Powder metallurgy friction block transition layer material, preparation method and use method

Abstract

The invention relates to a powder metallurgy friction block transition layer material, a preparation method and a use method. The transition layer material is composed of metal composite powder and an organic solvent. Wherein the metal composite powder accounts for 40-70% of the transition layer material; wherein the organic solvent comprises the following components in percentage by mass: 3 to 8 weight percent of stearic acid, 30 to 45 weight percent of hydrogenated rosin, 5 to 9 weight percent of polyamide wax, 1 to 3 weight percent of benzotriazole and the balance of hexanediol; the problem that the thermal expansion performance of the friction body and the steel backing is not matched is effectively solved, and the bonding strength of the friction body and the steel backing is remarkably improved. Test results show that the bonding strength of the sintered friction body and the steel backing can reach 18.67-35.42 MPa and is far higher than 4.2-8 MPa of the friction body which is not subjected to spraying treatment.

Description

Technical Field

[0001] The present invention relates to the technical field of high-speed rail transit train braking systems, and relates to a transition layer material between a friction body of a copper-based powder metallurgy composite material for railway braking and a steel back. Specifically, it relates to a powder metallurgy friction block transition layer material, a preparation method, and a usage method. Background Art

[0002] In the braking system of high-speed railway trains, the friction block is a key component of the brake pad, and its performance directly affects the braking effect and driving safety of the train. The friction block is usually composed of a friction body and a steel back that plays a supporting role. There needs to be good bonding strength between the two to ensure no detachment or damage during braking. However, due to the different material properties of the friction body and the steel back, such as the coefficient of thermal expansion, hardness, etc., direct bonding often fails to achieve an ideal bonding effect.

[0003] Currently, common bonding methods usually involve mechanical connections such as riveting or adhesive connections, etc. However, these methods have problems such as complex processing, low bonding strength, poor heat resistance, etc., which are particularly significant under high-speed, high-temperature, and high-load working conditions. A new bonding process and transition layer material are needed to improve the bonding strength between the friction body and the steel back and meet the high requirements of high-speed railway train braking systems. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art, the present invention provides a transition layer material coated on the surface of the steel back containing metal composite powder and organic solvent, which improves the bonding strength between the friction body and the steel back, and enhances the heat resistance and shear resistance of the friction block. The process is simple, the cost is low, and the effect is remarkable. It is applicable to the powder metallurgy friction block transition layer material, preparation method, and usage method for manufacturing friction blocks of high-speed railway train braking systems.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is a powder metallurgy friction block transition layer material, and the transition layer material is composed of metal composite powder and organic solvent; wherein the proportion of the metal composite powder in the transition layer material is 40% - 70%;

[0006] Among them: the mass percentages of the components in the organic solvent are: stearic acid 3 - 8wt%, hydrogenated rosin 30 - 45wt%, polyamide wax 5 - 9wt%, benzotriazole 1 - 3wt%, and the rest is hexanediol.

[0007] Preferably, the components in the metal composite powder include: copper powder, iron powder, zinc powder, manganese powder, tin powder, nickel powder, chromium powder and silicon powder; the mass percentage of each component is: zinc powder 10-20wt%, iron powder content is 5-10wt%, manganese powder 3-8wt%, nickel powder 3-10wt%, chromium powder 1-5wt%, tin powder 1-3wt%, silicon powder 0.2-1wt%, and the rest is copper powder.

[0008] Preferably, the metal composite powder accounts for 60% of the transition layer material.

[0009] Preferably, the mass percentage of each component in the metal composite powder is: 15wt% zinc powder, 7wt% iron powder, 5wt% manganese powder, 6wt% nickel powder, 3wt% chromium powder, 2wt% tin powder, 0.5wt% silicon powder, and 61.5wt% copper powder.

[0010] Preferably, the mass percentages of the components in the organic solvent are: 5 wt% stearic acid, 35 wt% hydrogenated rosin, 7 wt% polyamide wax, 2 wt% benzotriazole; and 51 wt% hexanediol.

[0011] A method for manufacturing a powder metallurgy friction block transition layer material, comprising:

[0012] Preparation of metal composite powder: weigh each metal material according to the following mass percentage: zinc powder 10-20wt%, iron powder content of 5-10wt%, manganese powder 3-8wt%, nickel powder 3-10wt%, chromium powder 1-5wt%, tin powder 1-3wt%, silicon powder 0.2-1wt%, and the rest is copper powder; put the weighed component materials into a ball mill and mix and grind them thoroughly to obtain a metal composite powder mixture, wherein the particle size of the metal composite powder is 40μm-60μm;

[0013] Preparation of organic solvent: weighing each solvent according to the following mass percentage: 3-8wt% of stearic acid, 30-45wt% of hydrogenated rosin, 5-9wt% of polyamide wax, 1-3wt% of benzotriazole, and the rest being hexylene glycol; pouring the weighed stearic acid, hydrogenated rosin, polyamide wax, and benzotriazole into a beaker in sequence for heating at a temperature of 100-150° C., stirring with a magnetic stirrer during the heating process at a speed of 500-1000 r / min for a time of 5-10 min, adding hexylene glycol after stirring evenly, and stirring for another 3-5 min, stopping heating after all organic components are completely mixed evenly and the solvent has no stratification and floccules, and cooling to room temperature to obtain an organic solvent;

[0014] The transition layer material is prepared by adding the prepared organic solvent into the metal composite powder and stirring them fully to obtain the transition layer material, wherein the metal composite powder accounts for 40%-70% of the transition layer material.

[0015] A method for using a transition layer material of a powder metallurgy friction block, comprising:

[0016] Clean the back surface of the steel body to be coated with the transition layer material;

[0017] Uniformly deposit the prepared transition layer material on the steel back of the cleaned steel body, and bond the steel body deposited with the transition layer material to the friction body, wherein the transition layer is located between the steel body and the friction body;

[0018] Place the bonded steel body and friction body in an air induction hot pressing sintering furnace, introduce nitrogen + 10% - 20% hydrogen as the protective gas, sintering temperature 850°C - 950°C, sintering pressure 3MPa - 5MPa, heat preservation time 15min, to obtain a complete friction block.

[0019] Preferably, the thickness of the transition layer located between the steel body and the friction body is 0.01 - 0.5mm.

[0020] The specific beneficial effects of the present invention are:

[0021] 1. By coating a layer of transition layer material on the steel back surface by screen printing, the problem of mismatched thermal expansion properties between the friction body and the steel back is effectively solved, and the bonding strength between the two is significantly improved. The test results show that the bonding strength between the friction body and the steel back after sintering can reach 18.67 - 35.42MPa, much higher than 4.2 - 8MPa without spraying treatment.

[0022] 2. Enhance the heat resistance and shear resistance of the friction block: The metal composite powder in the transition layer has good heat resistance and toughness, enabling the friction block to withstand high temperatures and shear stresses during braking and not easily damaged.

[0023] 3. Simplify the processing process: Compared with traditional bonding methods, there is no need for special treatments such as grooving the steel back surface and adding anchoring structures. The printing of the transition layer is convenient to implement, reducing the processing cost. Description of the Drawings

[0024] In order to more clearly illustrate the embodiments of the present invention and their design schemes, the drawings required for the present embodiments will be briefly introduced below. The drawings in the following description are only partial embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0025] Figure 1 It is an image after the friction body and the steel body are bonded and sintered with the transition layer material prepared in the embodiment of the present invention;

[0026] Figure 2It is the microscopic morphology image after the friction body and the steel body are combined and sintered with the transition layer material prepared in the embodiment. Detailed implementation mode

[0027] To make the objectives, technical solutions and advantages of the present invention clearer, the following will further describe in detail the embodiments of the present application in conjunction with the accompanying drawings.

[0028] When the following description relates to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation modes described in the following exemplary embodiments do not represent all implementation modes consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0029] Embodiment 1

[0030] This embodiment provides a powder metallurgy friction block transition layer material, which is composed of metal composite powder and organic solvent; among them, the proportion of metal composite powder in the transition layer material is 40%-70%; the metal composite powder in this embodiment is mixed by the following materials, specifically including copper powder, iron powder, zinc powder, manganese powder, tin powder, nickel powder, chromium powder and silicon powder; and the mass percentages of each component are: zinc powder 10-20wt%, the content of iron powder is 5-10wt%, manganese powder 3-8wt%, nickel powder 3-10wt%, chromium powder 1-5wt%, tin powder 1-3wt%, silicon powder 0.2-1wt%, and the rest is copper powder; the optimal mass percentage in the ratio of this embodiment is: zinc powder 15wt%, the content of iron powder is 7wt%, manganese powder 5wt%, nickel powder 6wt%, chromium powder 3wt%, 2wt% tin powder, silicon powder 0.5wt%, and copper powder 61.5wt%.

[0031] This embodiment uses the above metal powder as the main material of the transition layer, providing good heat resistance and toughness for the friction body, so that the friction block can withstand high temperature and shear stress during braking and is not easily damaged.

[0032] The organic solvent in this embodiment is composed of stearic acid, hydrogenated rosin, polyamide wax, benzotriazole and hexanediol, and the mass percentages of each component are: stearic acid 3-8wt%, hydrogenated rosin 30-45wt%, polyamide wax 5-9wt%, benzotriazole 1-3wt%, and the rest is hexanediol. This embodiment provides an optimal ratio, specifically: stearic acid 5wt%, hydrogenated rosin 35wt%, polyamide wax 7wt%, benzotriazole 2wt%; hexanediol 51wt%; the organic solvent composed of the above material ratio can make the transition layer easy to coat at room temperature and has good strength and toughness after drying.

[0033] In this embodiment, the transition layer material composed of metal composite powder and organic solvent, when in use, connects the friction body and the steel body with this transition layer, without the need for special treatments such as grooving the steel back of the steel body and adding an anchoring structure. The printing of the transition layer is convenient to implement, reducing the processing cost; at the same time, it effectively solves the problem of mismatched thermal expansion properties between the friction body and the steel back, significantly improving the bonding strength between the two. The test results show that the bonding strength between the friction body and the steel back after sintering can reach 18.67 - 35.42 MPa, far higher than 4.2 - 8 MPa of those without spraying treatment.

[0034] Example 2

[0035] This embodiment provides a powder metallurgy friction block transition layer material and its usage method, including:

[0036] Weigh 10 wt% of zinc powder, 5 wt% of iron powder, 3 wt% of manganese powder, 3 wt% of nickel powder, 1 wt% of chromium powder, 1 wt% of tin powder, 0.2 wt% of silicon powder, and 76.8 wt% of copper powder according to the ratio, and place them into a ball mill for uniform mixing; use the mixed metal powder as the solid phase, and the particle size of this metal powder is 60 μm; complete the preparation of the metal composite powder;

[0037] Measure 3 wt% of stearic acid, 30 wt% of hydrogenated rosin, 5 wt% of polyamide wax, and 1 wt% of benzotriazole, pour them into a beaker in sequence, stir with a magnetic stirrer, the stirring speed is 500 r / min, the heating temperature is 100 °C, the stirring time is 10 min. After stirring evenly, add 61 wt% of hexanediol, and stir for another 3 min. After all organic components are completely mixed evenly, turn off the heating system and cool to room temperature to complete the preparation of the organic solvent

[0038] Mix the prepared metal composite powder with the organic solvent to make a multi - coating material paste. Specifically, the metal composite powder accounts for 70% of the transition layer material paste, and stir until the transition layer material presents a delicate, uniform and shiny paste; obtain the transition layer material.

[0039] Clean the back surface of the steel body; use alcohol and acetone to remove the oil stains and impurities on the back surface of the steel body completely; then, neatly place the back of the steel body on the placing table, and deposit the transition layer material on the back surface of the steel body with a squeegee according to the principle of screen printing, and the thickness of the transition layer material paste layer is 0.01 mm; bond the steel body deposited with the transition layer material with the friction body;

[0040] Finally, place the steel body evenly coated with the transition layer material paste and the friction body in a vacuum induction hot - pressing sintering furnace, introduce nitrogen + 10% - 20% hydrogen as the protective atmosphere, the sintering temperature is 850 °C, apply a pressure of 3 MPa for sintering, and the holding time is 15 min to form a complete friction block as Figure 1 andFigure 2 As shown. Through testing, the bonding strength between the friction body and the steel back is 19.7 MPa.

[0041] Example 3

[0042] Weigh 15 wt% zinc powder, 7 wt% iron powder, 5 wt% manganese powder, 6 wt% nickel powder, 3 wt% chromium powder, 2 wt% tin powder, 0.5 wt% silicon powder, and 61.5 wt% copper powder according to the ratio, and place them in a ball mill for uniform mixing. Use the mixed metal powder as the solid phase; the particle size of the metal powder is 50 μm; obtain the metal composite powder;

[0043] Measure 5 wt% stearic acid, 35 wt% hydrogenated rosin, 7 wt% polyamide wax, and 2 wt% benzotriazole, pour them into a beaker in sequence, stir with a magnetic stirrer, the stirring speed is 800 r / min, the heating temperature is 125 °C, the stirring time is 8 min. After stirring evenly, add 51 wt% hexanediol and stir for another 4 min. After all organic components are completely mixed evenly, turn off the heating system and cool to room temperature to obtain the organic solvent.

[0044] Mix the prepared metal composite powder with the organic solvent to make the multi-layer coating material paste. Specifically, the metal composite powder accounts for 60% of the transition layer material paste, and stir until the transition layer material presents a delicate, uniform and shiny paste; obtain the transition layer material.

[0045] Clean the back surface of the steel body, remove the oil stains and impurities on the back surface of the steel body with alcohol and acetone. Then, neatly place the steel back on the placement table, and deposit the transition layer material paste on the back surface of the steel back with a squeegee according to the principle of screen printing. The thickness of the transition layer material paste layer is 0.1 mm; bond the steel body with the deposited transition layer material to the friction body;

[0046] Finally, place the steel body evenly coated with the transition layer material paste and the friction body in a vacuum induction hot pressing sintering furnace, introduce nitrogen + 10% - 20% hydrogen as the protective atmosphere, the sintering temperature is 900 °C, apply a pressure of 4 MPa for sintering, and the holding time is 15 min to form a complete friction block. Through testing, the bonding strength between the friction body and the steel back is 25.91 MPa.

[0047] Example 4

[0048] Weigh 20 wt% zinc powder, 6 wt% iron powder, 6 wt% manganese powder, 5 wt% nickel powder, 3 wt% chromium powder, 3 wt% tin powder, 1 wt% silicon powder, and 56 wt% copper powder according to the ratio, place them in a ball mill for uniform mixing, use the mixed metal powder as the solid phase, and the particle size of the metal powder is 40 μm; obtain the metal composite powder;

[0049] Measure 6 wt% of stearic acid, 40 wt% of hydrogenated rosin, 8 wt% of polyamide wax, and 3 wt% of benzotriazole. Pour them into a beaker in sequence, and stir with a magnetic stirrer at a stirring speed of 1000 r / min, a heating temperature of 150 °C, and a stirring time of 5 min. After stirring evenly, add 43 wt% of hexanediol and stir for another 5 min. After all the organic components are completely mixed evenly, turn off the heating system and cool to room temperature. This is the organic solvent.

[0050] Mix the prepared metal composite powder with the organic solvent to make a multi-layer coating material paste. Specifically, the metal composite powder accounts for 50% of the transition layer material paste, and stir until the transition layer material presents a delicate, uniform and shiny paste; obtain the transition layer material.

[0051] Clean the back surface of the steel body; remove the oil stains and impurities on the back surface of the steel back with alcohol and acetone; then, neatly place the steel back on the placement table, and deposit the transition layer material paste on the back surface of the steel body with a squeegee according to the principle of screen printing. The thickness of the transition layer material paste layer is 0.5 mm; fit the steel body deposited with the transition layer material with the friction body;

[0052] Finally, place the steel back evenly coated with the transition layer material paste and the friction body in a vacuum induction hot pressing sintering furnace, introduce nitrogen + 10% - 20% hydrogen as the protective atmosphere, sinter at a temperature of 950 °C, apply a pressure of 5 MPa for sintering, and keep the temperature for 15 min to form a complete friction block. After testing, the bonding strength between the friction body and the steel back is 35.42 MPa.

[0053] By coating the transition layer material containing the metal composite powder and the organic solvent on the surface of the steel back, the bonding strength between the friction body and the steel back is significantly improved, and the heat resistance and shear resistance of the friction block are enhanced; the invention has the advantages of simple process, low cost, and remarkable effect, and is suitable for the manufacture of friction blocks for high-speed railway train braking systems.

[0054] In addition, any combination can be made among various different embodiments of the present disclosure as long as it does not violate the idea of the present disclosure, and it should also be regarded as the content disclosed by the present disclosure.

Claims

1. A powder metallurgy friction block transition layer material, characterized in that: The transition layer material is composed of metal composite powder and organic solvent; wherein the metal composite powder accounts for 40%-70% of the transition layer material; The mass percentages of the components in the organic solvent are as follows: 3-8 wt% of stearic acid, 30-45 wt% of hydrogenated rosin, 5-9 wt% of polyamide wax, 1-3 wt% of benzotriazole, and the rest is hexanediol.

2. The powder metallurgy friction block transition layer material according to claim 1, characterized in that: The components of the metal composite powder include: copper powder, iron powder, zinc powder, manganese powder, tin powder, nickel powder, chromium powder and silicon powder; the mass percentage of each component is: zinc powder 10-20wt%, iron powder content is 5-10wt%, manganese powder 3-8wt%, nickel powder 3-10wt%, chromium powder 1-5wt%, tin powder 1-3wt%, silicon powder 0.2-1wt%, and the rest is copper powder.

3. The powder metallurgy friction block transition layer material according to claim 1, characterized in that: The metal composite powder accounts for 60% of the transition layer material.

4. The powder metallurgy friction block transition layer material according to claim 2, characterized in that: The mass percentage of each component in the metal composite powder is: 15wt% zinc powder, 7wt% iron powder, 5wt% manganese powder, 6wt% nickel powder, 3wt% chromium powder, 2wt% tin powder, 0.5wt% silicon powder, and 61.5wt% copper powder.

5. The powder metallurgy friction block transition layer material according to claim 1, characterized in that: The mass percentages of the components in the organic solvent are: 5 wt % of stearic acid, 35 wt % of hydrogenated rosin, 7 wt % of polyamide wax, 2 wt % of benzotriazole, and 51 wt % of hexylene glycol.

6. A method for manufacturing a powder metallurgy friction block transition layer material, characterized in that: include: Preparation of metal composite powder: weigh each metal material according to the following mass percentage: zinc powder 10-20wt%, iron powder content of 5-10wt%, manganese powder 3-8wt%, nickel powder 3-10wt%, chromium powder 1-5wt%, tin powder 1-3wt%, silicon powder 0.2-1wt%, and the rest is copper powder; put the weighed component materials into a ball mill and mix and grind them thoroughly to obtain a metal composite powder mixture, wherein the particle size of the metal composite powder is 40μm-60μm; Preparation of organic solvent: weighing each solvent according to the following mass percentage: 3-8wt% of stearic acid, 30-45wt% of hydrogenated rosin, 5-9wt% of polyamide wax, 1-3wt% of benzotriazole, and the rest being hexylene glycol; pouring the weighed stearic acid, hydrogenated rosin, polyamide wax, and benzotriazole into a beaker in sequence for heating at a temperature of 100-150° C., stirring with a magnetic stirrer during the heating process at a speed of 500-1000 r / min for a time of 5-10 min, adding hexylene glycol after stirring evenly, and stirring for another 3-5 min, stopping heating after all organic components are completely mixed evenly and the solvent has no stratification and floccules, and cooling to room temperature to obtain an organic solvent; The transition layer material is prepared by adding the prepared organic solvent into the metal composite powder and stirring them fully to obtain the transition layer material, wherein the metal composite powder accounts for 40%-70% of the transition layer material.

7. A method for using a powder metallurgy friction block transition layer material, characterized in that: include: Cleaning the back side of the steel body to be coated with the transition layer material; The prepared transition layer material is uniformly deposited on the steel back of the cleaned steel body, and the steel body on which the transition layer material is deposited is bonded to the friction body, wherein the transition layer is located between the steel body and the friction body; The bonded steel body and friction body are placed in an air induction hot pressing sintering furnace, nitrogen + 10% to 20% hydrogen is introduced as protective gas, the sintering temperature is 850°C-950°C, the sintering pressure is 3MPa-5MPa, and the insulation time is 15 minutes to obtain a complete friction block.

8. The method for using the powder metallurgy friction block transition layer material according to claim 7, characterized in that: The thickness of the transition layer between the steel body and the friction body is 0.01-0.5 mm.

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