A petroleum pipe thread processing tool material and a preparation method thereof

Abstract

The present application relates to the field of tool processing, and discloses a hard alloy tool material and a preparation method thereof, and the prepared hard alloy tool material has high strength, high hardness and high toughness, and the tool prepared by using the hard alloy tool material has high wear resistance, impact strength and fracture toughness, and is particularly suitable for processing external threads of petroleum pipes and internal threads of couplings, and is also suitable for processing nickel-based alloys, heat-resistant stainless steel and other materials.

Description

Technical Field

[0001] This invention relates to the field of cutting tool processing, specifically to a cutting tool material for threading oil pipes and its preparation method. Background Technology

[0002] Cemented carbide is an alloy material made from hard compounds of refractory metals and binder metals through powder metallurgy. It is characterized by high hardness, relatively good strength and toughness, and also possesses excellent properties such as heat resistance and corrosion resistance. Due to these characteristics, cemented carbide tools are often referred to as "industrial teeth" in the machine tool industry. These products are mainly used to manufacture cutting tools and wear-resistant parts, and have wide applications in aerospace, automotive, energy, mold making, and other machining fields.

[0003] Oil pipes are crucial components in the oil drilling industry, accounting for a significant proportion of oil development costs. The quality of oil pipes directly impacts the safety of oil production. Because oil pipes primarily operate in high-pressure, highly corrosive environments, they require stringent standards in terms of sealing, connection strength, and corrosion resistance. Due to limitations in processing and transportation, oil pipes have a fixed length and must be connected in series using couplings. Therefore, the machining quality of the external threads at both ends of the oil pipe and the internal threads within the couplings plays a vital role in the connection and performance of the oil pipe. Breakthroughs in oil pipe threading technology can be considered significant breakthroughs in the oil drilling industry.

[0004] Currently, high-end oil pipe threading tool manufacturers are mainly located overseas. Their tools offer good versatility and stability across various steel grades. In contrast, domestically produced tools are at a disadvantage. With market development, the strength and toughness of the materials being processed are increasing, and pipe thread structures are trending towards more specialized designs, making processing increasingly difficult. Existing tool materials have lower hardness and poorer toughness, making them prone to chipping, scratches on the machined surface, and other problems. Summary of the Invention

[0005] The present invention aims to provide a material for oil pipe threading tools, in order to improve the current situation where the main manufacturers of high-end oil pipe threading tools are located abroad, while domestic tools are at a disadvantage.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a tool material for threading oil pipes, which is prepared from the following raw material powders by mass fraction: 80-90 parts WC powder, 5-10 parts Co powder, and 8-15 parts multi-component solid solution powder.

[0007] Preferably, as an improvement, the WC powder consists of WC grains with a particle size of 0.8-2.0 μm.

[0008] Preferably, as an improvement, the multi-component solid solution powder is composed of W: 20-40%; Ti: 10-25%; Ta: 25-40%; Nb: 0-10%, with the remainder being C.

[0009] A method for preparing a material for threading oil pipes, comprising the following steps:

[0010] A. Mix the raw material powder evenly, add the molding agent to obtain the mixed powder;

[0011] B. Press the mixed powder under 200-300MPa to obtain a pressed blank;

[0012] C. Place the pressed blank in a sintering furnace, heat it under vacuum to 1440℃-1475℃, hold it for 0.5h-1h, introduce argon gas until the pressure reaches 2MPa-5MPa, hold the pressure for 0.5h-1h, then cut off the cooling program and cool it down to below 80℃ to sinter the product.

[0013] Preferably, as an improvement, in step A, 1%-4% of the total weight of the raw materials is added as a forming agent during the wet milling stage. This is more beneficial to the particle dispersion of the cemented carbide mixture.

[0014] Preferably, as an improvement, sintering in step C is carried out in a 200Kg degreasing and pressurizing integrated furnace. The sintering process includes a dewaxing stage, a heating sintering stage, and a final firing stage. The dewaxing stage lasts for 8-12 hours, during which the furnace temperature rises from room temperature to 320-450℃. The heating sintering stage lasts for 2-8 hours, during which the temperature rises from 320-450℃ to 1250℃-1440℃. The final firing stage reaches a temperature of 1440℃-1475℃.

[0015] Preferably, as an improvement, during the final firing stage, argon gas is intermittently introduced into the furnace after the initial heat treatment. This accelerates the cooling process.

[0016] The advantages of this invention are:

[0017] 1. The material prepared is a high-strength, high-hardness and high-toughness cemented carbide tool material. Tools made from it have high wear resistance, impact resistance and fracture toughness. It is particularly suitable for machining the external threads of oil pipes and the internal threads of couplings. It is also suitable for machining materials such as nickel-based alloys and heat-resistant stainless steel.

[0018] 2. The cemented carbide cutting tool material prepared by this method has high hardness and wear resistance.

[0019] 3. A pressure sintering process was adopted, which makes the sintered product more compact and has fewer internal pores.

[0020] 4. The "secondary premixing ball milling" process is adopted, in which the component with less content is pre-ball milled first, and then mixed with the hard phase WC and the binder phase Co. This improves the dispersion and uniformity of the components, refines the grains, and makes it easier for trace components to form solid solutions with Co after sintering, thereby stabilizing the cubic structure of Co and improving the toughness of the cemented carbide tool material.

[0021] 5. Grain inhibitors have been added to increase impact resistance and toughness. Attached Figure Description

[0022] Figure 1 This is a metallographic image of a tool material for threading oil pipes according to the present invention. Detailed Implementation

[0023] The following detailed description illustrates the specific implementation method:

[0024] A material for threading oil pipes, the metallographic structure of which is shown in the attached figure. Figure 1 As shown, 80-90 parts of WC powder, 5-10 parts of Co powder, and 8-15 parts of multi-component solid solution powder are prepared from the following raw material powders. The WC powder consists of WC grains with a particle size of 0.8-2.0 μm. The multi-component solid solution powder consists of W: 20-40%; Ti: 10-25%; Ta: 25-40%; Nb: 0-10%, with the balance being C.

[0025] Example 1: A method for preparing a material for threading cutting tools for oil pipes, comprising the following steps:

[0026] A. Mix the raw material powder evenly and wet-mill it using a ball mill. Use n-hexane as the wet milling medium and wet-mill for 60 hours. Control the carbon point to be below 92%. Add 1%-4% of the total weight of the raw materials as a forming agent in the final stage of wet milling. After wet milling, spray dry the mixture to obtain a mixed powder with a loose flow rate that meets the requirements.

[0027] B. Press the mixed powder under 200-300MPa to obtain a pressed blank;

[0028] C. Place the compact in a 200kg degreasing and pressurizing integrated furnace and heat it under vacuum to 1440℃-1475℃ for sintering. The sintering process includes a dewaxing stage, a heating and sintering stage, and a final firing stage. The dewaxing stage lasts for 8-12 hours, during which the furnace temperature rises from room temperature to 320-450℃. The heating and sintering stage lasts for 2-8 hours, during which the temperature rises from 320-450℃ to 1250℃-1440℃. The final firing stage reaches a temperature of 1440℃-1475℃. Then, the temperature is held for 0.5-1 hours to maintain a constant temperature. Argon gas is then intermittently introduced into the furnace until the pressure reaches 2MPa-5MPa. The pressure is held for 0.5-1 hours. Then, the temperature is lowered to below 80℃, and the product is sintered.

[0029] In this embodiment, grain refinement can be achieved by adding grain inhibitors, and the hardness of the product can be effectively improved by combining solid solutions with different compositions. The secondary premixing ball milling process of n-hexane-paraffin is used to improve the toughness of the cemented carbide tool material. The pressure sintering process is used to improve the density of the tool material through low-pressure sintering, making the sintered product more compact with fewer internal voids. The cemented carbide tool matrix material obtained in the end has been tested to have bending strength and Rockwell hardness that can effectively meet the requirements for machining oil pipe threads.

[0030] Example 2:

[0031] A material for threading oil pipes, wherein the mass fraction of the raw material powder is:

[0032] 79 parts WC powder, 8 parts Co, and 13 parts ternary solid solution composed of any three metals and C in a multi-element solid solution.

[0033] The material prepared by the above method is a gradient cemented carbide, and the cemented carbide tool matrix material KT1 was prepared according to the above method. Its bending strength was measured to be 2615 MPa, its Rockwell hardness to be 92.8 HRA, and its fracture toughness to be 10.0 MPa·m. 1 / 2 .

[0034] The material KT1 obtained in Example 2 was used to prepare a round thread machining insert. The surface was coated with a PVD coating. It was used to process P110 steel grade inserts at a domestic manufacturer. The average lifespan was 54 pieces / cutting edge, compared to 35 pieces / cutting edge of existing inserts. It failed due to normal wear and had no chipping.

[0035] Example 3:

[0036] A material for threading oil pipes, wherein the mass fraction of the raw material powder is:

[0037] 86 parts WC powder, 6 parts Co, and 8 parts quaternary solid solution

[0038] The material prepared by the above method is a gradient cemented carbide, and the cemented carbide tool matrix material KT2 is obtained according to the above method. Its bending strength is measured to be 2758 MPa, its Rockwell hardness to be 92.8 HRA, and its fracture toughness to be 10.5 MPa·m. 1 / 2 .

[0039] The material KT2 obtained in Example 3 was used to prepare a special threading cutting tool. The surface was coated with a PVD coating. It was used to process nickel-based alloy materials at a domestic manufacturer. The average lifespan was 3 pieces / blade, compared with the existing tool's 1.5 pieces / blade.

[0040] Example 4:

[0041] A material for threading oil pipes, wherein the mass fraction of the raw material powder is:

[0042] 77 parts WC powder, 8 parts Co, and 15 parts a quaternary solid solution composed of metal elements and C in a multi-component solid solution.

[0043] The material prepared by the above method is a gradient cemented carbide, and KT3, the matrix material for cemented carbide cutting tools, was obtained according to the above method. Its bending strength was measured to be 2648 MPa, its Rockwell hardness to be 92.2 HRA, and its fracture toughness to be 9.8 MPa·m. 1 / 2 .

[0044] The material KT3 obtained in Example 4 was used to prepare a round thread machining insert. The surface was coated with a PVD coating. It was used to process V125 steel grade inserts at a domestic manufacturer. The average lifespan was 30 pieces / cutting edge, compared to 25 pieces / cutting edge of existing inserts. It failed due to normal wear and tear, and there was no chipping.

[0045] Example 5:

[0046] A material for threading oil pipes, wherein the mass fraction of the raw material powder is:

[0047] 80 parts WC powder, 8 parts Co, and 15 parts ternary solid solution composed of any three metals and C in a multi-element solid solution.

[0048] The material prepared by the above method is a gradient cemented carbide, and KT4, the matrix material for cemented carbide cutting tools, was prepared according to the above method. Its bending strength was measured to be 3001 MPa, its Rockwell hardness to be 92.9 HRA, and its fracture toughness to be 10.1 MPa·m. 1 / 2 .

[0049] The material KT4 obtained in Example 5 was used to prepare a round thread machining insert. The surface was coated with a PVD coating. It was used to process 110S steel grade by a domestic manufacturer. The average life was 15 pieces / cutting edge, compared with the existing inserts which had 8 pieces / cutting edge. It failed due to normal wear and had no chipping.

[0050] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A material for threading oil pipes, characterized in that: It is prepared from the following raw material powders in parts by weight: 86 parts WC powder, 6 parts Co, and 8 parts multi-component solid solution powder, wherein the multi-component solid solution powder is a quaternary solid solution; the multi-component solid solution powder consists of W: 20-40% and Ti: 10-25%. Ta: 25-40%; Nb: 0-10%, the remainder is C.

2. The material for a threading tool for oil pipes according to claim 1, characterized in that: The WC powder is composed of WC crystals with a particle size of 0.8-2.0 μm.

3. A method for preparing a material for threading oil pipes, used to prepare a material for threading oil pipes as described in any one of claims 1-2, characterized in that: Includes the following steps: A. Mix the raw material powder evenly, add the molding agent to obtain the mixed powder; B. Press the mixed powder under 200-300MPa to obtain a pressed blank; C. Place the pressed blank in a sintering furnace, heat it under vacuum to 1440℃-1475℃, hold it for 0.5h-1h, introduce argon gas until the pressure reaches 2MPa-5MPa, hold the pressure for 0.5h-1h, then cut off the cooling program and cool it down to below 80℃ to sinter the product.

4. The method for preparing a cutting tool material for oil pipe threading according to claim 3, characterized in that: In step A, 1%-4% of the total weight of the raw materials is added as a molding agent during the wet grinding stage.

5. The method for preparing a cutting tool material for oil pipe threading according to claim 4, characterized in that: In step C, sintering is carried out in a 200Kg degreasing and pressurizing integrated furnace. The sintering process includes a dewaxing stage, a heating sintering stage, and a final firing stage. The dewaxing stage lasts for 8-12 hours, during which the furnace temperature rises from room temperature to 320-450℃. The heating sintering stage lasts for 2-8 hours, during which the temperature rises from 320-450℃ to 1250℃-1440℃. The final firing stage reaches a temperature of 1440℃-1475℃.

6. The method for preparing a cutting tool material for oil pipe threading according to claim 5, characterized in that: During the final combustion stage, argon gas is intermittently introduced into the furnace after heat preservation.

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