One of the leading places in the production of metal structures occupies an electrodesign welding of melting. It is considered a popular option to be semi-automatic welding, in the process of which the electrode supply or wire is mechanized. At the same time, the movement of the welding burner at the required speed through the length of the seam is carried out by the welder itself. The protection of the melted metal of the welding seam from the atmospheric exposure is carried out in the form of filing to the welded flux section in granules or protective gas for welding semi-automatic. For some cases, both are required.
Features of semi-automatic welding without gas
A semi-automatic welding, which is one of the traditional welding methods, is performed using the electrode wire. She, speaking as an electrode, is uninterrupted with a certain speed using a special drive into the welding head. The use of special fluxes allows to obtain a greater depth of the regulation of metals on a welded area, even with a small diameter of the wire and on small currents. Thanks to the high-quality seams obtained with any thickness of the parts, the use of welding semi-automatic welding semi-automatic welding increases significantly increases the performance of the work and the quality of the compounds.
Advocative welding with semi-automatic in the manufacture of structures with a small length of seams and when they are curved. It is convenient for simple small-scale production. Most often, it welded metal with thickness of parts up to 3 cm, with a bevel edge or without it, many single-pass angular, as well as two or one-sided butt seams. Also this method of welding makes seams of slit, with the penetration of the upper part of the outstanding compound and electric flares. For this, as a rule, hose semi-automatic welding hose has a universal holder.
Often, variable currents are used for semi-automatic welding, but also using permanent currents, the welding process is also possible. When the current increases, the flow rate of gas increases with semi-automatic welding. Before the start of welding, the place of the upcoming connection is necessary by opening the flap of the special bunker, to handle flux. With the beginning of the supply of the electrode, an arc is excited, which is supplied with smooth movements of the electrode along the surfaces of the edges, sprinkled with flux. In the case of shutdown of the feeder, when the arc is re-excited, removal from the edge of the electrode of the slags is required.
The operation of the holder of the holder along the seam axis during the welding of the semiautomation is carried out by the electric welder personally. At the same time, the holder can be moved, holding the weight, so take advantage of the crutch specially designed for its support. Minor changes in the distance between the holder and the surface of the part do not violate the proper maintenance of the welding process and, as a rule, do not affect the sizes of the seams and their shape. But to perform high-quality seams, practical experience is required to maintain the necessary speed of the movement of the holder and the accuracy of the direction of the electrodes along the axis of the seams.
Advantages and disadvantages of welding semi-automatic gas
A certain difficulty in performing gas welding with a semi-automatic basis is the inability to observe the course of the formation of the seam. The holder in the production of angular connections is placed in the angle of the joint of the fastened parts, so welding has to run side or towards yourself. With a combination of transverse oscillations of the holder with its movement along the seam axis, it is possible to obtain exhausted seams that are necessary when welding some compounds with large gaps. Also welding semi-automatic is appropriate in the production of intermittent seams.
Due to weak rigidity with high fragility of the powder wire used to welding without gas semi-automatic, its feed is produced using a special mechanism with small compression. In this case, harsh hose movements are not allowed. In addition, steady observance of the polarity of the connection on the holder with the "mass" is required: "+" to the product, "-" on the holder, that is, in the literal version. Such a need is due to the creation of high temperatures when the flux wire is supplied to form a protective gas cloud. The pressure of the gas during welding is adjusted depending on the welded metals and current forces.
By making the choice between the varieties of this type of welding with or without it, it is worth a preference to the second option. Of course, the first method allows to completely eliminate the penetration of oxygen into the place of direct welding. Due to this, the disadvantages associated with the content of carbon are eliminated, which allows to obtain high quality welded seams. But this method requires high labor and funds. We will have to move heavy gas cylinders, which is inappropriate to perform only a few seams. In addition, charging cylinders is unprofitable when welding is not used too often. Therefore, for example, aluminum welding semi-automatic gas without gas is much more profitable gas.
The advantage of the method of such welding without gas is also the lack of need to use gas equipment with a large energy intensity. In addition, it allows using a wide selection of welding wire with different fillers to obtain the required chemical composition of the weld metal and certain characteristics of the welding arc. Due to the absence of charging costs with the necessary gas cylinders welding with semi-automatic gas without gas is economical and accessible to everyone. And its most important advantage is the possibility of observation through a protective mask for the operation of the direct supply of electrode wire into the cutting.
But it is worth considering that it is impossible to use a semi-automatic for welding without gas using a conventional welding wire. The seam thus obtained will contain the sinks and differ in irregularity. It will significantly increase the spending of the wire, because its significant part will simply evaporate. In addition, the effect of oxygen will be tangible on the welding site, which means the formation of oxides will allow cavities in the seam.