Application of electric arc cutting
This technology is used during repair and construction work for dismantling metal structures, dismantling old pipelines, and rough cutting of scrap metal. It is used when it is necessary to burn holes or cut steel, cast iron products, and non-ferrous metal blanks.
Electric arc cutting is used in cases where it is not possible to carry out gas cutting, as well as in the absence of the necessary equipment for gas cutting of metal.
Electric arc cutting of metal - process
Required tools and equipment
During the work process you will need:
- a welding inverter (transformer), which produces a current of a given strength necessary to create a welding arc;
- metal hammer;
- cleaning brush;
- electrical wires with couplings;
- electrodes and holders for them.
For cutting metal, it is advisable to use electrodes that are marked with the OZR marking. They are distinguished by a special coating with a certain heat resistance, ensuring high productivity and good quality of the cutting strip. When used, a stable arc is formed, which creates the required amount of heat. Special OZR electrodes allow cutting with direct or alternating current from any spatial position.
Welding cutting is a process of increased danger to humans. Failure to comply with safety precautions and lack of necessary equipment can result in electric shock. Visible and ultraviolet rays have a negative effect on the eyes. Harmful substances released during cutting affect the functioning of the respiratory tract. There is a risk of getting burns to the surface of the skin from hot metal. Therefore, during the cutting process it is necessary to ensure:
- reliable protection of the metal body of the welding machine;
- the presence of exhaust ventilation in the room;
- special protective clothing: canvas overalls, mittens, protective mask with dark lenses, shoes with rubber soles, respirator.
Cutting metal by welding - how it happens
When cutting metal in a confined space, it is advisable that an assistant watch the worker’s actions from outside, ready to help in an extreme situation.
Technology of metal cutting using electric arc welding
The process of cutting metal is simpler than welding, since there are no special requirements for the quality of the edge. Therefore, this technology is optimal for training and mastering the principles of working with an inverter.
Before starting work, you must ensure that all electrical cables used are in good condition. Creating and maintaining an arc is not particularly difficult. It is ignited by tapping or striking the electrode on a metal workpiece. The amount of current on the inverter is set depending on the size of the electrodes, the thickness of the material, and the type of cut required. There are three main types of cuts.
Separation cutting
The material is installed in such a way as to ensure free flow of molten metal from the cut line. When the sheet is positioned vertically, separation cutting is carried out from top to bottom. On a horizontal surface, the cut is made from the edge of the material. If you are cutting a large sheet, you can start the process with a hole made in the middle of the workpiece.
Metal separation cutting - process diagram
Surface cutting
This type is used for laying grooves on the surface of the material, leveling out sagging and defects. During operation, the electrode should be positioned with an inclination of 5º-10º to the surface. During surface cutting, the movement is performed with a slight immersion into the cavity being created. If it is necessary to lay a wide groove, the electrode should perform transverse movements of a given size.
Hole cutting
This operation is performed by gradually expanding a small hole to the required size. When cutting holes, the perpendicular position of the electrode allows slight deviations towards the resulting circle.
Features of the use of different types of electrodes
For the process of cutting metal surfaces, it is possible to use various electrodes:
- metal melting;
- coal;
- non-melting tungsten.
Cutting with a consumable electrode is accompanied by the melting of metal by an electric arc from the impact zone. The work is performed with steel electrodes with a diameter of 2.5 to 6 mm, which are more refractory than when welding. A high-quality coating (manganese ore, potash) creates a small visor that covers the arc zone, which contributes to concentrated heating of the material.
Specification of ABIARC carbon electrodes
Carbon electrodes are used when a certain quality and width of the resulting cut is not required. During operation, the surface of the material is positioned with a slight slope to facilitate the flow of metal. In this way, workpieces made of cast iron, steel, and non-ferrous metals can be processed. It is optimal to use an electrode with a thickness of 10 mm.
Electric arc cutting of products made of non-ferrous metals and alloy steel can be done with non-consumable tungsten electrodes, which are used much less frequently than metal or carbon ones. In this case, cutting must be carried out in a protective gas atmosphere.
In the absence of special electrodes designed for cutting material, conventional welding electrodes can be used. In this case, you should choose the appropriate diameter: for thin metal, electrodes with a diameter of 3 mm are used, for thicker ones - from 4 to 6 mm.
The basics of welding with an inverter or what a beginner needs to know
Let's say you bought an inverter and really want to test it in practice, weld some piece of iron. Well, you can’t hesitate, because electric welding is a very exciting activity that is very addictive, so much so that it’s impossible to tear yourself away later.
I remember when I bought my first welding inverter. Not only pipes were used, but also nails, which I, however, failed to weld the first time. The error was due to the electrodes, I didn’t know at that time and bought electrodes for alternating current, which are not suitable when using an inverter.
The fact is that transformer devices are “omnivorous”, but as for inverters, DC electrodes must be selected for them. That’s why I had a hard time with nails the first time: the welding kept sticking to the metal, and I couldn’t tear the electrode off of it.
The second thing I would like to draw your attention to is the current strength. In fact, everything is very simple, and for welding thick metals, electrodes with a diameter of 3 mm and higher are used, and for welding thin metal, electrodes with a diameter of no more than two millimeters are used.
In turn, in order to weld with electrodes of different diameters, a certain current must be set on the welding inverter. The larger the diameter of the electrodes, the higher the welding current should be. And if for welding with 2 mm electrodes, a current of 30-50 A is used, then for 4 mm electrodes, the current value already exceeds a hundred amperes.
Advantages and disadvantages of electric arc cutting
Welding cutting, like any technology, has its advantages and disadvantages, taking into account which will allow you to get the job done quickly and achieve the expected result. The main disadvantages of the method include:
- low productivity, which is due to low speed;
- poor quality of the cut obtained as a result of hardening of leaks from the back side of the workpiece.
The listed disadvantages make the method inapplicable in conditions where it is necessary to maintain precise markings when cutting metal.
The main advantages that distinguish this method:
- no need to purchase special expensive equipment and tools;
- no special requirements for environmental conditions;
- quick training in operating techniques and mastering equipment;
- ability to work with direct or alternating current.
Many organizations in the construction, repair, and automotive industries, as well as home craftsmen, successfully use electric welding cutting, since this method is intended for simple, inexpensive cutting of various metal surfaces.
How to use site materials
Using site materials is as easy as shelling pears. It is enough to turn to just three navigation tools on the site.
- First, this is a list of the most recent publications on our site. If you select the link “Laser cutting of metal with your own hands - making a laser cutter yourself”, you will immediately go to the page of this material.
- Secondly, this is the section menu, which you see on the right in the side column. You can go to the “Arc Welding” section and select the materials “Welding inverters - reliability rating” or “Inverter welding machine - which one is better to choose for a private home.” In the same way, by clicking on the announcement you are interested in, you will be taken to the page with the publication.
- And thirdly, you can use the site search, the form of which is located in the right column at the very top. Enter, for example, the request “welding polypropylene pipes instructions” into this form, and the site will open a search results page for you, where all materials related to this request will be presented.
It is not necessary to comply with spelling and punctuation when making a request; a smart search on the site will still give you the results you need.
