Nanostructured flux cord wire for underwater welding

FIELD: metallurgy.

SUBSTANCE: flux cord wire consists of a steel shell and mix material inside. On its surface the composition coating formed by copper array with distributed in it nano-size particles of activating flux containing fluoride of alkali metal is made. The mix material contains the following components in the ratio, wt %: rutile concentrate 24-38.5; silicon dioxide 1.5-6.6; hematite 2.8-16.5; iron powder 32-45; ferromanganese 5-12; nickel 1-3; carbonate of alkali metal 3-7; complex fluoride of alkali metal 2-8.

EFFECT: flux cord wire has good welding processing properties, provides atomized transfer, the stability of arch burning and allows to improve the quality of welding joints due to active metallurgical reactions on bonding of steam and hydrogen.

3 cl, 1 dwg, 1 tbl

 

The invention relates to mechanical engineering and can be used for mechanized and automatic underwater welding and welding of metal parts.

Known composite electrode wire for arc welding and surfacing (see Parshin S. G., Parshin S. C. Composite electrode wire. RF patent №2355543 from 09.07.2007,, publ. 20.05.2009,). Composite wire consists of a metal tube placed in the cavity with a mixture of slag-forming and gas-forming components. On the surface of the metal tube is coated with a composite coating consisting of a metal matrix and distributed it dispersed phase of the activating flux.

This wire provides atomized transition of the metal electrode and allows you to increase the depth of penetration of the metal. However, the wire on the prototype is designed for welding in shielding gas and can not be used for mechanized method of wet underwater welding.

Known nanostructured composite wire for welding or surfacing (see Parshin S. G., Parshin S. C. Nanostructured composite wire. RF patent №2415742 from 30.06.2009, publ. 10.04.20011,, bull.1) containing a metal rod with a composite coating of a metal matrix and uniformly distributed over its volume of nano-sized, the output tubes with activating flux. Specified nanostructured wire has good welding properties and makes it possible to improve the characteristics of drip transition, to reduce the diameter of the droplets, the duration of the short circuit, to increase the frequency of droplet transfer and the depth of penetration of the metal.

However, nanostructured wire is designed for welding in shielding gas, no slag-forming components and cannot be used for mechanized underwater welding in the wet.

Known flux cored wire for underwater welding in the repair of hulls, repair of pipelines and other hydraulic structures (see Grishanov A. A., Pankov Century. And. flux Cored wire for welding steels. RF patent №2012471, B23K 35/368 from 20.02.1992,, publ. 15.05.1994 g), which was adopted for the prototype. This wire contains a steel shell and powder charge at the following content, wt.%: rutile concentrate 28-35; hematite 16-25; iron powder 30-40; Dubrovskiy potassium of 0.5-2; manganese 5-7; silicocalcium 1-2; Nickel 3,5-5.

The invention improves the quality of welded joints by improving its mechanical properties. However, the composition of the charge on the prototype contains an increased number of scavengers manganese and silicocalcium. When welding these components constitute m is logisphere oxides of manganese and calcium, allocated in the arcing zone and formation of the weld. The selection of aerosols causes an increase in turbidity in the area of welding and welder under water cannot be visually monitoring the melting of the metal and formation of the weld. In addition, when the specified welding wire toxic oxides of manganese and chromium oxides, which are harmful to the ecology of the aquatic environment.

Another significant disadvantage of the prototype is the increased surface tension of the slag system, which does not allow to install atomized and inkjet transfer of electrode metal in the melting of the steel shell. Underwater welding melting flux-cored wire is uneven with the formation of globular transition to a low frequency short circuit around 3.5-13 Hz the duration of the short circuit around of 0.004-0.02 s (see Lebedev, C. K., Prokudin B. N. Influence of characteristics of the power source to the welding process flux-cored wire under water // Automatic welding, 1989. No. 1. - S. 1-5).

Globular transition leads to uneven melting of the flux-cored wire, resulting in a thin steel shell melts faster than flyusovye core. This leads to the loss of flux core and lengthening of the arc. As a result of this increased voltage is e arc and decreases the magnitude of the welding current, reducing the depth of penetration of the metal. The increase in the arc length causes a decrease in the partial pressure of the gas mixture in a gas-vapor bubble that violates pushing water from the welding zone and vasosejowy protection of the weld pool.

The technical result of the invention is the improvement of welding-technological properties of the cored wire and weld quality due to the change in the design of flux-cored wire and the chemical composition of the mixture.

The essence of the invention lies in the fact that the cored wire is made of a steel shell, inside which is placed the powder charge. Unlike the prototype, on the surface of the cored wire is placed nanocomposite coating consisting of a mixture of the metal matrix and nano-sized particles, and the composition of the charge has the following content, wt.%: rutile concentrate 24-38,5; silicon dioxide 1,5-6,6; hematite 2,8-16,5; iron powder 32-45; ferromanganese 5-12; Nickel 1-3; carbonate of an alkali metal 3-7; complex fluoride of an alkali metal 2-8.

This combination of known and new features can improve the welding-technological properties of cored wire and the quality of welded joints for underwater welding of metal products. This is possible because poro is the same wire has nanocomposite coating, containing nano-sized particles activating flux. Melting steel shell with a composite coating of activating flux requires an increase in energy costs, as particles activating flux composed of halide salts and oxides with low enthalpy and high dissociation energy. Therefore, the speed of melting of the steel shell is reduced, which reduces the length of the arc, the immersion of the arc to the weld pool, the reduction of the volume of the vapour-gas bubble and increase in the partial pressure of the gas mixture in a gas-vapor bubble. It helps in increasing the depth of penetration of the metal and improves the protection of the weld pool from water penetration. The melting of the nanocomposite coating on the surface of the steel shell slag film, which reduces the interfacial tension of the molten drops of the steel shell and leads to the formation of atomized transition high frequency.

The invention is illustrated by Fig.1, which shows the flux-cored wire with a nanocomposite coating. We offer wire consists of a steel shell 1, which is located nanocomposite coating 2 consisting of a metal matrix with 3 evenly distributed over the volume of the matrix with nanosized particles of activating flux 4. Inside the inner cavity of the steel shell filled with a powdery mixture 5.

The purpose of the invention is achieved in that on the surface of the cored wire electrolytic method applied nanocomposite coating consisting of a mixture of metal (metal matrix) and the activating flux (nanodispersed phase). This coating provides good electrical contact with the current-carrying wire torch tip and effective impact on the arc activates the components of the coating, which contravirus arc and increase its probablyyou ability (Simonic A. G., Patiashvili C. I., Ivanov, A. A. the Effect of the contraction of the arc discharge with the introduction of electronegative elements // Welding engineering, 1976, No. 3, S. 49). During melting of the slag coating film, which reduces the interfacial tension of the metal. This reduces the diameter and the weight drops, which improves drip transfer of electrode metal in the weld pool.

Manufacturing technology, we offer wire does not require sophisticated equipment and can be performed in the industry known way (see Saifullin R. C. Composite electrochemical coatings and materials. M, Chemistry, 1972, 168 C.). Peeled cored wire is immersed in the electrolytic bath, which contains suspended in the electrolyte colloidal particles activating flux to the desired concentration. Depending on the composition of the flux and m is a metallic matrix coating applied sulfate, salt, cyanide or phosphate electrolytes. Cored wire is connected to the negative pole of the power source. Under the action of the polarization forces on the surface of the cored wire deposited nano-sized particles activating flux and simultaneously the positive ions are recovered from the electrolyte of the metal. For uniform distribution of particles in the volume of the electrolyte bath rinsed with argon. As a result, the wire is formed nanocomposite coating thickness of 2-15 μm with evenly distributed over the volume of the matrix with nanosized particles of activating flux. After coating flux cored wire and dried leaves in the Bay for use in mechanized or automatic welding.

The composition of the mixture has ore-acidic slag system which has a low moisture permeability (see Petrov, L. Welding materials. M: mechanical engineering, 1972 - 280 C.). The basis of the ore-acid slag consists of rutile TiO2with a density of 4.2 g/cm3, silicon dioxide SiO2with a density of 2.6 g/cm3, hematite Fe2O3with a density of 5.24 g/cm3so has dense vitreous structure with reduced viscosity and surface tension.

This allows the slag in the molten state close to the surface of the weld pool and to prevent the penetration in the water and hydrogen in the weld metal, that improves the weld formation and reduces the formation of defects in the weld metal. The wetting of the weld pool at high cooling rates under water contributes to the low viscosity of the acidic slag system TiO2-SiO2about 0.3 NS/m2, which further reduced by introducing a complex fluoride of an alkali metal.

The optimum content of rutile concentrate in the charge amounts, wt.%: 24-38,5, silicon dioxide 1,5-6,6, hematite 2.8 to 16.5 in. The specified ratio of the slag-forming components selected from the condition of minimum viscosity and surface tension of the system TiO2-SiO2(see Atlas of toxins. TRANS. with it. Metallurgy, 1985, 208 C.) in order to improve drip transition and formation of the weld under water. In addition, the ratio of TiO2-SiO2provides a uniform slag reduces the likelihood of delamination (see Toropov N. A., Borzakovskiy B. N. state Diagrams of silicate systems. Leningrad: Nauka, 1969. - 822 C.), and also has a minimum melting point (see Podgaetskii centuries, Kuzmenko Century, Welding slag. Kiev, Naukova Dumka. - 1988. - 256 S.)

With decreasing content of the slag-forming components below the optimum value of the amount of the produced slag is insufficient to protect the weld pool from penetration of water, hydrogen and oxygen is a, what affects the formation and quality of the weld. With the increasing content of the slag-forming components higher than the optimal value decreases the deposition rate and efficiency of heat input, which reduces the productivity of the welding process.

The introduction of the mixture of iron powder increases the deposition rate and efficiency of heat input, which increases the depth of penetration and performance of the welding process. The optimum content of the iron powder in the charge amounts, wt.%: 32-45. When reducing the content of iron powder below the optimum values decrease the deposition rate and efficiency of heat input, which causes a decrease in the depth of penetration and performance of the welding process. With the increasing content of iron powder above the optimal value deteriorates slag to protect the weld pool, which impairs the formation of the seam, the density of the weld metal and welding-technological properties of cored wire.

Introduction the composition of the charge of ferromanganese under the optimal content, wt.%: 5-12, contributes to the reduction of iron through metallurgical reactions deoxidation of iron oxides, the binding of impurities in the form of sulfur in refractory sulfides of manganese MnS. This improves the density of the deposited weld metal and mechanical ha is acteristic. With decreasing content of ferromanganese below the optimum values deteriorate the mechanical characteristics of the weld, and with the increasing content of ferromanganese higher than the optimal value decreases the transparency of the water environment due to the growth in the number of aerosol emissions.

Introduction to the composition mixture of Nickel under the optimal content, wt.%: 1-3, improves the mechanical characteristics of the weld, increases the ductility of the weld and increase the deposition rate. With decreasing Nickel content below the optimum value, there is no effect of improving the ductility of the weld metal, while increasing the Nickel content is higher than the optimal values deteriorate the weld formation and the density of the deposited metal.

The introduction of the mixture of the carbonate of an alkali metal such as Li2CO3when the optimal content, wt. %: 3-7, improves the stability of the arc by increasing the degree of ionization of the plasma and increasing the partial pressure of carbon dioxide in a gas-vapor bubble that reduces the concentration of water and hydrogen over the welding bath. Similar effects have carbon dioxide potassium salt K2CO3and Na2CO3. With decreasing content of carbonate salt of an alkali metal lower arc stability, while increasing the content snijers the efficiency of heat input and deposition rate.

Introduction the composition of the charge of the complex fluoride of an alkali metal, such as hexafluoroaluminate Na3AlF6low surface tension of about 130 MJ/m2provides atomized metal transfer. This effect occurs as a result of partial dissociation of the compounds according to the reaction: Na3AlF6=2NaF+NaAlF4. Tetravelent sodium NaAlF4has a low melting point and low surface tension of about 86,6 MJ/m2concentrated in the surface layer of slag and reduces the interfacial tension of the molten metal (see Lepinski B. M., Manakov, A. I. Physical chemistry of the oxide and akceptowalnym melts. M.: Nauka, 1977. - 192 S.). As a result of this reduced diameter drops and increases the frequency of droplet transfer.

As a result of decomposition and evaporation of Na3AlF6around the arc formed gaseous compounds NaF, AlF3, AlF2, AlF, which change the chemical composition of atmospheric vapour-gas bubble formed by the decomposition of water by the welding arc. The pressure of gaseous fluoride in the vapour-gas bubble increases with the concentration of AlF3who has the highest vapor. Saturation vapour-gas bubble fluorides promote the reaction of compounds NaF, AlF3, AlF2, With AlF dioxide is titanium TiO 2. The formation of fluorides of titanium TiF4, TiF3, TiF2that have high chemical activity in the reactions of hydrogen binding. A similar effect has the introduction of the charge of hexafluoroaluminate lithium Li3AlF6that when welding dissociates in connection LiF, AlF3, AlF2, AlF, and hexafluoroaluminate potassium (K2AlF6that welding dissociates in connection KF, AlF3, AlF2, AlF. A similar effect on the binding of water and hydrogen have hexaferrite Na2TiF6Li2TiF6, K2TiF6hexafluorosilicate Na2SiF6Li2SiF6, K2SiF6hexaferrite Na2ZrF6Li2ZrF6, K2ZrF6.

Increasing the concentration of active fluorine in the atmosphere of the gas bubble can effectively bind water molecules and the hydrogen atoms insoluble in the weld pool gaseous compounds hydrogen fluoride HF.

The optimum content of complex fluoride of an alkali metal is, wt.%: 2-8. When the reduction in the content of complex fluoride of an alkali metal below the optimum values deteriorate the process of melting flux-cored wire and drip transition, as well as the ability of the charge to the active binding of water and hydrogen, resulting in de is known in the weld metal of the weld. With the increasing content of complex fluoride of an alkali metal higher than the optimal value worsen the arc stability, slag to protect the weld pool, the weld formation and the density of the deposited metal.

As an example of application of the wire is considered mechanized arc welding samples from low carbon steel of size 300×200 mm and thickness of 10 mm, Particularly mild steel with a thickness of 0.2 mm, a width of 10 mm of steel 08KP were placed in a rolling mill, which was formed steel shell diameter of 4.5 mm Simultaneously with forming the inside of the steel shell fell asleep finely ground mixture of the following composition, wt.%: rutile concentrate 30; silicon dioxide 3; hematite 12; iron powder 35; ferromanganese 5; Nickel 3; lithium carbonate 5; hexafluoroaluminate sodium 7. Then the wire by the method of successive drawing was reduced to a diameter of 1.6 mm After degreasing the wire was passed through a colloidal solution of a copper-containing electrolyte particles NaF size of less than 1000 nm. The result was cored wire with nanocomposite coating thickness of 10 microns.

Received cored wire with nanocomposite coating was used for mechanized arc welding with application of the source power "Magma-U" dive to a depth of 14 m in water is the territory of the Baltic sea. Butt joint plates had two symmetric bevel edges on two sides, the designation of a welded joint C25 according to GOST 14771-76. Filling the seam cutting was carried out in two passes on each side when the arc voltage 32-36 In amperage 230 to 270 A. Studies drip transition produced by the waveform of the voltage e of the arc and the welding current intensity, which was measured using computer complex and Diadem 10.1" with a frequency of 20000 Hz.

Features drip transition for underwater welding with nanostructured powder by a wire
Type flux cored wireThe frequency of short circuits, HzThe duration of the short circuits withThe pause time between short circuits with
Without coating7-100,005-0,06250,05-0,13
Coated Cu + NaF16-210,0007-0,00280,034-0,09

Flux cored wire with the charge of the composition was stable arc, sustainable atomized transfer, provided the chalk is Acesulfame smooth formation of weld beads good slag protection of the weld pool.

Thus, the proposed flux-cored wire provides a technical effect, which is reflected in the improvement drip transition, stability of arc burning and formation of the weld underwater welding can be made and applied using means known in the art, therefore, it has industrial applicability.

1. Flux cored wire for underwater welding, consisting of a steel shell and placed inside blend containing rutile concentrate, hematite, iron powder, ferro-manganese, Nickel, characterized in that on its surface is placed composite coating in the form of a copper matrix with distributed it with nanosized particles of activating flux containing a fluoride of an alkali metal, and the mixture additionally contains silicon dioxide, carbonate of an alkali metal and a complex fluoride of an alkali metal at the following content, wt.%:

rutile concentrate24-38,5
silicon dioxide1,5-6,6
hematite2,8-16,5
iron powder 32-45
ferromanganese5-12
Nickel1-3
carbonate of alkaline metal3-7
complex fluoride of an alkali metal2-8

2. Flux cored wire under item 1, characterized in that as a carbonate of an alkali metal mixture contains a compound or mixture of compounds selected from the group of carbonates of lithium, potassium, sodium.

3. Flux cored wire under item 1 or 2, characterized in that as a complex fluoride of an alkali metal mixture contains a compound or mixture of compounds selected from the group of hexafluoroaluminate, hexaferrites, hexafluorosilicates, geksaftorsilikatov alkali metals.



 

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Powder wire // 2514754

FIELD: metallurgy.

SUBSTANCE: invention relates can be used for arc surfacing of equipment and tools operated at thermomechanical cyclic loading of, for example, the parts of copper teeming machines, hot forming machines, hot rolling rolls, etc. Powder wise consists of low-carbon steel shell made of Armco-iron and powder sharge. Proposed wire contains components in the following ratio in wt %: chromium - 15-18; molybdenum - 3-5.5; nickel - 2-6; manganese - 2-4; ferrosilicon - 0.8-2.5; ferrovanadium - 1.5-3.5; titanium - 0.5-1.0; aluminium - 0.5-1.0; boron carbide - 0.3-0.8; titanium diboride - 1.0-2.0; zirconium diboride - 0.5-1.5; sodium fluorosilicate - 0.5-1.0; iron powder - 0,5-7,5, steel shell making the rest. Surfacing by powder with above described charge can be performed in argon or by hidden arc welding.

EFFECT: higher hardness and longer life of tools operated at thermomechanical cyclic loading.

2 dwg, 2 tbl

FIELD: process engineering.

SUBSTANCE: invention relates to welding wire from stainless steel with flux core for welding zinc-coated steel sheet. Said wire comprises shell from stainless steel filled with flux. Total content of elements introduced in the form of metals or alloys into said shell and said flux, relative to total weight of welding wire, makes, in wt %: C - 0.01-0.05, Si - 0.1-1.5, Mn - 0.5-3.0, Ni - 7.0-10.0, Cr - 26.0-30.0, Fe and unavoidable impurities making the rest. Magnitude F defined the formula given below makes 30-50, F = 3×[Cr%] + 4.5×[Si%]-2.8×[Ni%]-84×[C%]-1.4[Mn%]-19.8 , where [Cr%], [Si%], [Ni%], [C%] and [Mn%], respectively, define total content of Cr, Si, Ni, C and Mn in wire shell and welding wire relative to total weight of the wire. Note here that said flux comprises the following slag-forming materials in wt % with respect to wire total weight: TiO2 - 3.8-6,8%, SiO2 - 1.8-3.2%, ZrO2 - 1.3% or smaller, including 0%, Al2O3 - 0.5% or less, including 0% and total content of said slag-forming materials makes 7.5-10.5%, note here that content of TiO2 makes 50-65% with respect to total weight of slag-forming materials.

EFFECT: ruled out cracking of weld seam, higher hardness and elasticity.

5 cl, 6 dwg, 5 tbl, 2 ex

FIELD: process engineering.

SUBSTANCE: invention relates to welding. Welding electrode comprises metallic electrode part and flux part adjacent thereto. Self-protected welding electrode comprises rare-earth aluminide in said flux and/or electrode part in amount of about 0.5 wt % to 15 wt % of flux part. Said aluminide is selected from the group consisting of cerium aluminide, lanthanum aluminide, neodymium aluminide and cerium-iron aluminide and combinations thereof. Presence of rare-earth aluminide inhibits an ingress of oxygen and nitrogen into weld seam metal and does not notably affect phase changes in metal.

EFFECT: better performances.

13 cl, 3 dwg

FIELD: process engineering.

SUBSTANCE: invention relates to arc surfacing of tools and part operated at high specific pressures and increased temperatures. Powder wire consists of low-carbon steep shell and powder fusion mix at the following ratio of components in wt %: chromium - 20.0-23.0, nickel - 6.0-8.0, ferromolybdenum - 8.0-9.0, ferrotitanium -0.2-0.6, nitrided chromium - 2.0-3.0, ultrafine powder of titanium carbonitride - 0.2-0.6, sodium fluorosilicate - 0.8-1.0, iron -1.3-9.3, shell low-carbon steel making the rest. Said ultrafine powder of titanium carbonitride features particle size of 0.01-0.1 mcm.

EFFECT: higher heat resistance of built-up metal, reduced resource intensity of building up.

2 dwg, 2 tbl, 1 ex

FIELD: restoration of worn parts of low carbon and low alloy steels operating in condition of abrasive wear and impact loads, applying of wear resistant coating.

SUBSTANCE: power wire includes steel envelope and powder like charge having components taken at next relation, mass %: ferrotitanium, 1 - 3; metallic chrome, 6 - 7; ferrosilicon, 0.3 - 0.5; ferromanganese, 1.5 - 2.5; graphite, 0.3 - 0.5; molybdenum, 0.8 - 1.5; fluorspar, 2.0 - 4.5; fieldspar, 0.3 -1.5; hematite, 0.3 - 1.0; steel envelope, the balance. Such wire allows to surface thin and small-size parts in shops, in field and installation condition at lower and vertical positions without using shield gas.

EFFECT: enhanced quality of surfaced parts.

1 tbl

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