Preparation method of hydraulic plunger pump cylinder body with enhanced interfacial strength

Abstract

The invention belongs to the technical field of industrial product processing and preparation, and particularly relates to a preparation method of a hydraulic plunger pump cylinder body with enhanced interfacial strength. The preparation method of the hydraulic plunger pump cylinder body with the enhanced interface strength specifically comprises the steps that copper-plated flake graphite and metal powder are mixed to obtain mixed powder; the mixed powder is subjected to cladding on the inner side of the steel hydraulic plunger pump cylinder body through laser cladding to form a cladding layer, copper in the mixed powder and medium steel on the inner side form metallurgical bonding, and the hydraulic plunger pump cylinder body is obtained; the conditions of the laser cladding are as follows: the laser power is 3000-5000 W, the scanning speed is 50-100 mm / s, the spot diameter is 0.5-2 mm, and the lap joint rate is 30%-60%. By the adoption of the laser cladding method, copper in the mixed powder and steel in the steel hydraulic plunger pump cylinder body can form metallurgical bonding, the interface bonding strength between the copper and the steel is effectively improved, and then the service life of the hydraulic plunger pump cylinder body is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of industrial product processing and preparation, and in particular relates to a method for preparing a hydraulic plunger pump cylinder body with enhanced interface strength. Background Art

[0002] The hydraulic piston pump is a typical positive displacement pump that is driven by a prime mover to convert mechanical energy into liquid pressure energy, which is then delivered to the system in the form of pressure and flow. Because it can deliver liquids under high pressure, this pump is widely used in many fields of industrial production and daily life. The manufacturing process of the traditional hydraulic piston pump cylinder is relatively cumbersome, and seamless steel pipes or pipe fittings obtained by casting or forging are usually used. These pipe fittings need to be processed through multiple processes, including rough boring, semi-finishing boring, finishing boring, and sometimes electroplating, as well as final polishing or honing. This manufacturing method is not only inefficient in production, but also relatively costly.

[0003] However, currently, copper-based graphite wear-resistant materials are used to form the inner wall of the steel hydraulic plunger cylinder through powder metallurgy process to prepare copper-steel bimetallic hydraulic plunger cylinder, or copper-based self-lubricating materials are directly used to prepare copper-based hydraulic plunger pump cylinder through powder metallurgy sintering, both of which have good wear resistance and corrosion resistance and good mechanical properties. After copper plating the graphite, a protective layer is formed on the inner wall of the steel hydraulic plunger cylinder by powder metallurgy. Since copper and steel are mechanically bonded, the bonding strength is weak, so the copper-steel bimetallic interface strength is not high. During use, the protective layer will fall off from the cylinder surface, thereby affecting the service life of the hydraulic plunger pump cylinder. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method for preparing a hydraulic plunger pump cylinder with enhanced interface strength, which effectively improves the interface strength of the copper-steel bimetallic interface.

[0005] In order to achieve the above object, the technical solution of the present invention is as follows.

[0006] A first aspect of the present invention provides a method for preparing a hydraulic plunger pump cylinder with enhanced interface strength, comprising the following steps:

[0007] The flake graphite is subjected to copper plating treatment to obtain copper-plated flake graphite;

[0008] The copper-plated flake graphite and metal powder are mixed in a mass ratio of 1-2:8-9 to obtain a mixed powder; the metal powder is obtained by mixing copper powder, nickel powder and zinc powder in a mass ratio of 75-85:5-20:5-10;

[0009] The mixed powder is added to the inner wall of a steel hydraulic plunger pump cylinder body, and under laser cladding, the copper element in the mixed powder and the steel element in the inner wall of the steel hydraulic plunger pump cylinder body form a metallurgically bonded cladding layer to obtain a hydraulic plunger pump cylinder body with enhanced interface strength;

[0010] The conditions of the laser cladding are: laser power of 3000-5000W, scanning speed of 50mm / s-100mm / s, spot diameter of 0.5mm-2mm, and overlap rate of 30%-60%.

[0011] The present invention adopts a laser cladding method, under the conditions of laser power of 3000-5000W, scanning speed of 50mm / s-100mm / s, spot diameter of 0.5mm-2mm, and overlap rate of 30%-60%, the copper element in the mixed powder can form a metallurgical bond, that is, a chemical bond, with the steel element in the inner wall of the steel hydraulic plunger pump cylinder, thereby effectively improving the interface bonding strength between copper and steel, so that the cladding layer will not fall off during use, and the service life of the hydraulic plunger pump cylinder is improved. In addition, the entire molding process is fast, which greatly improves the processing efficiency.

[0012] In another preferred embodiment, the thickness of the cladding layer is 1 mm to 5 mm.

[0013] In another preferred embodiment, the specific process of the copper plating treatment is as follows:

[0014] Plating flake graphite in plating solution A, adding plating solution B and stirring evenly, reacting at 30°C to 50°C for 20min to 40min, washing, filtering, and obtaining nickel-plated flake graphite;

[0015] In the plating solution A, the mass ratio of C4H4KNa, HCHO and water is 4.5-5.5:2.5-3.5:100;

[0016] In the plating solution B, the mass ratio of NaOH, CuSO4 and water is 0.5-1:8-12:100.

[0017] In another preferred embodiment, the mass volume ratio of the flake graphite, the plating solution A and the plating solution B is 1 kg: 4 L to 5 L: 4 L to 5 L.

[0018] In another preferred embodiment, the particle size of the flake graphite is 100 mesh to 200 mesh.

[0019] In another preferred embodiment, the mixing and stirring speed is 30 rpm / min to 100 rpm / min.

[0020] In another preferred embodiment, the mesh sizes of the copper powder, the nickel powder and the zinc powder are all 100-200 meshes.

[0021] A second aspect of the present invention provides a hydraulic piston pump cylinder with enhanced interface strength.

[0022] Compared with the prior art, the present invention has at least the following beneficial effects:

[0023] The present invention adopts a laser cladding method to form a metallurgical bond between the copper element in the mixed powder and the steel element in the inner wall of the steel hydraulic plunger pump cylinder, thereby effectively improving the interface bonding strength between copper and steel, and solving the problem of low copper-steel bimetallic interface strength due to mechanical bonding between copper and steel in traditional powder metallurgy or casting processes, and the protective layer falling off from the cylinder surface during use.

[0024] The present invention controls the laser cladding conditions, and with the coordination of various parameters, copper and steel are directly metallurgically bonded. The obtained cladding layer can better protect the hydraulic plunger pump cylinder, effectively improve the performance of the hydraulic plunger pump cylinder, and meet the service requirements of high-performance hydraulic plunger pump cylinders in the future. Compared with the traditional powder metallurgy preparation method, it has better copper-steel bimetallic interface bonding strength, higher mechanical, corrosion and wear resistance, simpler preparation process and lower cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a morphology diagram of the cladding layer in Example 1 of the present invention.

[0026] Figure 2 1 is a structural distribution diagram of the cladding layer in Example 1 of the present invention; in the figure, 1 is the cladding layer and 2 is the inner wall. DETAILED DESCRIPTION

[0027] The following will be combined with the specific implementation of the present invention to clearly and completely describe the technical solution in the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] The methods described in the embodiments of the present invention are conventional methods unless otherwise specified. The materials, reagents, etc. used can be obtained from commercial sources unless otherwise specified.

[0029] At present, graphite is copper-plated and then sintered by powder metallurgy to form the inner side of the steel hydraulic plunger cylinder body to improve the wear and corrosion resistance of the inner wall of the steel hydraulic plunger cylinder body. However, by using the powder metallurgy sintering method, the copper in the copper-plated graphite and the steel interface are mechanically bonded, so during use, the protective layer is prone to fall off, which seriously affects the performance and service life of the steel hydraulic plunger cylinder body.

[0030] The present invention adopts a laser cladding method, and under the conditions of controlling the laser cladding power to be 3000-5000W, the scanning speed to be 50mm / s-100mm / s, the spot diameter to be 0.5mm-2mm, and the overlap rate to be 30%-60%, the copper in the copper-plated graphite can directly form a metallurgical bond with the steel component on the inner wall of the steel hydraulic plunger cylinder body, that is, the copper and the steel two substances produce a metallurgical chemical reaction to form a tight bond, thereby effectively improving the interface bonding strength, effectively preventing the problem of the cladding layer falling off from the inner wall of the steel hydraulic plunger cylinder body, ensuring the performance of the hydraulic plunger pump cylinder body, and improving the service life of the hydraulic plunger pump cylinder body.

[0031] The following is a detailed description of a hydraulic plunger pump cylinder with enhanced interface strength and its preparation method. The present invention has no restrictions on the type and shape of the steel hydraulic plunger pump cylinder. The purity of the pure copper powder, pure nickel powder and pure zinc powder in the following embodiments is above 99%.

[0032] Example 1

[0033] A method for preparing a hydraulic plunger pump cylinder with enhanced interface strength comprises the following steps:

[0034] S1. Place 100-mesh flake graphite in plating solution A and stir evenly, then pour into plating solution B and stir evenly, react at 30°C for 20 minutes, then wash, filter and dry to obtain copper-plated flake graphite;

[0035] The mass volume ratio of flake graphite, plating solution A and plating solution B is 1kg:4L:4L;

[0036] In plating solution A, the mass ratio of C4H4KNa, HCHO and water is 4.5:2.5:100; in plating solution B, the mass ratio of NaOH, CuSO4 and water is 0.5:8:100.

[0037] S2, pure copper powder, pure nickel powder, and pure titanium powder are mixed in a mass ratio of 75:20:5 to obtain metal powder; nickel-plated flake graphite and metal powder are mixed in a mass ratio of 1:8, and mixed and stirred at 30 rpm / min for 5 hours to obtain mixed powder; the particle size of pure copper powder, pure nickel powder, and pure zinc powder are all 100 mesh.

[0038] S3. Under the parameters of laser power 3000W, scanning speed 50mm / s, spot diameter 0.5mm and overlap rate 30%, the mixed powder is clad on the inner wall of the steel hydraulic piston pump cylinder by laser cladding using the powder feeding method. The thickness of the cladding layer is measured during the powder feeding process. When the thickness of the cladding layer is 1mm, the cladding is stopped to obtain a hydraulic piston pump cylinder with enhanced interface strength.

[0039] Example 2

[0040] A method for preparing a hydraulic plunger pump cylinder with enhanced interface strength comprises the following steps:

[0041] S1, placing 150 mesh flake graphite in plating solution A and stirring evenly, then pouring into plating solution B and stirring evenly, reacting at 40°C for 30 minutes, then washing, filtering and drying to obtain copper-plated flake graphite;

[0042] The mass volume ratio of flake graphite, plating solution A and plating solution B is 1kg:5L:4L;

[0043] In the plating solution A, the mass ratio of C4H4KNa, HCHO and water is 4:3:100.

[0044] In plating solution B, the mass ratio of NaOH, CuSO4 and water is 0.75:10:100.

[0045] S2, pure copper powder, pure nickel powder, and pure titanium powder are mixed in a mass ratio of 80:12.5:7.5 to obtain metal powder; nickel-plated flake graphite and metal powder are mixed in a mass ratio of 1.5:8.5, and mixed and stirred at 65 rpm / min for 7.5 hours to obtain mixed powder; the particle size of pure copper powder, pure nickel powder, and pure zinc powder are all 150 mesh.

[0046] S3. Under the conditions of laser power 4000W, scanning speed 75mm / s, spot diameter 1mm and overlap rate 45%, the mixed powder is clad on the inner wall of the steel hydraulic piston pump cylinder by laser cladding using the powder feeding method. The thickness of the cladding layer is measured during the powder feeding process. When the thickness of the cladding layer is 3mm, the cladding is stopped to obtain a hydraulic piston pump cylinder with enhanced interface strength.

[0047] Example 3

[0048] A method for preparing a hydraulic plunger pump cylinder with enhanced interface strength comprises the following steps:

[0049] S1, after stirring the 200-mesh plating solution A evenly, pour the plating solution B into it and stir evenly, react at 50°C for 40 minutes, then wash, filter and dry to obtain copper-plated flake graphite;

[0050] The mass volume ratio of flake graphite, plating solution A and plating solution B is 1kg:5L:5L;

[0051] In plating solution A, the mass ratio of C4H4KNa, HCHO and water is 5.5:3.5:100; in plating solution B, the mass ratio of NaOH, CuSO4 and water is 1:12:100.

[0052] S2, pure copper powder, pure nickel powder, and pure titanium powder are mixed in a mass ratio of 85:5:10 to obtain metal powder; nickel-plated flake graphite and metal powder are mixed in a mass ratio of 2:9, and mixed and stirred at 100 rpm / min for 10 hours to obtain mixed powder; the particle size of pure copper powder, pure nickel powder, and pure zinc powder are all 200 mesh.

[0053] S3. Under the parameters of laser power 5000W, scanning speed 100mm / s, spot diameter 2mm and overlap rate 60%, the mixed powder is clad on the inner wall of the steel hydraulic piston pump cylinder by laser cladding using the powder feeding method. The thickness of the cladding layer is measured during the powder feeding process. When the thickness of the cladding layer is 5mm, the cladding is stopped to obtain a hydraulic piston pump cylinder with enhanced interface strength.

[0054] The mechanical properties of the inner wall of the hydraulic piston pump cylinder with enhanced interface strength obtained in Examples 1 to 3 were measured respectively. The hydraulic piston pump cylinder prepared by the conventional powder metallurgy method using the same raw materials was used as a control group, and the mechanical properties of its inner wall were measured. The results are shown in Table 1.

[0055] Table 1 Mechanical properties of different hydraulic piston pump cylinder inner wall

[0056] Group Tensile properties hardness Friction coefficient Wear rate Example 1 ≥230MPa ≥65HV ≤0.25 <![CDATA[≤2.0g / m 3 ]]> Example 2 ≥215MPa ≥60HV ≤0.22 <![CDATA[≤1.8g / m 3 ]]> Example 3 ≥200MPa ≥55HV ≤0.20 <![CDATA[≤1.5g / m 3 ]]> Control group >160MPa >30HV ＜0.25 <![CDATA[<5g / m 3 ]]>

[0057] From the results in Table 1, it can be seen that the tensile strength and hardness of the inner wall of the hydraulic plunger pump cylinder with enhanced interface strength in Examples 1 to 3 are significantly higher than those of the control group, and the wear rate is lower than that of the control group. This shows that the laser cladding method can effectively improve the interface bonding strength between copper and steel, thereby preventing the cladding layer from falling off, and improving the performance and service life of the hydraulic plunger pump cylinder with enhanced interface strength.

[0058] The cladding layer of the hydraulic piston pump cylinder with enhanced interface strength in Example 1 was analyzed for appearance and structure. The results are as follows: Figure 1 and Figure 2 As shown, from Figure 1 It can be seen that the cladding layer is dense and has no defects. Figure 2 It can be seen that the interface between the cladding layer and the inner wall of the hydraulic piston pump cylinder with enhanced interface strength is well bonded, the transition zone between the copper phase and the steel phase is small, and the dilution rate is low. It can be seen that laser cladding can effectively improve the interface strength between the copper phase and the steel phase.

[0059] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a hydraulic piston pump cylinder with enhanced interface strength, characterized in that: The following steps are involved: The flake graphite is subjected to copper plating treatment to obtain copper-plated flake graphite; The copper-plated flake graphite and metal powder are mixed in a mass ratio of 1-2:8-9 to obtain a mixed powder; the metal powder is obtained by mixing copper powder, nickel powder and zinc powder in a mass ratio of 75-85:5-20:5-10; The mixed powder is added to the inner wall of a steel hydraulic plunger pump cylinder body, and under laser cladding, the copper element in the mixed powder and the steel element in the inner wall of the steel hydraulic plunger pump cylinder body form a metallurgically bonded cladding layer to obtain a hydraulic plunger pump cylinder body with enhanced interface strength; The conditions of the laser cladding are: laser power of 3000-5000W, scanning speed of 50mm / s-100mm / s, spot diameter of 0.5mm-2mm, and overlap rate of 30%-60%.

2. The method for preparing a hydraulic plunger pump cylinder with enhanced interface strength according to claim 1, characterized in that: The thickness of the cladding layer is 1 mm to 5 mm.

3. The method for preparing a hydraulic piston pump cylinder with enhanced interface strength according to claim 1, characterized in that: The specific process of the copper plating process is as follows: Plating flake graphite in plating solution A, adding plating solution B and stirring evenly, reacting at 30°C to 50°C for 20min to 40min, washing, filtering, and obtaining nickel-plated flake graphite; In the plating solution A, the mass ratio of C4H4KNa, HCHO and water is 4.5-5.5:2.5-3.5:100; In the plating solution B, the mass ratio of NaOH, CuSO4 and water is 0.5-1:8-12:

100.

4. The method for preparing a hydraulic piston pump cylinder with enhanced interface strength according to claim 3, characterized in that: The mass volume ratio of the flake graphite, the plating solution A and the plating solution B is 1kg:4L-5L:4L-5L.

5. The method for preparing a hydraulic plunger pump cylinder with enhanced interface strength according to claim 1, characterized in that: The particle size of the flake graphite is 100-200 meshes.

6. The method for preparing a hydraulic piston pump cylinder with enhanced interface strength according to claim 1, characterized in that: The mixing stirring speed is 30 rpm / min to 100 rpm / min, and the mixing time is 5 h to 10 h.

7. The method for preparing a hydraulic plunger pump cylinder with enhanced interface strength according to claim 1, characterized in that: The mesh sizes of copper powder, nickel powder and zinc powder are all 100 mesh to 200 mesh.

8. A hydraulic plunger pump cylinder with enhanced interface strength prepared by the preparation method according to any one of claims 1 to 7.

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