RU2274536C2 - Method for producing composition powder wire for surfacing alloy on base of nickel aluminide - Google Patents

Abstract

FIELD: surfacing processes, namely surfacing materials, possibly producing of composition powder wire.

SUBSTANCE: method for producing wire having double-layer sheath with inner layer of ductile metal and outer layer of nickel comprises steps of forming from belts U-shaped portions of sheath layers of ductile metal and of nickel respectively; filling with charge U-shaped portion of inner layer of sheath; arranging technological butts of U-shaped portions of sheath diametrically opposite one to other and squeezing them. According to invention inner layer is formed of aluminum belt. Charge contains Al and Ni powders for filling pores at process of combined squeezing of layers. Wire components of Ta, W, Mo are simultaneously added to U-shaped portion together with charge and they are placed along axis of sheath. Thickness values of sheath layers are set in next range: for Ni, 0.4 - 0.8 mm; for aluminum, 0.076 - 0.185 mm at satisfying relation (Ni_ch + Ni_sh )/(Al_{ch +} Al_sh) = 6.52 where Ni_{ch ,} Ni_sh, Al_ch, Al_sh - mass values of Ni and Al in charge and in nickel and aluminum layers of sheath of powder wire, mass %.

EFFECT: homogenous melting of components of charge, sheath and cores, improved chemical and physical uniformity of produced alloy.

5 dwg, 1 tbl, 1 ex

Description

The invention relates to surfacing, in particular to surfacing materials used in metallurgical, petrochemical, atomic energy and general engineering, and can be used in the manufacture of composite flux-cored wires (CAT) mainly for electric arc and electroslag surfacing of complex alloyed heat-resistant alloys based on nickel aluminide Ni ₃ Al containing refractory - heavy and fusible - light alloying elements.

The problem of surfacing of such alloys is the difficulty of obtaining a homogeneous deposited metal due to uneven melting of the components of cored wires (PP), as well as due to the separation of heavy and light metal fractions in the charge of wires.

Known PP (Japan patent, No. 02255053, 23 K 35/02, 23 K 35/30, publ. 22.01.03), consisting of a Nickel shell with a charge through which a rod of the same material is passed, and he does not contact the shell, and the flux filler contains the metal in the amount necessary to reduce the resistance of the flux filler so that an arc forms between the tube and the shell.

Such a PP allows for more uniform melting of the charge and shell.

The main disadvantage of such a PP is the possibility of opening the shell, which leads to spontaneous precipitation of the charge and, as a result, to the heterogeneity of the deposited metal.

A known method of manufacturing a wick electrode wire for arc welding (German patent No. 195234006, 23 K 35/40, publ. 02.01.97). The wick electrode wire has two or more sheaths. The core of the wire (wick) in the form of PP is laid in the groove of a pre-rolled ribbon, which is closed in a tube.

The main disadvantage of such a wick electrode wire is the complexity and complexity of its manufacture.

Closest to the proposed method is the manufacture of PP (USSR Author's Certificate No. 1722756, 23 K 35/40, publ. Bull. No. 12, 1992), in which the wire contains at least two sheaths with technological joints located diametrically opposite relative to each other, and the mixture is in the inner shell.

However, in the manufacture of such a PP, the ratio of the thicknesses of the shell layers of 0.12 ... 0.30 must be observed, when these limits are exceeded, either local breaks in the inner layer are observed at its small thickness or an increased proportion of the steel shell in the deposited metal, which leads to decrease in its welding and technological properties.

The objective of the invention is the creation of a gearbox for surfacing an alloy based on nickel aluminide NiAl with improved welding and technological properties.

The technical result consists in the guaranteed provision during the melting of the gearbox of the weld metal based on nickel aluminide Ni ₃ Al, in the improvement of uniformity of melting of the components of the gearbox: the charge, shell and cores when placing electrically conductive powders of nickel and aluminum in the charge and reducing the chemical and physical heterogeneity of the resulting alloy due to uniform distribution of light and heavy components in the charge of the gearbox.

The technical result is achieved by the fact that in the method of manufacturing a flux-cored wire for welding and surfacing containing a two-layer sheath, the inner layer of which is made of ductile metal, and the outer one is made of nickel, including the formation of U-shaped profiles of sheath layers of ductile metal and nickel from tapes , filling the charge with a U-shaped profile of the inner layer of the shell, the location of the technological joints of the U-shaped profiles of the shells are diametrically opposed to one another and joint compression, inside The third layer is formed from an aluminum strip, the mixture contains Al, Ni powders to fill voids during the joint compression of the layers, while wire components from Ta, W, and Mo are introduced into the U-shaped profile along with the mixture, placing them coaxially to the shell, while the thickness shell layers are taken within: for nickel 0.4 ... 0.8 mm, and for aluminum 0.076 ... 0.185 mm, to fulfill the ratio:

where ni _shih ; Ni _obol ; Al _sheikh ; Al _sheath - masses of nickel and aluminum in the charge and in the nickel and aluminum layers of cored wire in mass percent.

In the process of crimping, plastic materials - nickel, aluminum, distributed evenly in the charge, are easily susceptible to plastic deformation, contributing to a better filling of voids formed by refractory wire components.

The presence in the charge of metal conductive powders of aluminum and nickel, distributed evenly in the charge, and wire components helps to reduce the total electrical resistance of the charge, bringing the gearbox closer to a single conductive rod, which contributes to uniform melting of the gearbox, increasing its welding and technological properties.

The introduction of refractory metals in the form of wire elements into the composition of the CPC charge gives the alloy based on nickel aluminide Ni ₃ Al heat resistance, while the separation of refractory and low-melting elements in the charge is prevented and their uniform distribution in the CPT is ensured.

. Эти пределы обусловлены диаметром КПП от 4 до 5 мм. Изготовление КПП диаметром менее 4 мм нецелесообразно, так как в этом случае предельно уменьшается коэффициент заполнения К_з, что ограничивает возможность легирования металла. Волочение готовой КПП с диаметра 5 мм на меньший диаметр нецелесообразно по причине возможного обрыва из-за малой деформационной способности высокопрочных проволок из тугоплавких металлов (Та, W, Мо). Получение КПП диаметром более 5 мм технически возможно, но не предусмотрено стандартами на сварочные и наплавочные проволоки.The ratio of the thicknesses of the outer layer of the shell - Nickel and the inner layer of the shell - aluminum are taken respectively in the range: for the outer layer of 0.4 ... 0.8, for the inner layer of 0.076 ... 0.185 (figure 2), to perform the ratio

. These limits are determined by the diameter of the gearbox from 4 to 5 mm. The manufacture of gearboxes with a diameter of less than 4 mm is impractical, since in this case the fill factor K _s is extremely reduced, which limits the possibility of alloying the metal. The drawing of the finished gearbox from a diameter of 5 mm to a smaller diameter is impractical due to possible breakage due to the small deformation ability of high-strength wires from refractory metals (Ta, W, Mo). Getting gearboxes with a diameter of more than 5 mm is technically possible, but not provided for by the standards for welding and surfacing wires.

The content of plastic materials (Al, Ni) in the charge varies depending on the selected thicknesses of the outer and inner shell layers (FIGS. 2, 3) so that the total nickel and aluminum content in the gearbox provides a weld metal matrix based on nickel aluminide Ni ₃ Al . The content of nickel and aluminum in the charge depends on the coefficient d, calculated from the ratio

where ni _shih ; Ni _obol ; Al _sheikh ; Al _shells are the masses of nickel and aluminum, respectively, in the charge and in the layers of the CPT shell. The dependence of the coefficient d on the thickness of the nickel and aluminum layers of the gearbox shell is shown in Fig.3. The greater the thickness of the shell layers, the lower the coefficient d, and hence the content of aluminum and nickel in the charge.

The invention is illustrated by drawings.

Figure 1 shows the manufacturing diagram of the gearbox.

Figure 2 shows a graph of the effect of the thickness of the outer nickel layer of the shell on the thickness of the inner aluminum layer of the shell.

Figure 3 shows a graph of the influence of the thickness of the outer layer of the shell on the coefficient d.

Figure 4 shows the ratio of the coefficients d and K _s (duty ratio).

Figure 5 shows the microstructure of the weld metal (× 500).

The method is implemented as follows. From cassettes 1 and 2 (Fig. 1) with tapes of the outer - nickel layer of the casing and the inner - aluminum layer of the casing of the tape, they are fed to the stripping device 3, where they are cleaned of grease and dirt. The peeled tapes are passed through forming devices 4 to give them the shape of segments with a cylindrical surface (Fig. 1, A-A). Then the U-shaped profile of the inner aluminum layer of the shell is passed through the dispenser 5, filling it with a charge containing electrically conductive, powdery plastic, easily deformable metals (Al, Ni). Simultaneously with the charge in the U-shaped profile from the cartridge 6, additionally refractory wire components are introduced mainly from refractory elements (Ta, W, Mo) and are placed coaxially with the shell (Fig. 1, BB). After that, the nickel and charge-filled aluminum profiles are crimped together in the die 7. The finished profile is shown in Fig. 1, BB.

Then, by means of a control drawing, the gearbox thus obtained is sealed for high-quality and reliable sealing of the charge.

Example.

в мас.%.According to the proposed method, a checkpoint with a diameter of 5 mm was made. Materials used: nickel tape NP2 GOST 2170 for the outer layer of the shell with a size of 0.6 × 16 mm and tape from aluminum alloy A97 GOST 7871 for the inner layer of the shell, the thickness of which is determined by figure 2 - 0.12 × 12 mm, wires of technically pure refractory metals (Ta, W, Mo) with a diameter of 0.6 mm each and technically pure metal powders of nickel and aluminum in an amount determined by the coefficient d. From the selected thickness h _Ni or h _Al, we find the coefficient d according to the graph of FIG. 3. Given the coefficient d, knowing the weight of Ni and Al _{obol obol,} the size of the nickel and the aluminum content of the cladding layers find Ni _{Shih Shih} and Al in the charge is based provide a ratio

in wt.%.

In the process of drawing the workpiece received a checkpoint with a fill factor of K _S = 0.83 (figure 4). In the manufacture of gearboxes, cliffs of the shell layers were not observed.

The uniformity of melting of the components of the CPT during argon arc and electroslag surfacing was controlled by the nature and sequence of melting of the entire CPT visually and by the nature of the structure of the deposited metal. In the state after surfacing, the structure of the deposited metal consists of doped intermetallic Ni ₃ Al (up to 80 volume%) uniformly distributed in the deposited metal (Fig. 5).

при которых диапазоны толщин слоев их оболочек выходят за заявляемые пределы. Результат сравнительных испытаний КПП представлен в таблице.A gearbox was made with compounds beyond the stated ratio

in which the ranges of thicknesses of the layers of their shells go beyond the claimed limits. The result of comparative tests of the gearbox is presented in the table.

Table
Comparative gearbox test results Preparation method Wire drawing productivity, kg / h Strength of cored wire, MPa

Input Ratio

The content of Ni ₃ Al in the structure, volume. % Transmission components melting synchronization Component distribution in gearbox Proposed 300-350 200-230 6.52 80 uniform uniform 5.1 33 uniform uniform 7.3 44 uniform uniform Base 90-120 130-150 - - uneven - Prototype 200-250 150-180 - - uneven -

что не позволяет получить в наплавленном металле алюминид никеля Ni₃Al, обрывы внутреннего слоя оболочки.An analysis of the data in the table shows that when the recommended thickness values are exceeded for the outer layer of 0.4 ... 0.8 and for the inner layer of 0.076 ... 0.185 (Fig. 3), the following are observed:

which does not allow obtaining nickel aluminide Ni ₃ Al in the deposited metal, breaks of the inner layer of the shell.

The two-layer gearbox made with the proposed method with additional wire components mainly from refractory materials (Ta, W, Mo) has improved technological properties, such as strength of the shell, reliable sealing of the charge and uniform distribution of components along the length of the wire. The simultaneous introduction of powder components together with wire components into the gearbox contributes to an increase in its strength, which makes it possible to increase productivity during drawing (see table). Industrial production of gearboxes is possible on existing technological equipment for the manufacture of PP with a slight readjustment.

Productivity in the manufacture of known PP (prototype) compared with the proposed lower.

Using the proposed method for the manufacture of gearboxes, in comparison with known methods for manufacturing PP, the following positive effect:

1. The possibility of obtaining a weld metal based on nickel aluminide Ni ₃ Al.

2. Uniform distribution of components in the gearbox.

3. Improving the performance of manufacturing PPC.

Claims (1)

A method of manufacturing a flux-cored wire for welding and surfacing containing a two-layer sheath, the inner layer of which is made of ductile metal, and the outer one is made of nickel, including the formation of U-shaped profiles of sheath layers from a plastic material and nickel from tapes, filling the charge with a U-shaped profile the inner layer of the shell, the location of the technological joints of the U-shaped profiles of the shells is diametrically opposed to one another and the combined compression, characterized in that the inner layer is formed of al of a yuminium ribbon, the charge contains Al, Ni powders for filling voids in the process of joint compression of the layers, while wire components from Ta, W, Mo are introduced into the U-shaped profile along with the charge, placing them coaxially to the shell, while the thickness of the shell layers is taken limits: for nickel 0.4-0.8 mm, and for aluminum 0.076-0.185 mm, to fulfill the ratio

where Ni _shih , Ni _obl ; Al _shih , Al _sheath - the mass of nickel and aluminum in the charge and in the nickel and aluminum layers of cored wire in mass percent.

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