- provides protection for the gas and slag weld pool;
- provides arc stability and transfer of electrode metal into the weld pool;
- provides the desired properties of the welded joint;
- displays harmful impurities into a slag crust.
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| Welding flux ESAB OK Flux 10.71 |
According to the method of production welding fluxes are divided into processed and ceramic (neplavlenye). Rudomineralnye components fused fluxes are melted in a furnace, and then pelletized, and subjected to calcination fractionation. ceramic fluxes are a mixture of dry ingredients, resulting from the mixing of minerals and alloys with liquid glass with further drying, calcination, and fractionation. The most common are fused fluxes.
Depending on the chemical composition of oxide fluxes are, soleoksidnye and salt.
Oxide fluxes are composed of metal oxides and can contain up to 10% of fluoride compounds. They are designed for welding of low alloy steels, and fluoride. Oskidnye fluxes on the content of SiO 2 are divided into beskremnistye (content of SiO 2 is less than 5%), nizkokremnistye (6-35% SiO 2 ), high-silicon (SiO content of 2 greater than 35%), and the manganese content - on bezmargantsevye (manganese content is less than 1 %), nizkomargantsevye (less than 10% manganese), srednemargantsevye (10-30% Mn) and vysokomargantsevye (more than 30% manganese).
Soleoksidnye (mixed) fluxes in comparison with oxide contain fewer oxides, salts and more. The number of SiO 2 in them is reduced to 15-30%, MnO up to 1-9% and the content of CaF 2 increased to 12-30%. Soleoksidnye fluxes used for welding alloy steels.
Salt fluxes do not contain oxides and consist of fluorides and chlorides of CaF 2 , NaF, BaCl 2 , etc. They are used for welding of reactive metals, as well as for the ESR.
Fluxes may be designed for welding high-alloy steels, carbon and alloy steels, nonferrous metals and alloys, etc.
According to the structure of grains (particles) welding flux may be glassy, pumiceous or cemented.
Reactivity of flux - one of its important characteristics, determined by the total oxidative capacity. Flux is a measure of the activity of the relative magnitude of A f with a value from 0 to 1. Depending on the chemical activity fluxes are classified into four types:
- highly active (A p > 0.6);
- active (A p from 0.3 to 0.6);
- low-activity (A p from 0.1 to 0.3);
- Passive (A p <0.1).
For welding low carbon steels using oxide fluxes. Here are two possible combinations of systems "-flux welding wire":
- High-silicon vysokomargantsevy flux in combination with low-carbon non-alloy wire (Sv08, CB08A, etc.)
- Or high-silicon nizkomargantsevy bezmargantsevy flux in combination with low-carbon wire, alloyed with manganese, for example, Sv10G2.
The most common domestic fluxes for welding low-carbon steels are as follows:
- high-silicon vysokomargantsevye - Vitreous AN-348, ASC-1, OSC-45, FC-3, FC-6, FC-9 and pumiceous AN-60, reactivity A p - 0.75 to 0.9-0.95 ;
- high-silicon glassy srednemargantsevye AH-1, AN-65, FC-7 reactivity A p - 0.75 to 0.9;
- high-silicon flux nizkomargantsevy MCA-4 (glassy), reactivity A f = 0.6;
When welding low-alloy steels are used fluxes with lower chemical activity (A p from 0.3 to 0.6) than when welding mild steels. They contain fewer oxides SiO 2 and MnO and more CaF 2 and CaO. Due to the lower activity of the welding flux decreases the oxidation of alloying elements in steel and improves ductility of the joint, but it deteriorates the formation of multiple joints, increases the probability of pore formation.
The most common domestic fluxes for welding low-alloy steels:
- nizkokremnistye nizkomargantsevye - FC-11, FC-15, FC-16, FC-22, MCA-1, AN-43;
- nizkokremnistye medium-manganese - AN-42, AN-47.
When welding of medium-and high-alloy steels are commonly used low-activity fluxes (A p from 0.1 to 0.3). They contain an even smaller amount of SiO 2 , almost no MnO, the content of CaO - 20%, CaF 2 - from 10-20 to 60% (for more content alloy steels CaF 2 in the flux increases).
Well-known domestic fluxes for welding medium-and high-alloy steel:
- low-activity - AN-15, AN-17, AN-18, AN-20, AN-45, AB-5, FC-17, FC-19, SF-18 PF-6;
- Active welding flux AN-26 (A f is about 0.5).
For welding of reactive metals such as titanium, used all the salt fluxes. They are not added oxides, as it leads to contamination of oxygen seams and a dramatic decrease in their plasticity. Fluxes produced by fluorides and chlorides of alkali and alkaline earth metals, for example, with the composition: 85-95% CaF 2 , 0-19% BaCl, 1-6% NaCl, 0-4% CaCl.
TABLE. The chemical composition of some of the fluxes used in arc welding
| Flux | Chemical composition,% | ||||||||
| silicon- earth SiO 2 | clay- earth Al 2 O3 | MnO | CaO | MgO | CaF2 | Fe2O3 ** | S | P | |
| АN-348-А* | 40–44 | ≤ 6 | 31–38 | ≤ 12 | ≤ 7 | 3–6 | 0,5–2,0 | ≤ 0,12 | ≤ 0,12 |
| OSC-45 * | 37–44 | ≤ 6 | 37–44 | ≤ 10 | ≤ 3 | 5–9 | 0,5–2,0 | ≤ 0,12 | ≤ 0,14 |
| АN-18 * | 17–21 | 14–18 | 2,5–5,0 | 14–18 | 7–10 | 19–23 | 13,5–16,5 | ≤ 0,05 | ≤ 0,05 |
| АN-42 * | 30–34 | 13–18 | 14–19 | 12–18 | – | 14–20 | ≤ 1,0 | ≤ 0,06 | ≤ 0,10 |
| АN-43 * | 18–22 | 30–36 | 5–9 | 14–18 | ≤ 2 | 17–21 | 2,0–5,0 | ≤ 0,05 | ≤ 0,05 |
| АN-47 * | 28–33 | 9–13 | 11–18 | 13–17 | 6–10 | 8–13 | 0,5–3,0 | ≤ 0,05 | ≤ 0,08 |
| АN-60 * | 42–46 | ≤ 6 | 36–41 | ≤ 10 | ≤ 3 | 5–9 | ≤ 0,9 | ≤ 0,05 | ≤ 0,05 |
| АN-65 * | 38–42 | ≤ 5 | 22–28 | ≤ 8 | 7–11 | 8–12 | ≤ 1,5 | ≤ 0,05 | ≤ 0,05 |
| FC-7 | 46–48 | ≤ 3 | 24–26 | ≤ 3 | 16–18 | 5–6 | ≤ 2 | ≤ 0,10 | ≤ 0,10 |
| FC-9 * | 38–41 | 10–13 | 38–41 | ≤ 8 | ≤ 3 | 2–3 | ≤ 1,5 | ≤ 0,10 | ≤ 0,10 |
| FC-17 | 24–28 | 18–22 | – | ≤ 6,0 | 23–27 | 11–18 | ≤ 1,0 | ≤ 0,03 | ≤ 0,025 |
| FC-19 | 20–25 | 18–23 | – | ≤ 6,0 | 20–25 | 16–21 | 1,0–3,0 | ≤ 0,03 | ≤ 0,03 |
| FC-22 | 33–37 | 16–21 | 6–9 | 5–9 | 18–22 | 8–12 | ≤ 1,0 | ≤ 0,04 | ≤ 0,03 |
| MCA-1 | 31–35 | 17–22 | 8–11 | 2–6 | 19–24 | 8–12 | ≤ 1,0 | ≤ 0,05 | ≤ 0,05 |
| 48-PF-6 | 3,5–6,0 | 20–24 | ≤ 0,3 | 16–20 | ≤ 2,0 | 50–60 | ≤ 1,0 | ≤ 0,025 | ≤ 0,025 |
| * - according to GOST 9087-81 "fused welding fluxes. Specifications | |||||||||
| ** - for the values according to GOST 9087-81 the content of iron oxides is given in terms of Fe 2 O 3 | |||||||||
| *** - for the flux AN-47 content of TiO 2 and ZrO 2 by weight of 4,0-7,0%, respectively, and 1,1-2,5% | |||||||||
| **** - for flux AN-65 content of TiO 2 and ZrO 2 by weight of 4,0-7,0%, respectively, and 4,0-7,0% | |||||||||
| ***** - fluxes for FC-17 and FC-19 content of K 2 O and Na 2 O 5-10%, the content of Cr 2 O3 - 0.5-2.0% | |||||||||
| ****** - for flux MCA-1 content of K 2 O and Na 2 O is less than 2.5% | |||||||||
| Flux | A typical field of application in arc welding |
| AN-348-A RCF-45 FC-9 | carbon low-alloy steel |
| AN-18 | medium-and high-alloy steels |
| АN-42 АN-43 АN-47 | carbon low-alloy steel and medium-high and high strength |
| АN-60 | carbon low-alloy steel, welded pipes |
| АN-65 | carbon low-alloy steel, welding at high speeds |
| FC-7 | low-carbon steel, welding at high currents |
| FC-17 | high-alloy austenitic steel |
| FC-19 | high-chromium steels |
| FC-22 | corner seams welded carbon and alloy steels |
| MCA-1 | welding of carbon and alloy steels with a high speed (up to 150 m / h) |
| 48-PF-6 | welding high-alloy wire |
The main stages of the production technology:
- Preparation of the charge
- Melting of flux
- Granulation
- Processing
- Quality control of the flux produced
- Packaging
Melting of the flux is in electric or gas-flame furnaces. Welding flux after the smelting furnace in the flame is always wet granulated and it turns glassy, and the flux melted in an electric furnace can be dry granulated pumice and be.
Granulation of flux can be carried out wet and dry. In wet granulation results in the melt pool filled with water and contact with cold water, divided into smaller particles. In the dry granulation method of the melt is poured into a metal pan or mold with the subsequent fragmentation of the ingot.
When processing the flux carried his dry, crushing and screening. At the end of screening of small and large fractions that do not meet specifications, return to the remelting.
For quality control of flux checked the grain size, specific gravity, chemical composition, moisture content and other characteristics.
Packing of flux can be carried out in plastic bags, five-layer paper bags, metal drums or boxes.
See also:
automatic arc welding
Welding materials:
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