit elements to be connected, they need to be warmed up. Heated surfaces are joined together. Further they reliably and hermetically fused.
Fourth, after complete cooling, the seam is cleaned.
Tips for welding polypropylene pipes:
- pipes must have equal thickness and diameter;
- at low temperatures, the room in which the work is carried out should be well heated;
- Before the welding process, the pipe and fitting must be degreased (the fitting is the connecting part of the pipeline).
Possible errors in the process
- Do not overheat the material. Incorrectly set temperature will negatively affect your work.
- The emergence of marriage provoke dirty pipes or a soldering iron.
- If water gets into the junction, it may break.
- Connection of heated pipes too slow.
- The source material is of poor quality.
- When combining products can not make excessive efforts.
Connection of pipes by electric welding is not easy. It has a lot of nuances. If you are a beginner, then the first job is best carried out under the supervision of a competent specialist, so that he points out errors if they occur. But patience and work will bring experience and results.