Welding and cutting metal at high temperatures

Application area

The ultimate goal of cutting is to obtain workpieces of the desired size by separating the metal into parts. In mass production or when it is necessary to cut thick material, metal cutting using electric arc welding is used. Since the method is not highly accurate, it is successfully used for dismantling large structures, such as pipelines. The simplicity of this method is attractive.

There is no requirement for a highly qualified welder. For welding and cutting equipment, a welding machine is required, and for tools, a special electrode is required.

Description of technology

Arc cutting of metal is performed using a welding inverter. It is, in fact, a transformer that produces a current of a certain strength sufficient to form a welding arc. This technology appeared quite a long time ago, thirty to forty years ago. While not ultra-modern, like plasma, it continues to be popular and widely used due to its ease of use, efficiency and ease of use.

Operating a welding machine, including cutting metal with a conventional or special electrode, is not particularly difficult and does not require professional knowledge and skills. But at the same time, it is necessary to take into account safety requirements, since welding work is associated with electrical voltage.

Technological process

The technologies of electric arc welding and metal cutting begin in the same way. The welding machine is connected to the network. It is connected to the part with one cable, and with the second to the holder with the electrode. The current value is set depending on the thickness of the material and the size of the electrode. By tapping the electrode on a metal surface, an arc is initiated. The metal begins to melt under the influence of high temperature.

When it comes into contact with oxygen in the air, oxidation of the metal that begins to harden occurs. This can lead to defects in the form of oxides. To avoid this, use an inert shielding gas. Most often, argon and helium play this role. The gas that is used for cutting and welding metals is supplied to the weld pool.

Cutting has three types:

1. Dividing . It assumes the possibility of molten metal flowing out of the resulting cut. The diameter of the electrode is larger than the width of the sheet. If the sheet is located in a vertical plane, then welding is carried out using the top-down method. The electrode is placed perpendicularly and moved along the intended line. If through holes must be made, then you should start with them.
2. Superficial . It is used when it is necessary to lay various types of grooves on the metal surface, as well as to remove defects in the form of sagging. To obtain wide grooves, the electrode performs transverse oscillatory movements. The movement is done when the electrode is slightly immersed deep into the metal.
3. Cutting holes . First make a small hole and then expand it to the desired size. A slight deviation of the electrode from perpendicular to the surface towards the circle is acceptable.

Preparing metal before welding

The next feature that new electric welders should know about is the removal of heavy rust from metal. If the metal is covered with a thick layer of rust, this will lead to the formation of poor contact, which will certainly lead to difficulties with welding.

Therefore, we are not lazy, and with a grinder, or perhaps a metal brush, if we do not bring the surface to a shine, then at least completely get rid of rust on it. In this case, the electrode will not stick to the metal, which, in turn, will not splash to the sides, so much so that the workpiece will take on a completely gloomy, and certainly not marketable appearance.

What else should be considered by novice welders who decide to master a welding inverter in a few days. First of all, this is the welding speed; the thinner the metal you weld, the higher it is. Sometimes it is better to first take thin sheets for tacks, and only then carefully weld the seam.

In this case, you need to grab the edges of two workpieces, moving the electrode from side to side. I think these simple tips are really enough to avoid messing up with electrodes like I did my first time. As they say, it is better to learn from other people's mistakes than from your own.

Cutting electrodes

When welding and cutting metals, special electrodes are used. The difference from conventional electrodes is the greater amount of heat generated by the welding arc and the increased heat resistance of the coating.

Cutting metals using welding can be done with different types of electrodes:

1. Non-melting . Made from tungsten. When using a non-consumable electrode process, the cut is quite rough. The process requires a protective gas environment. Used for alloy steel and non-ferrous metals.
2. Melting . To obtain a neat appearance, consumable electrodes are used.
3. Coal . Otherwise they are called graphite. Carbon electrodes are used for non-critical parts. Their advantage is slower melting. The peculiarity is that they do not melt, but burn. This reduces the amount of slag and produces a cleaner cut. Another feature is the ability to heat up to very high temperatures with low current.
4. Tubular . Tubular electrodes are used when cutting occurs using the oxygen-arc method. The basis of the electrode is a special tube with thick walls, hollow on the inside.

When deciding how to cut metal by welding, you should make a choice between these types of electrodes. Cutting can also be carried out with conventional electrodes. In this case, the current should be increased by 30-40%. This will require more electricity consumption, and accordingly, will increase the cost of the process.

Required tools and equipment

Before cutting metal with a purchased welding inverter, you need to prepare the equipment and tools required for this:

• the welding machine itself (presented on the construction and industrial equipment market in various versions from a variety of manufacturers);
• hammer and brush;
• electrodes. Until recently, metal cutting by arc welding was carried out using the most common electrodes. Nowadays, special electrodes are used more often, used for cutting by electric welding and designated as OZR. They are characterized by high heat resistance of the coating, which ensures faster cutting, increased productivity and cut quality. The use of special OZR electrodes allows the material to be cut in such a way that a much larger amount of heat is released, and the arc is stable and stable.

For safe work, the purchase of protective equipment is required, including:

• special suit (robe);
• mittens (gaiters);
• protective mask equipped with a light filter;
• boots whose soles are made of rubber;
• when working in a confined and small space, use a respirator.

Welder equipment
All of the above equipment, materials and equipment are available and can be easily purchased at almost any specialized store.

Why should you contact us?

We treat all clients with respect and carry out tasks of any size equally scrupulously.

Our production facilities allow us to process various materials:

• non-ferrous metals;
• cast iron;
• stainless steel.

When completing an order, our specialists use all known methods of metal machining. Modern equipment of the latest generation makes it possible to achieve maximum compliance with the original drawings.

In order to bring the workpiece closer to the sketch submitted by the customer, our specialists use universal equipment designed for jewelry sharpening of tools for particularly complex operations. In our production workshops, metal becomes a plastic material from which any workpiece can be made.

The advantage of contacting our specialists is their compliance with GOST and all technological standards. Strict quality control is carried out at every stage of work, so we guarantee our customers a conscientiously completed product.

Thanks to the experience of our craftsmen, the output is an exemplary product that meets the most demanding requirements. At the same time, we start from a strong material base and focus on innovative technological developments.

We work with customers from all regions of Russia. If you want to place an order for metalworking, our managers are ready to listen to all the conditions. If necessary, the client is provided with free specialized consultation.

• Laser cutting drawings are indispensable not only when carrying out large industrial orders or when producing high-precision mechanisms, but even if you need a small batch of relatively simple parts. And since most laser machines are equipped with a control module, you cannot do without the corresponding drawings. However, it is not enough to just draw a sketch by hand - the machine program simply will not understand it. Drawings for laser cutting must be made in a certain format and taking into account a number of rules. Only in this case will the output be a part that satisfies all the requirements. We'll talk about how to achieve this further.

Metalworking on CNC machines is indispensable where a large number of products with high processing accuracy are required. In addition, CNC machines also ensure high repeatability of manufactured products. This type of metalworking is becoming increasingly popular, but this does not mean that it has only positive aspects. To better understand what metalworking on CNC machines is, we will tell you about the operating principle of such equipment and the features of the processes.

Materials for arc welding include dozens of items, but the number of groups that include such an extensive range is small - only four main ones. Each of them has its own division, but for a wider audience it is worth indicating only the main categories

In addition to dividing into groups and types, it is also important to take into account consumption rates, as well as storage conditions. We will tell you about the main materials for arc welding, and also provide formulas for calculating their consumption and storage rules

Arc welding of pipes has its own characteristics, which are expressed not only in the type of connections, but also in carrying out certain manipulations depending on the ambient temperature. Depending on the type of pipe and weather conditions, appropriate electrodes are selected and preparatory operations are carried out. In addition to the correct choice of electrodes and other devices, it is necessary to decide on the welding technique. There are several approaches that are used by modern masters. We will talk about all this in more detail in our article.

Electric welding is intended not only for joining surfaces, but also for cutting them. The process of cutting metal by electric welding is carried out using the same equipment, but differs from creating a weld in that during cutting the metal is melted through until the parts of the workpiece are separated. This occurs as a result of using more current than when welding.

Welding Basics

To learn how to weld correctly, you need to understand the physical foundations of the welding process. Any welding machine creates in a small working area at the junction of two parts being welded a temperature above the melting point of the metal being welded, the so-called weld pool. In it, the part of the metal of both parts that has turned into liquid is mixed with each other and with the metal of the molten electrode. After the temperature decreases, the metal from the weld pool crystallizes, connecting the welded parts into one whole. By slowly moving the weld pool following the arc along the joint, the welder obtains a seam. High temperatures in amateur welding machines are achieved in two ways:

• electric arc;
• gas burner.
  Gas-burner

  How to properly solder with an electric arc

Electric welding is safer, since there is no risk of gas explosion, and is easier to learn for those who are just learning how to weld properly.

An electric arc is created by passing a high current through the air gap between the parts being welded and the electrode.

Types of cold welding

There are several varieties that differ not only in parameters, such as what maximum temperature cold welding can withstand, but also in appearance. The main types should be highlighted:

• Liquid composition - as a rule, consists of two components, which should be thoroughly mixed into one homogeneous mass immediately before starting work;
• Plasticine-like substance - presented in the form of bars, which consist of one or several layers, which also requires mixing before direct use;
• A universal composition that can be used as a gluing element for PVC, wood, metal and other things;
• Masses with the addition of a metal component that enhances strength and imparts other additional properties;
• Materials that are created specifically for working with motor vehicles;
• Substances for working under water.

Nuances for beginners in welding

There are several nuances that can be useful to anyone who wants to learn how to cook correctly:

Do not forget about grounding and the importance of regularly checking the quality of contact between the clamp and the workpiece. Check the cable insulation regularly. The current strength is selected immediately after connecting the ground. Before igniting the arc, the electrode should be installed at an angle of approximately 60 degrees to the plane of the workpiece, and the distance between its end and the workpiece should be about 0.5 cm. Electrode positions during welding

By mastering increasingly complex types of seams and joint configurations, the home craftsman will be able to learn how to weld correctly and will provide his household with all the necessary welded structures.