Laser cladding precision forging machine shaft sleeve material and preparation method thereof

Abstract

The invention belongs to the technical field of surface engineering, and relates to a laser cladding precision forging machine shaft sleeve material and a preparation method thereof. The functional layer alloy powder comprises the following components in percentage by mass: 2-5% of SiC powder and the balance of copper-based alloy powder; the copper-based alloy powder comprises the following components in percentage by mass: 5%-10% of Sn, 0.3%-0.5% of Si, 0.3%-0.5% of Mn, 0.5%-1.5% of Ni, 0.1%-0.6% of Fe, 8%-10% of Al, 0.01%-0.03% of Ce and the balance of copper. The copper alloy coating material is cladded on the inner surface of the shaft sleeve, so that the shaft sleeve has excellent buffering and energy absorbing effects, the coating has excellent wear resistance, and the tin-based babbitt metal coating is compounded on the surface through a spraying process, so that the shaft sleeve has excellent anti-attrition effect. The domestic precision forging machine shaft sleeve meeting the use requirements is produced through a composite manufacturing method combining a laser cladding process with a brush plating process and a high velocity oxy-fuel spraying process for the first time. And localization of imported spare parts is achieved, meanwhile, the production cost of enterprises can be reduced, and the method has profound significance in the industry.

Description

Technical Field

[0001] The present invention belongs to the technical field of surface engineering, and particularly relates to a laser cladding forging machine bushing material and a preparation method thereof. Background Art

[0002] A forging machine is a fast precision forging equipment, which is a short-stroke press that forges metal billets by several symmetric hammers at high frequency. This equipment has the characteristics of high striking frequency, fast striking speed, and high automation degree. It can achieve "pulsating loading" on forgings, so that only a small range of temperature drop occurs during the production process of forgings, and at the same time, the forgings can have a very high surface quality. The forging machine mainly consists of a forging box, a gear box, a chuck, a hammer head adjusting device, a conveying roller path, a tilting device, and systems such as electricity, hydraulics, compressed air, and cooling water. The forging machine has a wide range of application scenarios and plays an important role especially in the fields of aerospace, automotive, and mechanical manufacturing. For example, in the aerospace field, precision forging technology can be used to produce high-quality components such as engine blades, hydraulic pumps, and bearing parts; in the automotive field, it can be used to produce crankshafts, connecting rods, transmission shafts, etc.; in the mechanical manufacturing field, it can be used to produce various parts such as tools, jigs, and molds.

[0003] The bushing of the forging machine is a part that directly contacts the journal on the bearing, and mainly plays the roles of reducing wear, reducing noise, reducing the friction coefficient, and providing support and positioning. During the operation of the forging machine, the bushing reduces the direct contact of the force-bearing surface by sharing the frictional force between the journal and the bearing, thereby slowing down friction and wear and extending the service life of mechanical equipment. At the same time, the bushing can reduce the vibration and noise of the bearing, improve the working efficiency of mechanical equipment and the comfort of users.

[0004] At present, the bushings of forging machines mainly rely on imported purchases, and the purchase price is relatively expensive. Moreover, due to the increasingly tense international relations, coupled with the lengthening of the procurement cycle and its uncertain factors, it seriously affects the normal production rhythm of enterprises. Therefore, there is an urgent need for domestic bushings to meet domestic demand.

[0005] Imported bushings adopt a bimetal casting process with a surface electroplated babbit alloy lubricating layer. Our invented bushings adopt a brand-new manufacturing process, realizing the localization of bushings, and at the same time providing the buffering performance, wear resistance, and self-lubricating performance required for the operation of bushings. Summary of the Invention

[0006] In view of the problems existing in the prior art, the purpose of the present invention is to provide a laser cladding forging machine bushing material and its preparation method. By cladding a copper alloy coating material on the inner surface of the bushing, the present invention has excellent buffering and energy absorption effects under the working conditions of high forging frequencies and fast forging speeds of the forging machine. At the same time, the coating has excellent wear resistance, and a tin-based babbit alloy coating is compounded on the surface through a spraying process, which has excellent anti-friction effects. For the first time, a domestic forging machine bushing that meets the use requirements is produced through a composite manufacturing method combining the laser cladding process, the electro-brush plating process, and the supersonic flame spraying process. It not only realizes the localization of imported spare parts, but also can reduce the production cost of enterprises, which has profound significance in the industry.

[0007] To achieve the above purpose, the present invention adopts the following technical solutions.

[0008] A functional layer alloy powder for a laser cladding forging machine bushing material, comprising the following components by mass percentage: 2%-5% SiC powder, and the balance is copper-based alloy powder.

[0009] Further, the copper-based alloy powder comprises the following components by mass percentage: 5%-10% Sn, 0.3%-0.5% Si, 0.3%-0.5% Mn, 0.5%-1.5% Ni, 0.1%-0.6% Fe, 8%-10% Al, 0.01-0.03% Ce, and the balance is copper.

[0010] Further, the particle size of the SiC powder is 13-15 μm, the density is 6.46 g / cm 3 , and the purity is above 99.9%.

[0011] Further, the particle size of the copper-based alloy powder is -125~+300 mesh.

[0012] A preparation method for a laser cladding forging machine bushing material, comprising the following steps: Step 1: Select a ring-shaped forging blank, use quenched and tempered 42CrMo steel, and through the forging process, achieve a grain size of grade 9, a quenched and tempered hardness of 30-34 HRC, and a tensile strength > 1100 Mpa to obtain a basic forging; Step 2: Turn the basic forging to the established size; Step 3: Mix the above powders to obtain a mixed functional layer alloy powder, and perform inner wall laser cladding on the forging in Step 2 to obtain a clad forging; Step 4: After performing stress relief heat treatment on the clad forging, cool it in the furnace; Step 5: Rough machine the forging cooled in Step 4 to the required size; Step 6: Electro-dip nickel plate the forging rough machined in Step 5, and the coating thickness is 1-2 μm; Step 7: Supersonically spray tin-based Babbitt alloy on the forging after nickel plating in Step 6, with a coating thickness of 20 - 30 μm; Step 8: Achieve the dimensional requirements through internal hole turning; Step 9: Polish the surface of the forging in Step 8 with a 3M nylon grinding wheel. After testing with a roughness meter, it reaches 0.05 - 0.1 μm, and finally obtain the laser cladding precision forging machine bushing.

[0013] Furthermore, in Step 3, the laser cladding process parameters are as follows: powder feeding rate 15 g / min - 30 g / min, laser power 3 kw - 4 kw, spot diameter 3.6 mm, scanning speed 800 mm / min - 1500 mm / min, step 1.7 mm, overlapping rate 40 - 60%, single-layer cladding thickness 1.1 mm - 1.3 mm, and double-layer cladding is carried out with a thickness of 2.2 - 2.6 mm.

[0014] Furthermore, in Step 3, a gas protection cover with local gas protection is used during laser cladding to make the cladding process stable. After measurement by an oxygen analyzer, it reaches 50 ppm to ensure the purity of the structure.

[0015] Furthermore, in Step 4, the heat treatment system is 200 °C × 6 h.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows.

[0017] (1) In the cladding material of the precision forging machine bushing for laser cladding provided by the present invention, SiC with a preferably selected particle size range is added. The density of this substance is 6.46 g / cm 3 , which is similar to the density of the copper-based matrix and is more likely to be evenly distributed in the matrix. Its size is about 20 μm, and the morphology of its dissolution and precipitation presents an irregular spherical shape. It can well serve as a wear-resistant support and has good wettability with the copper-based matrix. The strength and toughness of the matrix and the good wear-resistant support of the wear-resistant particles work together; at the same time, the excellent thermal and electrical conductivity of SiC further improves the thermal conductivity of the copper matrix, controls the temperature rise during the operation of the bushing, and prevents the mating clearance from becoming too small due to thermal expansion and the core shaft from being locked.

[0018] (2) Rare earth Ce is added to the copper alloy powder in the present invention, which promotes the convection of the molten pool, making the insoluble SiC evenly distributed in the molten pool under the strong convection of the molten pool; however, the addition amount of rare earth needs to be strictly controlled. After exceeding the critical addition amount of this invention, SiC will completely dissolve and be solid-solved in the copper alloy matrix, making its toughness worse; SiC, as a wear-resistant fulcrum, improves the wear resistance of the copper alloy. The dual effects of wear resistance and wear reduction greatly improve the service life of the bushing.

[0019] (3)After the copper alloy cladding of the present invention, rough machining is carried out, and nickel is plated by electro-dipping process. The purpose is to make the coating of Babbitt alloy more adhesive when spraying, and to improve the bonding surface strength of the sprayed Babbitt alloy. This process makes it possible to bond the Babbitt alloy and the copper alloy, and gives full play to the excellent performance of each material.

[0020] (4)The present invention adopts a multi-layer structure of the inner hole of the shaft sleeve and a specific thickness design of different coatings, namely a millimeter-level copper alloy cladding layer by laser cladding, a micron-level pure nickel coating by electro-dipping, and finally a micron-level Babbitt alloy coating by supersonic spraying. The design concept of multiple coating processes combines multiple advanced forming processes, maximizing the advantages of each process, and finally realizing the localization of imported shaft sleeves. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a wear sample diagram of the material of the present invention and imported materials.

[0022] Figure 2 It is a 200× metallographic diagram of dissolution and precipitation after adding SiC in Example 1.

[0023] Figure 3 It is a 500× metallographic diagram of dissolution and precipitation after adding SiC in Example 2.

[0024] Figure 4 It is a metallographic diagram after adding SiC in Comparative Example 1.

[0025] Figure 5 It is a finished product diagram of the shaft sleeve in Example 1.

[0026] Figure 6 It is a diagram of the peeling of the Sn-based Babbitt alloy layer in Comparative Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0027] The technical solutions and drawings in the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] A functional layer alloy powder for a laser cladding forging machine shaft sleeve, comprising the following components in mass percentage: 2%-5% SiC powder, and the balance is copper-based alloy powder; the copper-based alloy powder is composed of the following components in mass percentage: 5%-10% Sn, 0.3%-0.5% Si, 0.3%-0.5% Mn, 0.5%-1.5% Ni, 0.1%-0.6% Fe, 8%-10% Al, 0.01-0.03% Ce, and the balance is copper.

[0029] Preferably, the SiC powder has a particle size of 13 - 15 μm and a density of 6.46 g / cm 3 , and the purity is above 99.9%; the copper-based alloy powder has a particle size of -125 to +300 mesh.

[0030] A preparation method of a laser cladding precision forging machine bushing material includes the following steps: Step 1: Select a ring-shaped forging blank, use quenched and tempered 42CrMo steel, and through the forging process, achieve a grain size of grade 9, a quenched and tempered hardness of 30 - 34 HRC, and a tensile strength > 1100 Mpa to obtain a basic forging; Step 2: Turn the basic forging to the established size; Step 3: Mix the above powders to obtain a mixed functional layer alloy powder, and perform inner wall laser cladding on the forging in Step 2. The laser cladding process parameters are: powder feeding rate 15 g / min - 30 g / min, laser power 3 kw - 4 kw, spot diameter 3.6 mm, scanning speed 800 mm / min - 1500 mm / min, step 1.7 mm, overlap rate 40 - 60%, single-layer cladding thickness 1.1 mm - 1.3 mm, and perform double-layer cladding with a thickness of 2.2 - 2.6 mm; use an atmosphere protection cover with local atmosphere protection during laser cladding to make the cladding process stable. After measurement by an oxygen analyzer, it reaches 50 ppm to ensure tissue purity; obtain the clad forging; Step 4: After stress relief heat treatment of the clad forging, the heat treatment system is 200 °C × 6 h, and it is cooled in the furnace; Step 5: Rough machine the forging cooled in Step 4 to the dimensional requirements; Step 6: Electro-galvanize the forging after rough machining in Step 5 with nickel, and the coating thickness is 1 - 2 μm; Step 7: Supersonically spray tin-based Babbitt alloy on the forging after nickel plating in Step 6, and the coating thickness is 20 - 30 μm; Step 8: Through internal hole turning, reach the dimensional requirements; Step 9: Polish the surface of the forging in Step 8 with a 3M nylon grinding wheel. After testing with a roughness meter, it reaches 0.05 - 0.1 μm, and finally obtain a laser cladding precision forging machine bushing.

[0031] Process performance detection: Conduct wear resistance evaluation on the functional copper layer (since relevant detections are not easy to evaluate after cladding on forgings of the required size, so this part of the forgings are in the form of plates for easy detection), conduct weight loss measurement and friction coefficient measurement. The results are shown in Table 1, and the test diagram is as Figure 1 shown.

[0032] Table 1 Performance test results of the functional layer of the present invention and imported copper plates. After cladding Wear amount Friction coefficient Imported copper plate —— 45mg 0.25 No. 1 (material of the present invention) 240HV 30mg 0.18

[0033] After wear resistance testing: It can be seen that the material is strengthened, with an obvious improvement in hardness, and the weight loss is also better than that of the imported coating, showing excellent wear resistance; at the same time, comparing the friction coefficient, it is also better than the imported coating, showing excellent self-lubricating performance.

[0034] Example 1.

[0035] A preparation method of a laser cladding forging machine bushing material includes the following steps.

[0036] Step 1: Select a ring-shaped forging blank, use quenched and tempered 42CrMo steel, and through forging process, reach a grain size of grade 9, quenched and tempered hardness of 30 - 34HRC, and tensile strength of 1150Mpa; Step 2: Then machine turn it to 454.12mm to meet the requirements before cladding; Step 3: Prepare the functional layer alloy powder. The powder is mixed by a powder mixer. The evenly mixed powder is sent for powder feeding at a rate of 20g / min, laser power of 3.2kw, scanning speed of 1000mm / min, step of 1.7mm, overlap rate of 50%, and single-layer cladding thickness of 1.1mm according to the laser cladding process parameters, and double-layer cladding is carried out with a thickness of 2.2mm; carry out cladding work on the surface of the forging. Among them, the mass percentage of the functional layer alloy powder is: 3% SiC powder, and the balance is copper-based alloy powder. The copper-based alloy powder is composed of the following mass percentage components: 8% Sn, 0.4% Si, 0.4% Mn, 1.0% Ni, 0.5% Fe, 9% Al, 0.02% Ce, and the balance is copper.

[0037] Step 4: After cladding, perform stress relief heat treatment. The heat treatment system is 200°C × 6h, and it is cooled in the furnace; Step 5: Carry out rough machining to 450.7mm; Step 6: Carry out electroplating nickel plating, and the coating thickness is 1 - 2μm; Step 7: Carry out supersonic spraying of Sn-based Babbitt alloy, and the coating thickness is 20 - 30μm; Step 8: Through internal hole turning, reach 450.64mm; Step 9: Finally, perform surface polishing with a 3M nylon grinding wheel. After testing with a roughness meter, it reaches 0.05 - 0.1μm, and a laser cladding forging machine bushing is obtained.

[0038] Example 2.

[0039] A preparation method of a laser cladding forging machine bushing material includes the following steps.

[0040] Step 1: Select a ring-shaped forging blank made of quenched and tempered 42CrMo steel. Through the forging process, achieve a grain size of grade 9, a quenched and tempered hardness of 30 - 34 HRC, and a tensile strength of 1180 Mpa.

[0041] Step 2: Then, machine and turn it to 454.2 mm to meet the requirements before cladding.

[0042] Step 3: Prepare the functional layer alloy powder. The powder is mixed by a powder mixer. The evenly mixed powder is fed at a rate of 25 g / min according to the laser cladding process parameters, with a laser power of 3.5 kw, a scanning speed of 1200 mm / min, a step of 1.7 mm, a lap rate of 50%, and a single-layer cladding thickness of 1.2 mm. Double-layer cladding is carried out with a thickness of 2.4 mm. Cladding work is performed on the surface of the forging. The mass ratio of the functional layer alloy powder is as follows: 3.5% SiC powder, and the balance is copper-based alloy powder. The copper-based alloy powder is composed of the following components by mass percentage: 9% Sn, 0.5% Si, 0.5% Mn, 1.2% Ni, 0.6% Fe, 9.5% Al, 0.03% Ce, and the balance is copper.

[0043] Step 4: After cladding, perform stress relief heat treatment. The heat treatment system is 200°C × 6 h, and it is cooled in the furnace. Step 5: Perform rough machining to 450.7 mm. Step 6: Perform electroplating nickel, with a coating thickness of 1 - 2 μm. Step 7: Perform supersonic spraying of Sn-based Babbitt alloy, with a coating thickness of 20 - 30 μm. Step 8: Through internal hole turning, reach 450.65 mm. Step 9: Finally, perform surface polishing with a 3M nylon grinding wheel. After testing with a roughness meter, it reaches 0.05 - 0.1 μm, and finally obtain a laser cladding precision forging machine bushing, as Figure 5 . The surface Sn-based Babbitt alloy coating adheres evenly after polishing.

[0044] Comparative Example 1.

[0045] A process verification of the material of a laser cladding precision forging machine bushing includes the following steps.

[0046] Step 1: Select a ring-shaped forging blank type sample made of quenched and tempered 42CrMo steel. Through the forging process, achieve a grain size of grade 9, a quenched and tempered hardness of 30 - 34 HRC, and a tensile strength of 1180 Mpa.

[0047] Step 2: Then, machine and process it to 200 mm to meet the requirements before cladding.

[0048] Step 3: Prepare the functional layer alloy powder. The powder is mixed by a powder mixer. The uniformly mixed powder is fed according to the laser cladding process parameters: powder feeding rate 25 g / min, laser power 3.5 kw, scanning speed 1200 mm / min, step 1.7 mm, overlapping rate 50%, single-layer cladding thickness 1.2 mm, and double-layer cladding is carried out with a thickness of 2.4 mm. The cladding work is carried out on the surface of the forging. The mass ratio of the functional layer alloy powder is as follows: 3.5% SiC powder, and the balance is copper-based alloy powder. The copper-based alloy powder is composed of the following components by mass percentage: 9% Sn, 0.5% Si, 0.5% Mn, 1.2% Ni, 0.6% Fe, 9.5% Al, 0.05% Ce, and the balance is copper.

[0049] Step 4: After cladding, perform stress relief heat treatment. The heat treatment system is 200 °C × 6 h, and it is cooled in the furnace. Step 5: Perform rough machining to 196.6 mm. Step 6: Perform electroplating nickel plating, and the coating thickness is 1 - 2 μm. Step 7: Perform supersonic spraying of Sn-based Babbitt alloy, and the coating thickness is 20 - 30 μm. Step 8: Perform internal hole turning. Step 9: Finally, perform surface polishing with a 3M nylon grinding wheel. After testing with a roughness meter, it reaches 0.05 - 0.1 μm.

[0050] Metallographic inspection is carried out on Example 1, Example 2 and Comparative Example 1, as Figure 2 、 Figure 3 shown. The size is about 20 μm. The morphology of the precipitated property phase dissolved presents an irregular spherical shape, which can well serve as wear-resistant support and has good wettability with the copper-based matrix. The strength and toughness of the matrix and the good wear-resistant support of the wear-resistant particles work together; Figure 4 On the contrary, it is not good.

[0051] Comparative Example 2.

[0052] A preparation method of a laser cladding precision forging machine bushing material includes the following steps.

[0053] Step 1: Select a ring-shaped forging blank, use quenched and tempered 42CrMo steel, and through the forging process, reach a grain size of grade 9, quenched and tempered hardness of 30 - 34 HRC, and tensile strength of 1180 Mpa.

[0054] Step 2: Then machine turn it to 454.2 mm to meet the requirements before cladding.

[0055] Step 3: Prepare the functional layer alloy powder. The powder is mixed by a powder mixer. The uniformly mixed powder is fed according to the laser cladding process parameters: powder feeding rate of 25 g / min, laser power of 3.5 kw, scanning speed of 1200 mm / min, step of 1.7 mm, overlapping rate of 50%, single-layer cladding thickness of 1.2 mm, and double-layer cladding is carried out with a thickness of 2.4 mm. The cladding work is performed on the surface of the forging. The mass ratio of the functional layer alloy powder is as follows: 3.5% SiC powder, and the balance is copper-based alloy powder. The copper-based alloy powder is composed of the following components by mass percentage: 9% Sn, 0.5% Si, 0.5% Mn, 1.2% Ni, 0.6% Fe, 9.5% Al, 0.03% Ce, and the balance is copper.

[0056] Step 4: After cladding, perform stress relief heat treatment. The heat treatment regime is 200 °C × 6 h, followed by furnace cooling. Step 5: Perform rough machining to 450.7 mm. Step 6: Perform supersonic spraying of Sn-based Babbitt alloy with a coating thickness of 20 - 30 μm. Step 7: Perform internal hole turning to 450.62 mm. During the turning process, it is found that there is a phenomenon of local peeling of the Sn-based Babbitt alloy layer, as Figure 6 shown.

Claims

1. A functional layer alloy powder for a laser cladding precision forging machine bushing material, characterized in that, It includes the following components by mass percentage: 2%-5% SiC powder, and the balance is copper-based alloy powder.

2. The functional layer alloy powder of the bushing material for a laser cladding precision forging machine according to claim 1, characterized in that, The copper-based alloy powder includes the following components by mass percentage: 5%-10% Sn, 0.3%-0.5% Si, 0.3%-0.5% Mn, 0.5%-1.5% Ni, 0.1%-0.6% Fe, 8%-10% Al, 0.01-0.03% Ce, and the balance is copper.

3. The functional layer alloy powder of the laser cladding precision forging machine bushing material according to claim 1, characterized in that, The particle size of the SiC powder is 13 - 15 μm, and the density is 6.46 g / cm 3 , and the purity is above 99.9%.

4. The functional layer alloy powder of the bushing material for the laser cladding precision forging machine according to claim 1, characterized in that, The particle size of the copper-based alloy powder is -125 to +300 mesh.

5. A preparation method of a laser cladding precision forging machine bushing material, characterized in that, It includes the following steps: Step 1: Select a ring-shaped forging blank, use quenched and tempered 42CrMo steel, and through the forging process, achieve a grain size of grade 9, a quenched and tempered hardness of 30-34 HRC, and a tensile strength > 1100 Mpa to obtain a basic forging. Step 2: Turn the basic forging to the established size. Step 3: Mix the above powders to obtain a mixed functional layer alloy powder, and perform inner wall laser cladding on the forging in Step 2 to obtain a clad forging. Step 4: After performing stress relief heat treatment on the clad forging, cool it in the furnace. Step 5: Rough machine the forging cooled in Step 4 to the dimensional requirements. Step 6: Electro-dip nickel plate the forging rough machined in Step 5, and the coating thickness is 1-2 μm. Step 7: Perform supersonic spraying of tin-based Babbitt alloy on the nickel-plated forging in Step 6, and the coating thickness is 20-30 μm. Step 8: Achieve the dimensional requirements through internal hole turning. Step 9: Polish the surface of the forging in Step 8 with a 3M nylon grinding wheel. After testing with a roughness meter, it reaches 0.05-0.1 μm, and finally obtain a laser clad precision forging machine bushing.

6. The preparation method of the laser cladding precision forging machine bushing material according to claim 5, characterized in that, In the said Step 3, the laser cladding process parameters are: powder feeding rate 15 g / min - 30 g / min, laser power 3 kw - 4 kw, spot diameter 3.6 mm, scanning speed 800 mm / min - 1500 mm / min, step 1.7 mm, overlapping rate 40~60%, single-layer cladding thickness 1.1 mm - 1.3 mm, and perform double-layer cladding with a thickness of 2.2-2.6 mm.

7. The preparation method of the laser cladding precision forging machine bushing material according to claim 5, characterized in that, In the said Step 3, a gas protection cover with local gas protection is used during laser cladding, and it reaches 50 ppm as measured by an oxygen analyzer.

8. The preparation method of the laser cladding precision forging machine bushing material according to claim 5, characterized in that, In the said Step 4, the heat treatment system is 200°C × 6 h.

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