Self-lubricating laser cladding sheet and manufacturing method of self-lubricating slide bed plate

Abstract

The present invention discloses a method for manufacturing a self-lubricating laser cladding sheet and a self-lubricating slider bed platen. The method comprises the following steps: Step 1: uniformly mixing 10-25 wt% graphite powder, 75-90 wt% pure copper powder, and an appropriate amount of sodium carboxymethyl cellulose powder, and then adding an appropriate amount of deionized water and stirring thoroughly to obtain a uniformly dispersed semi-solid mixture; Step 2: injecting the semi-solid mixture into a mold, drying, and demolding to obtain a self-lubricating laser cladding sheet. The present invention utilizes a laser cladding process to prepare a self-lubricating slider bed platen using the prepared self-lubricating laser cladding sheet. The self-lubricating slider bed platen exhibits excellent friction reduction, anti-wear, and corrosion resistance during service, and can improve the service condition of the switch rail without the need for grease application, reduce the workload of manual maintenance, and reduce the resistance of switch switching, thereby facilitating driving safety.

Description

Technical Field

[0001] The present invention belongs to the technical field of manufacturing railway turnout pad sliding tabletop parts, and in particular relates to a method for manufacturing a self-lubricating laser cladding sheet and a self-lubricating slide bed tabletop. Background Art

[0002] The slide bed plate is an important component of the turnout, and its main function is to clamp the base rail and support the point rail. The main cause of railway turnout accidents is insufficient displacement of the point rail due to insufficient lubrication on the slide bed plate surface. Therefore, the reliability of the turnout operation is closely related to the lubrication condition of the slide bed plate surface. At present, the slide bed plate materials used in turnout structures in my country are mainly carbon steel or low-alloy steel with hard chromium electroplating on the surface, which requires manual oiling and maintenance to ensure lubrication. However, manual maintenance methods are seriously affected by environmental factors and there are uncertainties caused by the on-site status of operators, resulting in high maintenance costs and potential risks. As the scale of China's railway transportation grows year by year, the feasibility of manual maintenance of railway turnouts on a large scale is greatly reduced. Summary of the Invention

[0003] In order to solve the above problems existing in the prior art, the present invention provides a method for manufacturing a self-lubricating laser cladding sheet and a self-lubricating slide bed plate. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0004] A method for manufacturing a self-lubricating laser cladding sheet comprises the following steps:

[0005] Step 1: 10-25 wt% of graphite powder, 75-90 wt% of pure copper powder and an appropriate amount of sodium carboxymethyl cellulose powder are mixed evenly, and then an appropriate amount of deionized water is added and stirred thoroughly to obtain a uniformly dispersed semi-solid mixture;

[0006] Step 2: injecting the semi-solid mixture into a mold, and demolding after drying to obtain a self-lubricating laser cladding sheet.

[0007] Furthermore, the sodium carboxymethyl cellulose powder accounts for 20-30% of the total weight of the graphite powder and the pure copper powder; and the deionized water accounts for 30-50% of the total weight of the graphite powder, the pure copper powder and the sodium carboxymethyl cellulose powder.

[0008] Furthermore, the self-lubricating laser cladding sheet has a thickness of 0.2 to 0.6 mm.

[0009] Another embodiment of the present invention discloses a method for manufacturing a self-lubricating slider table using the self-lubricating laser cladding sheet provided in any of the above embodiments, comprising the following steps:

[0010] Step 1: Fix the self-lubricating laser cladding sheet on the surface of the slide bed plate through an adhesive;

[0011] Step 2: Perform the first laser cladding on the self-lubricating laser cladding sheet fixed on the surface of the slide bed plate, so that the surface of the slide bed plate has a self-lubricating laser cladding layer;

[0012] Step 3: Perform the second laser cladding on the self-lubricating laser cladding layer to obtain a self-lubricating slide bed plate.

[0013] Preferably, the adhesive is sodium carboxymethylcellulose.

[0014] Further, the slide bed plate is made of carbon steel or low alloy steel plate.

[0015] Further, the laser scanning direction of the second laser cladding is perpendicular to the laser scanning direction of the first laser cladding.

[0016] Preferably, the process parameters of the first laser cladding are: laser power is 700 - 1200W; scanning speed is 50 - 300mm / s; spot diameter is 2 - 3mm; overlap rate is 30 - 70%.

[0017] Preferably, the process parameters of the second laser cladding are: laser power is 800 - 1000W; scanning speed is 150 - 200mm / s; spot diameter is 2.2 - 2.7mm; overlap rate is 40 - 50%.

[0018] Advantages of the present invention:

[0019] 1. In the present invention, by fixing a self-lubricating laser cladding sheet on the surface of the slide bed plate and performing laser cladding, a well-structured copper-based self-lubricating material layer is obtained. It has a high energy density, a dense cladding layer structure, no over-melting or incomplete penetration. The bonding strength at the copper / steel interface is above 200MPa, the friction coefficient is maintained at 0.1 - 0.2, and the corrosion resistance is not lower than level three of the ten-level standard for metal corrosion. Moreover, it can avoid the characteristics of traditional copper-based materials such as easy refraction, reflection, and strong heat dissipation under laser, so that the surface of the obtained cladding layer has no defects such as composition segregation, cracks, pores, inclusions, oxides, etc.;

[0020] 2. In the present invention, by preparing a copper-based self-lubricating material on the slide bed plate, it can exert excellent anti-friction, anti-wear, and anti-corrosion properties during service. It can improve the service conditions of the switch rail without applying grease, reduce the workload of manual maintenance, reduce the resistance of switch conversion, and is beneficial to train operation safety. It can be widely promoted and applied in the field of switch slide bed plates, promoting the economic construction and development of our country;

[0021] The following will further describe the present invention in detail with reference to the drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The photo of the manufactured self-lubricating laser cladding sheet;

[0023] Figure 2 This is a surface photo of the manufactured self-lubricating slider bed platen;

[0024] Figure 3 This is the energy spectrum of the self-lubricating layer on the surface of the self-lubricating slider table manufactured by the present invention after a 24-hour salt spray test;

[0025] Figure 4 This is the energy spectrum of the self-lubricating layer on the surface of the self-lubricating slider table manufactured by the present invention after a 72-hour salt spray test;

[0026] Figure 5 This is an energy spectrum diagram of the self-lubricating layer on the surface of the self-lubricating slider table manufactured by the present invention after a 120-h salt spray test. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below with reference to specific examples, but the embodiments of the present invention are not limited thereto.

[0028] Example 1

[0029] The embodiment of the present invention provides a method for manufacturing a self-lubricating laser cladding sheet, which specifically includes the following steps:

[0030] Step 1: 10 wt% of graphite powder, 90 wt% of pure copper powder and an appropriate amount of sodium carboxymethyl cellulose powder are mixed evenly, and then an appropriate amount of deionized water is added and stirred thoroughly to obtain a uniformly dispersed semi-solid mixture;

[0031] The sodium carboxymethyl cellulose powder accounts for 20% of the total weight of the graphite powder and the pure copper powder; and the deionized water accounts for 30% of the total weight of the graphite powder, the pure copper powder and the sodium carboxymethyl cellulose powder.

[0032] After the graphite powder, pure copper powder and sodium carboxymethyl cellulose powder are evenly mixed, the powder is subjected to EDS energy spectrum analysis to observe whether the powder is evenly dispersed. If not, it is necessary to remix and re-perform EDS energy spectrum analysis until the three powders are evenly mixed. After adding deionized water, the mixed powder should be fully mixed into a uniform semi-solid state without agglomerated adhesive blocks or dry powder.

[0033] Step 2: Inject the semi-solid mixture into a mold, and demould it after drying to obtain a self-lubricating laser cladding sheet. The photo of the sheet is as follows: Figure 1 shown.

[0034] The size of the mold is consistent with the size of the slide bed plate to be coated. In the embodiment of the present invention, the mold size is 30 cm × 30 cm × 1 cm. A release agent is applied to the mold in advance. The release agent that can be selected is vaseline. After drying, the self-lubricating laser cladding sheet is clean and flat, with a thickness of 0.2 - 0.6 mm.

[0035] If the thickness of the precursor is less than 0.2 mm, the Cu element in the cladding layer finally prepared on the slide bed plate will be corroded after 120 h of salt spray test, thus greatly weakening the anti-corrosion performance of the slide bed plate. When the thickness of the precursor is greater than 0.6 mm, the power parameters during subsequent laser cladding need to be increased correspondingly, or the number of laser cladding times needs to be increased. Based on the properties of the copper material itself, its process parameters are difficult to control and the cost is too high.

[0036] Example 2

[0037] The embodiment of the present invention provides another manufacturing method of the self-lubricating laser cladding sheet, which specifically includes the following steps:

[0038] Step 1: Mix 25 wt% of graphite powder, 75 wt% of pure copper powder and an appropriate amount of sodium carboxymethylcellulose powder evenly, and then add an appropriate amount of deionized water and stir well to obtain a uniformly dispersed semi-solid mixture;

[0039] Among them, the proportion of the sodium carboxymethylcellulose powder is 30% of the total weight of the graphite powder and the pure copper powder; the proportion of the deionized water is 50% of the total weight of the graphite powder, the pure copper powder and the sodium carboxymethylcellulose powder.

[0040] Perform EDS energy spectrum analysis on the powder body after mixing the graphite powder, pure copper powder and sodium carboxymethylcellulose powder evenly to observe whether the powder is dispersed evenly. If it is not dispersed evenly, it needs to be remixed and the EDS energy spectrum analysis is observed again until the three powders are mixed evenly. After adding deionized water, the mixed powder should be fully mixed into a uniform semi-solid state without agglomerated binder blocks or dry powder.

[0041] Step 2: Inject the semi-solid mixture into the mold, demold after drying, and obtain the self-lubricating laser cladding sheet.

[0042] The size of the mold is consistent with the size of the slide bed plate to be coated. In the embodiment of the present invention, the mold size is 30 cm × 30 cm × 1 cm. A release agent is applied to the mold in advance. The release agent that can be selected is vaseline. After drying, the self-lubricating laser cladding sheet is clean and flat, with a thickness of 0.4 mm.

[0043] Example 3

[0044] The embodiment of the present invention provides yet another manufacturing method of the self-lubricating laser cladding sheet, which specifically includes the following steps:

[0045] Step 1: 15 wt% of graphite powder, 85 wt% of pure copper powder and an appropriate amount of sodium carboxymethyl cellulose powder are mixed evenly, and then an appropriate amount of deionized water is added and stirred thoroughly to obtain a uniformly dispersed semi-solid mixture;

[0046] The sodium carboxymethyl cellulose powder accounts for 20% of the total weight of the graphite powder and the pure copper powder; and the deionized water accounts for 40% of the total weight of the graphite powder, the pure copper powder and the sodium carboxymethyl cellulose powder.

[0047] After the graphite powder, pure copper powder and sodium carboxymethyl cellulose powder are evenly mixed, the powder is subjected to EDS energy spectrum analysis to observe whether the powder is evenly dispersed. If not, it is necessary to remix and re-perform EDS energy spectrum analysis until the three powders are evenly mixed. After adding deionized water, the mixed powder should be fully mixed into a uniform semi-solid state without agglomerated adhesive blocks or dry powder.

[0048] Step 2: injecting the semi-solid mixture into a mold, and demolding after drying to obtain a self-lubricating laser cladding sheet.

[0049] The mold's dimensions match those of the slide bed to be coated. In this embodiment, the mold measures 30 cm x 30 cm x 1 cm. A release agent, such as vaseline, is applied to the mold in advance. After drying, the self-lubricating laser cladding sheet is clean and flat, with a thickness of 0.5 mm.

[0050] Example 4

[0051] The embodiment of the present invention provides a method for manufacturing a self-lubricating slide bed platen using the self-lubricating laser cladding sheet of Example 1, which specifically includes the following steps:

[0052] Step 1: The self-lubricating laser cladding sheet is fixed on the surface of the slide table by the adhesive sodium carboxymethyl cellulose, and is tapped in a direction perpendicular to the surface of the self-lubricating laser cladding sheet to ensure that the cladding sheet is firmly bonded to the slide table. The slide table is made of carbon steel or low alloy steel.

[0053] Step 2: performing a first laser cladding on the self-lubricating laser cladding sheet fixed on the surface of the slider bed platen, so that the surface of the slider bed platen has a self-lubricating laser cladding layer.

[0054] The process parameters of the first laser cladding are: laser power of 1200W, scanning speed of 300mm / s, spot diameter of 3mm, and overlap rate of 70%.

[0055] Step 3: performing a second laser cladding on the self-lubricating laser cladding layer to obtain a self-lubricating slide bed platen.

[0056] Among them, the process parameters of the second laser cladding are as follows: the laser power is 1000 W, the scanning speed is 200 mm / s, the spot diameter is 2.7 mm, the overlapping rate is 50%, and the laser scanning direction of the second laser cladding is perpendicular to that of the first laser cladding, so that the Cu and graphite in the final cladding layer are evenly distributed, and the thickness is 0.5 - 1 mm; after the second laser cladding is completed, a grinding machine is used to level the cladding layer on the surface of the slideway table board. The photo of this self-lubricating slideway table board is as Figure 2 shown, and this figure is a photo without grinding.

[0057] If only one laser cladding is carried out, due to the properties of the copper material, the thickness of the obtained cladding layer will be uneven and the performance will be poor. Through the two laser claddings of this application, the thickness of the cladding layer is appropriate and uniform, and through experimental verification, its corrosion resistance is excellent, the friction coefficient is small, and it has good wear resistance.

[0058] Example 5

[0059] The embodiment of the present invention provides a manufacturing method of a self-lubricating slideway table board using the self-lubricating laser cladding sheet of Example 2, which specifically includes the following steps:

[0060] Step 1: Fix the self-lubricating laser cladding sheet on the surface of the slideway table board through the adhesive sodium carboxymethyl cellulose, and tap along the direction perpendicular to the surface of the self-lubricating laser cladding sheet to ensure that the cladding sheet is firmly combined with the slideway table board. The slideway table board is made of carbon steel or low-alloy steel plate.

[0061] Step 2: Carry out the first laser cladding on the self-lubricating laser cladding sheet fixed on the surface of the slideway table board, so that the surface of the slideway table board has a self-lubricating laser cladding layer.

[0062] Among them, the process parameters of the first laser cladding are as follows: the laser power is 700 W, the scanning speed is 50 mm / s, the spot diameter is 2 mm, and the overlapping rate is 30%.

[0063] Step 3: Carry out the second laser cladding on the self-lubricating laser cladding layer to obtain a self-lubricating slideway table board.

[0064] Among them, the process parameters of the second laser cladding are as follows: the laser power is 800 W, the scanning speed is 150 mm / s, the spot diameter is 2.2 mm, the overlapping rate is 40%, and the laser scanning direction of the second laser cladding is perpendicular to that of the first laser cladding, so that the Cu and graphite in the final cladding layer are evenly distributed, and the thickness is 0.5 - 1 mm; after the second laser cladding is completed, a grinding machine is used to level the cladding layer on the surface of the slideway table board.

[0065] Example 6

[0066] The embodiment of the present invention provides a manufacturing method of a self-lubricating slide plate using the self-lubricating laser cladding sheet of Example 3, which specifically includes the following steps:

[0067] Step 1: Fix the self-lubricating laser cladding sheet on the surface of the slide plate through the adhesive sodium carboxymethylcellulose, and tap it in the direction perpendicular to the surface of the self-lubricating laser cladding sheet to ensure that the cladding sheet is firmly combined with the slide plate. The slide plate is made of carbon steel or low-alloy steel plate.

[0068] Step 2: Perform the first laser cladding on the self-lubricating laser cladding sheet fixed on the surface of the slide plate, so that the surface of the slide plate has a self-lubricating laser cladding layer.

[0069] Among them, the process parameters of the first laser cladding are: the laser power is 800W, the scanning speed is 100mm / s, the spot diameter is 2.5mm, and the overlapping rate is 50%.

[0070] Step 3: Perform the second laser cladding on the self-lubricating laser cladding layer to obtain a self-lubricating slide plate.

[0071] Among them, the process parameters of the second laser cladding are: the laser power is 900W, the scanning speed is 150mm / s, the spot diameter is 2.5mm, and the overlapping rate is 40%. And the laser scanning direction of the second laser cladding is perpendicular to the laser scanning direction of the first laser cladding, so that the distribution of Cu and graphite in the final cladding layer is uniform, and the thickness is 0.5-1mm; after the second laser cladding is completed, use a grinding machine to level the cladding layer on the surface of the slide plate.

[0072] Through Figure 3 ~and Figure 5 It can be observed that the thickness of the self-lubricating layer prepared by the present invention gradually decreases with the increase of the test time. From the characterization of the Cu element by the energy spectrum diagram, it can be seen that there is always a dense graphite / copper cladding layer on the surface of the substrate, and the combination between the self-lubricating layer and the substrate is good. Under the condition of 120h of neutral salt spray test, the graphite / copper cladding layer is not exhausted and can still play a role in protecting the substrate.

[0073] The present invention combines copper with graphite to form a laser cladding sheet, and uses the laser cladding process to prepare a self-lubricating coating on the surface of the slide table plate, so that the slide table plate not only has the good friction reduction and anti-wear performance of graphite, but also has the good corrosion resistance and impact toughness of copper material, reducing the workload of manual maintenance. Moreover, by optimizing the laser cladding process, the present invention overcomes the characteristics that traditional copper materials are prone to refraction, reflection, and strong heat dissipation under laser, and it is difficult to form a molten pool during the laser cladding process, solves the defect that due to the high thermal expansion coefficient of copper and the poor wettability with other metals, it is difficult for laser cladding to produce a strong metallurgical bond, resulting in poor bonding between the cladding layer and the substrate, and makes the surface of the obtained cladding layer free of defects such as composition segregation, cracks, pores, inclusions, and oxides.

[0074] The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several simple deductions or substitutions can still be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. A manufacturing method of a self-lubricating laser cladding sheet, characterized in that, It includes the following steps: Step 1: Mix 10 - 25 wt% of graphite powder, 75 - 90 wt% of pure copper powder and an appropriate amount of sodium carboxymethylcellulose powder evenly, and then add an appropriate amount of deionized water and stir well to obtain a semi-solid mixture with uniform dispersion; the proportion of the sodium carboxymethylcellulose powder is 20 - 30% of the total weight of the graphite powder and the pure copper powder; the proportion of the deionized water is 30 - 50% of the total weight of the graphite powder, the pure copper powder and the sodium carboxymethylcellulose powder; Step 2: Inject the semi-solid mixture into a mold, dry it and then demold to obtain a self-lubricating laser cladding sheet.

2. The manufacturing method of the self-lubricating laser cladding sheet according to claim 1, wherein The thickness of the self-lubricating laser cladding sheet is 0.2 - 0.6 mm.

3. A manufacturing method of a self-lubricating slide table plate using a self-lubricating laser cladding sheet, characterized in that, The self-lubricating laser cladding sheet is manufactured by using the manufacturing method of the self-lubricating laser cladding sheet according to any one of claims 1 - 2, and includes the following steps: Step 1: Fix the self-lubricating laser cladding sheet on the surface of the slide bed plate through an adhesive; Step 2: Perform the first laser cladding on the self-lubricating laser cladding sheet fixed on the surface of the slide bed plate so that the surface of the slide bed plate has a self-lubricating laser cladding layer; Step 3: Perform the second laser cladding on the self-lubricating laser cladding layer to obtain a self-lubricating slide bed plate.

4. The manufacturing method of the self-lubricating slide table board according to claim 3, characterized in that, The adhesive is sodium carboxymethylcellulose.

5. The manufacturing method of the self-lubricating slide table board according to claim 3, characterized in that, The slide bed plate is made of carbon steel or low alloy steel plate.

6. The manufacturing method of the self-lubricating slide table board according to claim 3, characterized in that, The laser scanning direction of the second laser cladding is perpendicular to the laser scanning direction of the first laser cladding.

7. The manufacturing method of the self-lubricating slide table board according to claim 3, characterized in that, The process parameters of the first laser cladding are: laser power is 700 - 1200 W; scanning speed is 50 - 300 mm / s; spot diameter is 2 - 3 mm; overlap rate is 30 - 70%.

8. The manufacturing method of the self-lubricating slide table board according to claim 3, characterized in that, The process parameters of the second laser cladding are: laser power is 800 - 1000 W; scanning speed is 150 - 200 mm / s; spot diameter is 2.2 - 2.7 mm; overlap rate is 40 - 50%.

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