Technical characteristics and decoding of the OK-46 electrode brand

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When we talk about home welding, it usually means that electrodes are used. We often hear that wire, semi-automatic welding machines or gas are used only by specialists in their field.

And novice welders use only electrodes in their work. However, this is a persistent stereotype. In fact, there are many types of electrical conductors, including those with rods for specialized applications.

E50A represents one of them. This type of electrode is used when welding structures of particular importance. Electrodes of this type include several models.

After reading this article, you will understand what the abbreviation E50A means, what functional properties these electrodes have, and what you need to consider when planning work using these rods.

• General information
• Abbreviation meaning
• Brands of electrical conductors
• Analogs
• Peculiarities
• Results

Characteristics

Domestic rod analogues of OK-46 SEOK-46, E46 are certified by the National Academy of Compliance Control (NAKS) . Used for welding carbon steels, including those with galvanic coating with a layer of zinc.

The main technical parameters are identical:

• Welding without spatial restrictions.
• Use of direct and alternating current (AC/DC) sources.
• Arc burning is stable.
• Spattering is moderate.
• The seam is not prone to fatigue deformation.
• Initial ignition, repeat after arc interruption without difficulty.
• Convenient for working with thin-walled structures, making short seams and tacks.
• Tolerant of insufficient metal cleaning and slight rust deposits.
• Available in Ø 1.6–5 mm.
• Size range 300–450 mm.
• Suitable for welding wide gaps.
• The no-load current of 50 A allows the use of household sources with voltage fluctuations.
• The inclination of the electrode is allowed within 350.
• Porosity only appears when the welder makes mistakes in selecting the current or ignoring drying.
• The vulnerability of rutile coating to dampness requires calcination at 1000 C.
• Easy slag removal.
• The rod is made of low-carbon steel SV-08, which has become a limitation in welding alloy steels.

An analogue of the OK-46 electrode for an equivalent replacement is OZS 12 . The quality of the connecting seam is lower for OZS 6. Group ANO 4 (6; 29M; 23), MR-3 for critical connections of pipelines and loaded structures have a number of limitations.

Rutile coating is technologically advanced. Coagulation of titanates in the upper layer of the weld pool accelerates the increase in slag viscosity. Magnesium and calcium bicarbonates and aluminosilicates bind silicon and oxygen, causing hot cracking and a decrease in impact strength.

Technical characteristics and welding features of different brands of the same type of electrode do not coincide.

Table for selecting operating current for electrodes E46 GOST 9467 75

General information

E50A are electrical conductors for welding metal structures of special reliability, which are made of tool steel, which contains a low concentration of impurities.

The resulting seams are used in work at low and high temperatures. These seams have high ductility, which is well felt during mechanical shocks.

This type of electrode is typically used in the shipbuilding and nuclear industries.

Electrodes OZS-12 and OK-46, what is the difference?

OZS 12 forms a connection of high quality parts at low currents. With rods Ø 2–3 mm, reliable welding is carried out with the transformer connected to a 220 V household network. Many indicators of OZS 12 and E46 are the same:

• There are no restrictions on the spatial position of the seam.
• The use of direct and alternating current (AC/DC) sources is allowed.
• Polarity limitation, straight only.
• Low demands on the cleanliness of cutting.
• Resistance of the deposited metal to fatigue deformation, which contributes to the durability of the connections.
• The coating helps protect the seam, the slag crust is uneven, and individual fragments are difficult to remove.
• The suture surface tends to be concave.
• Long-term transfer of static loads.
• Uniformity and stability of maintaining arc combustion.
• Recommended for pipe and T-joints.
• No tendency to crack.
• Re-ignition without sticking.

OZS 12, in comparison with welding electrodes OK-46, requires calcination with a temperature increase of 50% . The quality of the seam increases when welding with a long arc. Up to 60% of the electrode weight goes to waste and slag formation.

The coating has an atypical increased moisture absorption in the rutile family. Large inclusions tend to get baked in, and manual cleaning of the seam is labor-intensive.

Where to buy a welding electrode type E50 A.

From us you can purchase welding rods in packages of 1, 2.5 or 5 kilograms. We guarantee that products comply with the necessary regulations regarding production, storage and transportation. When ordering electrodes from us, you can be sure of the highest quality of the ordered products. We attach regulatory documentation and quality certificates to each order.

By calling the number indicated in the site contacts, you can leave a request, the processing speed of which will pleasantly surprise you.

E46A, technical specifications

E46A provide a weld with increased ductility and toughness due to a decrease in the proportion of sulfur and phosphorus in the rod (S and P in the range of 0.04–0.045%). Designed to operate under variable loads, including dynamic and low temperatures. Low-alloy steels with a carbon content of up to 2%, such as 15HSND, 14G2, are welded. Heat loads above 2000 are not desirable.

Analogs similar in weld quality: OMNIA-46, OK 48.00, OK Femax 38.95, Pipeweld 6010. Type E46A includes the following brands:

• With cellulose-rutile coating – SE-46-00, SZSM 46.00;
• With the main coating of the rod and the creation of an alkaline environment in the weld pool (neutralization of hydrogen against cracking) - ANO-8, UONI-13/45A, UONI-13/55K;
• With the inclusion of iron powder VN48U and ITS-1.

The decoding of the alphanumeric indication informs about the basic technical data in accordance with GOST 9467-75:

• E – electrode with external coating for manual electric arc welding;
• 46 – value of temporary tensile strength in kg per mm2;
• A – ductility and impact strength are designed for variable loads.

Welding process requirements include holding a short arc as a measure to eliminate porosity and lack of fusion . Calcination of electrodes for an hour at 3000 C before use.

Preference is given to direct current of reverse polarity. The requirements for surface cleanliness, especially regarding scale and rust, are high. Increasing the concentration of iron powder in the coating reduces the carbon content of the surfacing and the tendency to cracking.

Abbreviation meaning

Each abbreviation carries encrypted information, and E50A has its own meaning for each letter and number. "E" means that this type of electrical conductor is designed for manual arc welding with coated electrodes.

And the numbers “5” and “0” indicate the ultimate strength relative to ruptures. Thus, it is possible to calculate the loads that the connections can withstand, which is very important when working with load-bearing structures (trusses, etc.).

“A” means that the resulting seam will be plastic and viscous.

E50A

The scope of application has been expanded in comparison with OK-46A . In addition to pipeline and sea transport, products and structures with significant dynamic loads at low temperatures are included, including nuclear industry facilities.

Type E50A includes a number of interchangeable brands of Russian manufacturers based on Sv-08A welding wire: OZS-18, OZS-25, E-138/50N, ANO-TM, DSK-50U, TMU-21U, TMU-50, MTG-02, MTG-01K, TsU-5, TsU-5M. The coating is predominantly alkaline-basic.

The chemical composition of the overlay weld is identical. But the scope of application is different. Given the harsh operating conditions, universalization is impractical. The size of the coating layer and the variability of chemical components influence the process technology and are related to the purpose of the brand.

Foreign and domestic analogues suitable for replacing E50 electrodes, electrode brand: SE-08-00 (RF), OK 48.04 (Sweden), OK 53.70 (ESAB), Fox EV 50 (Germany), Phoenix K50 R (Germany), Garant (Germany) ), LB-52U (Japan).

The German brand Fox EV 50 compares favorably with its indifference to humidity due to water-repellent additives. TMU-21U is used primarily by oil and gas producers on Arctic pipelines.

Electrodes: marking and application

The brands of electrodes and their purposes are given in Tables 1-7.

Electrodes used in welding steels must provide high mechanical properties of the welded joint and high productivity of the welding process.

Electrode wire.

Electrode wire is made with a diameter of 1-12 mm. The length of electrodes cut from wire with a diameter of up to 3 mm is usually 350 mm, and with a diameter over 3 mm - 450 mm. In practice, electrodes with a diameter of 2–7 mm are predominantly used. Electrodes with a diameter of 2 mm are used to weld metal up to 2 mm thick, and with a diameter of 3 mm - metal with a thickness of 2 mm and above. For welding metal with a thickness of 5–10 mm, electrodes with a diameter of 4–5 mm are used, and for thicknesses over 10 mm, electrodes with a diameter of 5–7 mm are used. The chemical composition of the metal of steel electrode wire is established by GOST and has 19 grades. For welding low-carbon steel and many types of structural steels, three grades of wire are most widely used in production: Sv-I, Sv-IA and Sv-II.

These wire grades differ in the content of carbon, silicon and phosphorus. The best Sv-IA wire contains up to 0.10% C; 0.35—0.6% Mn; 0.15-0.25% Si; 0.03—0.04% S; up to 0.03% R. Mark Sv-II contains carbon up to 0.18%.

For manual arc welding, the electrode wire is coated with special coatings to protect the molten metal bath from absorbing oxygen and nitrogen from the air. The oxygen content in the weld metal above 0.2% and nitrogen above 0.15% sharply reduces the plastic properties of the weld metal: relative elongation, bend angle, impact strength. The absorption of nitrogen and oxygen by the molten metal during the welding process occurs both during the transition of metal drops from the electrode to the bath and in the bath itself and continues until the metal solidifies. Oxygen, which has great chemical activity, enters into compounds with iron: FeO, Fe3O4 and Fe2O3.

The lower oxide - oxide FeO - is formed earlier than others on the surface of a drop of molten metal and immediately dissolves in it. Higher oxides of iron at the moment of transferring a drop of metal into the bath are deoxidized by carbon, manganese, and silicon contained in the electrode wire. Burnout of these impurities reduces their content in the weld metal. On the surface of the weld pool, oxidation reactions continue and, despite the deoxidation processes occurring inside the pool, the metal is saturated with oxygen in the form of a solid solution of FeO in iron or oxide inclusions.

Saturation of the molten metal with air nitrogen can occur either through the formation of manganese nitrides MnN and silicon SiN or oxide NO at high temperatures. At a metal temperature of about 1000°C, this oxide precipitates from the solid solution and dissociates into atomic nitrogen and oxygen. Atomic nitrogen forms nitrides Fe4N and Fe2N with iron in the temperature range 500-800°C. To reduce the nitrogen and oxygen content in the weld metal, a number of measures are used: the content of deoxidizing agents (Mn, Si) in the electrode metal is increased, and a special electrode coating containing deoxidizing agents is applied. A good protection of the molten metal from oxygen and nitrogen in the air during manual arc welding is the use of coated electrodes, which, when melted, produce slags that protect the metal both during its transition from the electrode to the bath and in the bath itself. Depending on the thickness of the coating, electrodes are divided into thin-coated, with a coating layer thickness of 0.1-0.3 mm, and thick-coated, with a coating layer thickness of up to 2 mm. The weight of a thin coating is about 1%, and a thick one is about 20-35% of the weight of the electrode. Thin coatings are designed to increase arc stability and are therefore often called ionizing coatings. The most common ionizing coating is chalk, consisting by weight of 80-85% finely sifted chalk CaCO3 and 15-20% liquid soluble glass NaOSiO2.

Welds made by these electrodes, due to the lack of protection of the molten metal, have low tensile strength and low ductility. To obtain welds with high strength and ductility, thickly coated electrodes are used. The composition of the thick coating includes gas-forming, slag-forming and alloying substances and deoxidizers.

The gas-forming substances in coatings, such as wood flour, starch, food flour, cellulose, etc., are intended to create a protective gaseous environment (around the arc and the liquid metal pool) during the melting process of the electrode, consisting mainly of hydrogen and carbon monoxide. As a result of this protection, it is possible to eliminate the harmful effects of air on the liquid metal. Slag-forming substances included in thick coatings, such as feldspar, manganese ore, titanium ore, chalk, kaolin, etc., form slags when melting the electrode, protecting the molten metal from exposure to air and improving the conditions for the formation of weld metal.

Ferroalloys in the form of ferromanganese, ferrotitanium, ferrosilicon, etc. are introduced into coatings to deoxidize the weld metal and slag, convert ferrous oxide in the metal into other compounds, as well as to alloy the weld metal by increasing the content of certain elements in it, such as Mn, Si, Ti and etc.

For welding steels with a low content of alloying impurities, electrodes with rods made of low-carbon steel are used, but with the introduction of alloying elements in the form of ferroalloys (ferromanganese, ferrosilicon, ferrovanadium, ferrotitanium, etc.) into the coating along with the corresponding gas and slag-forming components.

Alloying elements from the coating, partially burning out, pass into the deposited weld metal and make it possible to obtain mechanical properties of the weld close to the properties of the metal being welded.
When welding high-alloy steels (stainless and heat-resistant), electrodes are used whose rods are identical in chemical composition to the metal being welded. To compensate for burnout during welding of the alloying elements contained in the wire, the corresponding components in the form of ferroalloys are introduced into the coating composition for these electrodes, in addition to gas and slag protective substances. In all coatings, liquid glass is used as a binder. In some cases, dextrin and organic glue are used.

Features and Limitations

The breaking load of the seam is determined to be 500 MPa with an additional margin of safety . At the same time, technological features introduce restrictions into the practice of application: for domestic brands of this type, only OZS-28 is available in a circular seam with a vertical descent from top to bottom. For others this is unacceptable.

UONI-13/55T, OZS-28, OZS-33 operate on welding machines with direct and alternating currents. Large group: UONI-13/55, UONI-13/55G, OZS-18, OZS-25, OZS-29, TMU-21U - are adapted exclusively for the use of direct current of reverse polarity.

The protective functions of alkaline coatings are based on the reaction of carbonates CaCO3, MgCO3 releasing carbon monoxide CO, which, as a reducing agent, absorbs oxygen, turning into carbon dioxide. Carbon dioxide gas protection is retained until the solidifying slag sets.

For electrodes of the E50A type, a short arc is generally recommended . An hour-long drying of the coating is considered mandatory. Use is limited to 3–4 days. Wet electrodes burn unstably. Triple calcination is the limit. Heat treatment destroys the coating.

The criterion for selecting externally coated arc electrodes for welding structural alloys should take into account network capabilities and personal skill. OZS-12 are considered easy to ignite and operate, while UONI 13/55 requires an experienced hand, especially during intermittent actions.

Quality certification

Electrodes intended for industrial use or for connecting critical structures are subject to mandatory certification.

Electrodes are subject to mandatory certification.

An official document on the territory of the Russian Federation is issued by the National Welding Control Agency (NAKS) to tool manufacturers and has a limited validity period (3 years).

Each certificate form has an individual number entered into the database and is certified by the signature of the NAKS President and seal.

The document states:

• type of certification (primary or periodic);
• brand and diameter of electrodes;
• testing methods and additional information.

When issuing a certificate, the controlling body receives a test batch of electrodes and carries out welding work followed by destructive testing of the seam. The results obtained confirm the product’s compliance with the standards; if the parameters deviate, a certificate is not issued. The presence of a certificate allows the use of electrodes for welding critical structures, but in the event of damage to the seam due to insufficient strength of the weld metal, the manufacturer bears financial and criminal liability in accordance with the legislation of the Russian Federation.

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