How to properly weld pipes with a semi-automatic machine

Correct welding with a semi-automatic machine - video: initial setup of the semi-automatic machine and operation

Semi-automatic welding machines are popular not only among professionals, but also among amateurs who profess a simple rule: if you want it done well, do it yourself. It is for them that the following material is “Semi-automatic welding”. attached.

Working with a semi-automatic welding machine differs from operations with household inverters, which not every amateur welder can handle. Moreover, such users will be interested in setting up a semi-automatic welding machine.

Features of the semi-automatic machine

A significant difference between semi-automatic welding and conventional arc welding is that the process is carried out not with the help of electrodes, but with the use of a special wire, which is fed automatically (from a reel). In this case, the welding itself is carried out manually.

A professional semi-automatic welding machine allows you to increase both the speed of the process and efficiency. In addition, this type of welding allows you to weld a wide variety of metals - at different angles, in different planes. In addition to black steel, you can weld stainless steel, aluminum, and other metals.

How does a semi-automatic welding machine work? clearly demonstrates that semi-automatic welding is carried out using a torch - in a protective gas environment. Current is supplied to the burner through a rectifier; in this case, the mass classically goes to the part being welded.

The function of shielding gases - argon, carbon dioxide or a mixture of inerts - is to displace air and the nitrogen and water vapor it contains from the welding zone, thus eliminating contamination of the weld.

Also, semi-automatic welding, the video of which you will find below, can be carried out without protective gas - with flux-cored or flux-cored wire, the so-called. direct current, when the plus is applied to the wire.

The semi-automatic machine gives the user the following advantages over manual arc welding: the ability to work with thin materials - from 0.5 mm; external coating or corrosion is not an obstacle to welding;

lower cost compared to other welding equipment.

At the same time, the semi-automatic machine also has its disadvantages. Firstly, this is arc radiation, the degree of which is higher than in conventional welding. In addition, when welding without shielding gas, metal droplets may be splashed over a larger area. Setting up a semiautomatic welding machine will help minimize such disadvantages.

Setting up a semi-automatic machine

A semi-automatic welding machine is a professional tool, so it needs precise adjustment. Moreover, the result depends on the correct settings.

To begin with, of course, you should carefully study the instructions and also know a number of parameters and characteristics of the process.

It is necessary to take into account such data as:

characteristics and thickness of welded materials;
nature of the seam (horizontal, vertical);
design features;
intensity of use of the device;
network load.

The semi-automatic machine is configured in strict compliance with all parameters specified in special tables. So, it is necessary to take into account the current strength, because too low can significantly affect the quality of the seam or make welding impossible.

In some models, only the voltage is regulated. The setting principle is as follows: thicker metal means higher operating voltage (and current).

The next step is to set up the wire feed; it must also correspond to the indicators in the table. The wire enters the mouthpiece from the reel through a special hose. There are models equipped with gearboxes.

For the same purpose, replaceable gears are used (they come complete with the device).

The feed speed setting takes into account the thickness of the metal, as well as the diameter of the wire. If the feed is too fast, there is a great danger that the electrode will not have time to melt. Too low a feed means the wire burns out quickly; the metal will not melt.

In any case, your own experience will be simply invaluable. This is how a semi-automatic welding machine is generally configured, video below.

Semi-automatic welding

Strictly follow all recommendations in accordance with the instructions. There are many different nuances that need to be taken into account.

If shielding gas is used, it is necessary to check the cylinder and adjust the required operating pressure on the reducer. The choice of gas itself depends on the type of metal and the task. Well, secure the cylinder properly.

To start welding, set the lever to the “Forward” position. After the funnel is filled with flux, install the holder so that the tip of the mouthpiece is in the welding zone.

Open the flap of the flux funnel and press the “Start” button. To light an arc, you just need to strike the holder on the metal. Don't forget about the protective mask and other safety measures.

It must be taken into account that the semi-automatic machine cannot be overloaded and cannot be cooked for a long time in continuous mode. Before you start, look at what semi-automatic welding is - the video is attached.

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Source: https://swarka-rezka.ru/pravilnaya-svarka-poluavtomatom-vid/

Semi-automatic welding: technology, correct settings and instructions for beginners - Machine

For welding metals, a laser beam, torch flame or plasma can be used, but one of the simplest and most compact options for devices for performing this type of work is a semi-automatic device.

To ensure that the metal seam is as smooth as possible and protected from oxidation, welding metals in this way is best done using shielding gas.

Semi-automatic welding for beginners is difficult only in the first minutes of mastering. To speed up the learning process as much as possible, you should study the basic rules for handling such a device in advance.

Semi-automatic welding machine: operating principle

In order not to “kill” the device when using a semi-automatic welding machine. To avoid injury, you should know about the safety rules and the operating principle of the device.

The semiautomatic welding machine consists of:

housing containing a powerful transformer;
hose for supplying current and gas to the burner;
cables for connecting to ground and the electrical network;
wire feed mechanism.

Also, for semi-automatic welding, you will need to purchase a reel with a special welding wire and a cylinder of carbon dioxide.

The operating principle of the semi-automatic device is as follows:

The welding current is supplied to the torch simultaneously with the shielding gas.
The torch uses a welding wire as an electrode, which is fed automatically using a special mechanism.
An electric arc is formed between the product being welded and the wire, which melts the metal in a protective gas environment, which allows you to obtain a high-quality weld without oxides.

The basic safety rules when working with semi-automatic welding machines are as follows:

the body of the welding machine must be grounded;
it is prohibited to use the device even with minor mechanical damage or any other malfunctions;
in case of significant interruptions in work, be sure to disconnect the device from the electrical network and turn off the supply of protective gas;
do not work near flammable and explosive substances;
Use a protective mask and gloves while working.

As soon as the basic principles of working with a semi-automatic machine are mastered, you can begin practical work.

Semi-automatic welding: first experience

To gain practical experience, it is recommended to first practice on unnecessary metal scraps before proceeding with complex work that requires highly qualified welders.

For practical work you need to prepare:

welding machine;
gloves;
protective mask;
gas cylinder.

The first thing you need to do is set up the welding machine. Correctly adjusted strength of the supplied current will allow you to make a welding seam perfectly smooth and without breaks.

This parameter directly depends on the thickness of the metal being welded, so before starting work, you must read the instructions for the electrical device. Which should indicate the amperage recommended by the manufacturer for a certain thickness of the parts being welded.

Selecting welding modes

You should also make the right choice of the welding wire feed speed, which is regulated by a special mechanism.

The optimal diameter of the wire for welding is 0.8 mm, but when working with very thin metal, you can install a 0.6 mm electrode so that at a reduced current the metal is melted without fading the arc.

If possible, it is better to purchase Italian wire for semi-automatic welding. Imported analogues are of higher quality, but the cost of such products will be several times higher.

Despite the higher cost, such an electrode is more suitable for beginners because it is easier to obtain the desired result, even with insufficient experience in handling an electric welding machine.

instructions: setup.

Cylinder with reducer

In order to protect the welding site from exposure to oxygen, shielding gas is supplied. The cheapest option for using shielding gas is to purchase a carbon dioxide cylinder with a reducer.

A reducer with a pressure gauge must be installed to monitor the pressure of the supplied gas. To carry out high-quality welding of metals in a shielding gas environment, it is enough to set the working pressure to about 0.2 atmospheres.

Protective mask

To protect your eyesight, semi-automatic cooking should only be done using a protective mask, for example, Chameleon. Modern products have a special adjustment in their design, which allows you to configure the protective mechanism in such a way that it provides high-quality protection only during arc burning.

When the plasma combustion process dies out, the window of the mask will be transparent enough to allow you to continue working without removing the protective device.

Such welding helmets will be especially convenient for novice welders; in outdated models, the protective glass was too shaded, which made the welding process very inconvenient, due to poor visibility of the weld after the arc has died out.

Welding technology

When all the preparatory work has been carried out, it is necessary to connect the “ground” to the metal being welded. If you have to work with small parts, then welding is done on a metal table, to which the corresponding conductor is connected.

If there is no table, then the work can be carried out on a horizontally located metal sheet with a thickness of at least 2 mm, to which the “ground” of the welding machine is connected.

Before starting the welding process, it is also necessary to adjust the amount of protrusion of the welding wire from the nozzle. It is recommended to install such a protrusion no more than 5 mm. If the wire protrudes more significantly before starting welding work, it must be shortened using wire cutters.

Before making a continuous weld, it is recommended to position the parts to be welded as close as possible and to carry out spot welding in at least two places by striking the electrode against the metal at the joint. This is necessary to ensure the immobility of the parts being welded.

If you need to weld one sheet of metal onto another, then in this case you can use clamps to securely fasten the welded parts. Once the immobility of the parts is ensured using any of the listed methods, you can begin making the weld.

To weld parts, an arc igniter is made and the metal is melted at the junction of the metals to form a seam. If during the first attempts to weld parts the arc does not ignite stably, it is necessary to increase the current supplied by the welding machine.

For proper arc formation, it is necessary to briefly touch the wire to the metal parts to which the “ground” is connected. Then tear off the wire to the minimum possible distance to form a stable electric arc. In this way, the seam is welded from one edge to the other, gradually moving the arc over the surface of the parts being welded.

thin metal connection.
welding thick metal for beginners.

Aluminum welding

The use of shielding gases in semi-automatic welding makes it possible to perform high-quality connections of aluminum parts in this way. Welding aluminum is a rather complex process even for an experienced specialist; it will be even more difficult for novice welders to complete such work.

How to semi-automatically cook aluminum parts:

the surface of the welded parts is cleaned from the oxide film;
the workpieces are heated in a furnace or using a gas burner;
the welding machine is switched on to high-frequency alternating current mode;
a cylinder with argon or argon-helium mixture is connected;
The arc is ignited and its length is maintained in the range of 12-15 mm.

In this way, parts made of this low-melting metal are welded. To perform the work, you will need to purchase aluminum products as filler wire. And to ensure stable wire feeding, the device must be equipped with a larger diameter nozzle.

Conclusion

For novice welders, you learned how to weld semi-automatically with carbon dioxide correctly from this article. To consolidate the information received, it is recommended to immediately begin practical exercises and carry out a trial connection of parts using this method. Lessons will allow you to quickly master a semi-automatic machine at home.

It is recommended to start welding aluminum and other non-ferrous metals only after welding of ferrous metals is well mastered. This article tells you how to cook stainless steel with a semi-automatic machine.

Source: https://regionvtormet.ru/stanki-i-oborudovanie/svarki-poluavtomatom-tehnologiya-pravilnaya-nastrojka-i-instruktsiya-dlya-nachinayushhih.html

for beginners - how to cook with a semi-automatic machine?

For a person who has never welded metal in his life, it can be difficult to understand how to start correctly, what to do at different stages in order to ultimately learn how to create an even and reliable connection. Let's look at what steps need to be taken, how semi-automatic welding occurs, for beginners - a video that clearly demonstrates some points.

Why semi-automatic?

Semi-automatic gas-shielded welding for a beginner or inexperienced welder has its advantages:

The electrode wire is supplied by the device itself, there is no need to monitor the length of the electrode, it is easier to maintain the optimal distance for an even arc. In addition, the feed speed is adjustable, which allows anyone to adjust it in a way that suits them.
The semi-automatic machine makes it relatively easy to work with thin metal, which makes it practically irreplaceable for auto body repair shops, especially with low qualifications of the welder.
Sufficiently long seams can be produced without stopping the process to replace the electrode. For a beginner, this will allow him not to interrupt a successful seam before it is completed.
Easy to learn welding process.

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The list of advantages of semi-automatic machines is different for everyone; it can consist of several dozen items. For a beginner, the points listed above will be enough to start learning on this type of welding machine.

Preparing the welding machine - wire and gas

The semi-automatic machine uses a special welding wire as an electrode. Its diameter can range from 0.6 mm to 1.2 mm. The most common wire is 0.8 mm. It is clear that before work you need to load a spool of wire into the apparatus, stretch it until it exits the burner, and adjust the pressure of the wire with the roller of the pulling mechanism. The wire material must match its characteristics as closely as possible to the material of the parts being connected.

Before installing the conductive tip, you need to check it for compliance with the wire being used. That is, for 0.8 mm wire, a ferrule with a nominal value of 0.8 should be used.

It is not recommended to cook with a semi-automatic device without gas. An exception to this rule can be considered devices that use special flux-cored wire. When the arc burns, the flux that is part of the electrode wire, burning, creates a cloud of gas that protects the weld pool from oxygen and, accordingly, from the formation of oxides.

In standard semi-automatic machines, inert or active gas in cylinders is used to protect the seam from oxides. It can be carbon dioxide CO2 or a mixture of carbon dioxide and argon CO2+Ar. The first one is cheaper and more common; for welding steels it is a completely workable option, but the spattering of metal is quite high. A mixture of argon (82%) and carbon dioxide (18%) provides a more stable arc and reduces metal spatter.

Before work, connect the gas cylinder to the tip of the device and set the operating pressure.

Preliminary adjustments and actions

Most inexpensive semi-automatic welders have only two adjustments on the panel - the operating voltage and the wire feed speed. The drawing of welding wire is often marked with the letter A, as the current strength, since the feed speed and the welding current are interrelated. Additionally, semi-automatic machines are sometimes equipped with a two-position wire feed speed switch - high and low drawing speed.

In devices that can be considered more advanced, there is also an inductance regulator. By setting this parameter you can change the nature of the arc. “Cold” arc (less inductance) - the seam is narrower, the metal penetration is deeper. With a “hot” arc (higher inductance), the weld bead is wide, smooth, and the metal is melted to a lesser depth.

To correctly adjust the parameters of the device in accordance with the thickness and properties of the material, the diameter of the wire used and other characteristics, you need to use the table included in the accompanying documentation for the semi-automatic welding machine.

It is advisable to keep the angle between the nozzle and the workpieces at about 60°, the distance between the end of the nozzle and the surface is 8–20 mm. Before starting a new welding section, you need to bite off the ball that forms at the end of the wire (it conducts current poorly and makes it difficult to ignite the arc).

Before starting welding work, the edges of the surface of the workpieces are cleaned of dirt, traces of corrosion, old paint, and additionally processed with a grinder so that the melt “grabs” the metal better. On parts of significant thickness, special chamfers are removed.

Adjustments during welding

After starting work, the adjustments change depending on how the arc behaves and what the test seam turns out to be. When welding, distinct clicking sounds are heard - this means the voltage is too high and the wire feed is slow. If the wire does not have time to melt, then the feed is too fast.

When training and making a test seam, the parameters are adjusted to obtain high quality joints and ease of operation. As you can understand from the video, semi-automatic welding for beginners is not very difficult.

With a little technical skill and careful attention, anyone can learn how to cook with a semi-automatic machine.

If you need to make a vertical seam, remember: with thin metal (up to 3 mm) the seam is made from top to bottom, with metal thicker than 3 mm - from bottom to top. Thin sheet metal is spot welded to prevent warping due to overheating. This allows you to preserve the geometry of parts and elements.

Defects in welds, reasons for their occurrence

It is almost impossible for a novice welder to avoid mistakes that lead to the following flaws:

undercut appears when the torch moves too quickly, the arc is long, or the current is high;
if the movement is too slow, the metal flows down under the influence of gravity, an influx is formed;
pores are formed due to poor gas protection, poor-quality surface pre-treatment, or too high a work speed;
low welding speed at high current can cause through-burning of the metal, which is also caused by an incorrect initial gap (too large);
lack of penetration occurs due to a small gap, contaminated metal and insufficient welding voltage.

The appearance of defects in welding seams can be completely avoided; it is enough to know the reasons for their occurrence and try to avoid mistakes. With experience, the number of flaws will become less and less.

Welding workpieces of considerable thickness

When joining workpieces with a thickness of more than 4 mm, preparation should be taken more carefully. In addition to cleaning the surface from dirt, paint and rust, the edges of the elements along which the welding seam will be carried out should be chamfered. How to properly remove a chamfer, at what angles, is regulated by GOSTs; information is also available on the Internet.

To ensure reliable connection of thick workpieces, it is necessary not only to conduct an arc along the edges being welded, but to make oscillatory movements with the torch. There are many types and methods of these movements, but most often the usual zigzag or reciprocating movements are used. The width of the molten weld metal approaching the surface of the part should be equal to the thickness of the workpiece.

Before starting work, you need to set the gap between the parts to be welded. Without a gap, the metal will not be welded to its full thickness, the seam will remain superficial and the necessary strength will not be provided. To strengthen T-joints made of thick metal, two more are placed on top of the finished seam - along the upper edge of the seam, extending onto the workpiece, and in the same way along the lower edge. This allows you to strengthen the seam, which can be important for parts with a thickness of 8 mm or more.

Despite the mistakes and some subtleties during training, semi-automatic welding is widely used; a video for beginners helps to visually distinguish the features, find out why certain errors appear and how to eliminate them. The importance of clarity is difficult to overestimate at the initial stages of using a welding machine, especially when independently mastering the equipment.

Source: https://proinstrumentinfo.ru/svarka-poluavtomatom-dlya-nachinayushhih-video/

Welding of water pipes: plastic, polypropylene, steel, galvanized

The welding process is considered the most convenient and acceptable method for installing reinforcement structures for a pipeline system, and this is quite understandable. This method of working to strengthen parts is the most durable and has a high level of reliability; fasteners created by welding do not require other devices. This is a relevant solution to the issue when planning the welding process regarding pipes for a water supply line.

Welding work for a pipeline channel and their classifying features

welding of water pipes from galvanized pipes

Today, welding work for pipeline fittings is divided into types such as:

1. Thermal.

2. Thermomechanical.

3. Mechanical.

The thermal type of welding involves welding through a melting process, for example, gas welding process, electron beam arc, laser, plasma and others.

The thermomechanical type of work is carried out using a device such as a magnetically controlled arc and involves a type of welding work such as butt resistance welding.

welding of heating from polypropylene pipes

The mechanical type of welding is performed through explosions and a friction process.

Depending on the media, welding methods are divided into types such as:

1. Gas welding work;

2. Laser welding;

3. Arc welding procedure;

4. Plasma welding process.

welding water pipes from steel pipes

Depending on the method of formation of butt (welding) seams, the following are distinguished:

1. Forced welding.

2. Free welding work.

Do-it-yourself water pipe welding from plastic pipes

Focusing on methods that provide protection, the welding area is classified:

1. Using gases that provide protective properties.

2. With the presence of wire made of electrodes, which has the property of self-protection.

3. Under a layer of flux.

Automated mechanized processes divide welding work into the following::

1. Manual welding.

2. Mechanized.

3. Automated.

4. Robotic.

welding water pipes using electric welding

Welding work for joining pipes

pressure welding of water pipes

In the welding process of steel products that do not rust, in most cases, arc welding is used. If the pipeline system flows into a mainline, then about 70% of all welding work is spent using automatic submerged arc welding.

In cases where the use of a mechanical method is impossible, they resort to manual arc welding, even in conditions of various positions of the joining sections, for example, it can be either a vertical or ceiling position, or even a lower one. Using manual welding, the electrodes move in a circle around the joining path at a speed of about 18 meters per hour; with mechanical and automated welding, the speed increases to 50 meters per hour.

semi-automatic welding of water pipes

The welding process with shielding gas is available in several variants:

1. With the participation of active gas.

2. Using inert gas.

3. Using a mixture of active and inert gases.

Then, when welding with shielding gas is used, electrodes are used that have the property of melting and those that do not have this property. Arc welding using shielding gas is appropriate when it is necessary to connect pipeline fittings occupying different spatial positions.

Pipe welding and edge preparation processes

Initially, before starting welding work, it is necessary to double-check the permitting documentation, including the quality certificate for the products, whether they comply with the design documents and technical specifications.

The ends of the pipeline fittings that will be connected must differ in size and bevel shape, in accordance with the planned welding work. If this is not the case, then mechanical processing is required to create the necessary parameters.

In the case of pipes with a small diameter, you need to use a trimmer, a grinder, a chamfering machine and a pipe cutter. In cases with large diameter pipes, in addition to a grinding machine, it will be necessary to use waterjet cutting and milling machines.

If additional processes are expected, for example, coil overlap or cutting in, then thermal methods can be used:

1. Air arc cutting process using grinding within 0.5 mm.

2. The process of cutting hydro-oxygen with the use of stripping the edge with an abrasive material.

3. Cutting using special electrodes. In this case, there is no need for mechanical processing.

4. Air-plasma cutting with processing procedures within 1 mm.

It is necessary to pay attention to the fact that before you start installing pipes, it is worth cleaning their insides from dirt and cleaning the edge areas and those surfaces that are adjacent to them within a width of up to 1 cm.

welding water pipes with an inverter

Preheating during the welding process of products

Preheating can be considered one of the most important procedures that help regulate the temperature regime in welding activities. The cooling rate of metals at temperatures up to 800 degrees Celsius determines the characteristic features and qualities of the joint during welding operations.

Having the ability to cool quickly, it ensures the emergence of structures with a high level of strength and a low level of ductility. The rate at which the metal is cooled can be adjusted by changing the initial temperature of the edge sections, using preheating, taking into account the specific wall thickness of the reinforcement parts for the pipeline system.

The preliminary heating process, in addition to ensuring the creation of a favorable climate for the active removal of hydrogen from the welding zone and seam, can also increase resistance to the possibility of cracks forming.

welding of polypropylene water pipes

To correctly determine the preheating temperature regime, it is worth taking into account many factors, such as the chemical component of the metal, the thickness of the walls, the temperature of the surrounding space and the type of electrode layer.

For heating, electric and gas heating devices are used, which can maintain the temperature regime in the weld area during the welding process. The heating zone is considered to be 0.75 cm on both sides of the docking area.

welding of water plastic pipes

Manual arc type of pipe welding

When installing pipeline fittings, in most cases, almost half of the entire welding process is performed by manual arc welding. It implies that it is necessary to combine individual pipes or sections, pass through various obstacles, an overlap, a valve assembly, an outlet or a reel.

The number of electrode elements directly depends on the mass of molten metal and the marking of the electrode elements themselves. Features of the manual arc welding technology are determined by the materials of the pipeline fittings being connected.

Initially, after determining the operating conditions and grade of metal, it is necessary to select the material for welding work. Afterwards, you need to choose a technique and strategy, as well as plan welding processes, which are completely subordinate to the planned construction stages. There are situations when such values can be affected by both the thickness of the walls and the diametrical indicators of the pipes.

welding water pipe under pressure

Welding work of products for water supply lines

In this context, the three most popular options are determined, depending on the type of electrode:

1. Processes with electrodes of protective properties;

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2. Working with electrodes for the main layer;

3. Welding processes in the hot zone and rooting the weld seam with electrodes with a protective property, and for lining and filling mass an electrode for the base layer.

semi-automatic water pipe welding

In the case of using electrodes with protective properties, then welding is performed in the absence of vibrations, and the end of the electrode is supported by the edge sections of the pipes. The work is carried out under the influence of a constantly passing current of direct or reverse polarity of at least 75.

In the case when the diameter of the electrode element is approximately 3 mm, then the current strength is no more than 110 amperes. In conditions of a diameter of 4 mm, 125 ampere in the semi-vertical position, and 160 ampere in the lower position. In other variants within 140 ampere. The speed of welding processes must be maintained within 22 meters per hour.

The welding process with electrodes for the main coating is carried out, on the contrary, with transverse oscillation produced from bottom to top, the amplitude of the oscillation is determined by the separation of the joining place.

When welding at individual places in a seam, some welders use a flow-dissected method. If there is a large diameter pipe, then there may be four welders. If only two workers are present, then welding is done in opposite directions.

Each new layer should be displaced from the pipeline fittings by 6 cm.

If you follow all the listed instructions and standards, welding work on structures for water supply will not be difficult to accomplish.

Source: https://o-trubah.com/klassifikaciya-trub/vodoprovodnye-truby/svarka-2/

How to cook semi-automatically - video, features

Semi-automatic welding (MIG) is a kind of evolution of manual arc welding (MMA). Even despite the availability of MMA inverters, it is better to use MIG welding for home use. But to fully appreciate its advantages, you need to know how to cook with a semi-automatic device. In fact, there is nothing complicated about it.

What you need to know about semi-automatic welding

Before cooking, you need to take into account the intricacies of the welding machine.

How to cook with a semi-automatic machine:

the positive terminal is connected to the burner, the negative terminal to the workpiece;
For each type of metal, a special wire is used. For example, for aluminum - aluminum, for stainless steel - stainless steel, etc.;
Amperage and wire feed speed are mutually related settings. The higher the current, the higher the speed and vice versa;
The current collecting tip used on the torch must match the diameter of the wire. This part is a consumable item and therefore requires periodic replacement;
the quality of the seam depends on the settings of the wire feeding mechanism;
the hose feeding the wire must be rigid - otherwise it may bend and the wire feeding will stop;
It is better to weld metal thinner than 1 mm in spots if you do not need to get a sealed seam. This way the workpiece will not overheat and burn out;
if the network voltage is lower than rated, for example 190 rather than 220 volts, it is better to use wire of a smaller diameter. For example, instead of 0.8, take 0.6 - the machine will cope with it much easier, and the seam will turn out to be of high quality.
For semi-automatic welding without gas, a special wire is used, and the positive terminal is connected to the workpiece.

When welding in the down position, the torch is held at an angle of approximately 60 degrees relative to the workpiece. The distance to the workpiece is 5-15 mm. The burner is driven away from you – “at an angle forward”.

Before starting work, you need to bite off the tip of the wire protruding from the burner. A ball forms on it, which does not conduct electricity well - it will be more difficult to light the burner.

It is necessary to periodically clean the tip and nozzle of the burner from splashes. If this is not done, the wire feed will become intermittent. Therefore, special silicone aerosols are used that protect surfaces from sticking - you need to spray them inside the burner.

General rules of welding

As in any business, semi-automatic welding has a base that the welder must know.

When welding parts with a thickness of more than 3 mm, a gap of 1-2 mm is made between them. This is necessary for complete penetration of the metal. If there is no gap, the seam will be superficial;
When heated, the metal pulls; to ensure uniformity of the gap, tacks are made on the top and bottom of the workpiece. If the penetration length is large, the number of tacks increases;
you need to ensure that the seam is evenly deposited on both workpieces.

These are simple rules to remember.

Setting up the welding machine

The quality of the weld seam depends on the correct settings of the semi-automatic machine. What needs to be configured:

Current strength.
Wire feed speed.
Gas pressure.

The kit includes instructions that indicate recommended settings for different types of seams and spatial positions. They should be taken as a guide, because... There is no standard that can be applied to all devices. Therefore, the settings are individual. The task is to obtain an even arc, deep penetration and a beautiful welding seam.

Since the wire enters the burner along with carbon dioxide, the gas pressure must be set. It is done within 1-2 atmospheres.

To set up a semi-automatic machine, unnecessary pieces of metal with the same thickness as the main blanks are suitable. A novice master will not be able to immediately set the optimal settings for the device, so experiments need to be carried out on metal that you don’t mind throwing away. A normal seam is smooth and uniform, without interruptions or sharp sagging. The video lessons in the article will help you understand the settings of the semi-automatic machine.

Types of welding seams

Different types of welds have different settings. The type of weld differs according to the type of connection and the spatial position of the workpieces.

By spatial position:

horizontal;
vertical;
ceiling;
lower.

By connection type:

into the joint;
T-bar;
overlapping;
corner.

The simplest joints of workpieces are overlap welding and butt welding in the lower position.

Vertical seam

To fully use welding, you need to know how to weld a vertical seam with a semi-automatic machine. The direction of the vertical seam depends on the thickness of the workpieces:

The thickness of the workpieces is up to 3 mm - direction from top to bottom.
Thickness more than 3 mm – direction from bottom to top.

The torch is at an angle of 45 degrees to the workpiece. As a rule, it is necessary to reduce the welding current and wire feed speed compared to welding similar workpieces in the lower position.

To obtain a high-quality weld, the welder is required to withstand 3 things:

Uniform burner speed.
Distance from the torch to the workpiece.
Correct angle.

It is important not to overheat the metal being welded so that it does not flow down. The rest will be done by a semi-automatic welding machine.

There is nothing difficult about welding parts up to 1 mm thick. On the contrary, welding thin sheet metal with a semi-automatic welding machine is no more difficult than welding thick sheet metal.

Thin sheet metal is welded in two ways:

normal – any types of connections;
riveted - the blanks are laid overlapping and welded through pre-made holes in the top sheet.

There are several rules for such welding:

current strength and wire feed speed decreases;
you cannot hold the torch in one place - you will either get an influx of welding bead or burn through the workpieces;
with the rivet method, welding begins from the center of the lower workpiece. If you start welding from the edges of the top, the metal will simply fill the hole, i.e. can't brew well

If you do not need to obtain a hermetically sealed connection, you do not need to weld with a continuous seam. For thin parts, points with an interval of 1-5 cm are sufficient. The welding process can be seen in the video accompanying the article.

When welding workpieces thinner than 4 mm, chamfers are removed from the edges. This is done to obtain deep penetration. The burner is not driven in a straight line, but with slight oscillatory movements. For example, zigzag, spiral, back and forth, etc. This will make the seam deeper and wider.

Rules:

a gap of 1-2 mm is made between the parts;
the width of the welding seam should be equal to the thickness of the workpiece (approximately), for example, if 2 parts with a thickness of 6 mm are being welded, the seam should extend 3 mm onto each of them;

If the thickness of the workpieces is more than 5 mm, it may be necessary to cook in several passes. The first seam is made in the center, the second and third - above and below the first seam.

In practice, it is not difficult to understand how to operate a semi-automatic machine. You can get acceptable results already on the first day of training. The main thing is not to be afraid to experiment and remember that the semi-automatic settings are individual for each welder.

Source: https://svarkalegko.com/tehonology/osobennosti-svarki-poluavtomatom.html

Semi-automatic welding technology for beginners: first experience

For welding metals, a laser beam, torch flame or plasma can be used, but one of the simplest and most compact options for devices for performing this type of work is a semi-automatic device.

To ensure that the metal seam is as smooth as possible and protected from oxidation, welding metals in this way is best done using shielding gas.

Semi-automatic welding: technology, correct settings and instructions for beginners

Welding parts can truly be called an art, and welders who devote themselves to this profession are highly valued both in home welding and in industry. There are many people who know how to light a welding arc, but you need to look for professionals who can make a high-quality seam and at the same time withstand the technology. And it’s even harder to find a specialist who knows how to weld semi-automatically: only with such welding can you achieve the highest quality result.

This machine can weld any metals of different thicknesses. Therefore, most often semi-automatic and automatic welding can be found in industry . If we compare this type of welding with conventional electric arc welding, the efficiency of the machines is much higher. Semi-automatic welding for beginners includes the study of theoretical and practical aspects, and they are very closely related to each other.

Semi-automatic welding and its varieties

Before cooking with a semi-automatic device, you need to study its design and capabilities in detail. The device itself is made in the form of a mechanical device, where a wire is located, which acts as an electrode, and there is also a mechanism for feeding it automatically.

The speed of wire extension and the current strength can be adjusted on the body of the device, it all depends on the melting temperature of a particular metal, as well as the speed of movement of the torch along the surface to be welded. There are many devices of this type on the market, but the process itself can be divided into two types. Both types have one thing in common - the ability to protect the metal during the welding process:

Welding under flux layer. Flux is a substance in powder form that is found in the electrode rod. Its chemical properties help protect the process from oxidation.
A welding process in which welding occurs under the protection of inert gases.

If we distinguish machines by current consumption, then they can be either single- or three-phase.

The former are capable of operating from a regular 220 V outlet, but sometimes the device does not have enough power due to frequent power fluctuations, which can lead to an unstable arc and reduce the quality of the seam.

The three-phase unit has more stable operation and high quality indicators, but there may be a problem with its connection. Despite the fact that these devices have differences, their equipment is the same:

Energy source.
Electrode (wire) feeding mechanism.
Holder.
Cable with clip.
Control block.
Gas cylinder.
Gas supply hose.

Welding process in the middle of shielding gas

Several types of gas , but carbon dioxide, helium or argon are more often used. Carbon dioxide and helium have low consumption, and are also the most affordable to purchase.

The main purpose of the gas is to protect the welded metal from oxidation, which affects the strength properties of the weld. If carbon dioxide is used, the surfaces that will be joined by a seam must be thoroughly cleaned of rust, dust and paint.

It is recommended to use a metal brush in combination with sandpaper for this.

Three types of semi-automatic welding:

Without separation from the metal body . The seam is applied in a continuous layer from the beginning to the intended end.
Spot welding . The parts are connected by welding points, at specified intervals, along the entire length of the welded surface.
Short circuit welding . Basically, this type of welding is automatic, and it is applied to thin sheet metal. The process occurs from electrical impulses that the device generates. The short circuit melts the metal and turns it into a drop that connects the parts together.

Semi-automatic welding using carbon dioxide most often takes place in alternating current mode. Before starting work, you need to configure the semi-automatic welding machine. The parameters are adjusted depending on the type of metal.

The gas consumption used depends on the current settings of the device. Unlike carbon dioxide, the wire leaves unchanged - the average consumption is 4 cm per second.

The exact settings and material consumption can be found in the device’s passport, where, according to GOST, the standards for each type of metal are indicated.

The equipment is configured and ready for work, the parts have been cleaned, and now you can proceed directly to the welding process. The first thing to do is to unscrew the gas supply valve, and only then ignite the arc. Touch the wire to the metal and start the process. The wire is automatically fed each time you press the “Start” button. What determines the quality of the weld? It is important to keep the wire perpendicular to the workpiece, but not to block the view of the seam bath being poured.

It is necessary to maintain the required gap between the parts that are being welded. According to the technology, it looks like this: with a part thickness of up to 10 mm, the gap should not exceed a millimeter, but if the bodies being welded are thicker than one centimeter, then the gap will be 10% of their thickness. It is good to weld parts in a lying position and on an iron gasket, which is placed below close to the base metal.

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How to weld aluminum

The semi-automatic machine is also designed for welding aluminum. But there are nuances in this process, due to the fact that such metal has its own characteristics. There is a thin layer of amalgam on the surface of aluminum. Its melting temperature is more than 2 thousand˚C, while the main body melts already at 650˚C. Therefore, argon acts as an inert gas in this case.

When welding aluminum, a special substrate is used for the work - this prevents it from spreading. The welding process is affected by direct current of reverse polarity - a cathode is attached to the part, and the torch plays the role of an anode. This technique improves the quality of melting of the part, and also quickly destroys the amalgam. Although the oxide layer can be removed by simply cleaning the edges of the parts with a fine abrasive.

Welding without the use of inert gas

A distinctive feature of this welding process is that the work can be done both using gas and welding can be done semi-automatically without gas, using ordinary wire. A popular method of welding parts is a seam coated with flux. But more often this method is used in industrial settings, since flux is an expensive material.

Under the influence of a high melting point, the powder creates a cloud of gas, which protects the weld pool from oxidation. And the tap on the inert gas cylinder is closed at this time. The main advantage of flux-cored wire is the ability to carry out the welding process even in strong winds. And in the case of supplying gas from a cylinder, the wind will be a hindrance.

But there are cases where the use of cored wire is not recommended: thin sheet metal and medium carbon steel. There is a danger of defects that may appear in the form of hot cracks. To increase the temperature of the welding arc and high-quality melting of the flux, you need to use the already known technique with reverse polarity - the cathode is placed on the part, the holder with the wire will act as the anode.

If your goal is to become a real professional, you need to study all the questions on the topic - how to properly cook with a semi-automatic machine and such an important factor as safety rules, and in the future apply the acquired knowledge and pass it on to the descendants of this profession. Never neglect safety rules when working with high temperatures and electricity. An important point is to protect your eyes and exposed areas of the body, so provide yourself with a mask and thick clothing that will protect you from burns.

Both beginners and experienced welders are recommended to make the first test weld on a hidden area, or better yet on a rough part, in this way the semi-automatic settings will be more accurate. When using the device for the first time, be sure to read the instructions and apply the information received in your work. Try to avoid overloading the semi-automatic welding machine - this will extend its service life.

It doesn’t matter what kind of welding, automatic or semi-automatic, you need to gain theoretical and practical knowledge of working with them. Although learning is a long process that requires patience and concentration, once you understand everything, the welding process will seem like a cakewalk. Some beginners ask the question: what is the difference between automatic welding and semi-automatic welding? Answer:

Automatic welding is an automatic process that is used mainly in production and does not require direct human participation.
Semi-automatic welding is a process in which the wire (electrode) is fed mechanically, and the ignition of the arc and movement of the holder along the body of the part is carried out by a person.

Source: https://tokar.guru/svarka/tehnologiya-svarki-poluavtomatom-s-gazom-i-provolokoy.html

How to weld semi-automatically with carbon dioxide?

Welding in a neutral gas environment is a reliable and durable connection of workpieces into one whole. The cost of carbon dioxide in relation to argon and helium is much lower and this improves the ratio of price and quality of work.

You need to know how to properly weld using a semi-automatic machine with carbon dioxide, while achieving good seam quality. You can weld using mixtures of gases when increased quality is needed, or you can learn to weld in a carbon dioxide environment using a semi-automatic machine and an adjustable feed of welding wire.

We will tell you in detail about this process, which allows you to save considerable money and achieve the desired result.

Welding methods in a protective environment

Welding with controlled semi-automatic wire feed into a short-circuit arc environment can take place in an active gas composition or in an inert gas composition that prevents oxidation in the area where the workpieces are joined. Carbon dioxide insulates the weld from oxygen and imparts elasticity and strength to the joint of the parts.

The use of semi-automatic inverters has added a new quality level to the process of joining workpieces and greater opportunities for repairing defective components and parts. This is especially important when welding various alloys of aluminum, titanium and stainless and alloy steels.

So, how to cook semi-automatically and what methods are used in our time? The most popular methods of joining metals in an inert gas environment are schemes using a protective shell, which prevents oxidation of the metals or alloys being welded.

Currently, the following methods are most actively used:

joining metals and alloys using the TIG method using an extremely refractory tungsten electrode in an inert gas environment and manually feeding the necessary filler wire into the weld pool;
MIG/MAG method, which allows semi-automatic, controlled supply of welding wire into the short-circuit arc zone under the influence of shielding gas.

It should be noted that the TIG method is cheaper, but less technologically advanced, since it requires manual feeding of the welding wire into the pool, whereas the MIG/MAG method requires a semi-automatic process.

MIG/MAG inverters allow you to weld a huge number of materials using a device for automatic, controlled feeding of welding wire of various compositions into the short-circuit arc area.

This process occurs by pulling the wire from the built-in drum through the Euro-sleeve and the torch directly into the welding zone.

This advanced circuit allows you to use an electrical circuit to delay the supply of pulsed current to the wire, which is the electrode, after applying the shielding gas. The torch is equipped with nozzles that allow you to feed wire of different diameters into the zone affected by the welding current at the required speed.

It is important to note that the composition and diameter of the welding wire depends on the thickness and composition of the workpieces and is selected individually for each process.

Advantages and disadvantages of welding in a carbon dioxide environment

Welding with this method, like any other, has its advantages and disadvantages, which make it easier to choose the best option in terms of price and quality of work. To understand how to properly brew semi-automatically with carbon dioxide, it is necessary to evaluate the prospects for using this particular method, which are as follows:

the cost of carbon dioxide is lower than the cost of argon or a mixture of inert gases;
welding quality is comparable to the use of inert gases;
productivity and narrow temperature zone allows you to weld thin sheet metal and all kinds of alloys;
impurities lead to the formation of slag, which is easily removed after the seam hardens.
lack of sensitivity to many workpiece contaminants;
high purity of carbon dioxide up to 99%, which ensures high quality welding seam;
feeding the wire of the composition required for welding into the melting zone at an adjustable speed;
After cleaning from slag, it is possible to re-pass the seam in order to increase its strength characteristics.

Like every method, carbon dioxide welding also has some disadvantages, primarily related to the chemical composition of the environment in which the metals are joined, they are as follows:

carbon dioxide welding is inferior in quality to work in an inert gas environment;
the seam becomes more porous and requires additional cleaning;
gas supply requires experimental adjustment;
The choice of wire is adjusted to the conditions of welding in carbon dioxide.

The chemical composition of the wire depends on the reactions occurring in the combustion zone of the short circuit arc, and requires particularly careful coordination of the composition of the workpieces being welded with the composition of the filler material. But the shortcomings are temporary and are due to getting used to the ambiguous process.

In general, the selection of wire type SV-08 GS or SV-08KhGSMF completely solves the problem of workpiece weldability. In the future, the process depends on the welding speed, current value and coordination of the composition of the parts and wire supplied to the metal melting zone.

And this only comes with experience and training, as does the selection of wire extension into the weld pool.

Qualified selection of wire composition when welding in carbon dioxide is extremely important, since the physical and chemical process of thermal action on the seam greatly affects the quality of the connection of metals and alloys.

Procedure and technology of work when welding with carbon dioxide

The need to prepare the workpieces is to clean the future seam from the oxide film, dirt and form the edges for the best connection of the parts. In practice, the thickness of the metal also affects the choice of a special welding mode, for example, with a metal thickness of 1.5–2 mm, the diameter of the welding wire is selected in the range from 0.8 to 1.2 mm.

The whole process is extremely individual and is adjusted experimentally down to the gas consumption and wire ejection in the zone of carbon dioxide action. It is important to observe the following principles:

ensure the correct selection of current strength for welding in a carbon dioxide environment;
set the feed speed of the corresponding wire into the weld pool area;
ensure the preparation of workpieces for the best articulation in the seam area;
set the optimal gas supply to the short circuit welding arc zone;
check the tightness of the connections to avoid carbon dioxide leakage.

After carrying out these procedures, it is necessary to test the quality and speed of welding on test parts, and edit the parameters of the welding process scheme. For large workpiece thicknesses, the first seam must be carried out with a low current, and when passing again, the current must be increased in proportion to the speed of the torch.

Penetration of a vertical weld should proceed from bottom to top to ensure consistent solidification of the lower part of the metal joint, while the consumption of carbon dioxide should be slightly increased. Gas flow can vary depending on process conditions from 5 l/min to 20 l/min. The sequence of passing movements of the welder's hand during a semi-automatic process in a halo of carbon dioxide should resemble the application of flakes of molten metal to the surface of the weld.

It is very important, especially in difficult-to-reach conditions, to follow safety rules and use protective equipment and a welding helmet, as well as be careful when using carbon dioxide.

Bottom line

To summarize, it must be said that semi-automatic welding in a carbon dioxide environment is an almost complete replacement for inert gas environments, but at the same time it is much cheaper. The practical application of this work scheme forces us to pay more attention to the technological process of welding parts and assemblies, which differs little from welding in argon or helium. We tried to describe this type of activity in as much detail as possible.

Source: https://electrod.biz/oborudovanie/poluavtomat/svarka-poluavtomatom-s-uglekislotoy.html

How to weld pipes using electric welding, semi-automatic welding, gas

24.02.2019

When installing highways and utility networks, pipeline welding with electric arc or gas equipment is often used. Electric welding of pipes is carried out manually and using semi-automatic machines. The choice of additive is made according to the grade of rolled pipe steel. Taking into account the technological features, low pressure pipelines can be installed independently.

Features of pipe welding

When welding steel pipelines, gas and electric welding are most often used. When installing high-pressure pipe structures, special requirements are placed on electrodes and filler wire. The layering of the joints depends on the wall thickness:

weld a joint up to 3 mm inclusive at a time;
over 3 to 6 mm, two penetrations must be made;
over 6 to 12 mm - create a three-layer connection;
over 12 mm it is better to go through the joint at least 4 times.

In pipe welding technology there are distinctive features of the choice of operating current:

amperage is selected according to the diameter of the electrode, multiplying the indicator by 35 (3 mm - 105 A, 4 mm - 140 A);
when welding pipes with a wall thickness of less than 4 mm, a current exceeding 150 A is not installed;
between the electrode and the rolled product, a distance equal to the thickness of the electrode plus 1 mm is maintained;
thin-walled rolled products are welded in one continuous pass, turning the rolled products, thick-walled rolled products can be welded in sections up to 15 cm long;
vertical and non-rotary joints are welded in two stages;
The melt pool is located 30° from the top point.

The finishing layer roller should protrude up to 3 mm above the pipe. The quality of the connection is checked after each penetration, when the scale is removed.

How to weld a pipeline correctly and evenly

Pipelines are installed:

Butt joint, the pipes are pushed tightly together, the gap is filled with molten metal. Thin-walled gaps are immediately filled completely. When two pipes thicker than 3 mm are welded, several counter penetrations are made, each time starting the seam from a different place.
Overlapping, this joining method is convenient for pipe blanks of different thicknesses. When welding metal pipes in this way, the bead forms a smooth transition from one diameter to another.
It is convenient to weld a pipe at an angle using electric welding in the lower position. In the upper one, gas welding is used.
A T-joint is formed when a pipeline branches or one branch of the main line is cut into another.

The pipe blanks are first connected to each other at several points so that the joint does not diverge. This process is called assembly. Then the entire seam is welded.

Preparing pipes for welding

In addition to cleaning and degreasing the surface, edges thicker than 3 mm are beveled so that the joint is densely filled with hot metal. Cutting edges for welding is carried out similarly to flat parts, at an acute angle. If necessary, thin pipe blanks are processed with a cutter to ensure smooth joints.

Source: https://svarkaprosto.ru/tehnologii/kak-varit-truby