Welding Steels




For manual arc welding of steels are widely used with consumable metal electrodes in the form of rods with length up to 450 mm from the welding wire coated with these coating layer, which provides stable arc burning, protection against harmful effects of air and metallurgical processing of the weld pool. In the cover includes the following components: gas-forming inorganic materials (marble CC03, magnesite MgC03) and organic matter (starch, dextrin); ionizing or stabilizing – the different compounds in the composition which contains potassium, sodium, calcium (chalk, feldspar, granite, etc.), slag-forming, forming the basis of coverage – usually ores (manganese, titanium) minerals (ilmenite and rutile concentrates, feldspar, silica, granite, fluorite, etc.), alloying elements and the elements-deoxidants – silicon, manganese, titanium, etc., used in alloys of these elements with iron, the so-called ferro-alloys; binders – aqueous solutions of sodium silicates and potassium, known as liquid glass. To improve the performance of welding in iron powder coating was added to 60% by weight coverage. Metal electrodes for arc welding of steel manufactured in accordance with gost 9466-75, providing for the following classification: by appointment – for welding carbon (Y), thermostable (T), alloy (A) and high-(B) steels, as well as for deposition of surface layers with specific properties (H) by type of coverage – with a sour coating (A), basic (B), cellulose (C), rutile (R), mixed and other ( II). Acid coating (Electrodes ANO-2, CM-5, etc.) consist mainly of oxides of iron and manganese (ore), silica, carbon ferromanganese. They are into technology, but the presence of Mn oxides makes them toxic.

Rutile (electrodes ANO-3, ANO-4, OZS-03, OZS-4, OZS-6, MP-3, MR-4 etc.) have in their composition a large number of rutile TiO2. Such coatings are less harmful to the respiratory welder than others. Cellulose coating (electrodes CWS-1, WCC-2, WOC-1, etc.) are composed of cellulose, organic resins, ferroalloys, talc, etc. These coatings are suitable for welding in any position, but give the weld metal is reduced ductility. Basic coverage (electrodes UONI-13/45, OZS-2, BSC-50, etc.) do not contain iron oxides and manganese. Weld metal, made by such electrodes, has a high plasticity.

By coating thickness depending on the ratio of electrode diameter D to diameter steel rod d distinguish electrodes with a thin coating of M (D / d 1,8). The permissible substantive provisions of welding coated electrodes are divided into groups: 1 – for all positions, 2 – for all positions, except vertical, 3 – for the lower, horizontal to vertical, 4 – for the bottom. Separate electrodes for welding on ac and dc forward and reverse polarity. Coated electrodes have a diameter metal rod from 1,6 to 12 mm and a length of 150 to 450 mm.