CN116984688A

CN116984688A - Vacuum brazing method for high-temperature alloy casting honeycomb component

Info

Publication number: CN116984688A
Application number: CN202311183220.8A
Authority: CN
Inventors: 黄慧玲; 王斌; 李凯驰; 吴明帆; 张志远; 张黎明; 谌曲平; 吕亮; 杨俊波; 冉鸿鹏
Original assignee: AECC South Industry Co Ltd
Current assignee: AECC South Industry Co Ltd
Priority date: 2023-09-13
Filing date: 2023-09-13
Publication date: 2023-11-03

Abstract

The application discloses a vacuum brazing method of a high-temperature alloy casting honeycomb component, which comprises the following steps of: s1, after the casting is cleaned, nickel is integrally plated on the brazing surface of the casting, and the thickness of a nickel layer plated with nickel is 0.015-0.02 mm; s2, filling brazing filler metal into the outer cylindrical surface of the honeycomb assembly; s3, combining the honeycomb and the casting and spot welding; s4, adding paste solder at the soldering position of the honeycomb and the casting, and drying the paste solder; s5, clamping the honeycomb assembly by using a plurality of clamps, wherein the clamps are uniformly dispersed and clamped in the circumferential direction of the honeycomb assembly; s6, brazing circulation. The method comprises the steps of adding sand blowing to the cleaning of the brazing surface, removing an oxide film on the surface of a casting substrate, and then brushing nickel on the whole surface, so that the wettability of the whole brazing surface is increased, and meanwhile, cold joint is prevented, the nickel layer thickness is selected to consider the diffusion of the nickel layer in the brazing process, and the protection effect of the nickel layer on the brazing surface is ensured; the fixture is introduced to tightly attach the honeycomb and the casting, so that the defects that the spot welding of the honeycomb and the casting is unstable after the nickel plating treatment of the honeycomb assembly can be overcome, and the gap of the honeycomb brazing part can be ensured.

Description

Vacuum brazing method for high-temperature alloy casting honeycomb component

Technical Field

The application relates to the technical field of brazing of aeroengine parts, in particular to a vacuum brazing method for a high-temperature alloy casting honeycomb component.

Background

The aeroengine sealing structure comprises a comb ruler sealing structure, a graphite sealing structure, a honeycomb sealing structure and the like, wherein the honeycomb sealing structure is most commonly used in an engine due to good sealing performance. In the field of aero-engines, the current situation of honeycomb sealing processing is: for easily welded materials such as stainless steel, wrought superalloy and the like, the processing technology of the honeycomb seal assembly is mature, and good brazing appearance and brazing qualification rate can be obtained after brazing. However, with the improvement of the performance of the aero-engine, in order to ensure the weight reduction of parts and the simplification of the structure, more and more casting cases are directly brazed with the honeycomb; however, the base material of the honeycomb component is cast high-temperature alloy, the content of easily oxidized elements (Al and Ti) of the base is high, a compact oxide film is formed on the surface, the honeycomb component is difficult to break under high-temperature vacuum, and the vacuum brazing performance is poor; the honeycomb belongs to a flexible part, the brazing seam clearance is difficult to control, the brazing difficulty of the cast brazing honeycomb assembly is high, and the problems of non-wetting of brazing filler metal on the surface of a substrate, unqualified appearance of a welding seam and low qualification rate of brazing seam are frequently caused after brazing.

The patent with publication number CN113878189a discloses a vacuum brazing process for an aeroengine honeycomb assembly, comprising the steps of: s1, preparing a honeycomb ring, and filling adhesive brazing filler metal into the honeycomb ring; s2, the brazing surface of the honeycomb ring and the outer ring comprises a nickel plating area and a non-nickel plating area, the non-nickel plating area of the outer ring is protected by adopting a protecting piece, the brazing surface, close to the outer end surface, of the outer ring is the nickel plating area, and sand blasting treatment is carried out on the nickel plating area; s3, brushing and plating special nickel on the outer ring nickel plating area, brushing and plating quick nickel, and removing the protective piece; s4, combining the honeycomb ring filled with the adhesive tape solder with the outer ring; s5, performing spot welding positioning on the honeycomb ring; s6, filling paste brazing filler metal into the joint of the outer end face of the honeycomb ring and the nickel plating area of the outer ring to obtain a pre-brazed piece; and S7, carrying out vacuum brazing treatment on the pre-brazed piece. According to the vacuum brazing process for the aeroengine honeycomb assembly, the outer ring is subjected to partial nickel plating, so that the problems that the welding of the honeycomb assembly made of a difficult-to-weld material is not firm and the surface of a brazing seam is discontinuous are solved.

The above patent is also directed to the brazing of the honeycomb component, but the problem of weak spot welding and discontinuous welding lines is mainly directed to, the problem of gap control of the brazing welding lines is not involved, and the problem of partial nickel plating is only carried out on certain parts of the honeycomb component, so that the cold welding can exist, and the welding quality still cannot meet the delivery requirement.

Disclosure of Invention

The application aims to overcome the defects of the prior art and provides a vacuum brazing method aiming at brazing a high-strength high-temperature alloy casting honeycomb component, ensuring that a honeycomb and a casting outer ring are tightly adhered and ensuring high weld quality.

The aim of the application is achieved by the following technical scheme:

a vacuum brazing method of a high-temperature alloy casting honeycomb component comprises the following steps:

s1, after the casting is cleaned, nickel is integrally plated on the brazing surface of the casting, and the thickness of a nickel layer plated with nickel is 0.015-0.02 mm;

s2, filling brazing filler metal into the outer cylindrical surface of the honeycomb assembly;

s3, combining the honeycomb and the casting and spot welding;

s4, adding paste solder at the soldering position of the honeycomb and the casting, and drying the paste solder;

s5, clamping the honeycomb assembly by using a plurality of clamps, wherein the clamps are uniformly dispersed and clamped in the circumferential direction of the honeycomb assembly;

s6, brazing circulation;

s5 in the fixture comprises a pressing plate, an I-shaped clamp and bolts, wherein the pressing plate is attached to the inner cylindrical surface of the honeycomb, the I-shaped clamp is provided with a first bending end and a second bending end which are parallel to each other, the first bending end extends to the inner hole sinking table of the casting and is attached to the sinking table wall, the second bending end is located outside the casting, threaded holes are formed in the first bending end and the second bending end for the bolts to penetrate through, the end parts of the bolts penetrating through the first bending end are abutted to the pressing plate, and the end parts of the bolts penetrating through the second bending end are abutted to the outer cylindrical surface of the casting.

Compared with the prior art, the application has the following beneficial effects:

1) Cleaning the brazing surface by adopting a cleaning, baking and sand blowing mode, removing an oxide film on the surface of a casting substrate by sand blowing, and brushing and plating nickel on the whole surface, wherein the method is suitable for the high strength of a welding line of a high-temperature alloy casting, and prevents cold joint while increasing the wettability of the whole brazing surface; the nickel layer plated with nickel is thicker than the traditional nickel layer, and the diffusion of the nickel layer in the brazing process is considered so as to ensure the protection effect of the nickel layer on the brazing surface;

2) When the honeycomb assembly is brazed, the fixture is introduced to tightly attach the honeycomb and the casting, so that the defects that the spot welding of the honeycomb and the casting is not firm after the nickel plating treatment of the honeycomb assembly, the strength of a welding spot is low and the honeycomb can be sprung out in the brazing process can be overcome, and the gap at the brazing position of the honeycomb can be ensured;

3) The pressing plate and I-shaped clamp materials of the clamp are the same as the casting base materials, so that the clamp and the honeycomb assembly have the same linear expansion coefficient, synchronous expansion occurs in the brazing process, and the honeycomb and the casting are ensured to be tightly pressed at the moment so as to ensure a gap.

Drawings

FIG. 1 is a schematic cross-sectional view of the clip described in example 1 on a honeycomb assembly;

FIG. 2 is a top view of the honeycomb assembly full turn clamping fixture described in example 1;

FIG. 3 is a schematic view of the clamping sequence of the clamp on the honeycomb assembly described in example 1;

fig. 4 is a schematic diagram of the spot welding at step S3 in example 2.

Detailed Description

In order to clearly illustrate the technical characteristics of the present solution, the following detailed description will explain the present solution by means of specific embodiments and with reference to the accompanying drawings.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application, however, the present application may be practiced in other ways than those described herein, and therefore the scope of the present application is not limited to the specific embodiments disclosed below.

In addition, in the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the drawings, are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present application. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

In the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; the device can be mechanically connected, electrically connected and communicated; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present application, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Example 1

The embodiment provides a brazing method for brazing a honeycomb assembly on an aeroengine, wherein castings in the honeycomb assembly are high-temperature alloy castings, the strength of the parts is high, and virtual welding is easy to occur. The brazing method comprises the following steps:

s1, after the casting is cleaned, nickel is integrally plated on the brazing surface of the casting:

the casting parts are loose due to the existence of the matrix, a large amount of cutting fluid, cooling fluid and the like exist in the machining process, the fluid is easy to enter the loose parts of the castings in the machining process, impurities, liquid pollutants and the like in the castings are volatilized and separated out due to the brazing vacuum environment and high-temperature heating, a brazing surface is polluted, and the brazing filler metal is prevented from being spread and wetted, so that the quality of welding seams is affected. In order to solve the problems, the cleaning step can be divided into three steps of ultrasonic cleaning, baking and sand blowing, so as to effectively remove oil stains at the brazing position of the casting parts, particularly oil stains in deep storage of the brazing surface of the casting, and the like, and improve the quality of the welded brazing seam.

Specifically, after the parts are cleaned by ultrasonic waves, the parts are placed in a vacuum brazing furnace for baking, the baking temperature is 400-700 ℃ for 30 min-3 h, the vacuum degree is ensured to be within 0.2Pa in the baking process, specifically, the vacuum brazing furnace is vacuumized to be below 0.1Pa and then heated, the temperature is raised to 500-700 ℃, the temperature is kept for 0.5-2 h at 500-700 ℃, and the pollutants and the greasy dirt are separated out and removed by utilizing the negative pressure and the high temperature of vacuum. And (3) after the brazing surface is baked and discharged, corundum sand is blown out, and surface residues and an oxide layer are blown out, wherein the granularity of sand grains is 180-240 meshes, the blowing pressure is within 0.5MPa, and no pollutant is required to be oozed out of the surface of the part after the sand blowing.

Then nickel is coated on the brazing surface, for example, in the comparison document of the background technology, partial nickel coating is usually adopted in the traditional brazing method, the thickness of the nickel layer is controlled within 0.01mm, and slag oxide films can be clamped in a welding line during brazing, so that the strength of parts is not high. According to the application, the casting parts are extremely easy to oxidize, and nickel is plated on the whole brazing surface in order to improve the wettability of the brazing filler metal on the surface of the casting substrate, so that the oxidation condition of the casting surface is avoided to the greatest extent, and the possibility of subsequent cold joint is reduced. In addition, the quality of the nickel coating can directly influence the brazing quality of the part, if the thickness of the nickel coating is insufficient, the nickel coating diffuses towards a matrix and the brazing filler metal during brazing, and the nickel coating cannot play a role in wetting the brazing filler metal after being discharged from a furnace and being oxidized at a nickel coating position; if the thickness of the nickel layer is too thick, the nickel layer is peeled off and falls off and cannot be completely diffused into the welding seam and the matrix, so that the quality of the welding seam and the joint structure are affected, therefore, the thickness of the nickel layer is controlled to be 0.015-0.02 mm, the protection effect of the nickel layer is ensured, and the nickel layer is thicker, even if the nickel layer is diffused in the brazing process, the nickel layer still exists on the brazing surface all the time, so that the wettability of the brazing filler metal can be ensured, the part can be prevented from being oxidized before the brazing filler metal melts, and the brazing filler metal is diffused into the matrix and the brazing filler metal after being melted and spread.

Wherein, the brushing plating nickel comprises brushing plating special nickel and brushing plating quick nickel, the voltage of brushing plating special nickel is 8-10V, and the time is 30-60 s; the voltage of the quick nickel for brushing plating is 8-10V, and the time is 8-30 min.

S2, filling brazing filler metal into the outer cylindrical surface of the honeycomb assembly.

The honeycomb strips are spliced into honeycomb rings by energy storage spot welding, and BNi82CrSiB adhesive tape solder with the thickness of 0.3-0.6 mm is rolled on the outer cylindrical surface of the honeycomb; scraping residual solder on the surface of the core lattice until the metal surface of the core lattice is exposed.

S3, combining the honeycomb and the casting and spot welding.

After the honeycomb is combined with the casting, the energy storage spot welder or the resistance spot welder is used for carrying out spot welding positioning on the honeycomb and the whole circle of the casting outer ring, the upper electrode is positioned with the honeycomb, the lower electrode is contacted with the outer ring, a welding spot is formed at the spot welding position, and the honeycomb is preliminarily ensured to be tightly attached to the casting outer ring.

S4, adding paste solder at the soldering position of the honeycomb and the casting, and drying the paste solder.

Adding certain BNi82CrSiB paste solder to the side feeding part of the honeycomb, and brushing a choking agent near the paste solder after brushing the paste solder to prevent the solder from flowing.

The paste solder is dried by baking or natural air drying, for example, the baking temperature is 50-200 ℃ and the baking time is 15-120 min.

S5, clamping the honeycomb assembly by using a plurality of clamps, wherein the clamps are uniformly dispersed and clamped in the circumferential direction of the honeycomb assembly.

Although the spot welding process can attach the honeycomb and the outer ring of the casting before entering the furnace to ensure the brazing gap, the honeycomb and the casting can be infirm in spot welding due to the fact that nickel plating is performed on the part, the strength of the welding spot is low, and when the honeycomb and the casting matrix are brazed, expansion and contraction exist, and the honeycomb can spring open. In addition, if the brazing gap between the joint surfaces is larger, the brazing result is greatly influenced, and as the honeycomb belongs to the structures of the flexible piece and the hexagonal holes in the core lattice holes, the clearance between the honeycomb and the outer ring of the casting is more strictly required, the honeycomb and the outer ring are required to be closely attached, and no gap exists at the brazing position. Therefore, in order to ensure the joint between the honeycomb and the casting in the brazing process, the embodiment also particularly introduces a clamp for clamping the honeycomb assembly so as to ensure the gap of the honeycomb brazing position.

As shown in fig. 1, the fixture 01 comprises a pressing plate 1, an i-shaped clamp 2 and a bolt 3, wherein the pressing plate 1 is attached to the inner cylindrical surface of the honeycomb a, the i-shaped clamp 2 is provided with a first bending end 21 and a second bending end 22 which are parallel to each other, the first bending end 21 extends to an inner hole sinking table of the casting B and is attached to the sinking table wall, the second bending end 22 is positioned outside the casting B, threaded holes are formed in the first bending end 21 and the second bending end 22 for penetrating through the bolt 3, the end part of the bolt 3 penetrating through the first bending end 21 is abutted to the pressing plate 1, and the end part of the bolt 3 penetrating through the second bending end 22 is abutted to the outer cylindrical surface of the casting B.

The specific structure of the pressing plate 1 is an arc section, the radian of the arc section is consistent with that of the inner cylindrical surface of the honeycomb, the thickness of the pressing plate is preferably more than or equal to 1.5mm, in the axial direction of the honeycomb assembly, the size of the honeycomb is required to be completely covered by the pressing plate, and preferably, the two ends of the pressing plate in the direction exceed the two end surfaces of the honeycomb optimally; the spacing between adjacent pressing plates is designed to be smaller as much as possible in the circumferential direction of the honeycomb so as to ensure that even if the I-shaped clamps are arranged in a scattered manner, the spacing area between the two clamps can compress the honeycomb and the casting.

The I-shaped clamp 2 is made of the same material as the casting, so that the clamp and the part have the same linear expansion coefficient, synchronous expansion of the part in the brazing process is realized, namely, the expansion amount of the I-shaped clamp is consistent with that of the outer ring, the I-shaped clamp is ensured to always press the honeycomb and the casting, and the gap is ensured.

As shown in fig. 2, among all the jigs circumferentially distributed in the honeycomb assembly, the interval between adjacent jigs is 30 to 50mm.

S6, brazing circulation.

Charging the honeycomb assembly into a furnace for vacuum brazing, and taking the technological parameters of the vacuum brazing: (1030-1060) DEG C X (5-15) min

S7, post-welding treatment.

And (5) removing the clamp after the honeycomb assembly is discharged from the furnace, removing the residual blocking agent by using clean rag, and checking the appearance and the welding rate of the welding seam.

Through inspection, the honeycomb component obtained by adopting the brazing method basically has no appearance defect, the brazing seam has no virtual welding, the welding seam welding rate reaches more than 90%, the vacuum brazing repair and repair welding rate of the cast honeycomb parts is reduced, the production efficiency is improved, and the production cost is saved.

Example 2

The embodiment requires clamping of the clamps on the basis of embodiment 1, namely, the clamping sequence of the plurality of clamps on the honeycomb assembly is carried out according to the following steps:

s51, placing a pressing plate on the inner cylindrical surface of the honeycomb.

S52, preassembling I-shaped clamps by taking 3-5 clamps as a group. The first bending end of the I-shaped clamp is screwed into the bolt to compress the pressing plate, the second bending end is screwed into the bolt to compress the outer circular surface of the casting, the screw is not required to be screwed at the moment, the I-shaped clamp is ensured to be clamped on the honeycomb assembly, and the casting cannot shake.

S53, as shown in FIG. 3, the (1) group is assembled, then the (2) group at the opposite diameter is assembled, then 90 degrees is rotated, the (3) group is assembled, then the (4) group is assembled, and the subsequent clamps are assembled in this way until the honeycomb assembly is filled in full circle.

S54, screwing the bolts according to the sequence of (1), 2, 3, 4, … …, and screwing for about 1.5-2 circles, so that the honeycomb is not damaged while being pressed.

The symmetrical clamping and symmetrical tightening modes of the clamp can ensure that the circumferential gaps of the honeycomb are uniform, and the quality of the honeycomb assembly is ensured, because the honeycomb is a whole ring, in an unconstrained state, the circumferential gaps are uniform, if the honeycomb is clamped along the circumference, the gaps at the clamping positions are smaller, and then the gaps at the clamping positions are larger, if the single clamp clamps are clamped in sequence, the circumferential gaps of the honeycomb are greatly different.

Example 3

This embodiment differs from embodiment 1 in that: the electrode for spot welding in the S3 comprises an upper electrode and a lower electrode, wherein the lower electrode is designed to be a copper plate capable of supporting the honeycomb assembly, the end face of the honeycomb assembly is attached to the surface of the copper plate, and the upper electrode is arranged on a spot welding pen for spot welding. During spot welding, as shown in fig. 4, the honeycomb assembly is directly placed horizontally, a spot welding pen is in contact with the inner cylindrical surface of the honeycomb to perform spot welding positioning, and a pedal of a spot welder is stepped on at an angle to trigger discharge.

In the conventional spot welding, for small-sized honeycomb parts, a worker can easily place the parts vertically between the upper and lower electrodes for spot welding due to the small size and light weight of the parts. However, for cast honeycomb assemblies, such as the honeycomb assembly in embodiment 1, the size of the parts is large, the parts cannot be easily erected by hundreds of jin, the parts are required to be rotated in the spot welding process to ensure full circle spot welding of the parts, 2-3 workers are required to move the parts and fix the parts in the process, a great deal of manpower is wasted, and the labor intensity of the workers is also great. In addition, because the honeycomb component of the aeroengine, generally the side edge of the guide vane is brazed with the honeycomb, after the casting is placed on the upper electrode and the lower electrode of the spot welder, the worker is difficult to observe the contact condition of the electrode descending and the part due to the shielding of the vane, so that the spot welding is difficult. Conventional spot welding electrodes therefore cannot accommodate spot welding of cast honeycomb components.

The spot welding electrode of this embodiment improves, has saved the labour, has alleviateed workman intensity of labour, and only one person can easily accomplish spot welding work, has improved production efficiency greatly.

It is apparent that the above examples are only examples for clearly illustrating the technical solution of the present application, and are not limiting of the embodiments of the present application. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the application are desired to be protected by the following claims.

Claims

1. The vacuum brazing method for the high-temperature alloy casting honeycomb component is characterized by comprising the following steps of:

s3, combining the honeycomb and the casting and spot welding;

s6, brazing circulation;

2. The vacuum brazing method of the high-temperature alloy casting honeycomb assembly according to claim 1, wherein the nickel brushing plating in the step S1 comprises special nickel brushing plating and quick nickel brushing plating, wherein the voltage of the special nickel brushing plating is 8-10V, and the time is 30-60S; the voltage of the quick nickel for brushing plating is 8-10V, and the time is 8-30 min.

3. The method of vacuum brazing a superalloy casting honeycomb component according to claim 1, wherein the material of the i-clip and the casting material are the same.

4. The vacuum brazing method of a superalloy casting honeycomb component according to claim 1, wherein the adjacent jigs are spaced apart by 30-50 mm among the jigs circumferentially distributed around the honeycomb component.

5. The vacuum brazing method of high temperature alloy cast honeycomb assemblies according to claim 1, wherein the cleaning of the castings in S1 comprises three steps of ultrasonic cleaning, baking and sand blowing sequentially.

6. The vacuum brazing method of the high-temperature alloy casting honeycomb assembly according to claim 5, wherein the baking temperature in the baking step is 400-700 ℃ for 30 min-3 h, and the vacuum degree is ensured to be within 0.2Pa in the baking process; in the sand blowing step, the granularity of sand particles is 180-240 meshes, and the sand blowing pressure is within 0.5 MPa.

7. The vacuum brazing method of the high-temperature alloy casting honeycomb assembly according to claim 1, wherein the paste brazing filler metal is brushed in the step S4, and a flow blocking agent is further brushed to prevent the brazing filler metal from overflowing.

8. The vacuum brazing method of the high temperature alloy cast honeycomb assembly according to claim 1, wherein the paste brazing filler metal is dried by baking at 50-200 ℃ for 15-120 min.

9. The vacuum brazing method of a high temperature alloy cast honeycomb assembly according to claim 1, wherein the electrode for spot welding in S3 comprises an upper electrode and a lower electrode, the lower electrode is a copper plate capable of supporting the honeycomb assembly, the end face of the honeycomb assembly is attached to the surface of the copper plate, and the upper electrode is mounted on a spot welding pen for spot welding.

10. The vacuum brazing method for the high-temperature alloy cast honeycomb assembly according to claim 1, wherein the brazing process parameter in the step S6 is (1030-1060) DEG C× (5-15) min.