Soldering of porous material with substrate

FIELD: process engineering.

SUBSTANCE: invention can be used in soldering of porous materials with substrate for, for example, sealing of gas turbine engine blade ends or in fabrication of noise damping panels. Powder solder alloy with organic binder is arranged between porous material and substrate. Soldering is performed with application of pressure for solder compaction. Content of solder alloy liquid phase displacing in soldering is limited by 10% by maintenance of soldering working temperature at the temperature of solidus-liquidus range and/or addition of filler to said soldering alloy. Soldering alloy can be configured to 100-500 mcm deep tape. Organic binder can be represented by acrylic resin copolymer. Soldering agent or filler powder features particle size of 10-100 mcm.

EFFECT: reliable bonding at minimum change in porosity owing to impregnation of porous material by not over 500 mcm.

7 cl, 1 tbl, 1 ex

 

The invention relates to the field of metallurgy and mechanical engineering, namely to soldering porous, including porous fibrous materials. The present invention may be used to seal the ends of the blades of gas turbine engines with the stator of the compounds in the manufacture of panels of sound attenuation, and in the manufacture of gas turbine engines for various purposes.

It is known that porous materials are combined with the substrate by methods of welding or soldering. The combination of these materials is challenging because it is necessary in the connection process to maintain the porosity of the material. Therefore, during the soldering process should be minimal penetration of the solder into the porous material. When soldering this material is the extensive system of capillaries through which the solder can fill the entire volume of the open porosity. To prevent the solder impregnation of the porous material it is necessary to strictly regulate the amount of applied solder. However, such adjustment is effective only when fixed and small gaps on the connected surfaces. Due to the fact that complicated machining of the connecting surfaces of the porous material, particularly porous fibrous material, the necessary biasing it to the parts being clamped. But the possibility of biasing limited�s, in the process of high-temperature brazing heat due to plastic deformation will occur wrinkling of the porous material with reduced porosity. In fact soldering of such material is strictly controlled and limited impregnation process of the solder placed on the connecting surfaces. Upon formation of fillets around the perimeter of solder plates to control the formation of the connection. Connections should not limit the performance of the basic material.

The known method of connection of a porous metal or ceramic materials by welding through the adapter (see application for invention of the Russian Federation No. 2001114099, publ. 22.05.2001). Welding is carried out on the ends of the porous preforms. This method of connection of the porous material can be used in the manufacture of parts such as filters, where this type of connection can be used for the manufacture of shells of ceramic material, or seal the ends of the washers, that is, on a relatively small surface of the sealing material. The loss of porosity in the ends of parts made from flat blanks of a porous material, such connections will not significantly affect the properties of the parts. But for sealing materials, where necessary, the connection of the material with podloga� on one of the planes of the porous preform, this way is unacceptable.

The closest analogue of the method of brazing porous material with the substrate is the method of the British patent GB 1298860 "the improvement of the method of obtaining the element casing of a gas turbine with a porous material". According to a known method on a substrate coated solder powder, apply pressure to the element for the compression of the solder between the coating and the substrate and carry out the soldering operation. Solder is applied using a plasma torch or by using varnish. The thickness of the solder powder is from 50 to 250 μm. The solder composition chosen is similar in composition to the substrate and a coating containing at least one element from the group iron, Nickel or cobalt. In particular, the use of solder Nickel-based "NICROBRAZ 50", containing 13% chromium and 10% phosphorus. The brazing operation is carried out in a container in the atmosphere halogenosilanes gas and then cooled in the chamber with hydrogen.

Significant disadvantages of this method is the following:

- the difficulty of adjusting the dosage of the solder and, as a consequence, the possibility of impregnation of the porous material, which reduces the porosity of the material.

- poor ability to control the quality of the formation of compounds due to the lack of regulation of the fillets on the outer boundaries of plates of porous fibrous material,if dosage solder understated. When higher doses are formed of the fillet, but there is an impregnation of porous material with solder.

An object of the invention is the provision of control of quality of formation of compounds on the formation of fillets at the external borders of the connections of the plates of porous fibrous material and the preservation of the porosity of the material during the soldering process. The properties of compounds are not to limit the technical characteristics of the porous material.

The technical result of the present invention is to obtain compounds of the porous material with a minimum of change of porosity (impregnation of the porous material on the value of not more than 500 μm).

The technical result is achieved in that a method of brazing porous material to the substrate, comprising placing between the porous material and the substrate solder containing a solder powder and organic binder, and the implementation of soldering with application of pressure to a pre-loaded solder, characterized in that the content is able to be transported in the soldering process of the liquid phase of the solder limit of 10% by maintaining the operating temperature soldering temperature range of the solidus - liquidus solder and/or the introduction of the solder filler.

Preferably as a solder, a mixture of solder powder and organic�ski binding.

Preferably as a solder, a mixture of solder powder, a filler and an organic binder.

Preferably solder use solder powder in an organic binder, made in the form of a tape with a thickness of 100-500 μm.

You can use as the organic ligaments copolymer acrylic resin.

You can use as a basis of an organic binder dispersion of polyvinyl acetate.

Preferably, the use of particles of the solder powder or powder filler in the range of 10 to 100 microns.

As shown by experiments, the lack of penetration of the solder into the porous material due to the limitation of the content of the liquid phase of the solder during the soldering process. This limitation can be achieved, for example, or the choice of thermal regime soldering at temperatures solidus - liquidus solder, or the use of filler in the solder, or both. Simultaneously, the solder layer in the solid-liquid state, ensures contact of the connected material at a much lower pressure preload. Soldering mode for a particular type of product can be selected according to the results of a study of the penetration of solder into the porous material (by restricting the content capable of moving the liquid phase of the solder during the soldering process) metallographical�they method on thin sections of connections which must not be more than 500 μm. Thus from the solidified solder on the border of the material to the substrate are formed fillet. Quality control of formation of a compound is judged by the formation of fillets between the porous material and the substrate.

Examples of the implementation.

For the practical implementation of the invention were the main materials used are porous fibrous material made from the fibres of the iron-based alloy, alloyed with chromium and aluminum, and the substrate was applied a heat-resistant Nickel alloy GSU. Plates of porous and fibrous material size 15x15x5 mm was Palis with an insert size 20x20x4 mm, cut from castings alloy ISO.

Soldering was used three solder: Nickel VPR, experienced-based solder iron doping system iron-chromium-aluminum-carbon and Nickel solder "NICROBRAZ 50", with a content of 13% chromium and 10% phosphorus. Unlike solder "NICROBRAZ 50, which can be used for relatively low operating temperatures of the compounds up to 300°C, the solder ITR and experienced solder on iron base ensure efficiency of the compounds to 1100°C.

When implementing the inventive method between the porous material and the substrate placed solder powder in an organic binder, then held the soldering operation pressure is applied to the ignition�opment of solder between the porous material and the substrate. Moreover, the soldering process was performed using a solder powder in which the content is able to move the liquid phase soldering not more than 10%, and ensured the penetration of solder into the pores of the material to a depth of not more than 500 microns.

The content is capable of moving liquid phase in the solder when soldering in the solid-liquid state of the solder is determined as follows: in a ceramic crucible placed dosed hitch solder, optionally in admixture with a filler in contact with the outer flat surface of this sample is the sample of porous fibrous material. Then heating is carried out in vacuum to a temperature of soldering, after soldering and removal of specimens from the oven, removed the sample of porous fibrous material and weighed hitch solder. The change in weight of the sample corresponds to the content capable of moving liquid phase in the solder at the designated temperature for soldering.

Limiting the content capable of moving the liquid phase of the solder during the soldering process can be achieved, preferably, but not necessarily, in several ways: the choice of thermal regime soldering at temperatures solidus - liquidus solder and/or use of the filler in the solder.

Selection of solder composition and the filler is made for each brand of porous fibrous material and the substrate. Maybe use� as a material for the solder powder of the Nickel solders or brazing alloys based on iron. You can use as a material for powder filler Nickel alloys. There are a variety of porous fibrous like material with open porosity, as well as substrates with which it is necessary to combine these materials, depends on the range of alloys and fillers.

Melting solders produced in a vacuum induction furnace models VIAM-1635 with subsequent remelting ingots billet finger. The manufacture of powders of these alloys was performed by the method of gas-jet sputtering with argon to install HERMIGA10/100VI or crushing of the chips. The filler used granulated powder alloy GSU. The size of the particles of the solder powder or powder of a filler comprised, as a rule, from 10 to 100 microns

For testing were made from a mixture of powders of the filler and solder in resin bond-based acrylic resin ribbons of various thicknesses from 100 to 500 μm. As a basis of an organic binder is applied dispersion of polyvinyl acetate (i.e., poly (vinyl acetate) dispersion state). The filler content in the solder is 60%.

Tape on resin bond cut the size of the porous material and located between the sealing material and the substrate. Brazing was performed in a vacuum furnace at temperatures of soldering for connections, we have managed�'s solders VPR and experienced solder - 1200-1220°C, and solder "NICROBRAZ 50" - 900-920°C. applying a layer of solder "NICROBRAZ 50" was carried out on the wafer substrate with the subsequent alignment layer and pinning it with lacquer al-82. On porous fibrous material to preload it in the soldering process to the plate of alloy GSU was placed a weight of 20 g of corundum ceramics.

The amount of penetration of the solder into the porous material were investigated in thin sections welded samples. The plane of the thin section was held perpendicular to the joint plane. The amount of penetration, as a rule, had been uneven, and recorded their maximum value. The presence of fillets and their sizes were determined on the binocular microscope and in thin sections connections.

These test results are presented in table 1.

The results of brazing porous fibrous material tape on resin bond with solder ITR.

Similar results are shown in table 1, are achieved without the use of filler, which is confirmed by experiments.

The data in table 1 shows that with the method known from the prior art, the fillet is not formed even at maximum thickness of the solder, but when this happens, the impregnation of the porous material at full depth. When the minimum thickness of the layer of solder the size of impregnation acceptable, but the failure of solder sample can be seen that the connection of a plate made of porous fibrous material occurred only in several points. Thus, it is seen that the solder fills, first of all, the capillary gaps inside the porous material. This feature of the formation of compounds makes it impossible to control the quality of connections of porous fibrous material with the substrate.

In the method according to the present invention, the conditions controlled formation of porous material with the substrate at a controlled impregnation solder this material. For both solders in this method, the quality control compounds can serve as education fillets. Destructive methods of control - metallographic analysis metallographic samples of compounds and analysis of fractures of the compounds show that in the presence of fillets of the solder remains on the joint plane with negligible penetration into the porous material. The destruction of the joints when testing is performed only by a porous material, in this case, metallographic analysis reveals sometimes the lack of penetration of the solder into the porous material.

For brazing alloy with a narrow melting range, such as solder ITR, the filler content in the mixture of the brazing-filler determines the amount of solder that will be used for brazing of porous fibrous material. Solder with a large range of melting (1180°C-1280°C), such as a solder alloy based on iron, the role of filler partly fulfil the remains of Noraplan�usasa part of the solder. The number of these residues decreases as the growth temperature soldering. Therefore, the content of the filler in the mixture of the brazing-filler may be reduced.

The proposed method allows soldering to produce parts hot GTE and noise-absorbing structures made with the use of porous fibrous material, will effectively use these materials and provide significant economic benefits from increased fuel efficiency and reduced noise during operation of gas turbine engines.

1. Method of brazing porous material to the substrate, comprising placing between the porous material and the substrate solder containing a solder powder and organic binder, and the implementation of soldering with application of pressure to a pre-loaded solder, characterized in that the content is able to be transported in the soldering process of the liquid phase of the solder limit of 10% by maintaining the operating temperature soldering temperature range of the solidus - liquidus solder and/or the introduction of the solder filler.

2. A method according to claim 1, characterized in that the solder used a mixture of solder powder and an organic binder.

3. A method according to claim 1, characterized in that the solder used a mixture of solder powder, a filler and an organic binder.

4. A method according to claim 1, characterized in that � as solder use solder powder in an organic binder, made in the form of a tape with a thickness of 100-500 μm.

5. A method according to any one of claims. 1-4, characterized in that as the organic binder used in the acrylic copolymer resin.

6. A method according to any one of claims. 1-4, characterized in that as the basis of an organic binder is applied dispersion of polyvinyl acetate.

7. A method according to any one of claims. 1-4, characterized in that the solder powder or a powder filler with a particle size of from 10 to 100 μm.



 

Same patents:

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FIELD: machine building.

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12 cl, 5 dwg

FIELD: metallurgy.

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3 dwg

Anticorrosion flux // 2528939

FIELD: chemistry.

SUBSTANCE: invention can be used in soldering aluminium components, e.g. heat exchangers. Lithium or compounds in form of lithium fluoroaluminate, particularly LiF or Li3AlF6, which contain Li cations, are added to a basic flux which includes potassium fluoroaluminate in which content of K3AlF6 is equal to or less than 5 wt %.

EFFECT: lithium cation-modified flux provides resistance of soldered joints to corrosion, caused by contact with stagnant water or aqueous compositions, for example when soldered components are stored in open air.

18 cl, 2 tbl, 11 ex

FIELD: engines and pumps.

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EFFECT: decreased amount of solder, accurate positioning of soldered joint.

9 cl, 12 dwg

FIELD: physics.

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EFFECT: high uniformity and specific power of the temperature field generated by infrared rays on the surface of the board and microcircuit owing to reflection of the infrared rays.

7 cl, 5 dwg

FIELD: soldering.

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EFFECT: improved quality of soldered joints.

12 cl, 3 ex

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