A flux for bimetallic sintering and preparation method thereof

Abstract

The present invention belongs to the technical field of bimetallic sintering, and specifically relates to a flux for bimetallic sintering and a preparation method thereof. The flux for bimetallic sintering comprises the following raw materials in parts by weight: 25 to 30 parts of rosin powder; 15 to 20 parts of sulfur powder; 30 to 35 parts of borax; and 25 to 30 parts of glycerol. The flux for bimetallic sintering fundamentally solves the flux problem of bimetallic sintering, and the raw materials are easy to control, thereby ensuring the stability of the bimetallic sintered product.

Description

Technical Field

[0001] The invention belongs to the technical field of bimetal sintering, and specifically relates to a flux used for bimetal sintering and a preparation method thereof. Background Art

[0002] Bimetal sintering is an important part of solving the life of hydraulic pumps and hydraulic motors. The stability and improvement of sintering quality is a major problem in the industry, especially the sintering of ductile iron and copper alloy materials is the core technology of the enterprise, and the key material is flux; flux can make bimetal sintering at a lower temperature, which can not only ensure the strength of the bimetal sintering bonding surface, but also ensure that the performance of the base material is not affected. However, at present, my country's flux cannot meet the quality requirements of bimetal sintering bonding surface and coating. The quality of products after sintering fluctuates greatly, and there are sometimes phenomena such as coating peeling and warping. Metallographic analysis found that various defects such as inclusions, cracks, pores, etc. appeared on the bonding surface after sintering, and the segregation of wear-resistant phases in the coating affected the bonding strength and wear resistance of the product. Summary of the invention

[0003] The purpose of the present invention is to provide a flux for bimetallic sintering and a preparation method thereof in view of the above-mentioned defects. The flux for bimetallic sintering fundamentally solves the flux problem of bimetallic sintering, the raw materials are easy to control, and the stability of the bimetallic sintered product is ensured.

[0004] The technical scheme of the present invention is: a flux for bimetallic sintering, comprising the following raw materials in parts by weight: 25-30 parts of rosin powder; 15-20 parts of sulfur powder; 30-35 parts of borax; and 25-30 parts of glycerol.

[0005] The flux used for bimetallic sintering comprises the following raw materials in parts by weight: 25 to 28 parts of rosin powder; 15 to 18 parts of sulfur powder; 32 to 35 parts of borax; and 25 to 28 parts of glycerol.

[0006] The flux for bimetallic sintering is characterized by comprising the following raw materials in parts by weight: 28 parts of rosin powder; 15 parts of sulfur powder; 32 parts of borax; and 25 parts of glycerol.

[0007] The flux for bimetallic sintering is characterized by comprising the following raw materials in parts by weight: 25 parts of rosin powder; 15 parts of sulfur powder; 35 parts of borax; and 25 parts of glycerol.

[0008] The method for preparing the flux for bimetallic sintering comprises the following steps:

[0009] a. Complete dehydration of borax: First, pour the borax into a refractory container; then put the refractory container into an electric furnace, turn on the power and heat it to

[0010] 500~600℃, and keep warm; the heat preservation time is 1~2h / kg, after keeping warm for 1~2h / kg, turn off the power, cool the melted borax to 50~70℃ with the furnace, and then take it out of the furnace for air cooling;

[0011] b. Borax crushing: Use a crusher to crush the dehydrated borax in step a to 200 mesh, and then use a 200 mesh standard sample sieve to screen the crushed borax;

[0012] c. Screening of sulfur and rosin: Use a 200-mesh standard sample sieve to screen sulfur powder and rosin powder respectively;

[0013] d. Weigh each component according to the formula;

[0014] e. Mixing: Mix the weighed borax, sulfur powder and rosin powder evenly, then add into glycerin and stir well before use.

[0015] The refractory container in step a is a crucible.

[0016] The electric furnace in step a is a BTF-1000 tempering furnace.

[0017] The pulverizer in step b is a CF-630 laboratory small airflow pulverizer.

[0018] In the step e, borax, sulfur and rosin are added into a small V-type mixer and mixed evenly.

[0019] The beneficial effects of the present invention are as follows: the flux for bimetallic sintering of the present invention combines rosin powder, sulfur powder, borax and glycerin as raw materials, and only when the four raw materials are combined together and coordinated with each other can the bimetallic sintering requirements be met, and the shear strength of the bonding surface of the product sintered with the flux is 200-260MPa; the sintering cylinder body and the friction pair formed by the material matched with it are strictly tested and verified as a whole machine (test verification pressure ≥30MPa, rotation speed 2000r / min), and after 2000 hours of testing, the copper layer does not peel off and no obvious wear marks appear.

[0020] In the preparation method of the flux for bimetallic sintering, borax is completely dehydrated. If the borax contains water, during the sintering process, the crystal water is separated to form water vapor, which is left on the sintering bonding surface and forms defects such as pores after cooling. The dehydration process is reasonable and simple to operate, and can effectively remove the water in the borax.

[0021] The flux for bimetallic sintering of the present invention fundamentally solves the flux problem of bimetallic sintering, the raw materials are easy to control, and the stability of the bimetallic sintered product is guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the metallographic structure diagram of the sintered bonding surface of the QT600-3 cylinder body in Example 1 (500X).

[0023] Figure 2 This is the metallographic structure diagram of the sintered bonding surface of the 40Cr cylinder block in Example 2 (100X).

[0024] Figure 3 This is the metallographic structure diagram of the sintered bonding surface of the 40Cr cylinder block in Example 2 (500X).

[0025] Figure 4 This is the metallographic structure diagram of the sintered bonding surface of the 42CrMo distribution plate in Example 3 (100X). DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with embodiments, but the present invention is not limited to these embodiments.

[0027] Example 1

[0028] The flux for bimetallic sintering is characterized by comprising the following raw materials in parts by weight: 30 parts of rosin powder; 15 parts of sulfur powder; 30 parts of borax; and 25 parts of glycerol.

[0029] The method for preparing the flux for bimetallic sintering comprises the following steps:

[0030] a. Complete dehydration of borax: First, pour analytically pure 99.5% borax into a crucible; then put the crucible into a BTF-1000 tempering furnace, turn on the power and heat it to 500-600℃, and keep it warm; the heat preservation time is 3-5h, and then turn off the power after 3-5h, cool the melted borax to 50-70℃ with the furnace, and then take it out of the furnace and air cool it;

[0031] b. Borax crushing: Use a CF-630 laboratory small airflow mill to crush the dehydrated borax in step a to 200 mesh, and then use a 200 mesh standard sample sieve to screen the crushed borax;

[0032] c. Screening of sulfur and rosin: Use a 200-mesh standard sample sieve to screen sulfur powder and rosin powder respectively;

[0033] d. Weigh each component according to the formula;

[0034] e. Mixing: Add the weighed borax, sulfur and rosin into a small V-type mixer and mix evenly, then add into glycerin and stir evenly before use.

[0035] The flux described in Example 1 is applied to the bimetallic sintering of the QT600-3 cylinder body and lead bronze. The specific steps of use are: the flux is coated on the sintered surface of the QT600-3 cylinder body, and the coating thickness is about 0.1 to 0.3 mm. After the flux is dried, the lead bronze is placed on the sintering surface, and the cylinder body is placed on the conveyor belt of the continuous heating furnace. The furnace temperature and the conveying speed are adjusted appropriately, and the cylinder body is sent into the furnace. After passing through the heating zone and the cooling zone in the furnace, the desired bimetallic cylinder body can be obtained.

[0036] from Figure 1 It can be seen that the sintered bonding surface has no defects, and the segregation size and distribution of lead in the copper layer are good. According to the YS / T485 test, the shear strength of the bimetallic sintered bonding surface of the QT600-3 cylinder body after sintering is 200-220MPa, which meets the requirements of the hydraulic pump cylinder body.

[0037] Example 2

[0038] The flux for bimetallic sintering is characterized by comprising the following raw materials in parts by weight: 25 parts of rosin powder; 15 parts of sulfur powder; 35 parts of borax; and 25 parts of glycerol.

[0039] The method for preparing the flux for bimetallic sintering comprises the following steps:

[0040] a. Complete dehydration of borax: First, pour analytically pure 99.5% borax into a crucible; then put the crucible into a BTF-1000 tempering furnace, turn on the power and heat it to 500-600℃, and keep it warm; the heat preservation time is 6-8h, and then turn off the power after 6-8h, cool the melted borax to 50-70℃ with the furnace, and then take it out of the furnace and air cool it;

[0041] b. Borax crushing: Use a CF-630 laboratory small airflow mill to crush the dehydrated borax in step a to 200 mesh, and then use a 200 mesh standard sample sieve to screen the crushed borax;

[0042] c. Screening of sulfur and rosin: Use a 200-mesh standard sample sieve to screen sulfur powder and rosin powder respectively;

[0043] d. Weigh each component according to the formula;

[0044] e. Mixing: Add the weighed borax, sulfur and rosin into a small V-type mixer and mix evenly, then add into glycerin and stir evenly before use.

[0045] The flux described in Example 2 is applied to the bimetallic sintering of a 40Cr cylinder body and lead bronze. The specific steps of use are: the flux is coated on the sintered surface of the 40Cr cylinder body, and the coating thickness is about 0.1 to 0.3 mm. After the flux is dried, lead bronze is placed on the sintering surface, and the cylinder body is placed on the conveyor belt of a continuous heating furnace. The furnace temperature and conveying speed are adjusted appropriately, and the cylinder body is sent into the furnace. After passing through the heating zone and cooling zone in the furnace, the desired bimetallic cylinder body can be obtained.

[0046] from Figure 2 , 3 It can be seen that the sintered bonding surface has no defects, and the segregation size and distribution of lead in the copper layer are good. According to YS / T485, the shear strength of the sintered 40Cr cylinder body is 240-260MPa, which meets the requirements of the hydraulic pump cylinder body.

[0047] Example 3

[0048] The flux for bimetallic sintering is characterized by comprising the following raw materials in parts by weight: 28 parts of rosin powder; 15 parts of sulfur powder; 32 parts of borax; and 25 parts of glycerol.

[0049] The method for preparing the flux for bimetallic sintering comprises the following steps:

[0050] a. Complete dehydration of borax: First, pour analytically pure 99.5% borax into a crucible; then put the crucible into a BTF-1000 tempering furnace, turn on the power and heat it to 500-600℃, and keep it warm; the heat preservation time is 3.5-6h, and then turn off the power after 3.5-6h, cool the melted borax to 50-70℃ with the furnace, and then take it out of the furnace and air cool it;

[0051] b. Borax crushing: Use a CF-630 laboratory small airflow mill to crush the dehydrated borax in step a to 200 mesh, and then use a 200 mesh standard sample sieve to screen the crushed borax;

[0052] c. Screening of sulfur and rosin: Use a 200-mesh standard sample sieve to screen sulfur powder and rosin powder respectively;

[0053] d. Weigh each component according to the formula;

[0054] e. Mixing: Add the weighed borax, sulfur and rosin into a small V-type mixer and mix evenly, then add into glycerin and stir evenly before use.

[0055] The flux described in Example 3 is applied to the bimetallic sintering of 42CrMo distribution plate and lead bronze. The specific usage steps are: apply the flux on the surface of the sintered substrate of the 42CrMo distribution plate, and the coating thickness is about 0.1-0.3mm. After the flux is dried, lead bronze is placed on the sintering surface, and the cylinder body is placed on the conveyor belt of the continuous heating furnace. After adjusting the appropriate furnace temperature and conveying speed, the cylinder body is sent into the furnace. After passing through the heating zone and cooling zone in the furnace, the required bimetallic distribution plate can be obtained.

[0056] from Figure 4 It can be seen that the sintered bonding surface has no defects, and the segregation size and distribution of lead in the copper layer are good. According to the YS / T485 test, the shear strength of the 42CrMo distribution plate after sintering is 230-260MPa, which meets the requirements of the distribution plate.

[0057] In addition to the above embodiments, the present invention can also be applied to other bimetallic sintering of ductile iron or steel and lead bronze. Any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope required by the present invention.

Claims

1. A flux for bimetallic sintering, characterized in that: The method is composed of the following raw materials in parts by weight: 25-30 parts of rosin powder; 15-20 parts of sulfur powder; 30-35 parts of borax; 25-30 parts of glycerol; The flux for bimetal sintering comprises the following steps: a. Complete dehydration of borax: first pour the borax into a refractory container; then put the refractory container into an electric furnace, turn on the power to raise the temperature to 500-600℃, and keep it warm; the insulation time is 1-2h / kg, and after the temperature reaches 1-2h / kg, turn off the power, cool the melted borax to 50-70℃ with the furnace, and then take it out of the furnace for air cooling; b. Borax crushing: Use a crusher to crush the dehydrated borax in step a to 200 mesh, and then use a 200 mesh standard sample sieve to screen the crushed borax; c. Screening of sulfur and rosin: Use a 200-mesh standard sample sieve to screen sulfur powder and rosin powder respectively; d. Weigh each component according to the formula; e. Mixing: Mix the weighed borax, sulfur powder and rosin powder evenly, then add into glycerin and stir well before use.

2. The flux for bimetallic sintering according to claim 1, characterized in that: The invention is composed of the following raw materials in parts by weight: 25 to 28 parts of rosin powder; 15 to 18 parts of sulfur powder; 32 to 35 parts of borax; and 25 to 28 parts of glycerol.

3. The flux for bimetallic sintering according to claim 1, characterized in that: The invention is composed of the following raw materials in parts by weight: 28 parts of rosin powder; 15 parts of sulfur powder; 32 parts of borax; and 25 parts of glycerin.

4. The flux for bimetallic sintering according to claim 1, characterized in that: The invention is composed of the following raw materials in parts by weight: 25 parts of rosin powder; 15 parts of sulfur powder; 35 parts of borax; and 25 parts of glycerin.

5. The flux for bimetallic sintering according to claim 1, characterized in that: The refractory container in step a is a crucible.

6. The flux for bimetallic sintering according to claim 1, characterized in that: The electric furnace in step a is a BTF-1000 tempering furnace.

7. The flux for bimetallic sintering according to claim 1, characterized in that: The pulverizer in step b is a CF-630 laboratory small airflow pulverizer.

8. The flux for bimetallic sintering according to claim 1, characterized in that: In the step e, the borax, sulfur powder and rosin powder are added into a small V-type mixer and mixed evenly.

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