CN112794715A

CN112794715A - Multi-material-column CVI furnace and aircraft brake disc manufacturing method

Info

Publication number: CN112794715A
Application number: CN202011589996.6A
Authority: CN
Inventors: 熊翔; 张红波; 王雅雷
Original assignee: Central South University
Current assignee: Central South University
Priority date: 2020-12-29
Filing date: 2020-12-29
Publication date: 2021-05-14
Anticipated expiration: 2040-12-29
Also published as: CN112794715B

Abstract

The invention provides a multi-material column type CVI furnace and a method for manufacturing an airplane brake disc, wherein the multi-material column type CVI furnace is used in a carbon-carbon composite material forming process of the airplane brake disc manufacturing method, a material stacking platform (2) and a blocking body (5) are arranged in a furnace body of the multi-material column type CVI furnace, a plurality of material stacking stations are arranged on the material stacking platform, workpieces are stacked at each material stacking station to form a material column, all the material columns on the material stacking platform form a material column group, the blocking body is positioned between the outer contour of the material column group and the inner wall of the furnace body, the material column group is surrounded along the circumferential direction of the furnace body, the height of the blocking body is not lower than that of the material column group, and an airflow channel is reserved between the blocking body and the outer contour of the material column group. The multi-material column type CVI furnace provided by the invention is not easy to block an inlet of a tail gas pipeline, so that the maintenance cost is reduced.

Description

Multi-material-column CVI furnace and aircraft brake disc manufacturing method

Technical Field

The invention relates to the field of aircraft brake disc manufacturing, in particular to a multi-material-column CVI furnace and an aircraft brake disc manufacturing method.

Background

A Chemical Vapor Infiltration (CVI) method is one of the common methods for manufacturing carbon-carbon composite materials for airplane brake discs at home and abroad, in order to reduce the production cost, equipment used by airplane brake disc manufacturers is gradually changed from a single-material column type CVI furnace to a multi-material column type CVI furnace, the loading capacity of the multi-material column type CVI furnace is large, the required carbon source gas flow is increased, the deposited tail gas is increased after the carbon source gas supply is increased, the tail gas is diffused and deposited in the free space in the furnace, the inlet of a tail gas pipeline is easily blocked, and the equipment maintenance pressure is increased. Therefore, how to improve the multi-column CVI furnace to reduce the occurrence of the clogging condition becomes a technical problem to be solved by those skilled in the art.

Disclosure of Invention

In view of the above, the invention provides a multi-material-column type CVI furnace and a method for manufacturing an aircraft brake disc, wherein the multi-material-column type CVI furnace is used in a carbon-carbon composite material forming procedure of the method for manufacturing the aircraft brake disc, and an inlet of an exhaust pipeline is not easy to block, so that the maintenance cost is reduced.

In order to achieve the purpose, the invention provides the following technical scheme:

the utility model provides a many material column type CVI stove, includes the furnace body and is located the windrow platform in the furnace body, be provided with a plurality of windrow stations on the windrow platform, the work piece is in every windrow station department piles up and forms a stockpile, all on the windrow platform the stockpile group is constituteed to the stockpile, many material column type CVI stove still includes the fender body that highly is not less than the stockpile group, the fender body is located between the outline of stockpile group and the inner wall of furnace body, surrounds the stockpile group along the circumference of furnace body, just leave airflow channel between the fender body and the outline of stockpile group.

Optionally, in the multi-column CVI furnace, the baffle is detachably connected to the stockpiling platform.

Optionally, in the multi-material-column CVI, the upper surface of the material stacking table is circular, the material column is cylindrical, the blocking body is divided into a plurality of blocking columns along the circumferential direction of the furnace body, the cross section of each blocking column is an arc-side triangle, one arc side of each arc-side triangle takes the center of the material stacking table as the center of a circle, and the other two arc sides respectively take the centers of the adjacent material columns as the centers of circles.

Optionally, in the multi-column CVI furnace described above, the number of the stacking stations is three and is evenly distributed around the center of the stacking table.

Optionally, in the multi-column CVI furnace, a preheating device for preheating gas is disposed right below the stockpiling platform.

Optionally, in the multi-column CVI furnace, a pressure measuring pipe is disposed in the center of the preheating device, and a top end of the pressure measuring pipe is located between the preheating device and the stacking table.

Optionally, in the multi-material-column type CVI furnace, a tail gas absorption device is placed at the top of the material column, the tail gas absorption device comprises a material pressing box and a waste gas adsorption material with a porous structure, the waste gas adsorption material is arranged in the material pressing box, and the side wall of the material pressing box is provided with air holes.

Optionally, in the multi-column CVI furnace described above, the baffle is made of graphite or carbon material.

A method of manufacturing an aircraft brake disc comprising a carbon-carbon composite forming process using a multi-pin CVI furnace as disclosed in any one of the above.

According to the technical scheme, the baffle is arranged between the inner wall of the furnace body and the outer contour of the material column group in the multi-material-column CVI furnace, the height of the baffle is not lower than that of the material column group, the material column group is surrounded along the circumferential direction of the furnace body, a part of free space in the furnace is filled by the baffle, and the baffle has a certain flow guiding effect on reaction tail gas, so that the diffusion of the reaction tail gas in the furnace is limited to a certain extent, the retention time of the reaction tail gas in the furnace is shortened, and the condition that the inlet of a tail gas pipeline is blocked due to the deposition of a large amount of tail gas is avoided.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a schematic view of a multi-material-column CVI furnace provided by an embodiment of the invention with a furnace body 6 omitted;

FIG. 2 is a schematic cross-sectional view of FIG. 1;

fig. 3 is a cross-sectional view of a multi-column CVI furnace provided in accordance with an embodiment of the present invention, taken along line a-a of fig. 2.

Labeled as:

1. a supporting seat; 2. a stockpiling platform; 3. a material column; 4. a pressure box; 5. a blocking body; 6. a furnace body; 7. a piezometric tube; 8. a preheating device.

Detailed Description

For the purpose of facilitating understanding, the present invention will be further described with reference to the accompanying drawings.

Referring to fig. 1 to 3, fig. 1 is a schematic view of a multi-pin CVI furnace provided in an embodiment of the present invention without a furnace body 6, fig. 2 is a schematic cross-sectional view of fig. 1, and fig. 3 is a cross-sectional view of the multi-pin CVI furnace provided in an embodiment of the present invention along a line a-a of fig. 2. It should be noted that the material column 3 is shown in the figures for the purpose of illustrating the working principle of the multi-column CVI furnace, the material column 3 being formed by stacking workpieces (e.g. prefabricated parts of brake discs of aircraft).

In the furnace body 6 of many material column type CVI stove, windrow platform 2 sets up on supporting seat 1, is provided with a plurality of windrow stations on windrow platform 2, and the stock column 3 just is located these windrow stations, and all stock columns 3 on the windrow platform 2 constitute the stock column group. The multi-charge-column CVI furnace provided by the embodiment of the invention comprises a baffle body 5 with the height not lower than that of a charge column group, wherein the baffle body 5 is positioned between the outer contour of the charge column group and the inner wall of a furnace body 6, the charge column group is surrounded along the circumferential direction of the furnace body 6, and an airflow channel is reserved between the baffle body 5 and the outer contour of the charge column group. In a specific practical application, the baffle 5 may be made of graphite or carbon material. Compared with the traditional multi-material column type CVI furnace, the baffle body 5 fills a part of free space in the furnace body 6 and has a certain flow guiding effect on reaction tail gas, so that the diffusion of the reaction tail gas in the furnace body 6 is limited to a certain extent, and the retention time of the reaction tail gas in the furnace body 6 is reduced, therefore, the multi-material column type CVI furnace provided by the invention is not easy to block an inlet of a tail gas pipeline, and the maintenance cost is lower.

As shown in fig. 2, in this embodiment, the upper surface of the stacking table 2 is circular, the number of the stacking stations is three, and the stacking stations are uniformly distributed around the center of the stacking table 2, the pillars 3 are cylindrical, the blocking body 5 (i.e., the shadow portion in fig. 2) is divided into a plurality of blocking pillars along the circumferential direction of the furnace body 6, the cross sections of the blocking pillars are arc-side triangles, one arc side of each arc-side triangle takes the center of the stacking table 2 as the center of a circle, and the other two arc sides respectively take the centers of the adjacent pillars 3 as the center of a circle. In order to adjust the height of the baffle column according to the height of the material column 3, the baffle column can be further divided into a plurality of stop blocks along the height direction of the furnace body 6. As can be seen from fig. 1 and 2, the blocking body 5 is located on the stacking platform 2, and in order to keep the blocking body 5 stable during operation, the bottom end of the blocking body 5 is usually fixedly connected with the upper surface of the stacking platform 2, but in order to facilitate taking out the workpiece after the reaction, the blocking body 5 is usually detachably connected with the stacking platform 2.

In other embodiments, the upper surface of the stacking table 2 may have other shapes, such as a regular hexagon; the number of the stacking stations can also be set to other values, such as six, wherein one is at the center, and the other five are uniformly distributed at the outer ring; the cross section shape of the baffle 5 can be designed according to the specific space structure between the outer contour of the charge column group and the inner wall of the furnace body 6.

Under the condition that the gas flow is large, large temperature difference is easy to occur at the upper part and the lower part of the material column 3, which brings adverse effect to the quality consistency of workpiece products, and for this reason, a preheating device 8 for preheating gas is arranged right below the stacking platform 2 in the embodiment, as shown in fig. 3. In order to better monitor the gas pressure in the furnace, the pressure measuring pipe 7 may be disposed at the center of the preheating device 8, and the top end of the pressure measuring pipe 7 may be extended between the preheating device 8 and the stacking table 2.

The excessive macromolecular substances contained in the deposited tail gas are the main reason for generating carbon black and tar on the furnace wall, in order to reduce the frequency of cleaning equipment and reduce the maintenance pressure, the multi-material column type CVI furnace of the embodiment further comprises a tail gas absorption device, as shown in figures 1 and 3, the tail gas absorption device is positioned at the top of the material column 3 and comprises a pressure box 4 and a waste gas adsorption material with a porous structure arranged in the pressure box 4, and the side wall of the pressure box 4 is provided with air holes.

Based on the multi-material column type CVI furnace, the invention also provides a manufacturing method of the aircraft brake disc, and the multi-material column type CVI furnace provided by the invention is used in the forming process of the carbon-carbon composite material. The procedure of the carbon-carbon composite material forming process is described below with specific examples:

s1, the density after high-temperature heat treatment is 0.45g/cm³The carbon brake disc prefabricated body is arranged in a multi-material column type CVI furnace with the isothermal area of phi 600mm multiplied by 1600mm, gaskets are laid between the carbon brake disc prefabricated bodies, the furnace arrangement structure is shown in figures 1 and 3, and carbon felts and leftover materials of the carbon brake disc prefabricated bodies are placed in a pressure material box 4 and used as carriers for absorbing tail gas.

And S2, starting a vacuum pump (matched equipment of the multi-material-column CVI furnace) to pump to a limit vacuum degree (namely the maximum negative pressure allowed by the CVI furnace), closing the vacuum pump and each valve, and testing the pressure rise rate. And if the pressure rise rate is qualified, electrifying, heating to 900-1100 ℃, introducing carbon source gas (30-50% of propylene and 50-70% of nitrogen in volume fraction), adjusting the flow of the carbon source gas, controlling the pressure in the furnace to be 1-2 kPa, and carrying out CVI densification.

And S3, depositing for 400h, and changing the carbon brake disc preform into an airplane brake disc blank made of the carbon-carbon composite material. Stopping electrifying, closing the vacuum pump, closing the propylene air inlet valve, introducing nitrogen to the micro positive pressure, and closing the nitrogen air inlet valve. And when the furnace body is naturally cooled to below 300 ℃, filling nitrogen again to micro positive pressure, and then opening the furnace.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to the embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. The utility model provides a many material column type CVI stove, includes furnace body (6) and is located windrow platform (2) in furnace body (6), be provided with a plurality of windrow stations on windrow platform (2), the work piece is in every windrow station department piles up and forms a stock column, all on windrow platform (2) the stock column group is constituteed to the stock column, its characterized in that still includes height and is not less than the fender (5) of stock column group, fender (5) are located between the outline of stock column group and the inner wall of furnace body (6), surround along the circumference of furnace body (6) the stock column group, just leave airflow channel between fender (5) and the outline of stock column group.

2. A multiple column CVI furnace according to claim 1, wherein the baffles (5) are removably connected to the stockpiling platform (2).

3. The multi-column CVI furnace according to claim 2, wherein the upper surface of the stockpiling platform (2) is circular, the stockpiling column is cylindrical, the baffle (5) is divided into a plurality of baffle columns along the circumferential direction of the furnace body (6), the cross section of each baffle column is a triangle with arc sides, one arc side of the triangle with arc sides takes the center of the stockpiling platform (2) as the center of a circle, and the other two arc sides respectively take the centers of the adjacent stockpiling columns as the center of a circle.

4. A multiple column CVI furnace according to claim 3, characterised in that the number of said stocking stations is three and is evenly distributed around the centre of the stocking table (2).

5. A multi-column CVI furnace as claimed in any one of claims 1 to 4 in which a preheating means (8) for preheating the gas is provided directly below the stockpiling platform (2).

6. A multiple column CVI furnace according to claim 5 in which the preheating device (8) is centrally provided with a pressure measuring tube (7), the top end of the pressure measuring tube (7) being located between the preheating device (8) and the stockpiling platform (2).

7. The multi-column CVI furnace according to claim 5, characterized in that a tail gas absorption device is placed on the top of the column, the tail gas absorption device comprises a pressure box (4) and a waste gas adsorption material with a porous structure arranged in the pressure box (4), and the side wall of the pressure box (4) is provided with air holes.

8. The multi-column CVI furnace of claim 5, wherein the baffles are made of graphite or carbon material.

9. A method for manufacturing an aircraft brake disc, comprising a carbon-carbon composite material forming process, wherein the carbon-carbon composite material forming process uses a multi-column CVI furnace according to any one of claims 1 to 8.