Welding electrodes - the main study participant works

electrodes for welding Principle

current transmission principle in these electrodes is simple.One end of the 3 cm for coating has to grab it could be a holder for contact with the current circuit.The second end bit is cleared by coating, to make contact with the object when the arc ignition.

During melting in the arc of complex processes occur.As a result, the redox reaction in a gaseous medium at the boundary section of the slag, metal and alloying occurs arc, oxidation and deoxidation, which create a seam.

Classification of welding electrodes

Classification of welding electrodes is carried out by the following criteria:

• thickness of the coating rod;
• material rod;
• kind of slag, which is formed during melting;
• type of coverage;
• appointment for welding of special steels;
• properties of the weld metal;
• polarity and the type of current used for work;
• permissible spatial position welding or welding.

electrodes for manual arc welding should ensure steady burning and easy ignition of the welding arc.Furthermore, it is desirable that the coating of the electrode is melted properly, and coating the weld slag is easily and uniformly occurred after the scraping operation.When operating in the weld metal to avoid cracks and pores.

before selecting electrodes for DC welding, it is necessary to get acquainted with their classes:

• SSSI 13/45 - has a basic coating, and is used for low alloy and carbon steels.With it you can handle the metals having a large thickness, vessels, working under pressure and to eliminate casting defects.
• SSSI 13/55 - has the same designation as SSSI 13/45, and welding can be not only pressure vessels, and steel construction.
• OZS-12 - used to work with the low-carbon steel construction.The work can be in any position other than vertical.
• OZS-4 - provides the ability to produce work on the oxidized surface, suitable for low-alloy and carbon steels.
• MR-3C - for the same steel as the previous type, except that it creates a neat seam, than facilitates the entire work process.

typology of coatings for welding electrodes

To make the right choice for welding electrodes, it is necessary to make all the details of coverage, type of metal and the weld appearance into consideration.According to the type of coverage you can select certain types of welding electrodes, for which we give a few words about the composition and use.

materials coated with an acidic oxide containing iron, silicon, manganese, and in some instances titanium.The weld metal has an increased tendency to hot cracking.These electrodes can be used for AC welding and permanent.

Options with basic coating composed of magnesium and calcium carbonate, fluorspar CaF2.They have become indispensable for welding hardening steels, which are prone to the appearance of cold cracking as a result of exposure to hydrogen, rolling in the heat-affected zone of the metal.Such coatings

low oxidizing ability helps move the electrode from alloying elements in the weld.Furthermore, they are used for welding high strength steels.The weld metal is so resistant to the appearance of hot cracks.Rigid structures can be connected and used for thick surfacing joints at several layers.

But they have drawbacks: low constancy of the arc, a tendency to the appearance of pores while the increase in arc welds during welding, if the metal surface has a rust or scale.

materials with cellulosic coated cellulose-based have.The weld metal of high includes hydrogen.They allow weld downward, while the other electrode is obtained at such low quality path algorithm.

electrodes coated with rutile base include rutile, which is composed of titanium dioxide TiO2, and carbonates and aluminosilicates.Before work they must be dried at 200-degree temperature of 1 hour a day, and only possible to work with them.They can make steel, the surface of which has any rust and scale, the pores will not be formed.They have a greater resistance to the appearance of hot cracking than sour coated electrodes.

Their benefits can be considered: easy ignition, great fatigue resistance welding joints, low tendency to the appearance of pores during ignition and rapid elongation of the arc.These electrodes can cook low-alloyed and low carbon steel;You can not cook designs that operate at elevated temperatures.