Welding electrodes for manual arc welding
Classification of covered electrodes
Classification of covered electrodes
The composition of electrode coatings
The composition of electrode coatings
Appointment of individual coating components SSSI-13
Appointment of individual coating components SSSI-13
Manufacturing Electrodes
how production and manufacturing of electrodes take place
Welding Electrodes
Showing posts with label welding electrodes. Show all posts
Showing posts with label welding electrodes. Show all posts
3:47 AM
12:55 AM
Manufacturing Electrodes
how production and manufacturing of electrodes take place
Manufacturing of electrodes
Modern high-quality electrodes are produced on plants of the electrode or electrode in special workshops. Steel electrode wire for the manufacture of electrodes and the cut rule on the rods to length. Typically, the editing operation, and cutting combined in one right-chipping machine. The surface of the wire is carefully cleaned of rust and other contaminants. Components of the coating must be pre-crushed fine.
During the welding process in a short period of time from the coating components, refractory, and often very poorly soluble in the slag, the slag should be formed. Complete fusion and the formation of the desired composition of the slag in a time like this can happen only when there is a very fine grinding and thorough mixing of the components of coating.
Fragmentation of the components coming in large chunks, is made in two stages: coarse and fine crushing, or grinding. Coarse grinding is different crushers. Subtle grinding or milling of components, often produced in ball mills. Ground components of the ball mill is usually screened on sieves with a number of holes per 1 cm2 1600-3600. From prepared, milled and sifted ingredients produced obmazochnoy paste electrodes. Currently, there are two basic ways to produce smeared electrodes: 1) the dipping or dipping, and 2) crimping.
Paste for dipping should be roughly kneading until creamy state. First mix the dry ingredients, then mix them in a binder solution, usually sodium silicate solution. In the method of dipping the electrode rods are immersed in a bath of liquid obmazochnoy paste and slowly pull out of it, the rods are covered with a uniform layer of coating. The method is preserved only for dipping coatings unsuitable for the application of crimping, for thin coatings and small electrode workshops that do not have obmazochnoy presses.
A more sophisticated and prevalent in the modern factories of the electrode coating application method is carried out on special crimping presses the electrode operating at high pressures, 400-800 am. Obmazochnoy molding paste has the consistency of damp earth and under pressure in the hand stick together into a ball. Obmazochnoy paste periodically. Loaded into a cylinder press. Electrode rods are pushed through the die cylinder in the range of 200 to 600 pc. per minute and leave covered with a dense layer of coating is quite uniform thickness. Upon emerging from the press one end of the electrode holder is trimmed to capture. The modern news electrode provides a capacity of approximately 2,000 tons of electrodes per year in one shift.
Electrodes made dipping are pre-drying at temperatures up to 40-50 ° C Pre-drying is necessary to eliminate the cracking of coating layer, which can be obtained at too high a forced drying. Electrodes because of the small pressure-tested moisture content in the paste does not require pre-drying and immediately subjected to final drying. The final drying or calcination of the electrodes is intended to remove all moisture as possible from the pasta and add a layer coating the maximum mechanical strength due to chemical reactions between the glass and liquid components of the coating.
The final drying can be carried out forcefully, at high temperatures. For electrodes that do not contain organic matter, temperature calcination can be brought to the 300-400g, C, for coatings with organic substances - not more than 150-180g, C to avoid decomposition of organic matter. At the end of drying, the electrodes are in control and packaging. From each batch, a sample of electrodes for welding trial. The electrodes should be stored in a dry heated room in order to avoid damage to the electrodes.
See also:
Classification of covered electrodes
The composition of electrode coatings
Appointment of individual coating components SSSI-13
Manufacturing Electrodes
Welding Electrodes
Manufacturing of electrodes
Modern high-quality electrodes are produced on plants of the electrode or electrode in special workshops. Steel electrode wire for the manufacture of electrodes and the cut rule on the rods to length. Typically, the editing operation, and cutting combined in one right-chipping machine. The surface of the wire is carefully cleaned of rust and other contaminants. Components of the coating must be pre-crushed fine.
During the welding process in a short period of time from the coating components, refractory, and often very poorly soluble in the slag, the slag should be formed. Complete fusion and the formation of the desired composition of the slag in a time like this can happen only when there is a very fine grinding and thorough mixing of the components of coating.
Fragmentation of the components coming in large chunks, is made in two stages: coarse and fine crushing, or grinding. Coarse grinding is different crushers. Subtle grinding or milling of components, often produced in ball mills. Ground components of the ball mill is usually screened on sieves with a number of holes per 1 cm2 1600-3600. From prepared, milled and sifted ingredients produced obmazochnoy paste electrodes. Currently, there are two basic ways to produce smeared electrodes: 1) the dipping or dipping, and 2) crimping.
Paste for dipping should be roughly kneading until creamy state. First mix the dry ingredients, then mix them in a binder solution, usually sodium silicate solution. In the method of dipping the electrode rods are immersed in a bath of liquid obmazochnoy paste and slowly pull out of it, the rods are covered with a uniform layer of coating. The method is preserved only for dipping coatings unsuitable for the application of crimping, for thin coatings and small electrode workshops that do not have obmazochnoy presses.
A more sophisticated and prevalent in the modern factories of the electrode coating application method is carried out on special crimping presses the electrode operating at high pressures, 400-800 am. Obmazochnoy molding paste has the consistency of damp earth and under pressure in the hand stick together into a ball. Obmazochnoy paste periodically. Loaded into a cylinder press. Electrode rods are pushed through the die cylinder in the range of 200 to 600 pc. per minute and leave covered with a dense layer of coating is quite uniform thickness. Upon emerging from the press one end of the electrode holder is trimmed to capture. The modern news electrode provides a capacity of approximately 2,000 tons of electrodes per year in one shift.
Electrodes made dipping are pre-drying at temperatures up to 40-50 ° C Pre-drying is necessary to eliminate the cracking of coating layer, which can be obtained at too high a forced drying. Electrodes because of the small pressure-tested moisture content in the paste does not require pre-drying and immediately subjected to final drying. The final drying or calcination of the electrodes is intended to remove all moisture as possible from the pasta and add a layer coating the maximum mechanical strength due to chemical reactions between the glass and liquid components of the coating.
The final drying can be carried out forcefully, at high temperatures. For electrodes that do not contain organic matter, temperature calcination can be brought to the 300-400g, C, for coatings with organic substances - not more than 150-180g, C to avoid decomposition of organic matter. At the end of drying, the electrodes are in control and packaging. From each batch, a sample of electrodes for welding trial. The electrodes should be stored in a dry heated room in order to avoid damage to the electrodes.
See also:
Classification of covered electrodes
The composition of electrode coatings
Appointment of individual coating components SSSI-13
Manufacturing Electrodes
Welding Electrodes
12:52 AM
Appointment of Individual Coating Components SSSI-13
Appointment of individual coating components SSSI-13
Appointment of individual coating components SSSI-13 can be explained as follows. The main part of marble CaCO3 decomposes when heated to calcium oxide CaO, which goes into the slag, and gas CO2 to CO is partially restored. Carbon dioxide, CO2 produces oxidizing action of hydrogen and associates caught in the welding zone in water vapor H2O. Gases, CO2 and CO are practically insoluble in the metal. CO2 fills the welding zone, forcing the air out of it and creating a protective atmosphere. The oxidative effect of CO2 on the metal is compensated by strong deoxidizing agents in the weld pool. Fluorspar CaF2 lowers the melting point and viscosity of slag. When heated CaF2 partially decomposes, releasing hydrogen fluoride reacts with very strong hydrogen fluoride, do not dissolve in the metal.
Covering non-hygroscopic, does not include components containing hydrogen, and in the manufacture of calcined at a temperature of 300-400 ° C. As a result, the hydrogen content in weld metal is reduced to a minimum by eliminating the source of the formation of pores and cracks, it is several times smaller than the ore- acidic surfaces. Quartz is introduced into the coating to liquefy the slag and reducing burnout of silicon metal. Ferromanganese and ferrosilicon as an alloying element is introduced. Ferrotitanium containing about 23% Ti is introduced as a strong reducing agent and modifier of weld metal during welding titanium burns almost completely, and in the weld metal is practically undetectable.
Weight given the quality of coatings is 30-40% by weight of the electrode rod. To compile obmazochnoy paste to dry mixture was added 30% aqueous solution of sodium silicate density of 1.40 or 12-13% based on dry matter.
There are special electrodes that provide improved performance for weld metal. For this purpose, the electrode coating is added to iron powder, produced in special plants. The amount of iron powder varies in different electrodes from 5 to 50% by weight of the electrode rod, and more; coating weight can be up to 100-180% of the weight of the rod. The deposition rate increases up to 12-20 g / h, and against the common values of 8-10 g / a, h, deposition rates can be increased by 1.5-2 times for the same current. The use of high-performance electrode with iron powder were low, and one of the reasons is that it is often the deciding factor is the rate of melting of the electrode is not, and the base metal.
See also:
Classification of covered electrodes
The composition of electrode coatings
Appointment of individual coating components SSSI-13
Manufacturing Electrodes
Welding Electrodes
Appointment of individual coating components SSSI-13 can be explained as follows. The main part of marble CaCO3 decomposes when heated to calcium oxide CaO, which goes into the slag, and gas CO2 to CO is partially restored. Carbon dioxide, CO2 produces oxidizing action of hydrogen and associates caught in the welding zone in water vapor H2O. Gases, CO2 and CO are practically insoluble in the metal. CO2 fills the welding zone, forcing the air out of it and creating a protective atmosphere. The oxidative effect of CO2 on the metal is compensated by strong deoxidizing agents in the weld pool. Fluorspar CaF2 lowers the melting point and viscosity of slag. When heated CaF2 partially decomposes, releasing hydrogen fluoride reacts with very strong hydrogen fluoride, do not dissolve in the metal.
Covering non-hygroscopic, does not include components containing hydrogen, and in the manufacture of calcined at a temperature of 300-400 ° C. As a result, the hydrogen content in weld metal is reduced to a minimum by eliminating the source of the formation of pores and cracks, it is several times smaller than the ore- acidic surfaces. Quartz is introduced into the coating to liquefy the slag and reducing burnout of silicon metal. Ferromanganese and ferrosilicon as an alloying element is introduced. Ferrotitanium containing about 23% Ti is introduced as a strong reducing agent and modifier of weld metal during welding titanium burns almost completely, and in the weld metal is practically undetectable.
Weight given the quality of coatings is 30-40% by weight of the electrode rod. To compile obmazochnoy paste to dry mixture was added 30% aqueous solution of sodium silicate density of 1.40 or 12-13% based on dry matter.
There are special electrodes that provide improved performance for weld metal. For this purpose, the electrode coating is added to iron powder, produced in special plants. The amount of iron powder varies in different electrodes from 5 to 50% by weight of the electrode rod, and more; coating weight can be up to 100-180% of the weight of the rod. The deposition rate increases up to 12-20 g / h, and against the common values of 8-10 g / a, h, deposition rates can be increased by 1.5-2 times for the same current. The use of high-performance electrode with iron powder were low, and one of the reasons is that it is often the deciding factor is the rate of melting of the electrode is not, and the base metal.
See also:
Classification of covered electrodes
The composition of electrode coatings
Appointment of individual coating components SSSI-13
Manufacturing Electrodes
Welding Electrodes
12:50 AM
The Composition of Electrode Coatings
The composition of electrode coatings
The composition of electrode coatings
Here are some compositions of electrode coatings.
Electrodes GMM 5 - rudnokislogo type, designed for welding low carbon steels. Electrodes such as E42 are permitted to make all sorts of important structures of the low-carbon steels, working with the application of static, dynamic and variable loads under normal, high and low temperatures. The rod electrode wire Sv-08 or CB-08A. The composition of coating OMM-5 is shown below (in percentage by weight).
Titanium (ilmenite) concentrate - 37%
Manganese ore (pyrolusite) - 21%
Feldspar - 13%
Ferromanganese - 20%
Starch - 9%
Titanium concentrate, ie, enriched ore consists mainly of the mineral ilmenite, which is a titanate of iron oxide FeO-TiO2. Manganese ore consists mainly of pyrolusite - peroxide of manganese. Feldspar - a natural mineral - aluminum silicate, sodium and potassium. Ferromanganese used for electrode coatings, on average, contains about 70% Mn. Titanium ore, manganese ore, feldspar, and liquid glass, fusing and interacting with the metal and ferro-manganese to form during welding slag. Titanium dioxide from titanium ore slag makes short.
The oxygen in the titanium oxide of iron ore and manganese ore, ferromanganese oxidizes with the release of considerable heat, heats and dilutes the slag makes boiling bath.
Alkali feldspar and silicate increase the stability of the arc. Manganese oxides in the slag reduces the loss of manganese bath. Ferromanganese deoxidized and alloyed weld metal to make up losses of manganese and raising some of its contents. Starch, decomposing to form a protective shell of gas around the arc. Here is the composition of the electrode coating CM-9-type rutile (by weight):
Rutile - 48
Magnesite - 5
Feldspar - 30
Ferromanganese - 15
Dextrin - 2
Rutile - a natural mineral consisting essentially of TiO2, magnesite - a mineral mainly of MgCO3; dextrin - a derivative of starch, is added in small quantities to enhance the plasticity obmazochnoy paste, making it easier to work obmazochnoy presses. Examples of fluorine-electrode-type calcium can serve as electrodes SSSI-13.
Mechanical properties of welded joints are characterized by high strength and toughness, such as UONI-13/45 UONI-13/55 and toughness of 25-30 kGm/sm2, which is an extremely high value and is far superior toughness values of base metal.
The electrodes are recommended for welding in the down position, but it is also possible to weld in vertical and overhead positions. Constant current, the polarity is reversed, ie, plus on the electrode. When working on an alternating current is necessary to use an oscillator. There are varieties of electrodes of SSSI-13, which added to the plaster stronger ionizers, which gives the opportunity to work on alternating current without the oscillator. The quality of welding electrodes SSSI-13 should recognize the outstanding and mechanical properties of the weld and the weld metal obtained is often higher than the base metal.
See also:
Classification of covered electrodes
The composition of electrode coatings
Appointment of individual coating components SSSI-13
Manufacturing Electrodes
Welding Electrodes
The composition of electrode coatings
Here are some compositions of electrode coatings.
Electrodes GMM 5 - rudnokislogo type, designed for welding low carbon steels. Electrodes such as E42 are permitted to make all sorts of important structures of the low-carbon steels, working with the application of static, dynamic and variable loads under normal, high and low temperatures. The rod electrode wire Sv-08 or CB-08A. The composition of coating OMM-5 is shown below (in percentage by weight).
Titanium (ilmenite) concentrate - 37%
Manganese ore (pyrolusite) - 21%
Feldspar - 13%
Ferromanganese - 20%
Starch - 9%
Titanium concentrate, ie, enriched ore consists mainly of the mineral ilmenite, which is a titanate of iron oxide FeO-TiO2. Manganese ore consists mainly of pyrolusite - peroxide of manganese. Feldspar - a natural mineral - aluminum silicate, sodium and potassium. Ferromanganese used for electrode coatings, on average, contains about 70% Mn. Titanium ore, manganese ore, feldspar, and liquid glass, fusing and interacting with the metal and ferro-manganese to form during welding slag. Titanium dioxide from titanium ore slag makes short.
The oxygen in the titanium oxide of iron ore and manganese ore, ferromanganese oxidizes with the release of considerable heat, heats and dilutes the slag makes boiling bath.
Alkali feldspar and silicate increase the stability of the arc. Manganese oxides in the slag reduces the loss of manganese bath. Ferromanganese deoxidized and alloyed weld metal to make up losses of manganese and raising some of its contents. Starch, decomposing to form a protective shell of gas around the arc. Here is the composition of the electrode coating CM-9-type rutile (by weight):
Rutile - 48
Magnesite - 5
Feldspar - 30
Ferromanganese - 15
Dextrin - 2
Rutile - a natural mineral consisting essentially of TiO2, magnesite - a mineral mainly of MgCO3; dextrin - a derivative of starch, is added in small quantities to enhance the plasticity obmazochnoy paste, making it easier to work obmazochnoy presses. Examples of fluorine-electrode-type calcium can serve as electrodes SSSI-13.
Mechanical properties of welded joints are characterized by high strength and toughness, such as UONI-13/45 UONI-13/55 and toughness of 25-30 kGm/sm2, which is an extremely high value and is far superior toughness values of base metal.
The electrodes are recommended for welding in the down position, but it is also possible to weld in vertical and overhead positions. Constant current, the polarity is reversed, ie, plus on the electrode. When working on an alternating current is necessary to use an oscillator. There are varieties of electrodes of SSSI-13, which added to the plaster stronger ionizers, which gives the opportunity to work on alternating current without the oscillator. The quality of welding electrodes SSSI-13 should recognize the outstanding and mechanical properties of the weld and the weld metal obtained is often higher than the base metal.
See also:
Classification of covered electrodes
The composition of electrode coatings
Appointment of individual coating components SSSI-13
Manufacturing Electrodes
Welding Electrodes
12:40 AM
Classification of Covered Electrodes
Classification of covered electrodes
Classification of covered electrodes
At the present time in our country for welding carbon and alloy structural steels are used according to GOST 9467-60 the electrodes, which is based on the mechanical properties of weld metal or weld performed by the electrode. In addition, limited sulfur and phosphorus content in the weld metal.
Type of electrode denoted by the letter E, followed by the letter denotes the number of lower value of tensile strength. Standard provides for the types of electrodes from E34 to E145; if, after the letter of A, then it means that the electrode provides higher values of the plastic properties of weld metal and welded joint.
The electrode type E34 gives the lowest strength and low ductility of the metal and apply the electrodes coated with a thin stabilizing is permitted only in the production of less critical welded structures, E42 and E46 are suitable for critical structures made of carbon steel, E50 and E55 - for of medium-and low-alloy steels, E60 , E70, E85, E100, E125 and E145 - to high-strength alloy steels, and for the types of E85-E145 weld after weld heat treatment takes place. E34-E70 types are wire rod from St-08, E85-E145 - stainless wire.
However, the electrode of the same type, such as E42, is available with different coatings, giving the electrode significant technological features that are not marked for a visit. Consequently, there remains another brand of electrodes, installed by the manufacturer of electrodes and electrode introduced into the passport. Legend marks completely arbitrary, and the brand may vary, for example, a number of the coating with the same composition.
Based on the chemical composition of the classification of high-quality coating of electrode surfaces:
1. Rudnokislye coatings containing oxides of iron and manganese (usually in the form of ores), silica, a large number of ferro-manganese, to create a gas protection welding zone is introduced into the coating of organic material (cellulose, wood flour, starch, etc.) which are decomposed by heat and burn with a mixture of protective gases. The electrodes have a fairly high speed of melting, the deposition rate 8 - 11 g / h, and are suitable for welding in all positions on the direct and alternating current, weld metal for the type of electrodes E42 and contains less than 0.12S, less than 0,10 Si; 0 ,6-0, 9 Mn, P less than 0.05 and less than 0.05 S.
With the melting of the electrode is an intensive exothermic reaction with oxygen and carbon manganese oxides, heated molten pool and provides a smooth surface of the weld metal with a little scaly. With high content of manganese ore produced smoke is bad for the welder and the lack of ventilation may gradually poison its compounds of manganese. The electrodes are widely used in the manufacture of various products from low-carbon and low alloy steels, but at a number of the Soviet Union, the use of these electrodes is limited or prohibited because of their toxicity.
2. Rutile coatings are significant of the mineral rutile, consisting mainly of titanium dioxide, TiO2. In the cover, in addition to rutile, introduced silica, ferro-manganese, calcium or magnesium carbonates. Coatings on technological qualities are close to rudnokislym provide a better formation, less spatter and release gases, are considered less harmful to the welder. The weld metal meets the electrodes E42 and E46 type, the electrodes can be used for more important structures of low-carbon and low alloy steels.
3. Fluorine-calcium coatings are composed of calcium carbonate and magnesium, fluorspar and ferro-alloys. Coatings are also called primary, as they give short slag main character, and electrodes coated with such a well known nizkovodorodistymi as weld metal contains less hydrogen than other coatings.
Gas protection is provided by Bath dioxide and carbon monoxide formed during the decomposition of carbonates under the influence of heat. The electrodes are usually used with direct current reverse polarity (plus on the electrode).
The weld metal composition corresponds to a quiet steel, very clean, low oxygen, nitrogen and hydrogen, reduced sulfur, and phosphorus, increased - manganese (0.5-1.5%) and silicon (0.3-0.6%) . Metal is resistant to aging, has high mechanical properties, including toughness, and often superior to the mechanical properties of the base metal. Electrodes with this coating is recommended for the most important structures of carbon and alloy steels.
Electrodes with fluorine-coated calcium for many years are the best quality of weld metal. Sensitive to the presence of scale, rust, oil on the edges of the base metal and in these cases give the pores, as in the dampness of the electrodes. The properties of weld metal can be varied within wide limits by varying the amount of ferro-alloys in the coating. Widely known for this type of electrode, marked SSSI-13, and he has several varieties; UONI-13/45, UONI-13/55, etc., the second number indicates the strength of weld metal.
4. Organic coatings are composed of organic material, usually of the oxycellulose, which added slag-forming materials, titanium dioxide, silicates, etc., and ferromanganese as a deoxidizer and alloying agent. Electrodes are suitable for welding in all positions on the direct and alternating current, insensitive to the quality of assembly and of the metal surface, especially suitable for use in mounting and field conditions. Give a satisfactory weld metal corresponding to the electrodes E42-E50 types. Widely used in the U.S. assembly operations.
See also:
Classification of covered electrodes
The composition of electrode coatings
Appointment of individual coating components SSSI-13
Manufacturing Electrodes
Welding Electrodes
Classification of covered electrodes
At the present time in our country for welding carbon and alloy structural steels are used according to GOST 9467-60 the electrodes, which is based on the mechanical properties of weld metal or weld performed by the electrode. In addition, limited sulfur and phosphorus content in the weld metal.
Type of electrode denoted by the letter E, followed by the letter denotes the number of lower value of tensile strength. Standard provides for the types of electrodes from E34 to E145; if, after the letter of A, then it means that the electrode provides higher values of the plastic properties of weld metal and welded joint.
The electrode type E34 gives the lowest strength and low ductility of the metal and apply the electrodes coated with a thin stabilizing is permitted only in the production of less critical welded structures, E42 and E46 are suitable for critical structures made of carbon steel, E50 and E55 - for of medium-and low-alloy steels, E60 , E70, E85, E100, E125 and E145 - to high-strength alloy steels, and for the types of E85-E145 weld after weld heat treatment takes place. E34-E70 types are wire rod from St-08, E85-E145 - stainless wire.
However, the electrode of the same type, such as E42, is available with different coatings, giving the electrode significant technological features that are not marked for a visit. Consequently, there remains another brand of electrodes, installed by the manufacturer of electrodes and electrode introduced into the passport. Legend marks completely arbitrary, and the brand may vary, for example, a number of the coating with the same composition.
Based on the chemical composition of the classification of high-quality coating of electrode surfaces:
1. Rudnokislye coatings containing oxides of iron and manganese (usually in the form of ores), silica, a large number of ferro-manganese, to create a gas protection welding zone is introduced into the coating of organic material (cellulose, wood flour, starch, etc.) which are decomposed by heat and burn with a mixture of protective gases. The electrodes have a fairly high speed of melting, the deposition rate 8 - 11 g / h, and are suitable for welding in all positions on the direct and alternating current, weld metal for the type of electrodes E42 and contains less than 0.12S, less than 0,10 Si; 0 ,6-0, 9 Mn, P less than 0.05 and less than 0.05 S.
With the melting of the electrode is an intensive exothermic reaction with oxygen and carbon manganese oxides, heated molten pool and provides a smooth surface of the weld metal with a little scaly. With high content of manganese ore produced smoke is bad for the welder and the lack of ventilation may gradually poison its compounds of manganese. The electrodes are widely used in the manufacture of various products from low-carbon and low alloy steels, but at a number of the Soviet Union, the use of these electrodes is limited or prohibited because of their toxicity.
2. Rutile coatings are significant of the mineral rutile, consisting mainly of titanium dioxide, TiO2. In the cover, in addition to rutile, introduced silica, ferro-manganese, calcium or magnesium carbonates. Coatings on technological qualities are close to rudnokislym provide a better formation, less spatter and release gases, are considered less harmful to the welder. The weld metal meets the electrodes E42 and E46 type, the electrodes can be used for more important structures of low-carbon and low alloy steels.
3. Fluorine-calcium coatings are composed of calcium carbonate and magnesium, fluorspar and ferro-alloys. Coatings are also called primary, as they give short slag main character, and electrodes coated with such a well known nizkovodorodistymi as weld metal contains less hydrogen than other coatings.
Gas protection is provided by Bath dioxide and carbon monoxide formed during the decomposition of carbonates under the influence of heat. The electrodes are usually used with direct current reverse polarity (plus on the electrode).
The weld metal composition corresponds to a quiet steel, very clean, low oxygen, nitrogen and hydrogen, reduced sulfur, and phosphorus, increased - manganese (0.5-1.5%) and silicon (0.3-0.6%) . Metal is resistant to aging, has high mechanical properties, including toughness, and often superior to the mechanical properties of the base metal. Electrodes with this coating is recommended for the most important structures of carbon and alloy steels.
Electrodes with fluorine-coated calcium for many years are the best quality of weld metal. Sensitive to the presence of scale, rust, oil on the edges of the base metal and in these cases give the pores, as in the dampness of the electrodes. The properties of weld metal can be varied within wide limits by varying the amount of ferro-alloys in the coating. Widely known for this type of electrode, marked SSSI-13, and he has several varieties; UONI-13/45, UONI-13/55, etc., the second number indicates the strength of weld metal.
4. Organic coatings are composed of organic material, usually of the oxycellulose, which added slag-forming materials, titanium dioxide, silicates, etc., and ferromanganese as a deoxidizer and alloying agent. Electrodes are suitable for welding in all positions on the direct and alternating current, insensitive to the quality of assembly and of the metal surface, especially suitable for use in mounting and field conditions. Give a satisfactory weld metal corresponding to the electrodes E42-E50 types. Widely used in the U.S. assembly operations.
See also:
Classification of covered electrodes
The composition of electrode coatings
Appointment of individual coating components SSSI-13
Manufacturing Electrodes
Welding Electrodes