A method for producing a spiral stud having a composite amorphous structure protective layer

Abstract

The application discloses a production method of a spiral stud with a composite amorphous structure protective layer, and steps are as follows: (1) oil removal, cleaning and sand blasting treatment are performed on the stud body to obtain a clean stud body, and the stud body has an outer thread formed by rolling; (2) spraying: a zirconium-based amorphous powder is sprayed on the surface of the stud body by using a plasma spraying method to form an amorphous coating, and the amorphous coating is cooled to normal temperature; rolling: the stud body with the amorphous coating is heated and rolled; the spraying and rolling are repeated for 3-5 times to manufacture a coated stud; and (3) the coated stud is heated to 430-450 DEG C under a nitrogen atmosphere, and is cooled to room temperature after being kept at the temperature for a set time. The amorphous coating is heated in the application, part of the structure is formed into nanocrystals, the existence of the amorphous state and the nanocrystal interface can promote the diffusion of the passivation element, accelerate the formation of the passivation film, reduce the electrochemical activity, improve the plasticity of the coating, and is favorable to improving the corrosion resistance of the amorphous alloy.

Description

Technical Field

[0001] This invention relates to a method for producing spiral rail spikes with a composite amorphous protective layer. Background Technology

[0002] Railway rails are fixed to sleepers using spiral spikes. Because these spikes are constantly exposed to the atmosphere, they are continuously affected by rainwater, train wastewater, and chemicals and minerals left behind during transportation, resulting in severe corrosion. Therefore, improving the corrosion resistance of spiral spikes is essential. Summary of the Invention

[0003] To improve the corrosion resistance of spiral rail spikes, this application proposes a method for producing spiral rail spikes with a composite amorphous structure protective layer, characterized by the following steps:

[0004] (1) The rail spike body is degreased, cleaned and sandblasted. The rail spike body is made of carbon steel material to obtain a clean rail spike body. The rail spike body has an external thread formed by rolling.

[0005] (2) Spraying: Zirconium-based amorphous powder is used as the spraying material, and plasma spraying is used to spray the surface of the road stud body to form an amorphous coating, which is then cooled to room temperature.

[0006] Rolling: The rail spike body with an amorphous coating is heated to 390-400℃ and the amorphous coating is rolled. When rolling the amorphous coating, the thread rolling die used is the same as the thread rolling die used to form the external thread on the rail spike body.

[0007] Repeat spraying and rolling 3-5 times to produce coated road studs;

[0008] (3) Under a nitrogen atmosphere, the coated rail spikes are heated to 430-450°C at a set heating rate, and then cooled to room temperature after holding at the temperature for a set time. Specifically, the thickness of the amorphous coating is 400-600 μm.

[0009] For degreasing and cleaning, soak in acetone for 20-50 minutes, then ultrasonically clean with anhydrous ethanol for 30-50 minutes, and finally dry at 40-90℃; for sandblasting, the sandblasting pressure is 0.5-0.7MPa.

[0010] Amorphous alloys possess a single, uniform solid-phase chemical structure, free from structural defects commonly found in crystal structures such as grain boundaries, dislocations, stacking faults, and twins. They also lack compositional segregation and the precipitation of second phases, preventing intergranular corrosion. Furthermore, elements with strong passivation capabilities, such as Fe, Cr, Ni, Co, Mo, Ta, Nb, and W, facilitate the formation of passivation films on the amorphous alloy surface, resulting in coatings with strong corrosion resistance and enhancing the corrosion resistance of spiral rail spikes.

[0011] The rails are held fastened to the sleepers by spring fasteners, which are then pressed together by spiral spikes. The spiral spikes are anchored to the sleepers and form a single unit with them. When a train passes at high speed, it exerts strong pressure, friction, and elastic vibration on the rails, subjecting the spiral spikes to both static tensile stress and cyclic stress from the passing train. After an amorphous alloy coating is formed on the surface of the spiral spike, cyclic stress is generated on the coating due to the engagement of the threads. Because amorphous alloys have low plasticity, under the pressure of the threads, they are prone to shear deformation and quasi-brittle fracture, leading to cracks in the coating. These cracks allow corrosive substances to corrode the spike itself.

[0012] In this application, the amorphous coating is heated at 430-450°C, which is below the glass transition temperature of the zirconium-based amorphous alloy. During the heat preservation process, part of the structure of the amorphous alloy is formed into Zr2Cu and Zr2Ni crystalline phases, becoming nanocrystals. The presence of the amorphous state and nanocrystal interface can promote the diffusion of passivation elements, accelerate the formation of the passivation film, and improve the corrosion resistance of the amorphous alloy.

[0013] Meanwhile, heating and heat preservation of the amorphous coating can annihilate the free volume of the amorphous alloy, reduce the interatomic distance and chemical potential, relax the structure, and put the metal atoms in a low energy level state, reducing electrochemical activity and making the amorphous alloy less prone to corrosion reaction, thereby improving the corrosion resistance of the amorphous alloy.

[0014] During the heating and heat preservation process, some amorphous structures form nanocrystals, becoming crystalline and effectively improving the plasticity of amorphous alloys. Because the internal structure of amorphous alloys is disordered, exhibiting isotropic characteristics macroscopically, and lacking grain boundaries, dislocations, and crystallographic orientation effects, the deformation and fracture of amorphous alloy materials typically exhibit characteristics different from metallic crystalline materials, such as high strength, high hardness, and high elastic limit. This causes amorphous alloys to primarily undergo shear deformation at room temperature, resulting in highly localized strain and making them prone to quasi-brittle fracture along a single shear band. Since the fastening of spiral rail spikes utilizes the interlocking of threads, the threads of the spiral rail spike are subjected to compression along the axial direction by the meshing internal threads, thus creating a shearing effect. This makes the amorphous alloy on the spiral rail spike prone to the aforementioned quasi-brittle fracture behavior. Utilizing the good plasticity of crystalline metals possessed by nanocrystals, the threads of the spiral rail spike can produce elastic deformation under the compression of the meshing internal threads, reducing the chance of fracture in the amorphous coating and maintaining its integrity.

[0015] Specifically, the zirconium-based amorphous powder comprises, by mass percentage: 50-54 wt% Zr, 24-28 wt% Cu, 7-9 wt% Al, 3-4 wt% Ti, and 7-10 wt% Ni. The amorphous coating formed using this zirconium-based amorphous powder exhibits high fatigue strength, enabling it to withstand the frequent stress changes experienced by the spiral rail spikes. This prevents the amorphous coating from cracking, which could allow external corrosive substances to enter the rail spike body through cracks, causing corrosion.

[0016] Specifically, to form a uniform amorphous coating, in step (2), the plasma spraying parameters are as follows: argon flow rate of 40-70 L / min, hydrogen flow rate of 10-25 L / min, current of 300-450 A, voltage of 40-50 V, spraying distance of 40-110 mm, powder feed rate of 15-30 g / min, and spray gun moving speed of 10-40 mm / s. The nozzle type of the spray gun is either wide-mouth or narrow-mouth, and the spraying angle during plasma spraying is 88-92°.

[0017] Furthermore, to facilitate spraying, the road stud body is fixed on a rotating table with a rotation speed of 100-200 r / min.

[0018] Specifically, in step (3), the heating rate is set to 7-9℃ / min. If the heating rate is set too fast, the spiral rail spike body will expand too quickly, causing cracks in the amorphous coating. If the heating rate is set too slow, production efficiency will be reduced.

[0019] Specifically, in step (3), the holding time is set to 25-50 minutes. As the holding time increases, the corrosion resistance of the amorphous alloy first increases and then begins to decrease. This is likely because, with the increase in holding time, the crystallization ratio gradually increases, and the proportion of nanocrystals gradually increases, which is beneficial for the accelerated formation of the passivation film. However, the number of trigger points for pitting corrosion caused by nanocrystals increases, making localized corrosion more likely. However, due to crystallization, the thermodynamic stability of the amorphous alloy increases. Therefore, in the early stages of crystallization, thermodynamic stability is advantageous in the competition with localized corrosion. As the proportion of crystalline phase increases, defects increase, and localized corrosion gradually begins to dominate, leading to a decrease in corrosion resistance. Therefore, an appropriate holding time can keep the crystallization ratio within a suitable range to improve the corrosion resistance of the amorphous alloy.

[0020] Furthermore, the amorphous coating consists of 3-5 sub-coatings, each of which is formed using the following steps:

[0021] Spraying: Zirconium-based amorphous powder is used as the spraying material and plasma spraying is applied to the surface of the road stud body to form a layer. After cooling to room temperature, the thickness of the layer is 100-150μm.

[0022] Rolling: The rail spike body with the sub-coating is heated to 390-400℃ at a heating rate of 7-9℃ / min, and the sub-coating is rolled. When rolling the sub-coating, the thread rolling die used is the same as the thread rolling die used to form the external thread on the rail spike body.

[0023] Repeat spraying and rolling 3-5 times to make coated road studs.

[0024] Multiple spraying processes are used to form an amorphous coating, which effectively improves the uniformity and corrosion resistance of the coating. Heating at 390-400°C increases the plasticity of the amorphous alloy. Rolling the sub-coatings causes slight deformation and improves the bonding between the amorphous coating and the road stud body, allowing some of the amorphous alloy to penetrate into the road stud body.

[0025] Although amorphous alloys have relatively high corrosion resistance, they also have some defects. For example, in actual production, there are often some very small physical defects on the surface of amorphous alloys. These small physical defects damage the passivation film on the surface of amorphous alloys and are high-risk areas for electrolytic corrosion. When rolling the sub-coating, the plasticity of the amorphous coating is used to generate a certain deformation, which can reduce the number of these physical defects and thus reduce the incidence of pitting corrosion. Attached Figure Description

[0026] Figure 1 This is the XRD pattern of the No. 1 spiral rail spike prepared in Example 1.

[0027] Figure 2 This is a TEM image of the No. 1 spiral rail spike prepared in Example 1. Detailed Implementation

[0028] Example 1

[0029] Production of #1 spiral rail spikes:

[0030] (1) The rail spike body was soaked in acetone for 30 minutes to remove oil stains, then ultrasonically cleaned with anhydrous ethanol for 40 minutes, dried at 50℃, and finally sandblasted at a pressure of 0.6MPa to obtain a clean rail spike body. The rail spike body is made of Q235# carbon steel. The external thread of the rail spike body is formed by rolling.

[0031] (2) Spraying: Zirconium-based amorphous powder is used as the spraying material and plasma spraying is applied to the surface of the clean road stud body to form a layer, followed by cooling. During spraying, the road stud body is fixed on a rotating table with a rotation speed of 120 r / min.

[0032] Rolling: The rail spike body with the sub-coating is heated to 390°C at a heating rate of 8°C / min, and the sub-coating is rolled. During rolling, the same thread rolling die as that used to form the external thread of the rail spike body is used.

[0033] When rolling the sub-coating, the thread rolling die used is the same as the thread rolling die used to form the external thread on the rail spike body.

[0034] The coating process involves four repeated spraying and rolling processes to form an amorphous coating, resulting in coated road studs. Each coat has a thickness of 110 μm.

[0035] In this embodiment, the zirconium-based amorphous powder has the following composition by mass percentage: 50 wt% Zr, 27 wt% Cu, 9 wt% Al, 4 wt% Ti and 10 wt% Ni.

[0036] The plasma spraying parameters are as follows: argon flow rate 40 L / min, hydrogen flow rate 15 L / min, current 300 A, voltage 40 V, spraying distance 40 mm, powder feed rate 20 g / min, and spray gun movement speed 30 mm / s. The spray gun nozzle type is a wide-mouth type, and the spraying angle during plasma spraying is 90°.

[0037] (3) Under a nitrogen atmosphere, the coated road stud is heated to a set temperature of 432°C at a set heating rate of 8°C / min, and after holding at the temperature for 30 minutes, it is cooled to room temperature to produce No. 1 spiral road stud.

[0038] The No. 1 spiral rail spike was inspected separately, and the results were obtained. Figure 1 and Figure 2 The photo shown, in which Figure 1 For XRD patterns, Figure 2 This is a TEM image. (Through...) Figure 1 It can be determined that the formed amorphous coating contains Zr₂Cu and Zr₂Ni nanocrystals. Figure 2 The image shows nanocrystals distributed in a dispersed manner. Figure 2 In the magnified image in the upper right corner, the white bright spots are nanocrystals.

[0039] Example 2

[0040] Production of #2 spiral rail spikes:

[0041] (1) The rail spike body was soaked in acetone for 40 minutes to remove oil stains, then ultrasonically cleaned with anhydrous ethanol for 30 minutes, dried at 60℃, and finally sandblasted at a pressure of 0.7MPa to obtain a clean rail spike body. The rail spike body is made of Q235# carbon steel. The external thread of the rail spike body is formed by rolling.

[0042] (2) Spraying: Zirconium-based amorphous powder is used as the spraying material and plasma spraying is applied to the surface of the clean road stud body to form a layer, followed by cooling. During spraying, the road stud body is fixed on a rotating table with a rotation speed of 180 r / min.

[0043] Rolling: The rail spike body with the sub-coating is heated to 400°C at a heating rate of 8°C / min, and the sub-coating is rolled. During rolling, the same thread rolling die as that used to form the external thread of the rail spike body is used.

[0044] When rolling the sub-coating, the thread rolling die used is the same as the thread rolling die used to form the external thread on the rail spike body.

[0045] The coating process involves five repeated spraying and rolling cycles to form an amorphous coating, resulting in coated road studs. Each coat has a thickness of 110 μm.

[0046] In this embodiment, the zirconium-based amorphous powder has the following composition by mass percentage: 54 wt% Zr, 28 wt% Cu, 7 wt% Al, 3 wt% Ti and 8 wt% Ni.

[0047] The plasma spraying parameters are as follows: argon flow rate 70 L / min, hydrogen flow rate 25 L / min, current 450 A, voltage 50 V, spraying distance 110 mm, powder feed rate 15 g / min, and spray gun movement speed 40 mm / s. The spray gun nozzle type is a wide-mouth type, and the spraying angle during plasma spraying is 90°.

[0048] (3) Under a nitrogen atmosphere, the coated road stud is heated to a set temperature of 450°C at a set heating rate of 8°C / min, and after holding at the temperature for 40 minutes, it is cooled to room temperature to produce No. 2 spiral road stud.

[0049] Example 3

[0050] Production of #3 spiral rail spikes:

[0051] (1) The rail spike body was soaked in acetone for 50 minutes to remove oil stains, then ultrasonically cleaned with anhydrous ethanol for 50 minutes, dried at 90℃, and finally sandblasted at a pressure of 0.5 MPa to obtain a clean rail spike body. The rail spike body is made of Q235# carbon steel. The external thread of the rail spike body is formed by rolling.

[0052] (2) Spraying: Zirconium-based amorphous powder is used as the spraying material and plasma spraying is applied to the surface of the clean road stud body to form a layer, followed by cooling. During spraying, the road stud body is fixed on a rotating table with a rotation speed of 150 r / min.

[0053] Rolling: The rail spike body with the sub-coating is heated to 393°C at a heating rate of 9°C / min, and the sub-coating is rolled. During rolling, the same thread rolling die as that used to form the external thread of the rail spike body is used.

[0054] When rolling the sub-coating, the thread rolling die used is the same as the thread rolling die used to form the external thread on the rail spike body.

[0055] The coating process involves four repeated spraying and rolling processes to form an amorphous coating, resulting in coated road studs. Each spraying operation produces a sub-coating thickness of 140 μm.

[0056] In this embodiment, the zirconium-based amorphous powder has the following composition by mass percentage: 52 wt% Zr, 28 wt% Cu, 9 wt% Al, 4 wt% Ti and 7 wt% Ni.

[0057] The plasma spraying parameters are as follows: argon flow rate 50 L / min, hydrogen flow rate 20 L / min, current 350 A, voltage 42 V, spraying distance 60 mm, powder feed rate 30 g / min, and spray gun movement speed 10 mm / s. The spray gun nozzle type is a wide-mouth type, and the spraying angle during plasma spraying is 90°.

[0058] (3) Under a nitrogen atmosphere, the coated road stud is heated to a set temperature of 437°C at a set heating rate of 9°C / min, and after holding at the temperature for 50 minutes, it is cooled to room temperature to produce No. 3 spiral road stud.

[0059] Example 4

[0060] Production of #4 spiral rail spikes:

[0061] (1) The rail spike body was soaked in acetone for 20 minutes to remove oil stains, then ultrasonically cleaned with anhydrous ethanol for 40 minutes, dried at 40℃, and finally sandblasted at a pressure of 0.7MPa to obtain a clean rail spike body. The rail spike body is made of Q235# carbon steel. The external thread of the rail spike body is formed by rolling.

[0062] (2) Spraying: Zirconium-based amorphous powder is used as the spraying material and plasma spraying is applied to the surface of the clean road stud body to form a layer, which is then cooled to room temperature. During spraying, the road stud body is fixed on a rotating table with a rotation speed of 160 r / min.

[0063] Rolling: The rail spike body with the sub-coating is heated to 397°C at a heating rate of 7°C / min, and the sub-coating is rolled. During rolling, the same thread rolling die as that used to form the external thread of the rail spike body is used.

[0064] When rolling the sub-coating, the thread rolling die used is the same as the thread rolling die used to form the external thread on the rail spike body.

[0065] The coating process involves four repeated spraying and rolling processes to form an amorphous coating, resulting in coated road studs. Each spraying operation produces a sub-coating thickness of 120 μm.

[0066] In this embodiment, the zirconium-based amorphous powder has the following composition by mass percentage: 54 wt% Zr, 24 wt% Cu, 8 wt% Al, 4 wt% Ti and 10 wt% Ni.

[0067] The plasma spraying parameters are as follows: argon flow rate 60 L / min, hydrogen flow rate 20 L / min, current 400 A, voltage 46 V, spraying distance 90 mm, powder feed rate 25 g / min, and spray gun movement speed 20 mm / s. The spray gun nozzle type is a wide-mouth type, and the spraying angle during plasma spraying is 90°.

[0068] (3) Under a nitrogen atmosphere, the coated road stud is heated to a set temperature of 430°C at a set heating rate of 7°C / min, and after holding at the temperature for 25 minutes, it is cooled to room temperature to produce No. 4 spiral road stud.

[0069] Comparative Example 1

[0070] Production of #5 spiral rail spikes:

[0071] (1) The rail spike body was soaked in acetone for 30 minutes to remove oil stains, then ultrasonically cleaned with anhydrous ethanol for 40 minutes, dried at 50℃, and finally sandblasted at a pressure of 0.6MPa to obtain a clean rail spike body. The rail spike body is made of Q235# carbon steel. The external thread of the rail spike body is formed by rolling.

[0072] (2) Spraying: Zirconium-based amorphous powder is used as the spraying material and plasma spraying is applied to the surface of the clean road stud body to form a layer, followed by cooling. During spraying, the road stud body is fixed on a rotating table with a rotation speed of 120 r / min.

[0073] Rolling: The rail spike body with the sub-coating is heated to 390°C and the sub-coating is rolled. During rolling, the same thread rolling die as that used to form the external thread of the rail spike body is used.

[0074] When rolling the sub-coating, the thread rolling die used is the same as the thread rolling die used to form the external thread on the rail spike body.

[0075] The spraying and rolling processes are performed only once to form an amorphous coating, which is then used to manufacture coated road studs. The thickness of the coating layer is 440 μm.

[0076] In this embodiment, the zirconium-based amorphous powder has the following composition by mass percentage: 50 wt% Zr, 27 wt% Cu, 9 wt% Al, 4 wt% Ti and 10 wt% Ni.

[0077] The plasma spraying parameters are as follows: argon flow rate 40 L / min, hydrogen flow rate 15 L / min, current 300 A, voltage 40 V, spraying distance 40 mm, powder feed rate 20 g / min, and spray gun movement speed 30 mm / s. The spray gun nozzle type is a wide-mouth type, and the spraying angle during plasma spraying is 90°.

[0078] (3) Under a nitrogen atmosphere, the coated road stud is heated to a set temperature of 432°C at a set heating rate of 8°C / min, and after holding at the temperature for 30 minutes, it is cooled to room temperature to produce No. 5 spiral road stud.

[0079] In this comparative example, multiple coatings were not applied.

[0080] Comparative Example 2

[0081] Production of #6 spiral rail spikes:

[0082] (1) The rail spike body was soaked in acetone for 30 minutes to remove oil stains, then ultrasonically cleaned with anhydrous ethanol for 40 minutes, dried at 50℃, and finally sandblasted at a pressure of 0.6MPa to obtain a clean rail spike body. The rail spike body is made of Q235# carbon steel. The external thread of the rail spike body is formed by rolling.

[0083] (2) Spraying: Zirconium-based amorphous powder was used as the spraying material and plasma spraying was applied to the clean surface of the road stud body to form a layer, followed by cooling. During spraying, the road stud body was fixed on a rotating table with a rotation speed of 120 r / min. In this comparative example, the layer was not rolled.

[0084] The coating was applied four times to form an amorphous coating, thus creating the coated road studs. Each coat was applied to a layer with a thickness of 110 μm.

[0085] In this embodiment, the zirconium-based amorphous powder has the following composition by mass percentage: 50 wt% Zr, 27 wt% Cu, 9 wt% Al, 4 wt% Ti and 10 wt% Ni.

[0086] The plasma spraying parameters are as follows: argon flow rate 40 L / min, hydrogen flow rate 15 L / min, current 300 A, voltage 40 V, spraying distance 40 mm, powder feed rate 20 g / min, and spray gun movement speed 30 mm / s. The spray gun nozzle type is a wide-mouth type, and the spraying angle during plasma spraying is 90°.

[0087] (3) Under a nitrogen atmosphere, the coated road stud is heated to a set temperature of 432°C at a set heating rate of 8°C / min, and after holding at the temperature for 30 minutes, it is cooled to room temperature to produce a No. 6 spiral road stud.

[0088] In this comparative example, multiple sprayings were performed, but the resulting sub-layers were not rolled.

[0089] Comparative Example 3

[0090] Production of #7 spiral rail spikes:

[0091] (1) The rail spike body was soaked in acetone for 30 minutes to remove oil stains, then ultrasonically cleaned with anhydrous ethanol for 40 minutes, dried at 50℃, and finally sandblasted at a pressure of 0.6MPa to obtain a clean rail spike body. The rail spike body is made of Q235# carbon steel. The external thread of the rail spike body is formed by rolling.

[0092] (2) Spraying: Zirconium-based amorphous powder is used as the spraying material and plasma spraying is applied to the surface of the clean road stud body to form a layer, followed by cooling. During spraying, the road stud body is fixed on a rotating table with a rotation speed of 120 r / min.

[0093] Rolling: The spike body with the sub-coating is heated to 390°C at a heating rate of 8°C / min, and the sub-coating is rolled. During rolling, the same thread rolling die as that used to form the external thread of the spike body is used. This produces a #7 spiral spike.

[0094] When rolling the sub-coating, the thread rolling die used is the same as the thread rolling die used to form the external thread on the rail spike body.

[0095] The coating was repeated four times by spraying and rolling to form an amorphous coating, producing #8 track spikes. Each coat had a thickness of 110 μm.

[0096] In this embodiment, the zirconium-based amorphous powder has the following composition by mass percentage: 50 wt% Zr, 27 wt% Cu, 9 wt% Al, 4 wt% Ti and 10 wt% Ni.

[0097] The plasma spraying parameters are as follows: argon flow rate 40 L / min, hydrogen flow rate 15 L / min, current 300 A, voltage 40 V, spraying distance 40 mm, powder feed rate 20 g / min, and spray gun movement speed 30 mm / s. The spray gun nozzle type is a wide-mouth type, and the spraying angle during plasma spraying is 90°.

[0098] This comparative example does not have step (3) and does not undergo crystallization treatment.

[0099] Comparative Example 4

[0100] Production of #8 spiral rail spikes:

[0101] (1) The rail spike body was soaked in acetone for 30 minutes to remove oil stains, then ultrasonically cleaned with anhydrous ethanol for 40 minutes, dried at 50℃, and finally sandblasted at a pressure of 0.6MPa to obtain a clean rail spike body. The rail spike body is made of Q235# carbon steel. The external thread of the rail spike body is formed by rolling.

[0102] (2) Spraying: Zirconium-based amorphous powder is used as the spraying material and plasma spraying is applied to the surface of the clean road stud body to form a layer, followed by cooling. During spraying, the road stud body is fixed on a rotating table with a rotation speed of 120 r / min.

[0103] Rolling: At room temperature, the sub-coating layer is rolled. During rolling, the same thread rolling die as the one used to form the external thread of the road stud body is used.

[0104] When rolling the sub-coating, the thread rolling die used is the same as the thread rolling die used to form the external thread on the rail spike body.

[0105] The coating process involves four repeated spraying and rolling processes to form an amorphous coating, resulting in coated road studs. Each coat has a thickness of 110 μm.

[0106] In this embodiment, the zirconium-based amorphous powder has the following composition by mass percentage: 50 wt% Zr, 27 wt% Cu, 9 wt% Al, 4 wt% Ti and 10 wt% Ni.

[0107] The plasma spraying parameters are as follows: argon flow rate 40 L / min, hydrogen flow rate 15 L / min, current 300 A, voltage 40 V, spraying distance 40 mm, powder feed rate 20 g / min, and spray gun movement speed 30 mm / s. The spray gun nozzle type is a wide-mouth type, and the spraying angle during plasma spraying is 90°.

[0108] (3) Under a nitrogen atmosphere, the coated road stud is heated to a set temperature of 432°C at a set heating rate of 8°C / min, and after holding at the temperature for 30 minutes, it is cooled to room temperature to produce No. 8 spiral road stud.

[0109] In this comparative example, the two coatings were rolled at room temperature.

[0110] Comparative Example 5

[0111] Production of #9 spiral rail spikes:

[0112] This comparative example is basically the same as Example 1, except that the heating rate in step (3) is different. In this comparative example, the heating rate in step (3) is 5℃ / min.

[0113] Comparative Example 6

[0114] Production of #10 spiral rail spikes:

[0115] This comparative example is basically the same as Example 1, except that the heating rate in step (3) is different. In this comparative example, the heating rate in step (3) is 12℃ / min.

[0116] Comparative Example 7

[0117] Production of #11 spiral rail spikes:

[0118] This comparative example is basically the same as Example 1, except that the set temperature in step (3) is different. In this comparative example, the set heating rate in step (3) is 400°C.

[0119] Comparative Example 8

[0120] Production of #12 spiral rail spikes:

[0121] This comparative example is basically the same as Example 1, except that the temperature setting in step (3) is different. In this comparative example, the heating rate setting in step (3) is 500°C.

[0122] Comparative Example 9

[0123] Production of #13 spiral rail spikes:

[0124] This comparative example is basically the same as Example 1, except that the heat preservation setting time in step (3) is different. In this comparative example, the heat preservation setting time in step (3) is 15 minutes.

[0125] Comparative Example 10

[0126] Production of #14 spiral rail spikes:

[0127] This comparative example is basically the same as Example 1, except that the heat preservation setting time in step (3) is different. In this comparative example, the heat preservation setting time in step (3) is 65 min.

[0128] Corrosion resistance tests were conducted on spiral rail spikes #1-#14. The results of the corrosion resistance test reports are shown in Tables 1 and 2. The corrosion resistance test conditions in Table 1 refer to the GBT-10125-2012 Salt Spray Corrosion Standard.

[0129] Table 1 Corrosion Resistance Test Conditions

[0130] Test conditions Standard value Test values sodium chloride solution concentration 50±5g / L 50g / L Density of sodium chloride solution <![CDATA[1.029-1.036g / mm 3 ]]> <![CDATA[1.032g / mm 3 ]]> pH value 6.5-7.2 7.0 spray pressure 70-170kPa 98kPa

[0131] During the experiment, the corrosion of the sample was observed every 10 hours, and the time when red spots appeared was recorded.

[0132] Table 2 Corrosion Resistance Test Conditions

[0133]

[0134] Table 2 shows that the test time of the #9 spiral road spike in Comparative Example 5 also reached over 1000 hours. However, the #10 spiral road spike in Comparative Example 6 showed red spots after 720 hours, indicating that excessively high heating rates may cause the road spike body to expand too quickly, leading to cracks in the amorphous coating and forming defects. This allows external corrosive substances to easily enter through these cracks and corrode the road spike body. The test times of the spiral road spikes produced in other comparative examples did not reach 900 hours, indicating that layered spraying to form sub-layers and rolling each sub-layer under heating is more conducive to forming an amorphous coating with a good structure.

Claims

1. A method for producing a spiral rail spike with a composite amorphous protective layer, characterized in that, Includes the following steps: (1) The rail spike body is degreased, cleaned and sandblasted. The rail spike body is made of carbon steel to obtain a clean rail spike body. The rail spike body has an external thread formed by rolling. (2) Using zirconium-based amorphous powder as the spraying material, plasma spraying is used to spray the surface of the road stud body to form an amorphous coating and make coated road studs. The amorphous coating consists of 3-5 sub-coatings, each of which is formed using the following steps: Spraying: Zirconium-based amorphous powder is used as the spraying material and plasma spraying is applied to the surface of the road stud body to form a layer. After cooling to room temperature, the thickness of the layer is 100-150μm. Rolling: The rail spike body with the sub-coating is heated to 390-400℃ at a heating rate of 7-9℃ / min, and the sub-coating is rolled. When rolling the sub-coating, the thread rolling die used is the same as the thread rolling die used to form the external thread on the rail spike body. Repeat spraying and rolling 3-5 times to produce coated road studs; (3) Under a nitrogen atmosphere, heat the coated road studs to 430-450°C at a set heating rate, and cool them to room temperature after holding for a set time; the set heating rate is 7-9°C / min, and the set holding time is 25-50min.

2. The production method according to claim 1, characterized in that, The composition of the zirconium-based amorphous powder, by mass percentage, is: 50-54 wt% Zr, 24-28 wt% Cu, 7-9 wt% Al, 3-4 wt% Ti and 7-10 wt% Ni.

3. The production method according to claim 1, characterized in that, In step (2), the parameters for plasma spraying during spraying are as follows: argon flow rate of 40-70 L / min, hydrogen flow rate of 10-25 L / min, current of 300-450 A, voltage of 40-50 V, spraying distance of 40-110 mm, powder feeding rate of 15-30 g / min, and spray gun moving speed of 10-40 mm / s.

4. The production method according to claim 1, characterized in that, The rail spike body is fixed on a rotating platform, which rotates at a speed of 100-200 r / min.

5. The production method according to claim 1, characterized in that, The thickness of the amorphous coating is 400-600μm.

Images