Processing technology of high-durability iron backing plate for high-speed rail fastener

Abstract

The invention relates to the technical field of mechanical casting, in particular to a machining process of a high-durability iron base plate for a high-speed rail fastener. Comprising the following steps that S1, a carburant is added into a cast iron raw material for smelting treatment, then smelting treatment, refining and impurity removal, cooling and discharging are conducted, and a cast iron stock solution is obtained; s2: (1) adding a spheroidizing agent into the cast iron stock solution for spheroidizing to obtain a nodular cast iron solution A; (2) adding an antioxidant inoculant into the nodular cast iron liquid A, and sequentially carrying out primary inoculation, secondary inoculation and third inoculation to obtain nodular cast iron liquid B; s3, the nodular cast iron liquid B is subjected to casting molding, heat treatment and discharging, and an iron base plate A is obtained; s4, the iron base plate A is immersed in the composite electroplating solution, double-pulse electroplating treatment is conducted, cleaning, nitrogen blow-drying and curing are conducted, and the iron base plate is obtained; therefore, the high-durability iron base plate for the high-speed rail fastener is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical casting, in particular to a processing technology of a high-durability iron pad for high-speed rail fasteners. Background Art

[0002] With the rapid development of high-speed railway technology, higher requirements are put forward for the safety, stability and comfort of train operation. Among them, iron pads, as key components of high-speed rail fastener systems, are subjected to huge pressure and vibration from tracks and trains, so their durability and mechanical properties are particularly important. In the prior art, iron pads prepared by alloy preparation methods usually have poor mechanical properties and insufficient durability due to insufficient optimization of alloy formula, inaccurate control of heat treatment process, and poor anti-oxidation effect of inoculant, which limits the application of iron pads.

[0003] In summary, it is of great significance to prepare a high-durability iron plate for high-speed rail fasteners. Summary of the invention

[0004] The object of the present invention is to provide a processing technology for a high-durability iron plate for high-speed rail fasteners to solve the problems raised in the prior art.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A processing technology for a high-durability iron plate for a high-speed rail fastener comprises the following steps:

[0007] S1: adding a carburizer to the cast iron raw material for smelting treatment, followed by smelting treatment, refining and impurity removal, cooling, and unloading to obtain cast iron stock solution;

[0008] S2: (1) adding a spheroidizing agent to the cast iron stock liquid for spheroidization treatment to obtain a ball-milled cast iron liquid A; (2) adding an antioxidant inoculant to the ball-milled cast iron liquid A for primary inoculation, secondary inoculation, and tertiary inoculation in sequence to obtain a ball-milled cast iron liquid B;

[0009] S3: The ductile iron liquid B is subjected to casting, heat treatment, and furnace discharge to obtain an iron plate A;

[0010] S4: immersing the iron backing plate A in the composite electroplating solution, performing double pulse electroplating treatment, washing, drying with nitrogen, and curing to obtain the iron backing plate.

[0011] More optimally, the composition of the ball-milled cast iron liquid B includes the following elements, by mass percentage: 2.5% to 3.8% carbon, 1.5% to 2.5% silicon, 1.0% to 1.4% chromium, 1.2% to 2.3% niobium, 0.03% to 0.06% magnesium, 0.02% to 0.03% rare earth elements, manganese ≤0.45%, and the rest is iron and unavoidable impurities ≤0.04%.

[0012] More optimally, in S1, the temperature of the smelting treatment is 1500-1550°C, the smelting treatment time is 30-60min; the temperature of the smelting treatment is 1450-1500°C; the temperature of the refining and impurity removal is 1400-1450°C;

[0013] The recarburizer includes one or more of a graphitized recarburizer and a silicon-manganese alloy; the added amount of the recarburizer accounts for 1.2wt% to 2.5wt% of the cast iron stock solution.

[0014] In the scheme, one or more of a graphitized carburizer and a silicon-manganese alloy are introduced during the smelting process of cast iron raw materials. The graphitized carburizer can increase the carbon content of the molten iron, improve the distribution of graphite, reduce the oxidation of the molten iron, prevent the shrinkage of the molten iron, and reduce the production cost. The silicon-manganese alloy can effectively remove oxygen from the molten iron and improve the purity of the molten iron, thereby improving the mechanical properties and promoting graphitization.

[0015] More optimally, in S2, the spheroidizing process adopts a covering method at a temperature of 1450-1500°C; the spheroidizing agent includes FeSiMg6RE2; the amount of the spheroidizing agent added accounts for 0.9wt%-1.5wt% of the ball-milled cast iron liquid A;

[0016] During the one-time inoculation process, the particle size of the antioxidant inoculant is 4-8 mm, and the amount added accounts for 0.1 wt%-0.3 wt% of the ball-milled cast iron liquid B;

[0017] During the secondary inoculation, the particle size of the antioxidant inoculant is 2 to 5 mm, and the amount added accounts for 0.2 wt% to 0.5 wt% of the ball-milled cast iron liquid B;

[0018] During the three inoculation processes, the particle size of the antioxidant inoculant is 1-3 mm, and the amount added accounts for 0.4wt%-0.8wt% of the ball-milled cast iron liquid B.

[0019] In the scheme, three inoculations were adopted. The particle size of the antioxidant inoculant added during the three inoculations and the proportion of the antioxidant inoculant in the spheroidal cast iron liquid B were different. The main function of the first inoculation is to promote the nucleation and refinement of graphite. At this stage, adding larger particle size and smaller amount of antioxidant inoculant for preliminary inoculation can form a large number of graphite nuclei in the molten iron, providing a basis for subsequent graphite growth. At the same time, the antioxidant inoculant can also effectively reduce the oxygen content in the molten iron, prevent the formation of oxidized inclusions, and improve the purity and fluidity of the molten iron.

[0020] The purpose of secondary inoculation is to further refine the graphite structure and improve the roundness and uniformity of the graphite nodules. At this stage, by adding smaller antioxidant inoculant particles and slightly more than the primary inoculation, more graphite nuclei can be formed in the molten iron, promoting the uniform distribution and refinement of graphite. At the same time, the secondary inoculation can also enhance the solidification ability of the molten iron and reduce the occurrence of defects such as shrinkage cavities and shrinkage.

[0021] The third inoculation is mainly to consolidate the results of the first two inoculations and ensure the final shape and quality of the graphite structure. At this stage, by adding smaller particles and more antioxidant inoculants, the graphite structure can be further refined and the mechanical properties and processing properties can be improved. At the same time, the third inoculation can also reduce defects such as white cast tendency and cracks.

[0022] More optimally, the method for preparing the antioxidant inoculant comprises the following steps:

[0023] S1: Preparation of modified silicone resin: bismaleimide and organotin are added to tetrahydrofuran, heated at 55-75°C for 30-60 minutes, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane is added, reacted at 95-110°C for 12-14 hours, and distilled under reduced pressure, filtered, and dried to obtain amino resin; 2-tert-butyl-6-methylphenol, carbene diboric acid, and amino resin are added to acetonitrile in sequence, stirred and reacted at room temperature for 12-24 hours, and the solvent is evaporated to obtain modified silicone resin;

[0024] S2: Preparation of modified coating: Add nano-alumina, silicon carbide powder, nano-silicon dioxide, modified organic resin, nano-aluminum powder and glass powder to xylene in sequence, stir, mix, grind and filter, add methylethanolamine and mix evenly to obtain a modified coating with a thickness of 20±4 μm;

[0025] S3: Preparation of an antioxidant inoculant: Spray the inoculant onto the modified coating with a thickness of 20±4 μm by air spraying, and cure it at room temperature for 24 to 30 hours to obtain an antioxidant inoculant.

[0026] In a further embodiment, the inoculant includes FeSi75 inoculant.

[0027] Wherein, during the grinding process, the zirconium oxide grinding beads are used for grinding at 2200-2700 r / min for 30-40 min.

[0028] More optimally, the scheme introduces an antioxidant inoculant, and adds the vinyl and organotin in bismaleimide as catalysts to tetrahydrofuran solvent to react with the siloxane of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane to generate a resin containing amino groups. Subsequently, the amino resin is further modified using the phenolic hydroxyl group and carbene diboric acid in 2-tert-butyl-6-methylphenol as condensation agents to obtain a modified silicone resin with antioxidant properties. The modified coating is prepared by combining the modified silicone resin with an inorganic filler and a curing agent. The prepared modified coating tightly combines the two by spraying and curing, which can make up for the lack of antioxidant properties of the inoculant itself, thereby promoting graphite nucleation and refinement, and improving the mechanical properties and durability of the iron pad.

[0029] More optimally, the raw materials of the amino resin include the following raw materials by weight: 6 to 9 parts of bismaleimide, 0.3 to 0.5 parts of organotin, 35 to 45 parts of tetrahydrofuran, and 2 to 3 parts of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane;

[0030] The raw materials of the modified silicone resin include the following raw materials by weight: 2 to 3 parts of 2-tert-butyl-6-methylphenol, 0.2 to 0.4 parts of carbene diboric acid, 9 to 12 parts of amino resin, and 35 to 45 parts of acetonitrile;

[0031] The raw materials of the modified coating with a thickness of 20±4 μm include the following raw materials by mass: 3 to 4 parts of nano-aluminum oxide, 2 to 3 parts of silicon carbide powder, 1 to 1.5 parts of nano-silicon dioxide, 5 to 6 parts of modified organic resin, 0.5 to 1.2 parts of nano-aluminum powder, 1 to 2 parts of glass powder, 30 to 40 parts of xylene, and 6 to 7 parts of methylethanolamine.

[0032] In the solution, the glass powder is a low melting point glass powder.

[0033] More optimally, in S3, the casting temperature is 1450-1490°C, and the heat treatment process is specifically as follows: after casting, heating at 800-900°C for 1-2 hours, then reducing the temperature to 400-480°C at a rate of 5-7°C / min, keeping warm for 1-2 hours, and cooling.

[0034] More optimally, the preparation method of the composite electroplating solution comprises the following steps: adding ferrous sulfate, potassium bromide, sodium chloride, citric acid, manganese sulfate, and silicon powder into deionized water, and stirring at 15 to 30° C. for 15 to 20 minutes to obtain a composite electroplating solution;

[0035] The raw materials of the composite electroplating solution include the following components: by mass, 40-50 parts of ferrous sulfate, 0.3-1 parts of potassium bromide, 5-6 parts of sodium chloride, 0.5-1 parts of citric acid, 0.3-5 parts of manganese sulfate, 1.5-30 parts of silicon powder, and 50-60 parts of deionized water.

[0036] In the scheme, the surface treatment of the iron pad A is performed by immersing the iron pad A in a composite electroplating solution for electroplating, thereby improving the surface quality of the iron pad A, enhancing the corrosion resistance, and improving the mechanical properties. During the electroplating process, the ferrous ions and manganese ions in the composite electroplating solution move toward the iron pad A and are deposited on the surface of the iron pad A to form a coating. Citric acid in the electroplating solution acts as a surfactant, which stabilizes the ions in the electroplating solution, prevents them from being hydrolyzed or precipitated prematurely, and improves the performance of the coating. Silicon powder is co-deposited into the coating during the electroplating process to form a composite coating. It has better mechanical properties, wear resistance, corrosion resistance, and durability.

[0037] More optimally, in S4, during the curing process, the set temperature value of the curing furnace is 210±5°C, and the set temperature is set according to the change of the ambient temperature. When the ambient temperature is >20°C, the curing furnace temperature is set to 205°C~210°C; when the ambient temperature is <20°C, the curing furnace set temperature is set to 210°C~215°C.

[0038] More optimally, an iron pad is prepared using a processing technology for high-durability iron pads for high-speed rail fasteners.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1. The scheme introduces a carburizer during the smelting process of cast iron raw materials to improve the deoxidation effect, improve the carburization effect, improve the graphite morphology, and reduce costs, thereby indirectly improving the mechanical properties and durability;

[0041] 2. The scheme introduces the antioxidant inoculant prepared by modified grafting for three inoculations. By adjusting the particle size and addition amount of the antioxidant inoculant, the antioxidant performance of the iron pad can be improved, the graphite structure can be optimized, the uniformity and consistency of the iron pad can be improved, and defects and cracks can be reduced, thereby improving production efficiency and improving the mechanical properties and durability of the iron pad;

[0042] 3. In the scheme, the iron pad A is immersed in a composite electroplating solution for electroplating to perform surface treatment, so that the prepared iron pad has better mechanical properties, wear resistance, corrosion resistance and durability. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. 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.

[0044] It should be noted that the following parts are by mass, and the purchase manufacturers of all raw materials involved in the present invention are not subject to any special restrictions. Examples include: In the following embodiments, the specification of the graphitized recarburizer is 1-5 mm, the item number is 003, and it is purchased from Shijiazhuang Mayue Building Materials Co., Ltd.; the particle size of the silicon manganese alloy is 2-12 mm, the impurity content is 0.01%, and the brand is Fenglan Metallurgy; the spheroidizer is FeSiMg6RE2; the inoculant is FeSi75; the particle size of the nano-alumina is 20-30 nm, purchased from Yumu (Ningbo) New Materials Co., Ltd., and the particle size of the silicon carbide powder is The diameter is 30-50nm, the item number is AM-SiC-051-1, purchased from Zhejiang Yamei Nano Technology Co., Ltd., the item number of nano silicon dioxide is ML-SiO2-N07, purchased from Manli Nano Technology (Ningbo) Co., Ltd., the specification of nano aluminum powder is 40-50nm, purchased from Shanghai Yunfu Nano Technology Co., Ltd., the softening point of low melting point glass powder is about 450℃, the Mohs hardness is 4-6, the melting temperature is 480-550℃, the model is 1407130, the item number is FSM1407130; the item number of methylethanolamine is HFD-036.

[0045] In the following scheme, the composition of the ball-milled cast iron liquid B includes the following elements, by mass percentage: 3.1% carbon, 2% silicon, 1.2% chromium, 1.7% niobium, 0.045% magnesium, 0.025% rare earth elements, 0.4% manganese, and the rest is iron and unavoidable impurities 0.03%.

[0046] The recarburizer includes one or more of a graphitized recarburizer and a silicon-manganese alloy.

[0047] The preparation method of the antioxidant inoculant is as follows: S1: Preparation of modified silicone resin: (1) Add 7.5 parts of bismaleimide and 0.4 parts of organotin to 40 parts of tetrahydrofuran, heat at 65°C for 45 minutes, add 2.5 parts of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, react at 102.5°C for 13 hours, distill under reduced pressure, filter, and dry to obtain amino resin; (3) Add 2.5 parts of 2-tert-butyl-6-methylphenol, 0.3 parts of carbene diboric acid, and 10.5 parts of amino resin to 40 parts of acetonitrile in sequence, stir and react at room temperature for 18 hours, evaporate the solvent, and obtain modified silicone resin;

[0048] S2: Preparation of modified coating: 3.5 parts of nano-alumina, 2.5 parts of silicon carbide powder, 1.2 parts of nano-silicon dioxide, 5.5 parts of modified organic resin, 0.8 parts of nano-aluminum powder, and 1.5 parts of glass powder were added to 35 parts of xylene in sequence, stirred, mixed, ground, and filtered, and 6.5 parts of methylethanolamine were added and mixed evenly to obtain a modified coating with a thickness of 20 μm;

[0049] S3: Preparation of an antioxidant inoculant: The modified coating with a thickness of 20 μm is sprayed with an inoculant by air spraying, and cured at room temperature for 27 hours to obtain an antioxidant inoculant.

[0050] Embodiment 1: A processing technology for a high-durability iron plate for a high-speed rail fastener comprises the following steps:

[0051] Step 1: adding 1.8 wt% of a carburizer to the cast iron raw material at 1525° C. for smelting for 45 minutes, then smelting at 1475° C., refining and removing impurities at 1425° C., cooling, and taking out of the furnace to obtain a cast iron stock solution;

[0052] Step 2: (1) adding 1.2wt% FeSiMg6RE2 spheroidizing agent to the cast iron stock liquid and performing spheroidizing treatment at 1475°C to obtain ball-milled cast iron liquid A; (2) adding 0.2wt% antioxidant inoculant with a particle size of 6mm to the ball-milled cast iron liquid A for a first inoculation, then adding 0.35wt% antioxidant inoculant with a particle size of 3.5mm for a second inoculation, and finally adding 0.6wt% antioxidant inoculant with a particle size of 2mm for a third inoculation to obtain ball-milled cast iron liquid B;

[0053] Step 3: Casting the ductile iron liquid B at 1470°C, heating at 850°C for 1.5 hours, then reducing the temperature to 440°C at a rate of 6°C / min, keeping the temperature for 1.5 hours, cooling, and removing from the furnace to obtain an iron plate A;

[0054] Step 4: (1) Add 45 parts of ferrous sulfate, 0.6 parts of potassium bromide, 5.5 parts of sodium chloride, 0.8 parts of citric acid, 2.6 parts of manganese sulfate, and 16 parts of silicon powder to 55 parts of deionized water, and stir at 22°C for 18 minutes to obtain a composite electroplating solution; (2) Immerse the iron pad A in the composite electroplating solution, perform double-pulse electroplating treatment, wash, blow dry with nitrogen, set the setting temperature of the curing furnace to 210°C, and set the setting temperature according to the change of ambient temperature. When the ambient temperature is >20°C, the curing furnace temperature is set to 208°C; when the ambient temperature is <20°C, the curing furnace setting temperature is set to 213°C to obtain an iron pad.

[0055] Embodiment 2: A processing technology for a high-durability iron plate for a high-speed rail fastener comprises the following steps:

[0056] Step 1: adding 1.2 wt% of carburizer to the cast iron raw material at 1525° C. for smelting for 45 min, then smelting at 1475° C., refining and removing impurities at 1425° C., cooling, and taking out of the furnace to obtain cast iron stock solution;

[0057] Step 2: (1) adding 0.9wt% FeSiMg6RE2 spheroidizer to the cast iron stock liquid and performing spheroidization treatment at 1475°C to obtain ball-milled cast iron liquid A; (2) adding 0.1wt% antioxidant inoculant with a particle size of 4mm to the ball-milled cast iron liquid A for a first inoculation, then adding 0.2wt% antioxidant inoculant with a particle size of 2mm for a second inoculation, and finally adding 0.4wt% antioxidant inoculant with a particle size of 1mm for a third inoculation to obtain ball-milled cast iron liquid B;

[0058] Step 3: Casting the ductile iron liquid B at 1470°C, heating at 850°C for 1.5 hours, then reducing the temperature to 440°C at a rate of 6°C / min, keeping the temperature for 1.5 hours, cooling, and removing from the furnace to obtain an iron plate A;

[0059] Step 4: (1) Add 40 parts of ferrous sulfate, 0.3 parts of potassium bromide, 5 parts of sodium chloride, 0.5 parts of citric acid, 0.3 parts of manganese sulfate, and 1.5 parts of silicon powder to 50 parts of deionized water, and stir at 22°C for 18 minutes to obtain a composite electroplating solution; (2) Immerse the iron pad A in the composite electroplating solution, perform double pulse electroplating treatment, wash, blow dry with nitrogen, set the setting temperature of the curing furnace to 210°C, and set the setting temperature according to the change of ambient temperature. When the ambient temperature is >20°C, the curing furnace temperature is set to 208°C; when the ambient temperature is <20°C, the curing furnace setting temperature is set to 213°C to obtain an iron pad.

[0060] Embodiment 3: A processing technology for a high-durability iron plate for a high-speed rail fastener, comprising the following steps:

[0061] Step 1: adding 2.5wt% carburizer to the cast iron raw material at 1525°C for 45min of smelting treatment, then smelting treatment at 1475°C, refining and impurity removal at 1425°C, cooling, and taking out of the furnace to obtain cast iron stock solution;

[0062] Step 2: (1) adding 1.5wt% FeSiMg6RE2 spheroidizing agent to the cast iron stock liquid and performing spheroidizing treatment at 1475°C to obtain ball-milled cast iron liquid A; (2) adding 0.3wt% antioxidant inoculant with a particle size of 8mm to the ball-milled cast iron liquid A for a first inoculation, then adding 0.5wt% antioxidant inoculant with a particle size of 5mm for a second inoculation, and finally adding 0.8wt% antioxidant inoculant with a particle size of 3mm for a third inoculation to obtain ball-milled cast iron liquid B;

[0063] Step 3: Casting the ductile iron liquid B at 1470°C, heating at 850°C for 1.5 hours, then reducing the temperature to 440°C at a rate of 6°C / min, keeping the temperature for 1.5 hours, cooling, and removing from the furnace to obtain an iron plate A;

[0064] Step 4: (1) Add 50 parts of ferrous sulfate, 1 part of potassium bromide, 6 parts of sodium chloride, 1 part of citric acid, 5 parts of manganese sulfate, and 30 parts of silicon powder to 60 parts of deionized water, and stir at 22°C for 18 minutes to obtain a composite electroplating solution; (2) Immerse the iron pad A in the composite electroplating solution, perform double pulse electroplating treatment, wash, blow dry with nitrogen, set the setting temperature of the curing furnace to 210°C, and set the setting temperature according to the change of ambient temperature. When the ambient temperature is >20°C, the curing furnace temperature is set to 208°C; when the ambient temperature is <20°C, the curing furnace setting temperature is set to 213°C to obtain an iron pad.

[0065] Comparative Example 1: Based on Example 1, in the inoculation treatment, the particle size of the three inoculations and the amount of the antioxidant inoculant were changed, and the other processes remained unchanged, specifically:

[0066] Step 2: (1) adding 1.2wt% FeSiMg6RE2 spheroidizer to the cast iron stock liquid and performing spheroidization treatment at 1475°C to obtain ball-milled cast iron liquid A; (2) adding 0.2wt% antioxidant inoculant with a particle size of 2mm to the ball-milled cast iron liquid A for one inoculation, then adding 0.3wt% antioxidant inoculant with a particle size of 3.5mm for a second inoculation, and finally adding 0.5wt% antioxidant inoculant with a particle size of 6mm for a third inoculation to obtain ball-milled cast iron liquid B.

[0067] Comparative Example 2: Based on Example 1, only one inoculation treatment was performed, and the rest of the process remained unchanged, specifically:

[0068] Step 2: (1) adding 1.2 wt% FeSiMg6RE2 spheroidizer to the cast iron stock liquid and performing spheroidization treatment at 1475° C. to obtain ball-milled cast iron liquid A; (2) adding 0.6 wt% antioxidant inoculant with a particle size of 6 mm to the ball-milled cast iron liquid A for a first inoculation treatment to obtain ball-milled cast iron liquid B.

[0069] Comparative Example 3: Based on Example 1, the antioxidant inoculant is changed to FeSi75 inoculant, and the other processes remain unchanged, specifically:

[0070] Step 2: (1) adding 1.2wt% FeSiMg6RE2 spheroidizer to the cast iron stock liquid and performing spheroidization treatment at 1475°C to obtain ball-milled cast iron liquid A; (2) adding 0.2wt% FeSi75 inoculant with a particle size of 6mm to the ball-milled cast iron liquid A for a first inoculation, then adding 0.35wt% FeSi75 inoculant with a particle size of 3.5mm for a second inoculation, and finally adding 0.6wt% FeSi75 inoculant with a particle size of 2mm for a third inoculation to obtain ball-milled cast iron liquid B.

[0071] Comparative Example 4: Based on Example 1, the composite film is not electroplated on the iron backing plate, and the other processes remain unchanged, specifically:

[0072] Step 3: Cast the ductile iron liquid B at 1470°C, heat it at 850°C for 1.5 hours, then reduce the temperature to 440°C at a rate of 6°C / min, keep it warm for 1.5 hours, cool it, and take it out of the furnace to obtain an iron pad.

[0073] Testing experiment: The high-durability iron plate for high-speed rail fasteners prepared in Examples 1 to 3 and Comparative Examples 1 to 4 was subjected to the following performance tests: (1) Tensile strength test: The iron plate prepared in Examples 1 to 3 and Comparative Examples 1 to 4 was subjected to performance test with reference to GB / T 1348-2009; (2) Brinell hardness test: The iron plate prepared in Examples 1 to 3 and Comparative Examples 1 to 4 was subjected to performance test with reference to the national standard GB / T 231.1 to 231.3.

[0074]

[0075] Table 1

[0076] Result analysis: According to the data analysis in Table 1, it can be seen that the present invention introduces the antioxidant inoculant prepared by modified grafting for three inoculations. By adjusting the particle size and the amount of the antioxidant inoculant, the antioxidant performance of the iron pad can be improved, the graphite structure can be optimized, the uniformity and consistency of the iron pad can be improved, and defects and cracks can be reduced, thereby improving the production efficiency and improving the mechanical properties and durability of the iron pad. By immersing it in a composite electroplating solution for electroplating to perform surface treatment, the prepared iron pad has more excellent mechanical properties, wear resistance, corrosion resistance and durability.

[0077] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A processing technology for a high-durability iron plate for high-speed rail fasteners, characterized in that: The following steps are involved: S1: adding a carburizer to the cast iron raw material for smelting treatment, followed by smelting treatment, refining and impurity removal, cooling, and unloading to obtain cast iron stock solution; S2: (1) adding a spheroidizing agent to the cast iron stock liquid for spheroidization treatment to obtain a ball-milled cast iron liquid A; (2) adding an antioxidant inoculant to the ball-milled cast iron liquid A for primary inoculation, secondary inoculation, and tertiary inoculation in sequence to obtain a ball-milled cast iron liquid B; S3: The ductile iron liquid B is subjected to casting, heat treatment, and furnace discharge to obtain an iron plate A; S4: immersing the iron backing plate A in the composite electroplating solution, performing double pulse electroplating treatment, washing, drying with nitrogen, and curing to obtain the iron backing plate.

2. The processing technology of a high-durability iron plate for high-speed rail fasteners according to claim 1 is characterized in that: The composition of the ball mill cast iron liquid B includes the following elements, calculated by mass percentage: 2.5% to 3.8% carbon, 1.5% to 2.5% silicon, 1.0% to 1.4% chromium, 1.2% to 2.3% niobium, 0.03% to 0.06% magnesium, 0.02% to 0.03% rare earth elements, manganese ≤ 0.45%, and the rest is iron and unavoidable impurities ≤ 0.04%.

3. The processing technology of a high-durability iron plate for high-speed rail fasteners according to claim 1 is characterized in that: In S1, the temperature of the smelting treatment is 1500-1550°C, and the smelting treatment time is 30-60min; the temperature of the smelting treatment is 1450-1500°C; the temperature of the refining and impurity removal is 1400-1450°C; the recarburizer includes one or more of a graphitized recarburizer and a silicon-manganese alloy; the amount of the recarburizer added accounts for 1.2wt%-2.5wt% of the cast iron stock solution.

4. The processing technology of a high-durability iron plate for high-speed rail fasteners according to claim 1 is characterized in that: In S2, the spheroidization process adopts a capping method at a temperature of 1450-1500°C; The spheroidizing agent includes FeSiMg6RE2; the amount of the spheroidizing agent added accounts for 0.9wt% to 1.5wt% of the ball-milled cast iron liquid A; During the first inoculation, the particle size of the antioxidant inoculant is 4-8 mm, and the amount added accounts for 0.1wt%-0.3wt% of the spheroidal cast iron liquid B; during the second inoculation, the particle size of the antioxidant inoculant is 2-5 mm, and the amount added accounts for 0.2wt%-0.5wt% of the spheroidal cast iron liquid B; during the third inoculation, the particle size of the antioxidant inoculant is 1-3 mm, and the amount added accounts for 0.4wt%-0.8wt% of the spheroidal cast iron liquid B.

5. The processing technology of a high-durability iron plate for high-speed rail fasteners according to claim 4 is characterized in that: The preparation method of the antioxidant inoculant comprises the following steps: S1: Preparation of modified silicone resin: bismaleimide and organotin are added to tetrahydrofuran, heated at 55-75°C for 30-60 minutes, 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane is added, reacted at 95-110°C for 12-14 hours, distilled under reduced pressure, filtered, and dried to obtain amino resin; 2-tert-butyl-6-methylphenol, carbene diboric acid, and amino resin are added to acetonitrile in sequence, stirred and reacted at room temperature for 12-24 hours, and the solvent is evaporated to obtain modified silicone resin; S2: Preparation of modified coating: Add nano-alumina, silicon carbide powder, nano-silicon dioxide, modified organic resin, nano-aluminum powder and glass powder to xylene in sequence, stir, mix, grind and filter, add methylethanolamine and mix evenly to obtain a modified coating with a thickness of 20±4 μm; S3: Preparation of an antioxidant inoculant: Spray the inoculant onto the modified coating with a thickness of 20±4 μm by air spraying, and cure it at room temperature for 24 to 30 hours to obtain an antioxidant inoculant.

6. The processing technology of a high-durability iron plate for high-speed rail fasteners according to claim 5 is characterized in that: The raw materials of the amino resin include the following raw materials by weight: 6 to 9 parts of bismaleimide, 0.3 to 0.5 parts of organotin, 35 to 45 parts of tetrahydrofuran, and 2 to 3 parts of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane; The raw materials of the modified silicone resin include the following raw materials by weight: 2 to 3 parts of 2-tert-butyl-6-methylphenol, 0.2 to 0.4 parts of carbene diboric acid, 9 to 12 parts of amino resin, and 35 to 45 parts of acetonitrile; The raw materials of the modified coating with a thickness of 20±4 μm include the following raw materials by mass: 3 to 4 parts of nano-aluminum oxide, 2 to 3 parts of silicon carbide powder, 1 to 1.5 parts of nano-silicon dioxide, 5 to 6 parts of modified organic resin, 0.5 to 1.2 parts of nano-aluminum powder, 1 to 2 parts of glass powder, 30 to 40 parts of xylene, and 6 to 7 parts of methylethanolamine.

7. The processing technology of a high-durability iron plate for high-speed rail fasteners according to claim 1 is characterized in that: In S3, the casting temperature is 1450-1490°C, and the heat treatment process is specifically as follows: after casting, heating at 800-900°C for 1-2 hours, then reducing the temperature to 400-480°C at a rate of 5-7°C / min, keeping the temperature for 1-2 hours, and cooling.

8. The processing technology of a high-durability iron plate for high-speed rail fasteners according to claim 1 is characterized in that: The preparation method of the composite electroplating solution comprises the following steps: adding ferrous sulfate, potassium bromide, sodium chloride, citric acid, manganese sulfate and silicon powder into deionized water, stirring at 15 to 30° C. for 15 to 20 minutes to obtain the composite electroplating solution; The raw materials of the composite electroplating solution include the following components: by mass, 40-50 parts of ferrous sulfate, 0.3-1 parts of potassium bromide, 5-6 parts of sodium chloride, 0.5-1 parts of citric acid, 0.3-5 parts of manganese sulfate, 1.5-30 parts of silicon powder, and 50-60 parts of deionized water.

9. The processing technology of a high-durability iron plate for high-speed rail fasteners according to claim 1 is characterized in that: In S4, during the curing process, the set temperature value of the curing furnace is 210±5°C, and the set temperature is set according to the change of the ambient temperature. When the ambient temperature is >20°C, the curing furnace temperature is set to 205°C~210°C; when the ambient temperature is <20°C, the curing furnace set temperature is set to 210°C~215°C.

10. An iron plate prepared by the processing technology of a high-durability iron plate for high-speed railway fasteners according to any one of claims 1 to 9.

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