Semi-automatic welding has advantages in comparison with a non-compatible electrode.

• Everyone knows how important it is to lead the welding process without separating the arc, while maintaining the constant distance between the electrode and the part (arc surveillance). If the parameters are correctly set, the semiautomatic device independently adjusts this clearance in case there are small deviations from the optimal position of the burner. In other words, the device takes half of the tasks, which were previously solved mainly by the skill of the welder, on themselves.
• No need to keep the additive material. The right hand is released, which allows you to freely manipulate the detail.
• The speed and efficiency increases.

Standard welding with melting electrode consists of:

• inverter power supply (IIP);
• copyright wire supply unit;
• special burner
• crocodile masses
• ballery with protective gas with a flow meter.

There are inverters in which IIP and the feeding mechanism are assembled under one case. Such devices working on the principle of "all in one" are most often acquired to satisfy personal needs:

• welding sheet material (especially thin sheet),
• welding canopy or wickets in the country
• installation of pipelines, etc.

As well as to solve special issues, such as the body repair of passenger cars per service station.

In the factory conditions, more powerful equipment is usually used, so IIP and wire feeds are divided into them.

The principle of the operation of the semi-automatic is simple: it straightens the alternating current entering the entrance, permanent at the output. On constant, the current vector is determined by its polarity and how the cable is connected to the terminals.

The wire used is designed for a specific polarity. For the widespread wire type 09G2C, the current "+" DC on the burner is used.

In the process of welding, when the distance from the melting electrode to the metal changes, the operating current and voltage is automatically adjusted in such a way that the arc cliff did not occur. IIP "tries" to maintain stress constant, and the current power increases or decreases.

The feeding unit consists of a spindle on which the coil is fixed, and the wire through the guide enters into the hole of the feed roller. The feed wheel is calculated on a certain wire diameter and can be replaced.

We considered frequently repetitive issues that define beginner welders, developing work on a semi-automatic inverter type apparatus.

What protection gas is used when working semi-automatic?

Semi-automatic welding is produced in carbon dioxide medium, which is 100% carbon dioxide. You can work exclusively in argon, or in a mixture of argon and carbon dioxide.
The welding wire simultaneously appears to be covered with a copper layer, to improve the electrocontum and the smoothness of its feed.

what should be the pressure of the protective gas?

Choose 0.6 ... 0.8 MPa. This is if everything is fine and a new burner is used. If its wear takes place, it is allowed to add gas a little. The main thing is that there are no pores in the welding seam. If the porosity still takes place, then the pressure is insufficient (or very large due to which air can enter the welding zone, especially when working with an outer angle). Although the pores may arise due to the "dirty" gas, if there is a place Be wind or draft. It is especially felt by the purity of gas during welding of aluminum - seams will simply cover the layer of soot and gary. When working with aluminum, choose only a singular argon.

What wire do you use? What polarity must be observed?

Omned Welding Welding OK Autrood 12.51 ESAB

The most universal - 08g2c, all welders are familiar with it without exception. It is used for welding low-gluing and electrical steels. Naturally, this material is now under various brands. The ESAB, famous for the whole world, produces 08g2c called OK Autrood 12.51 - its composition is strictly controlled, which allows for stable mechanical properties of the seam. The state of the copper surface is also subject to control, which is not too thick and not too thin, i.e. It has an optimal value. Why is it important? Because poor-quality wire quickly leads to the failure of the feeding mechanism, due to the contamination with its copper dust and scolf.

The condition of the seam and the feed authority directly depends on the quality of the wire and copper coating

The welding of a solid wire is carried out on the current of the reverse polarity, that is, the burner is connected to the output with the "plus" sign.
Also, for corrosion-resistant steels, an ER-308 LSI additive is used - contains 20% chromium and 10% nickel - just the ratio that gives the seam the greatest resistance to corrosion.

Is welding without protective gas possible? If so, what is its features? What are the pros and minus of this method of welding?

Powder Self-Protection Wire E71T-GS

Perhaps and do without inert / active gases.
In such cases, powdered wire is used, which in its action is similar to a piece electrode used in manual arc welding.

Powder wire is a hollow tube filled with flux. The latter during combustion provides the necessary gas protection against external influences for the proper formation of the weld.

Powder wire is still often called flux, it is less rigid than normal, so for correct operation with it without stopping the feed mechanism, it is necessary to weaken the force compression force. Or it is not necessary to twist too much.

The wire is mild and will be frozen. In order not to have similar problems, before its first feed, the tip on the burner should be removed and only after that it stretches. Tip Set only the appropriate size. Nozzle set no need, as welding will be carried out without protective gas. Inverter should set voltage parameters, feed speed and inductance using smooth adjustment knobs.

There are still features of working with such a wire - this is the need to change polarity on a semi-automatic inverter. The welder must be adapted for this. For example, on the apparatus Overman 180, the polarity change is made inside the housing next to the feeding mechanism (terminals are unscrewed and the wires change in places). Do not forget the same way that the size of the feed roller groove must correspond to the wire diameter.

A sheet welding of 1-2 mm thick must be performed by short seams of an angle back, in which case the seam is formed much better. For the welding of thin metal, there is a wire 0.8 mm on sale. Maximum diameter of 2.4 mm - for serious industrial tasks.

Advantages:

• no need to carry heavy cylinders behind them, mobility.

Disadvantages:

• high cost wire,
• carefully need to relate to its quality,
• the slag peel is formed on the seam surface, which must be cleaned.