Non-magnetic self-lubricating hardware material and preparation method thereof

Abstract

The application discloses a non-magnetic self-lubricating hardware material, which is composed of the following raw materials according to mass percentage: C 3.3%-3.8%, Si 2.0%-2.6%, Ni 10%-14%, Mo 0.5%-1.0%, V 0.5%-1.0%, Mn 0.1%-0.2%, P≤0.1%, S≤0.015%, and the balance of Fe, wherein the total of the content of the above components is 100%. The application further discloses a preparation method of the material: step 1, weighing bread iron, silicon iron, nickel plate, chromium iron, molybdenum iron, vanadium iron and carbon additive, and melting the weighed materials in a medium-frequency furnace to obtain a first liquid; step 2, pouring the first liquid into a holding furnace, and adding silicon barium inoculant and rare earth magnesium spheroidizing agent to fully stir; step 3, adopting a horizontal continuous casting method to obtain a casting; step 4, water-cooling the first metal piece in a vacuum furnace; step 5, low-temperature tempering the second metal piece in a muffle furnace; and step 6, machining the third metal piece into a hardware shape. The application solves the problems of poor wear resistance, poor corrosion resistance and large electric loss of the existing iron hardware.

Description

Technical Field

[0001] This invention belongs to the field of hardware materials technology, specifically relating to non-magnetic self-lubricating hardware materials, and also to a method for preparing non-magnetic self-lubricating hardware materials. Background Technology

[0002] Power fittings play a crucial role in power transmission and transformation projects, and their quality, stability, and reliability directly determine the safe operation of the power grid system. In recent years, the rapid development of my country's power industry, coupled with the large transmission volume, long crossing distances, and the need to traverse diverse and complex climates and terrains, has placed higher demands on the electrical performance, mechanical performance, reliability, durability, energy efficiency, and economy of power fittings for overhead transmission lines. Currently, commonly used materials for transmission line fittings include malleable cast iron, weathering steel, aluminum, and aluminum alloys. Malleable cast iron and steel fittings offer excellent mechanical properties, but suffer from drawbacks such as inconvenient installation, poor corrosion resistance, and high hysteresis and eddy current losses. Aluminum fittings effectively address these issues, but their higher price and the lower strength of aluminum and aluminum alloys make them unsuitable for the power industry's requirements, limiting their application to environments with less stringent mechanical performance requirements.

[0003] Iron fittings account for the largest market share, but they face three major drawbacks: 1. poor corrosion resistance; 2. poor wear resistance; 3. high power loss. The losses generated by iron fittings during operation account for approximately 0.01-0.03% of the total power loss of transmission and reception capacity. Statistics show that at an operating current of 400A, the hysteresis eddy current power loss of iron suspension clamps reaches 39W. The total power loss caused by iron suspension clamps in high-voltage lines nationwide exceeds 340 million kW. The total electricity cost loss is 130 million yuan per year. Summary of the Invention

[0004] The purpose of this invention is to provide a non-magnetic self-lubricating hardware material, which solves the problem of large magnetic hysteresis loss caused by strong magnetism in existing iron hardware materials.

[0005] Another object of the present invention is to provide a method for preparing non-magnetic self-lubricating hardware materials.

[0006] The technical solution adopted in this invention is a non-magnetic self-lubricating hardware material, which is composed of the following raw materials by mass percentage: C 3.3%~3.8%, Si 2.0%~2.6%, Ni 10%~14%, Mo 0.5%~1.0%, V 0.5%~1.0%, Mn 0.1%~0.2%, P≤0.1%, S≤0.015%, with the balance being Fe, and the total content of the above components is 100%.

[0007] Another technical solution adopted in this invention is a method for preparing non-magnetic self-lubricating hardware materials, which is implemented according to the following steps: Step 1: Weigh out the following materials by mass percentage: C 3.3%~3.8%, Si 2.0%~2.6%, Ni 10%~14%, Mo 0.5%~1.0%, V 0.5%~1.0%, Mn 0.1%~0.2%, P≤0.1%, S≤0.015%, with the balance being Fe. The total content of all the above components is 100%. Weigh out the bread iron, ferrosilicon, nickel plate, ferrochrome, ferromolybdenum, ferrovanadium, and carbon raiser. Step 2: Place the raw materials weighed in Step 1 into an intermediate frequency furnace and melt them at high temperature to obtain the first liquid; Step 3: Pour the first liquid into the heat preservation furnace, and add the barium silicon inoculant and rare earth magnesium spheroidizing agent into the heat preservation furnace and stir thoroughly to obtain the second liquid; Step 4: Pour the second liquid into the preheated horizontal continuous casting furnace and obtain the first metal part by horizontal continuous casting method; Step 5: Place the first metal part in a vacuum furnace and introduce argon gas. After keeping it at a certain temperature, quench it in water to room temperature to obtain the second metal part. Step 6: Place the second metal part in a muffle furnace for low-temperature tempering to obtain the third metal part; Step 7: Machin the third metal part into the shape of a metal fitting, and you will get the desired result.

[0008] Another feature of the technical solution of this invention is that: In step 3, the amount of silicon barium inoculant added is 1.0% to 1.5% of the mass of the first liquid, and the amount of rare earth magnesium spheroidizing agent added is 1.0% to 2.0% of the mass of the first liquid.

[0009] In step 5, the vacuum pressure inside the vacuum furnace shall not exceed -0.1 MPa, and the interval between the first metal being taken out of the vacuum furnace and water-quenched shall not exceed 30 seconds.

[0010] In step 5, the temperature of the vacuum furnace is 1050 ℃~1150 ℃, and the holding time is 4h~8h.

[0011] In step 6, the holding temperature of the muffle furnace is 100 ℃~200 ℃, and the holding time is 1h~4h.

[0012] The matrix structure of both the second and third metal parts is austenite + Mo and V carbides.

[0013] The beneficial effects of this invention are: 1) The non-magnetic self-lubricating hardware material contains no less than 10% by volume spherical graphite, which can form a self-lubricating film during service to improve the wear resistance of the hardware; 2) The matrix structure of non-magnetic self-lubricating hardware is austenitic, with low magnetism, which can significantly reduce electromagnetic loss; 3) The austenite in the matrix of the non-magnetic self-lubricating hardware provides high plasticity and toughness, while Mo and V carbides provide high strength, ensuring the excellent mechanical properties of the material; 4) The austenite in the matrix of non-magnetic self-lubricating hardware has high corrosion resistance, avoiding the traditional process of hot-dip galvanizing the surface of iron hardware to improve corrosion resistance, thus reducing environmental pollution; 5) During service, non-magnetic self-lubricating fittings are subjected to wind and sand impacts. The austenite in the fittings can undergo a martensitic phase transformation induced by strain, which increases the hardness of the material and further improves its wear resistance. Attached Figure Description

[0014] Figure 1 This is a microstructure photograph of the ductile iron material prepared in Example 1 of this invention, showing the distribution of ductile iron. Figure 2 These are scanning micrographs of the cast iron material prepared in Example 2 of this invention; Figure 3 These are XRD images and scanning microstructure images of the material after heat treatment in Example 3 of this invention; Figure 4 These are scanning micrographs of the material after heat treatment in Embodiment 4 of the present invention; Figure 5 This is an EDS image of the material after heat treatment in Example 4 of this invention. Detailed Implementation

[0015] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0016] The non-magnetic self-lubricating hardware material is composed of the following raw materials by mass percentage: C 3.3%~3.8%, Si 2.0%~2.6%, Ni 10%~14%, Mo 0.5%~1.0%, V 0.5%~1.0%, Mn 0.1%~0.2%, P≤0.1%, S≤0.015%, with the balance being Fe. The total content of the above components is 100%.

[0017] The preparation method of non-magnetic self-lubricating hardware material is implemented according to the following steps: Step 1: Weigh out the following materials by mass percentage: C 3.3%~3.8%, Si 2.0%~2.6%, Ni 10%~14%, Mo 0.5%~1.0%, V 0.5%~1.0%, Mn 0.1%~0.2%, P≤0.1%, S≤0.015%, with the balance being Fe. The total content of all the above components is 100%. Weigh out the bread iron, ferrosilicon, nickel plate, ferrochrome, ferromolybdenum, ferrovanadium, and carbon raiser. Step 2: Place the raw materials weighed in Step 1 into an intermediate frequency furnace and melt them at high temperature to obtain the first liquid; Step 3: Pour the first liquid into the heat preservation furnace, and add the barium silicon inoculant and rare earth magnesium spheroidizing agent into the heat preservation furnace and stir thoroughly to obtain the second liquid; In step 3, the amount of silicon-barium inoculant added is 1.0%~1.5% of the mass of the first liquid, the amount of rare earth magnesium spheroidizing agent added is 1.0%~2.0% of the mass of the first liquid, and the residual magnesium content in the final material is controlled to be 0.02~0.05% of the mass of the first liquid, and the rare earth element content is 0.02~0.05% of the mass of the first liquid. The addition of spheroidizing agents and inoculants is to promote graphitization, improve the morphology and distribution of graphite, and obtain uniformly distributed spherical graphite. Step 4: Pour the second liquid into the preheated horizontal continuous casting furnace and obtain the first metal part by horizontal continuous casting method; Step 5: Place the first metal part in a vacuum furnace and introduce argon gas. After keeping it at a certain temperature, quench it in water to room temperature to obtain the second metal part. In step 5, the vacuum pressure inside the vacuum furnace is no greater than -0.1 MPa, and the interval between taking the first metal out of the vacuum furnace and water quenching it is no greater than 30 seconds. The purpose is to prevent the carbon dissolved in the γ phase from precipitating. In step 5, the temperature of the vacuum furnace is 1050 ℃~1150 ℃, and the holding time is 4h~8h; Ni is an austenite stabilizing element. Temperatures of 1050 ℃ to 1150 ℃ can make the Ni element distribution more uniform, thereby obtaining a fully austenitic structure and a non-magnetic, corrosion-resistant matrix. Mo and V elements can form dispersed carbides, which can improve the strength of the material. Step 6: Place the second metal part in a muffle furnace for low-temperature tempering. The purpose of tempering is to relieve stress and obtain the third metal part. In step 6, the holding temperature of the muffle furnace is 100 ℃~200 ℃, and the holding time is 1h~4h; The matrix structure of both the second and third metal parts is austenite + Mo and V carbides; Step 7: Machin the third metal part into the shape of a metal fitting, and you will get the desired result.

[0018] Example 1 The preparation method of non-magnetic self-lubricating hardware material is implemented according to the following steps: Step 1: Weigh the raw materials according to the following percentages by mass: C 3.4%, Si 2.0%, Ni 11%, Mo 0.6%, V 0.6%, Mn 0.15%, P 0.03%, S 0.01%, with the balance being Fe. Weigh the raw materials as bread iron, ferrosilicon, nickel plate, ferrochrome, ferromolybdenum, ferrovanadium, and carbon raiser. Step 2: Melt the weighed raw materials at high temperature in an induction furnace to obtain the first liquid; Step 3: Pour the first liquid into the heat preservation furnace, and add 1.3% by weight of the first liquid barium inoculant and 1.8% by weight of the first liquid rare earth magnesium spheroidizing agent to it and stir thoroughly to obtain the second liquid; Step 4: Pour the second liquid into the preheated horizontal continuous casting furnace and use the horizontal continuous casting method to obtain the casting, i.e., the first metal. Step 5: Place the first metal part in a vacuum furnace at 1100 ℃ with a vacuum pressure of -0.2 MPa, and introduce argon gas. After holding at this temperature for 6 hours, quench it in water to room temperature to obtain the second metal part. Step 6: Place the second metal part in a muffle furnace at 200 ℃ and keep it at that temperature for 2 hours, then air cool it to room temperature to obtain the third metal part; Step 7: The third metal part is machined into the shape of a hardware fitting, and the desired result is obtained.

[0019] Example 2 The preparation method of non-magnetic self-lubricating hardware material is implemented according to the following steps: Step 1: Weigh the raw materials according to the following percentages by mass: C 3.6%, Si 2.2%, Ni 10%, Mo 0.6%, V 0.6%, Mn 0.12%, P 0.02%, S 0.01%, with the balance being Fe. Weigh the raw materials as bread iron, ferrosilicon, nickel plate, ferrochrome, ferromolybdenum, ferrovanadium, and carbon raiser. Step 2: Melt the weighed raw materials at high temperature in an induction furnace to obtain the first liquid; Step 3: Pour the first liquid into the heat preservation furnace, and add 1.0% by weight of the first liquid of silicon barium inoculant and 1.0% by weight of the first liquid of rare earth magnesium spheroidizing agent and stir thoroughly to obtain the second liquid; Step 4: Pour the second liquid into the preheated horizontal continuous casting furnace and use the horizontal continuous casting method to obtain the casting, i.e., the first metal. Step 5: Place the first metal part in a vacuum furnace at 1050 ℃ with a vacuum pressure of -0.2 MPa, and introduce argon gas. After holding at this temperature for 8 hours, quench it in water to room temperature to obtain the second metal part. Step 6: Place the second metal part in a muffle furnace at 200 ℃ and keep it at that temperature for 4 hours, then air cool it to room temperature to obtain the third metal part; Step 7: The third metal part is machined into the shape of a hardware fitting, and the desired result is obtained.

[0020] Example 3 The preparation method of non-magnetic self-lubricating hardware material is implemented according to the following steps: Step 1: Weigh the raw materials according to the following percentages by mass: C 3.5%, Si 2.6%, Ni 12%, Mo 0.7%, V 0.5%, Mn 0.1%, P 0.02%, S 0.01%, with the balance being Fe. Weigh the raw materials as bread iron, ferrosilicon, nickel plate, ferrochrome, ferromolybdenum, ferrovanadium, and carbon raiser. Step 2: Melt the weighed raw materials at high temperature in an induction furnace to obtain the first liquid; Step 3: Pour the first liquid into the heat preservation furnace, and add 1.5% by weight of the first liquid barium inoculant and 2.0% by weight of the first liquid rare earth magnesium spheroidizing agent to it and stir thoroughly to obtain the second liquid; Step 4: Pour the second liquid into the preheated horizontal continuous casting furnace and use the horizontal continuous casting method to obtain the casting, i.e., the first metal. Step 5: Place the first metal part in a vacuum furnace at 1120 ℃ with a vacuum pressure of -0.2 MPa, and introduce argon gas. After holding at this temperature for 5 hours, quench it in water to room temperature to obtain the second metal part. Step 6: Place the second metal part in a muffle furnace at 150 ℃ and keep it at that temperature for 3 hours, then air cool it to room temperature to obtain the third metal part; Step 7: The third metal part is machined into the shape of a hardware fitting, and the desired result is obtained.

[0021] Example 4 The preparation method of non-magnetic self-lubricating hardware material is implemented according to the following steps: Step 1: Weigh the raw materials according to the following percentages by mass: C 3.5%, Si 2.5%, Ni 13%, Mo 0.5%, V 0.8%, Mn 0.13%, P 0.03%, S 0.01%, with the balance being Fe. Weigh the raw materials as bread iron, ferrosilicon, nickel plate, ferrochrome, ferromolybdenum, ferrovanadium, and carbon raiser. Step 2: Melt the weighed raw materials at high temperature in an induction furnace to obtain the first liquid; Step 3: Pour the first liquid into the heat preservation furnace, and add 1.4% by weight of the first liquid barium inoculant and 1.7% by weight of the first liquid rare earth magnesium spheroidizing agent to it and stir thoroughly to obtain the second liquid; Step 4: Pour the second liquid into the preheated horizontal continuous casting furnace and use the horizontal continuous casting method to obtain the casting, i.e., the first metal. Step 5: Place the first metal part in a vacuum furnace at 1080 ℃ with a vacuum pressure of -0.2 MPa, and introduce argon gas. After holding at this temperature for 6 hours, quench it in water to room temperature to obtain the second metal part. Step 6: Place the second metal part in a muffle furnace at 180 ℃ and keep it at that temperature for 3 hours, then air cool it to room temperature to obtain the third metal part; Step 7: The third metal part is machined into the shape of a hardware fitting, and the desired result is obtained.

[0022] The non-magnetic self-lubricating hardware material prepared by this invention has a microstructure containing a large number of finely and uniformly distributed spherical graphite particles, such as... Figure 1As shown, it can form a graphite film on the surface of the fittings during service, reducing the coefficient of friction, improving wear resistance, and achieving self-lubricating properties. The as-cast microstructure of the prepared material is as follows: Figure 2 As shown, the microstructure is bainite + martensite. The XRD results of the metal casting after heat treatment are as follows... Figure 3 As shown, the microstructure is entirely austenitic. In addition, Mo and V carbides are dispersed throughout the matrix, such as... Figure 4 As shown, its carbide EDS energy spectrum is as follows: Figure 5 As shown. Supersaturated austenite and Mo and V carbides provide high strength, while austenite provides high ductility and toughness, thus ensuring good mechanical properties of the material. Austenite has excellent corrosion resistance, which can effectively avoid the current situation of using hot-dip galvanizing for corrosion protection in traditional iron fittings, thereby reducing costs and environmental pollution. On the other hand, the non-magnetic properties of austenite can significantly reduce hysteresis loss and save energy. In summary, the non-magnetic self-lubricating fitting of the present invention can solve the problems faced by existing iron fittings: (1) poor wear resistance; (2) poor corrosion resistance; (3) high electrical loss, effectively improving their service life.

Claims

1. A non-magnetic, self-lubricating hardware material, characterized in that, The preparation method is specifically implemented according to the following steps: Step 1: Weigh out the following materials by mass percentage: C 3.3%~3.8%, Si 2.0%~2.6%, Ni 10%~14%, Mo 0.5%~1.0%, V 0.5%~1.0%, Mn 0.1%~0.2%, P≤0.1%, S≤0.015%, with the balance being Fe. The total content of all the above components is 100%. Weigh out the bread iron, ferrosilicon, nickel plate, ferromolybdenum, ferrovanadium, and carbon raiser. Step 2: Place the raw materials weighed in Step 1 into an intermediate frequency furnace and melt them at high temperature to obtain the first liquid; Step 3: Pour the first liquid into the heat preservation furnace, and add the barium silicon inoculant and rare earth magnesium spheroidizing agent into the heat preservation furnace and stir thoroughly to obtain the second liquid; Step 4: Pour the second liquid into the preheated horizontal continuous casting furnace and obtain the first metal part by horizontal continuous casting method; Step 5: Place the first metal part in a vacuum furnace and introduce argon gas. After keeping it at a certain temperature, quench it in water to room temperature to obtain the second metal part. Step 6: Place the second metal part in a muffle furnace for low-temperature tempering to obtain the third metal part; Step 7: Machin the third metal part into the shape of a hardware fitting, and you will get the final product; In step 3, the amount of barium silicon inoculant added is 1.0% to 1.5% of the mass of the first liquid, and the amount of rare earth magnesium spheroidizing agent added is 1.0% to 2.0% of the mass of the first liquid.

2. The non-magnetic self-lubricating fitting material according to claim 1, characterized in that, In step 5, the vacuum pressure inside the vacuum furnace is no greater than -0.1 MPa, and the interval between the first metal being taken out of the vacuum furnace and water-quenched is no greater than 30 seconds.

3. The non-magnetic self-lubricating fitting material according to claim 1, characterized in that, In step 5, the temperature of the vacuum furnace is 1050 ℃~1150 ℃, and the holding time is 4h~8h.

4. The non-magnetic self-lubricating fitting material according to claim 1, characterized in that, In step 6, the holding temperature of the muffle furnace is 100 ℃~200 ℃, and the holding time is 1h~4h.

5. The non-magnetic self-lubricating fitting material according to claim 1, characterized in that, The matrix structure of both the second and third metal parts is austenite + Mo and V carbides.

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