Welding performed in a shielding gas environment (helium or argon) requires tungsten electrodes, which are classified as non-consumable. Due to its refractoriness, the tungsten electrode can withstand high temperatures and a long uninterrupted service life. Currently, this welding material has a fairly extensive classification, where there is quite a large number of types divided by brands.

Marking and characteristics of tungsten electrodes

Marking of tungsten electrodes is stipulated by international standards. Therefore, it is easy to choose them for the required purpose in any country, no matter where you are. It is the marking that reflects both the type of the selected electrode and its chemical composition.

The marking begins with the letter "W", which stands for tungsten itself. In its pure form, the metal is present in the product, but the characteristics of such an electrode are not very high, because it is too refractory element. Alloying additives help to improve the welding qualities.

• Pure tungsten rod is designated "WP". The tip of the rod is green. We can say that it belongs to the category of tungsten electrodes for welding aluminum and copper with alternating current. The content of tungsten in the alloy is not less than 99.5%. The disadvantage is the limitation in the thermal load. Therefore, the sharpening of the tungsten electrode (its end) "WP" is made in the form of a ball.
• "C" is cerium oxide. Bar with a gray tip. It is this additive that allows you to use the electrode when working with any type of current (direct or alternating), maintains a stable arc even at low current. Content - 2%. By the way, cerium is the only non-radioactive material from a series of rare earth metals.
• "T" - thorium dioxide. A rod with a red tip. Such electrodes are used for welding non-ferrous metals, low-alloyed and carbon steels, stainless steel. It is a commonly used electrode in conducting welding work argon welding. It has one drawback - the radioactivity of thorium, so it is recommended that welding be carried out in open areas and in well-ventilated rooms. The welder must follow the safety precautions. Note that thoriated tungsten electrodes for argon arc welding hold their shape well at the highest currents. Even the “WP” brand (pure tungsten) cannot cope with such loads. Content - 2%.
• "Y" is yttrium dioxide. Bar with a dark blue tip. With its help, critical structures are usually welded from different metals: titanium, copper, stainless steel, carbon and low alloy steels. Work is carried out only on direct current (direct polarity). The yttrium additive increases such an indicator as the stability of the cathode spot at the end of the electrode itself. This is the reason why it can operate within a fairly wide range of welding current. Content - 2%.
• "Z" - zirconium oxide. A rod with a white tip. It is used for argon welding of aluminum and copper with alternating current. This type of electrode provides a very stable arc. At the same time, the element is quite demanding on the cleanliness of the welding joint. Content - 0.8%.
• "L" - lanthanum oxide. There are two positions here: WL-15 and WL-20. The first bar with a golden tip, the second with a blue one. Welding with a tungsten electrode with the addition of lanthanum oxide is the ability to use both alternating current and direct current. Let's add here the ease of starting the arc (initial and re-ignition), this type has the smallest wear on the end of the rod, a stable arc at the highest current, low tendency to burn through, the carrying capacity is twice as high as that of a pure tungsten rod. The content of lanthanum oxide in WL-15 is 1.5% and in WL-20 is 2%.

The classification by digital marking is as follows. The first numbers after the letters indicate the content of alloying additives in the alloy. The second group of numbers, separated from the first by a hyphen, is the length of the tungsten rod. The most common size is 175 mm. But on the market you can also find 50 mm lengths, 75 and 150. For example, WL-15-75 is an electrode with lanthanum oxide, which contains 1.5% of the additive. The length of the bar is 75 mm. Its tip is golden.

Methods for sharpening tungsten electrodes

Sharpening of tungsten electrodes is the most important component of a properly conducted welding process. Therefore, all welders involved in welding in an argon environment carry out this operation very carefully. It is on the shape of the tip that it depends on how the energy transmitted from the electrode to the two metals being welded will be correctly distributed, what will be the pressure of the arc. And the shape and dimensions of the weld penetration zone, and, accordingly, its width and depth, will already depend on these two parameters.

Attention! The parameters and shape of sharpening are selected from the type of electrode used and from the parameters of the two metal blanks being welded.

• The working end of WP, WL electrodes is a sphere (ball).
• A bulge is also made on WT, but with a small radius. Rather, they simply indicate the roundness of the electrode.
• The rest of the types are sharpened under the cone.

When an aluminum joint is welded, a sphere forms on the electrode by itself. Therefore, when welding aluminum, there is no need to sharpen the electrode.

What sharpening errors can lead to.

• The sharpening width is very different from the norm, that is, it can be very wide or very narrow. In this case, the probability of non-penetration of the seam greatly increases.
• If asymmetric sharpening is carried out, then this is a guarantee of the deviation of the welding arc to one side.
• The sharpening angle is too sharp - the service life of the electrode is reduced.
• The sharpening angle is too obtuse - the depth of penetration of the seam decreases.
• The marks left from the abrasive tool are not located along the axis of the bar. Get an effect like a wandering arc. That is, the stable and uniform burning of the welded arc is disturbed.

By the way, there is a simple formula that determines the length of the sharpened area. It is equal to the diameter of the bar, multiplied by a constant factor - 2.5. There is also a table that indicates the ratio of the diameter of the electrodes to the length of the end to be sharpened.

It is necessary to sharpen the end of the tungsten rod across, like a pencil. You can sharpen on an electric emery or on a grinder. To achieve uniform metal removal throughout the sharpening zone, you can fix the bar in the drill chuck. And rotate it at low speeds of the power tool.

Currently, manufacturers of special electrical equipment offer a machine for sharpening non-consumable tungsten electrodes. A convenient and accurate option to make high-quality sharpening. The machine includes:

• Diamond disk.
• Dust filter.
• Setting the revolutions of the working shaft.
• Sharpening angle setting. This parameter varies between 15-180°.

Research, to find the optimal sharpening angle, is carried out constantly. In one research institute, a test was conducted where a WL grade tungsten electrode was checked for quality weld by sharpening it at different angles. Several angular dimensions were chosen at once: from 17 to 60°.

The exact parameters of the welding process were determined:

• Welded two metal sheets of corrosion-resistant steel with a thickness of 4 mm.
• Welding current - 120 amperes.
• Speed ​​- 10 m / h.
• Welding position is lower.
• The consumption of inert gas is 6 l/min.

The results of the experiment are as follows. An ideal seam was obtained when a bar with a sharpening angle of 30 ° was used. At an angle of 17°, the shape of the weld was tapered. At the same time, the welding process itself was unstable. The resource of the cutting electrode decreased. At large sharpening angles, the pattern of the welded process also changed. At 60°, the weld width increased, but its depth decreased. And although the welding process itself has stabilized, it cannot be called high-quality.

As you can see, the sharpening angle plays an important role in the welding process. It doesn't matter if stainless steel, steel or copper electrodes are used. In any case, you need to properly sharpen the bar, because the consequences can be extremely negative. Description of bars by color and chemical characteristics helps to make the right choice, and at the same time choose the shape of sharpening.

Electrodes for contact welding designed to supply current to the elements, compress them and remove the generated heat. This detail is one of the most important in the equipment, since the possibility of processing the assembly depends on its shape. The stability of the electrode determines the level of welding quality and the duration of continuous operation. The electrodes are curly and straight. The production of direct type elements is regulated in the GOST 14111–77 standard.

Curly parts are characterized by the fact that their axis is offset relative to the cone (landing surface). They are used for welding knots and elements of a complex shape, which are difficult to reach.

Design features

Electrodes intended for resistance welding include a cylindrical part, a working part and a landing part. In the inner cavity of the element there is a special channel, which is designed to supply water that cools the electric holder.

The working part has a spherical or flat surface. Its diameter is selected in accordance with the thickness of the processed products and the material used. The strength of the electrode is provided by the middle part.

The landing part must have a conical shape so that the part is securely fixed in the electric holder. Its processing must occur with a purity of at least class 7.

Part custom properties affected by distance from the very bottom of the cooling channel to the working edge: life, stability, etc. If this distance is small, then the cooling of the element will be much more efficient, but it will also be able to withstand much fewer regrinds.

Inserts based on molybdenum and tungsten are placed inside copper parts. Products made in this way are used for welding anodized or galvanized steel.

Production materials

The resistance of electrodes is the ability of the elements not to lose their shape and dimensions, as well as to resist the transfer of material of the elements and electrodes being welded. This indicator is determined by the material and design of the welding electrode, as well as the conditions and mode of operation. The wear of parts depends on the characteristics of the working tool (angle of the working surface, diameter, material, etc.). Melting, excessive heating, oxidation during operation of the electrode in a corrosive and / or wet environment, displacement or distortion, compression deformation and other factors significantly increase the wear of working elements.

The tool material must be selected in accordance with the following rules:

1. Its level of electrical conductivity should be comparable to pure copper;
2. Effective thermal conductivity;
3. High degree of mechanical resistance;
4. Ease of processing by cutting or high pressure;
5. Resistant to cyclic heating.

Compared to 100% copper, its alloys are more resistant to mechanical loads, which is why copper alloys are used for such products. Alloying products with zinc, beryllium, chromium, magnesium, zirconium does not reduce the electrical conductivity, but significantly increases strength, and silicon, iron and nickel increase its hardness.

Choice

In the process of selecting suitable electrodes for spot welding special attention should be paid to the size and shape of the working element of the product. You should also take into account the characteristics of the material being processed, its thickness, the shape of the welding units and the welding mode.

The resistance welding tool has different working surfaces:

1. flat;
2. Spherical.

Products with a spherical working surface are not particularly sensitive to bevels, therefore they are often used in suspended and radial installations, as well as for shaped electrodes with deflection. Manufacturers from the Russian Federation recommend this type of electrode for processing light alloys, as they help prevent undercuts and dents during spot welding. However, this problem can also be prevented if flat electrodes are used, the end of which is enlarged. And electrodes equipped with hinges can even replace spherical type electrodes, but they are recommended for welding metal sheets, the thickness of which does not exceed one and a half millimeters.

Working element dimensions tools are selected in accordance with the type and thickness of the processed materials. The results of the study, which was conducted by experts French company ARO showed that the required diameter can be calculated using the following formula:

del \u003d 3 mm + 2t, where "t" is the thickness of the sheets to be welded.

It is more difficult to calculate the required diameter of the tool with unequal sheet thicknesses, welding of different types of materials and welding of a whole “package” of elements. It is clear that to work with parts of different thicknesses, the diameter of the product must be selected relative to the thinnest metal sheet.

When welding a set of elements, the diameter should be selected based on the thickness of the external elements. For welding materials various types the smallest penetration has a metal alloy with a minimum electrical resistivity. In this case, a device made of a material with increased thermal conductivity should be used.

Spot welding is a type of contact welding. With this method, the heating of the metal to its melting point is carried out by the heat that is formed during the passage of a large electric current from one part to another through the place of their contact. Simultaneously with the passage of current and some time after it, the parts are compressed, as a result of which mutual penetration and fusion of the heated sections of the metal occur.

The features of contact spot welding are: short welding time (from 0.1 to several seconds), high welding current (more than 1000A), low voltage in the welding circuit (1-10V, usually 2-3V), significant force compressing the welding spot (from several tens to hundreds of kg), a small melting zone.

Spot welding is most often used for joining sheet blanks with an overlap, less often for welding rod materials. The range of thicknesses welded by it is from a few micrometers to 2-3 cm, however, most often the thickness of the welded metal varies from tenths to 5-6 mm.

In addition to spot welding, there are other types of contact welding (butt, seam, etc.), but spot welding is the most common. It is used in the automotive industry, construction, radio electronics, aircraft manufacturing and many other industries. During the construction of modern liners, in particular, several million weld points are produced.

Deserved popularity

The disadvantages include the lack of tightness of the seam and the concentration of stresses at the welding point. Moreover, the latter can be significantly reduced or even eliminated by special technological methods.

Sequence of processes in resistance spot welding

• Compression of parts, causing plastic deformation of microroughnesses in the chain electrode-part-part-electrode.
• Switching on an electric current pulse, which leads to heating of the metal, its melting in the joint zone and the formation of a liquid core. As the current passes, the core increases in height and diameter to a maximum size. Bonds are formed in the liquid phase of the metal. At the same time, the plastic sedimentation of the contact zone continues to the final size. The compression of the parts ensures the formation of a sealing belt around the molten core, which prevents the metal from splashing out of the welding zone.
• Turning off the current, cooling and crystallization of the metal, ending with the formation of a cast core. On cooling, the volume of the metal decreases and residual stresses arise. The latter are an undesirable phenomenon that is being fought different ways. The force that compresses the electrodes is removed with some delay after the current is turned off. This provides the necessary conditions for better crystallization of the metal. In some cases, in the final stage of resistance spot welding, it is even recommended to increase the clamping force. It provides metal forging, which eliminates weld inhomogeneities and relieves stress.

At the next cycle, everything repeats again.

Basic parameters of resistance spot welding

Distinguish between hard and soft welding modes. The first is characterized by high current, short duration of the current pulse (0.08-0.5 seconds depending on the thickness of the metal) and high compression force of the electrodes. It is used for welding copper and aluminum alloys with high thermal conductivity, as well as high-alloy steels to maintain their corrosion resistance.

In the soft mode, the workpieces are heated more smoothly with a relatively small current. The duration of the welding pulse is from tenths to several seconds. Soft modes are shown for steels prone to hardening. Basically, it is soft modes that are used for resistance spot welding at home, since the power of the devices in this case may be lower than with hard welding.

Dimensions and shape of electrodes. Electrodes make direct contact welding machine with parts to be welded. They not only supply current to the welding zone, but also transmit compressive force and remove heat. The shape, dimensions and material of the electrodes are the most important parameters of spot welding machines.

Depending on their shape, the electrodes are divided into straight and curly. The former are the most common, they are used for welding parts that allow free access of electrodes to the welded zone. Their sizes are standardized by GOST 14111-90, which establishes the following diameters of electrode rods: 10, 13, 16, 20, 25, 32 and 40 mm.

According to the shape of the working surface, there are electrodes with flat and spherical tips, characterized respectively by the values ​​of the diameter (d) and radius (R). The contact area of ​​the electrode with the workpiece depends on the value of d and R, which affects the current density, pressure, and the size of the core. Spherical surface electrodes have greater tool life (capable of making more points before regrinding) and are less susceptible to misalignment than flat surface electrodes. Therefore, with a spherical surface, it is recommended to manufacture electrodes used in tongs, as well as figured electrodes that work with large deflections. When welding light alloys (for example, aluminum, magnesium), only electrodes with a spherical surface are used. The use of electrodes with a flat surface for this purpose leads to excessive dents and undercuts on the surface of points and increased gaps between parts after welding. The dimensions of the working surface of the electrodes are selected depending on the thickness of the metals being welded. It should be noted that electrodes with a spherical surface can be used in almost all cases of spot welding, while electrodes with a flat surface are very often not applicable.

The landing parts of the electrodes (places connected to the electric holder) must ensure reliable transmission of the electrical impulse and the pressing force. Often they are made in the form of a cone, although there are other types of connections - according to cylindrical surface or carving.

Very importance has an electrode material that determines their electrical resistance, thermal conductivity, thermal stability and mechanical strength at high temperatures. During operation, the electrodes heat up to high temperatures. The thermocyclic mode of operation, together with a mechanical variable load, causes increased wear of the working parts of the electrodes, resulting in a deterioration in the quality of the joints. In order for the electrodes to be able to resist difficult conditions work, they are made of special copper alloys with high heat resistance and high electrical and thermal conductivity. Pure copper is also capable of working as electrodes, however, it has a low resistance and requires frequent regrinding of the working part.

Welding current. The strength of the welding current (I CB) is one of the main parameters of spot welding. It determines not only the amount of heat released in the welding zone, but also the gradient of its increase in time, i.e. heating rate. The dimensions of the welded core (d, h and h 1) directly depend on I CB and increase in proportion to the increase in I CB.

It should be noted that the current that flows through the welding zone (I CB) and the current flowing in the secondary circuit of the welding machine (I 2) differ from each other - and the more, the smaller the distance between the weld points. The reason for this is the shunt current (Ish) flowing outside the welding zone - including through previously made points. Thus, the current in the welding circuit of the machine must be greater than the welding current by the value of the shunt current:

I 2 \u003d I CB + I w

To determine the strength of the welding current, you can use different formulas that contain various empirical coefficients obtained empirically. In cases where precise definition welding current is not required (which happens most often), its value is taken from tables compiled for different welding modes and various materials.

Increasing the welding time allows welding with currents much lower than those given in the table for industrial devices.

welding time. The welding time (t CB) is understood as the duration of the current pulse when performing one weld point. Together with the strength of the current, it determines the amount of heat that is released in the connection zone when an electric current passes through it.

With an increase in t CB, the penetration of parts increases and the dimensions of the core of the molten metal increase (d, h and h 1). At the same time, heat removal from the melting zone also increases, parts and electrodes heat up, and heat is dissipated into the atmosphere. When a certain time is reached, a state of equilibrium may occur, in which all the input energy is removed from the welding zone, without increasing the penetration of parts and the size of the core. Therefore, an increase in t SW is advisable only up to a certain point.

When accurately calculating the duration of the welding pulse, many factors must be taken into account - the thickness of the parts and the size of the weld point, the melting point of the metal being welded, its yield strength, heat accumulation coefficient, etc. There are complex formulas with empirical dependencies, which, if necessary, carry out the calculation.

In practice, most often the welding time is taken according to the tables, correcting, if necessary, the accepted values ​​in one direction or another, depending on the results obtained.

Compression force. The compressive force (F CB) affects many processes of resistance spot welding: the plastic deformations occurring in the joint, the release and redistribution of heat, the cooling of the metal and its crystallization in the core. With an increase in F CB, the deformation of the metal in the welding zone increases, the current density decreases, and the electrical resistance in the electrode-part-electrode section decreases and stabilizes. Provided that the dimensions of the core remain unchanged, the strength of the weld points increases with increasing compression force.

When welding in hard conditions, higher values ​​of F CB are used than in soft welding. This is due to the fact that with an increase in rigidity, the power of the current sources and the penetration of parts increase, which can lead to the formation of splashes of molten metal. A large compression force is just designed to prevent this.

As already noted, in order to forge a weld point in order to relieve stress and increase the density of the core, the resistance spot welding technology in some cases provides for a short-term increase in the compression force after the electric pulse is turned off. The cyclogram in this case looks as follows.

In the manufacture of the simplest contact welding machines for home use, there is little reason to engage in accurate parameter calculations. Approximate values ​​for electrode diameter, welding current, welding time and clamping force can be taken from tables available in many sources. It is only necessary to understand that the data in the tables are somewhat overestimated (or underestimated, if we keep in mind the welding time) compared to those that are suitable for home devices where soft modes are usually used.

Preparation of parts for welding

High demands are placed on the surface quality of parts made of aluminum and magnesium alloys. The purpose of surface preparation for welding is to remove, without damage to the metal, a relatively thick film of oxides with high and uneven electrical resistance.

Spot welding equipment

• machines for welding with alternating current;
• low-frequency spot welding machines;
• capacitor type machines;
• DC welding machines.

Each of these types of machines has its own advantages and disadvantages in technological, technical and economic aspects. The most widely used machines for welding with alternating current.

AC resistance spot welding machines. circuit diagram machines for spot welding with alternating current is shown in the figure below.

The voltage at which welding is carried out is formed from the mains voltage (220/380V) using a welding transformer (TC). The thyristor module (CT) ensures the connection of the primary winding of the transformer to the supply voltage for the required time for the formation of a welding pulse. Using the module, you can not only control the duration of the welding time, but also control the shape of the applied pulse by changing the opening angle of the thyristors.

If the primary winding is made not from one, but from several windings, then by connecting them in various combinations with each other, it is possible to change the transformation ratio, obtaining various meanings output voltage and welding current on the secondary winding.

except power transformer and a thyristor module, AC resistance spot welding machines have a set of control equipment - a power source for the control system (step-down transformer), relays, logic controllers, control panels, etc.

Capacitor welding. The essence of capacitor welding is that at first, electrical energy is relatively slowly accumulated in the capacitor when it is being charged, and then it is consumed very quickly, generating a large current pulse. This allows welding to be carried out using less power from the network compared to conventional spot welding machines.

In addition to this main advantage, capacitor welding has others. With it, there is a constant controlled consumption of energy (the one that has accumulated in the capacitor) for one welded joint, which ensures the stability of the result.

Welding occurs in a very short time (hundredths and even thousandths of a second). This gives a concentrated heat release and minimizes the heat affected zone. The latter advantage allows it to be used for welding metals with high electrical and thermal conductivity (copper and aluminum alloys, silver, etc.), as well as materials with sharply different thermal properties.

Rigid capacitor micro welding is used in the radio-electronic industry.

The amount of energy stored in capacitors can be calculated using the formula:

W = C U 2 /2

where C is the capacitance of the capacitor, F; W - energy, W; U - charging voltage, V. By changing the resistance value in the charging circuit, they regulate the charging time, charging current and power consumed from the network.

Resistance spot welding defects

The quality of welding depends on the acquired experience, which mainly boils down to maintaining the required duration of the current pulse based on visual observation (by color) of the weld point.

A correctly made weld point is located in the center of the joint, has the optimal size of the cast core, does not contain pores and inclusions, does not have external and internal splashes and cracks, and does not create large stress concentrations. When a tensile force is applied, the destruction of the structure occurs not along the cast core, but along the base metal.

Spot welding defects are divided into three types:

• deviations of the dimensions of the cast zone from the optimal ones, displacement of the core relative to the joint of the parts or the position of the electrodes;
• violation of the continuity of the metal in the connection zone;
• change in properties (mechanical, anti-corrosion, etc.) of the metal of the weld point or areas adjacent to it.

The most dangerous defect is the absence of a cast zone (lack of penetration in the form of "gluing"), in which the product can withstand the load at a low static load, but is destroyed under the action of a variable load and temperature fluctuations.

The strength of the connection is also reduced with large dents from the electrodes, ruptures and cracks in the edge of the overlap, and splashing of metal. As a result of the exit of the cast zone to the surface, the anti-corrosion properties of the products (if any) are reduced.

Complete or partial lack of fusion, insufficient dimensions of the cast core. Possible reasons: Welding current too low, clamping force too high, worn out working surface electrodes. Insufficient welding current can be caused not only by its low value in the secondary circuit of the machine, but also by the electrode touching the vertical walls of the profile or by too close a distance between the weld points, leading to a large shunt current.

The defect is detected by external inspection, by lifting the edges of the parts with a punch, ultrasonic and radiation devices to control the quality of welding.

External cracks. Causes: too high welding current, insufficient compression force, lack of forging force, contaminated surface of parts and / or electrodes, leading to an increase in the contact resistance of parts and damage temperature regime welding.

The defect can be detected with the naked eye or with a magnifying glass. Effective capillary diagnostics.

Breaks at the edges of the lap. The reason for this defect is usually the same - the weld point is located too close to the edge of the part (insufficient overlap).

It is detected by external examination - through a magnifying glass or with the naked eye.

Deep dents from the electrode. Possible causes: too small size (diameter or radius) of the working part of the electrode, excessive forging force, improperly installed electrodes, too big sizes cast zone. The latter may be due to excess welding current or pulse duration.

Internal splash (outflow of molten metal into the gap between parts). Causes: Permissible values ​​of current or duration of the welding pulse are exceeded - too large a zone of molten metal has formed. The compression force is low - a reliable sealing belt around the core was not created or an air cavity formed in the core, which caused the molten metal to flow into the gap. The electrodes are installed incorrectly (misaligned or skewed).

It is determined by the methods of ultrasonic or radiographic control or external examination (due to the splash, a gap may form between the parts).

External splash (outlet of metal to the surface of the part). Possible reasons: switching on of the current pulse with uncompressed electrodes, too high value of the welding current or pulse duration, insufficient compressive force, distortion of the electrodes relative to the parts, contamination of the metal surface. The last two reasons lead to uneven current density and melting of the surface of the part.

determined by external examination.

Internal cracks and shells. Causes: The current or pulse duration is too high. The surface of the electrodes or parts is dirty. Small compression force. Missing, late or insufficient forging force.

Shrinkage cavities can occur during the cooling and crystallization of the metal. To prevent their occurrence, it is necessary to increase the compression force and apply forging compression at the moment of core cooling. Defects are detected by X-ray or ultrasonic testing.

Displacement of the cast core or its irregular shape. Possible reasons: electrodes are installed incorrectly, the surface of the parts is not cleaned.

Defects are detected by X-ray or ultrasonic testing.

burn. Causes: the presence of a gap in the assembled parts, contamination of the surface of parts or electrodes, the absence or low force of compression of the electrodes during the current pulse. To avoid burn-through, current should only be applied after full compression force has been applied. determined by external examination.

Correction of defects. The method of correcting defects depends on their nature. The simplest is repeated spot or other welding. It is recommended to cut or drill the defective place.

If it is impossible to weld (due to the undesirability or inadmissibility of heating the part), instead of a defective weld spot, you can put a rivet by drilling out the welding spot. Other correction methods are also used - cleaning the surface in case of external splashes, heat treatment to relieve stress, straightening and forging when the entire product is deformed.

When using the content of this site, you need to put active links to this site, visible to users and search robots.

RX cutters manufactured by SINTERLEGHE according to patent EP2193003 allow you to:

Sharpen electrodes of various tip shapes using one cutter

Divide the removed material chips between the top and bottom electrode

Reduce the cost of consumables due to the high strength and hardness of the blade material

You can use SINTERLEGHE developments to work with other manufacturers of grinding machines (see picture)

As a result of the tests to confirm the patent EP2193003 for RX cutters, the following results were achieved:

Reducing the cost of purchasing electrodes by 50%

Reduced spatter

Improving the quality and appearance of welding points

Reducing the number of line stops for electrode replacement

Reducing the number of torch models used

Reducing torch costs

Reduced electricity consumption

ELETRODE DIMENSIONS AFTER SHARPENING

The RX SINTERLEGHE cutter (patent EP 2193003) can be used when using sharpening machines from other manufacturers:

Germany: Lutz - Brauer - AEG - Wedo

Italy: Sinterleghe - Gem - Mi-Ba

France: AMDP-Exrod

USA: Semtorq, Stillwater

Japan: Kyokuton-Obara

Used everywhere. They are used for welding aluminum, stainless steel, non-ferrous metals and many other materials. The tungsten electrode + shielding gas combination is a good choice for those who want to achieve quality welds.

But any welder will tell you that for a decent result, it is not enough to know welding technology alone. It is also necessary to remember small tricks that will simplify and even improve the result of your work. One of these tricks is the sharpening of the electrode. In this article, we will briefly describe why it is needed and how you can sharpen a tungsten electrode yourself.

Tungsten is one of the most refractory metals used to make electrodes. The melting point of tungsten is over 3000 degrees Celsius. Under normal welding conditions, these temperatures are not used. Therefore, tungsten electrodes are called non-consumable. When applied, they practically do not change in size.

But despite this, tungsten electrodes can still become shorter. During the welding process (for example, when striking the arc or when forming a seam), the electrode can grind against the metal surface. In most cases, it's not that bad. But sometimes a blunt electrode causes lack of fusion.

How to solve this problem? Very simple: sharpen. A sharpened tungsten electrode regularly performs its function, forming high-quality durable seams.

How to sharpen an electrode

Sharpening of the tungsten electrode can be carried out in a variety of ways. This can be an abrasive wheel, chemical sharpening, sharpening with a special paste or mechanical sharpening. The latter is performed with the help of special devices. They can be both portable and stationary.

The sharpening shape can be spherical or conical. The spherical shape is more suitable for DC welding, and the conical shape is more suitable for AC welding. Some welders note that they do not notice much difference when welding with electrodes with different form sharpening. But our experience has shown that there are differences. And if you are a professional welder, the difference will be obvious.

The optimal length of the sharpened part can be calculated by the formula Ø*2 . That is, if the electrode diameter is 3 mm, then the length of the sharpened part should be 6 mm. And so by analogy with any other diameter. After sharpening, slightly dull the end of the electrode by tapping it on a hard surface.

Another important parameter is the angle of the electrode sharpening. It will depend on what amount of welding current you will use.

So, when welding at a low value of the welding current, an angle of 10-20 degrees will be enough for sharpening. The optimal angle is 20 degrees.

A sharpening angle of 20-40 degrees is a good option when welding with medium welding currents.

If you use high currents, then the sharpening angle can be from 40 to 120 degrees. But we do not recommend sharpening the rod more than 90 degrees. Otherwise, the arc will burn unstable and it will be difficult for you to form a seam.