Preparation method of ventilated powder metallurgy brake disc

Abstract

The present application relates to a method for preparing a ventilated powder metallurgy brake disc. By stacking and pressurizing disc blanks, a sintered blank of a ventilated powder metallurgy brake disc having a heat dissipation channel of arbitrary shape can be prepared. Then, a pre-calculated soluble solid powder is filled into the heat dissipation channel by a filling method. The presence of the soluble solid powder can ensure that the disc body will not collapse or deform during the hot pressing and shaping process. After the hot pressing and shaping, the soluble solid powder can be easily removed by placing the brake disc in a dissolving medium, thereby realizing the low-cost preparation of ventilated powder metallurgy brake discs having heat dissipation channels of various shapes.

Description

Technical Field

[0001] The present invention relates to the technical field of brake disc preparation, in particular to a method for preparing a ventilated powder metallurgy brake disc. Background Art

[0002] Aluminum-based composite materials have garnered widespread attention due to their low density, high strength, high hardness, and excellent wear resistance. Aluminum-based brake discs, in particular, can reduce weight by 40% to 65% compared to traditional cast iron discs, achieving significant lightweighting benefits. These materials are being extensively researched and applied in both rail transit and passenger car brake disc applications.

[0003] Currently, methods for preparing aluminum-based composite brake discs include stir casting, powder metallurgy, melt infiltration, and spray deposition. Due to the complex operating conditions and high braking temperatures of automotive brake discs, medium- to high-volume fraction aluminum-based composite materials are required for their application in automotive brake discs to improve their heat resistance. The aluminum-based composites produced by stir casting have a limited content and insufficient heat resistance; the melt infiltration method can only produce aluminum-based composites with a high overall ceramic content, making processing difficult. The powder metallurgy method is relatively flexible and can locally strengthen the brake disc, specifically increasing the ceramic content of the friction ring and significantly improving the brake disc's heat resistance.

[0004] However, the traditional powder metallurgy method can only form holes vertically and cannot produce transverse ventilation channels, which limits the ventilation and heat dissipation capabilities of ceramic reinforced aluminum-based composite brake discs, forcing ceramic reinforced aluminum-based composite brake discs to face more severe high-temperature working conditions. At the same time, the inability to produce transverse ventilation channels also reduces the lightweight effect of the brake disc, affecting the promotion and application of ceramic reinforced aluminum-based composite brake discs.

[0005] CN115045932B discloses a method for manufacturing a ventilated brake disc. The method involves superimposing a first disc blank with a second disc blank, enclosing corresponding grooves to form a ventilation channel, and then hot-pressing and sintering the disc. A support sleeve is then placed in the ventilation channel and densified. An aluminum tube is positioned over a steel rod as the support sleeve, and high-temperature lubricating oil is applied between the aluminum tube and the steel rod. The outer diameter of the support sleeve is then calculated according to a formula. This allows the steel rod to be easily removed after densification, while the aluminum tube can be removed or retained in the ventilation channel as appropriate. This allows the powder metallurgy method to produce a ventilated brake disc with transverse ventilation channels. However, this technical solution can only be used to produce ventilation channels with a linear distribution; it is difficult to produce ventilation channels with an arc-shaped distribution. Summary of the Invention

[0006] Based on this, it is necessary to provide a method for preparing a ventilated powder metallurgy brake disc that can prepare various types of heat dissipation channels.

[0007] A method for preparing a ventilated powder metallurgy brake disc comprises the following steps:

[0008] A first disk blank and a second disk blank are provided, wherein the first disk blank includes an integrally formed end portion, a neck portion extending axially along the end portion, and a disk portion extending radially along the neck portion, wherein a surface of the disk portion facing away from the end portion is provided with a plurality of protrusions, and the second disk blank is mirror-symmetrical to the disk portion;

[0009] The first disk blank and the second disk blank are superimposed so that the protrusions of the disk portion contact with the protrusions of the second disk blank in a one-to-one correspondence, and the contact portions are pressurized and sintered to obtain a sintered blank with an open outer diameter and a closed inner diameter;

[0010] Providing a closed aluminum housing with a feed port and soluble solid powder;

[0011] After the outer diameter of the sintered compact is sealed with the closed aluminum shell, the soluble solid powder is added through the feed port, and the feed port is sealed to obtain a sintered compact filled with the soluble solid powder. The amount of the soluble solid powder charged is calculated according to the following formula:

[0012]

[0013] in,

[0014] M is the amount of soluble solid powder added, in g;

[0015] φ1 is the outer diameter of the brake disc to be prepared, in cm;

[0016] φ2 is the inner diameter of the brake disc to be prepared, in cm;

[0017] φ3 is the equivalent diameter of the brake disc connector to be prepared, in cm;

[0018] n is the number of connectors;

[0019] H is the height of the brake disc ventilation channel to be prepared, in cm;

[0020] ρ is the compacted density of the soluble solid powder, in g / cm 3 ;

[0021] After hot pressing and shaping the sintered compact filled with soluble solid powder, the closed aluminum shell and the soluble solid powder are removed to obtain the ventilated powder metallurgy brake disc.

[0022] In one embodiment, the outer diameter of the brake disc is 28 cm to 40 cm.

[0023] In one embodiment, the inner diameter of the brake disc body to be prepared is 15 cm to 20 cm.

[0024] In one embodiment, the equivalent diameter of the brake disc connector to be prepared is 0.5 cm to 1.5 cm.

[0025] In one embodiment, the number of the connecting members is 100 to 300.

[0026] In one embodiment, the height of the brake disc ventilation channel to be prepared is 0.5 cm to 2 cm.

[0027] In one embodiment, the thickness of the closed aluminum shell is 0.4 mm to 0.8 mm.

[0028] In one embodiment, the temperature of the hot pressing shaping is 500° C. to 570° C., and the pressure is 100 MPa to 400 MPa.

[0029] In one embodiment, the compaction density of the soluble solid powder under the hot pressing shaping condition is 2.0 g / cm 3 ~2.1g / cm 3 .

[0030] In one embodiment, the soluble solid powder is a neutral water-soluble powder, and the particle size of the neutral water-soluble powder is 200um to 1000um.

[0031] The above-mentioned method for preparing a ventilated powder metallurgy brake disc utilizes the method of disc blank superposition and pressure sintering to realize the preparation of a ventilated powder metallurgy brake disc sintered blank having a heat dissipation channel of arbitrary shape. Then, the heat dissipation channel is filled with a pre-calculated soluble solid powder by filling. The presence of the soluble solid powder can ensure that the disc body will not collapse and deform during the hot pressing process. After hot pressing, the brake disc can be placed in a dissolving medium to easily remove the soluble solid powder, thereby realizing the low-cost preparation of ventilated powder metallurgy brake discs having heat dissipation channels of various shapes. DETAILED DESCRIPTION

[0032] To facilitate understanding of the present invention, the present invention will be described more fully below, along with preferred embodiments thereof. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the disclosure of the present invention.

[0033] It should be noted that when an element is referred to as being “disposed on” another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or there may be an intermediate element at the same time.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0035] A method for preparing a ventilated powder metallurgy brake disc according to one embodiment includes the following steps S110 to S150:

[0036] S110 , providing a first disk blank and a second disk blank.

[0037] The first disc blank includes an integrally formed end portion, a neck portion extending axially along the end portion, and a disc portion extending radially along the neck portion, and a surface of the disc portion facing away from the end portion is provided with a plurality of protrusions.

[0038] It can be understood that the first disc blank and the second disc blank can be obtained by designing corresponding molds according to the ventilated powder metallurgy brake disc to be prepared, and then performing powder compression molding.

[0039] S120, superimposing the first disc blank and the second disc blank so that the protrusions of the disc portion contact with the protrusions of the second disc blank in a one-to-one correspondence, and then pressurizing and sintering the contact portions to obtain a sintered blank with an open outer diameter and a closed inner diameter.

[0040] The pressure sintering temperature is 580° C. to 640° C., and the pressure is 5 MPa to 10 MPa.

[0041] It will be appreciated that pressure is applied at the point of contact.

[0042] Pressurizing and sintering the contact points can make the first disc blank and the second disc blank tightly connected, and the liquid phase generated during the sintering stage can fully diffuse and fuse, offsetting the disadvantage of loose interface due to sintering shrinkage.

[0043] The protrusions on the disc portion are in one-to-one contact with the protrusions on the second disc blank, and after pressure sintering, they become connecting parts for the subsequent ventilated powder metallurgy brake disc.

[0044] S130, providing a closed aluminum shell with a feed port and soluble solid powder.

[0045] It is understood that the soluble solid powder cannot react adversely with the brake disc during the entire preparation process of the brake disc, and its dissolving medium will not react adversely with the brake disc either.

[0046] In this embodiment, the soluble solid powder is a neutral water-soluble powder, such as sodium chloride, potassium chloride, etc., and its dissolving medium is water.

[0047] Furthermore, the particle size of the neutral water-soluble powder is 200 to 1000 μm. If the particle size is too large, the gaps between the particles during the filling process will be too large, making it difficult to ensure sufficient filling of the particles, or the brake disc thickness will be compressed significantly at the same filling volume. If the particle size is too small, the particle flowability will be poor, and it will also be difficult to ensure sufficient filling of the particles.

[0048] In this embodiment, the thickness of the closed aluminum shell is 0.4mm to 0.8mm. If it is too thin, the shell will be easily deformed, resulting in insufficient sealing. If it is too thick, the material distribution on the outside will be affected, resulting in the need to leave a large amount of disk processing allowance to ensure that the aluminum shell can be removed in the end.

[0049] S140, after the outer diameter of the sintered blank is sealed with the above-mentioned closed aluminum shell, soluble solid powder is added through the feed port, and the feed port is sealed to obtain a sintered blank filled with soluble solid powder.

[0050] Among them, the loading amount of soluble solid powder is calculated according to the following formula:

[0051]

[0052] M is the amount of soluble solid powder added, in g;

[0053] The outer diameter of the brake disc to be prepared, in cm;

[0054] is the inner diameter of the brake disc to be prepared, in cm;

[0055] is the equivalent diameter of the brake disc connector to be prepared, in cm;

[0056] n is the number of connectors;

[0057] H is the height of the brake disc ventilation channel to be prepared, in cm;

[0058] ρ is the compacted density of the soluble solid powder, in g / cm 3 .

[0059] The loading amount of soluble solid powder is calculated according to the above formula. On the one hand, the loading amount of soluble solid powder can be flexibly designed according to the size of the final product. On the other hand, it can effectively evaluate whether the addition of soluble solid powder meets the requirements during actual operation.

[0060] In this embodiment, the outer diameter of the brake disc body to be prepared is 28 cm to 40 cm, that is, the value range of φ1 is 28 to 40. The inner diameter of the brake disc body to be prepared is 17 cm to 25 cm, that is, the value range of φ2 is 17 to 25. The equivalent diameter of the brake disc connector to be prepared is 0.5 cm to 1.5 cm, that is, the value range of φ3 is 0.5 to 1.5. The number of connectors is 100 to 300, that is, the value range of n is 100 to 300 and is an integer. The height of the brake disc ventilation channel to be prepared is 0.5 cm to 2 cm, that is, the value range of H is 0.5 to 2.

[0061] S150, hot pressing and shaping the sintered compact containing the soluble solid powder, removing the closed aluminum shell and the soluble solid powder to obtain a ventilated powder metallurgy brake disc.

[0062] In this embodiment, the temperature of the hot pressing shaping is 500° C. to 570° C., and the pressure is 100 MPa to 400 MPa.

[0063] The above-mentioned method for preparing a ventilated powder metallurgy brake disc utilizes the method of disc blank superposition and pressure sintering to realize the preparation of a ventilated powder metallurgy brake disc sintered blank having a heat dissipation channel of arbitrary shape. Then, the heat dissipation channel is filled with a pre-calculated soluble solid powder by filling. The presence of the soluble solid powder can ensure that the disc body will not collapse and deform during the hot pressing process. After hot pressing, the brake disc can be placed in a dissolving medium to easily remove the soluble solid powder, thereby realizing the low-cost preparation of ventilated powder metallurgy brake discs having heat dissipation channels of various shapes.

[0064] The following are specific examples.

[0065] Example 1

[0066] A ventilated powder metallurgy brake disc is prepared using the method of steps S110 to S150. The ventilated powder metallurgy brake disc has an outer diameter φ1 of 40 cm, an inner diameter φ2 of 20 cm, a ventilation channel height of 1 cm, a number n of connectors of 200, an equivalent diameter φ3 of 1 cm, and a soluble solid powder of sodium chloride with a particle size of 300 μm. Under hot pressing conditions (hot pressing temperature of 520°C and pressure of 300 MPa), the compacted density is 2.1 g / cm 3 Based on this, it can be calculated that the amount of sodium chloride added is 1648.5g.

[0067] The ventilated powder metallurgy brake disc prepared in Example 1 successfully passed the AMS test under extreme operating conditions. This technology successfully enables the powder metallurgy method to produce various ventilated brake discs, effectively improving the heat dissipation efficiency of the brake disc under high-temperature conditions, especially under long-term high-temperature conditions, and significantly enhancing the performance of the brake disc.

[0068] Comparative Examples 1 to 3

[0069] Comparative Examples 1-3 were essentially the same as Example 1, except that the amount of sodium chloride added in Comparative Examples 1-3 was determined solely by visual inspection. However, during the preparation process, some of the samples in Comparative Examples 1-3 were found to contain excessive sodium chloride, resulting in deformation of the enclosed aluminum shell during hot pressing, which in turn caused the disc to collapse and deform. Other samples were found to contain insufficient sodium chloride, resulting in partial collapse of the disc during hot pressing. In none of the samples in Comparative Examples 1-3 was sufficient sodium chloride added to prevent the disc from collapsing and deforming during hot pressing.

[0070] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A method for preparing a ventilated powder metallurgy brake disc, characterized in that: The following steps are involved: A first disk blank and a second disk blank are provided, wherein the first disk blank includes an integrally formed end portion, a neck portion extending axially along the end portion, and a disk portion extending radially along the neck portion, wherein a surface of the disk portion facing away from the end portion is provided with a plurality of protrusions, and the second disk blank is mirror-symmetrical to the disk portion; The first disk blank and the second disk blank are superimposed so that the protrusions of the disk portion contact with the protrusions of the second disk blank in a one-to-one correspondence, and the contact portions are pressurized and sintered to obtain a sintered blank with an open outer diameter and a closed inner diameter; Providing a closed aluminum housing with a feed port and soluble solid powder; After the outer diameter of the sintered compact is sealed with the closed aluminum shell, the soluble solid powder is added through the feed port, and the feed port is sealed to obtain a sintered compact filled with the soluble solid powder. The amount of the soluble solid powder charged is calculated according to the following formula: in, M is the amount of soluble solid powder added, in g; The outer diameter of the brake disc to be prepared, in cm; is the inner diameter of the brake disc to be prepared, in cm; is the equivalent diameter of the brake disc connector to be prepared, in cm; n is the number of connectors; H is the height of the brake disc ventilation channel to be prepared, in cm; ρ is the compacted density of the soluble solid powder, in g / cm 3 ; After hot pressing and shaping the sintered compact containing the soluble solid powder, the closed aluminum shell and the soluble solid powder are removed to obtain the ventilated powder metallurgy brake disc.

2. The method for preparing a ventilated powder metallurgy brake disc according to claim 1, characterized in that: The outer diameter of the brake disc body to be prepared is 28 cm to 40 cm.

3. The method for preparing a ventilated powder metallurgy brake disc according to claim 1, characterized in that: The inner diameter of the brake disc body to be prepared is 15 cm to 20 cm.

4. The method for preparing a ventilated powder metallurgy brake disc according to claim 1, characterized in that: The equivalent diameter of the brake disc connector to be prepared is 0.5 cm to 1.5 cm.

5. The method for preparing a ventilated powder metallurgy brake disc according to claim 1, characterized in that: The number of the connecting pieces is 100 to 300.

6. The method for preparing a ventilated powder metallurgy brake disc according to claim 1, characterized in that: The height of the brake disc ventilation channel to be prepared is 0.5 cm to 2 cm.

7. The method for preparing a ventilated powder metallurgy brake disc according to claim 1, characterized in that: The temperature of the hot pressing shaping is 500° C. to 570° C., and the pressure is 100 MPa to 400 MPa.

8. The method for preparing a ventilated powder metallurgy brake disc according to claim 1, characterized in that: The thickness of the closed aluminum shell is 0.4 mm to 0.8 mm.

9. The method for preparing a ventilated powder metallurgy brake disc according to any one of claims 1 to 8, characterized in that: The compacted density of the soluble solid powder under the hot pressing shaping condition is 2.0 g / cm 3 ~2.1g / cm 3 .

10. The method for preparing a ventilated powder metallurgy brake disc according to claim 9, characterized in that: The soluble solid powder is a neutral water-soluble powder, and the particle size of the neutral water-soluble powder is 200um to 1000um.

Images