A high-strength fatigue-resistant steel sucker rod and its manufacturing process

Abstract

The invention discloses a high-strength fatigue-resistant steel sucker rod. The chemical composition contains C 0.35-0.45% and various elements such as Si and Mn. The elements work together, C provides strength, Si improves strength, hardness and oxidation resistance, Mn increases toughness, etc., and impurities are precisely adjusted to ensure excellent steel performance, adapt to oil well stress, reduce costs and prevent fracture. The manufacturing process includes: raw materials are smelted in an electric furnace according to the ratio to obtain molten steel; during refining, deoxidize and desulfurize after refining at 1550-1600℃ for 30-40 minutes; continuous casting controls the billet drawing speed of 0.8-1.2m / min and cooling intensity; rolling 1050-1100℃ heating, 850-900℃ final rolling; 880-920℃ oil quenching and 550-600℃ tempering; and finally mechanical processing to the required dimensional accuracy. Its exquisite craftsmanship and optimized design make the sucker rod high in strength, fatigue resistance, good precision, broad application prospects, high economic value, and can be efficiently used in oil extraction to meet industry needs.

Description

Technical Field

[0001] The invention relates to a sucker rod made of high-strength fatigue-resistant steel and a manufacturing process thereof. Background Art

[0002] In the field of oil production, the performance of the sucker rod, as a key component, directly affects the production efficiency and cost. Traditional sucker rods have exposed many problems during long-term use and are difficult to meet the growing demand for oil production.

[0003] In terms of chemical composition, existing sucker rod materials often do not accurately blend the elements. The C content of some sucker rods may deviate from the reasonable range, resulting in insufficient strength or poor toughness; the content of alloying elements such as Si and Mn also lacks scientific coordinated design, and cannot fully play their role in improving strength, hardness, toughness, oxidation resistance, hardenability, etc. For example, some sucker rods have unreasonable Si content and poor oxidation resistance, which makes them easily corroded in the complex environment of oil wells, affecting their service life; improper Mn content leads to insufficient hardenability, uneven internal structure of steel, easy to produce stress concentration, and increase the risk of fatigue fracture. Moreover, the control of impurity elements is not strict enough, and the impurity content is high, resulting in poor purity and quality stability of steel, and more internal defects, which further reduces the mechanical properties and fatigue resistance of the sucker rod. Frequent replacement not only increases mining costs, but also affects the continuity of mining operations.

[0004] From the manufacturing process point of view, the temperature and time control of the traditional refining process are not precise enough. The temperature fluctuates greatly, and it is impossible to effectively remove harmful impurities such as sulfur and phosphorus in the molten steel, and it is also difficult to homogenize the composition of the molten steel, resulting in more inclusions inside the steel, loose structure, greatly reduced strength and toughness, and unable to effectively prevent the initiation and expansion of fatigue cracks. In the continuous casting process, the regulation of the billet drawing speed and cooling intensity lacks precision, and the solidification process is often unstable, resulting in cracks, looseness and other defects inside the continuous casting billet, which buries hidden dangers for subsequent processing and seriously affects the overall quality and performance consistency of the sucker rod. In the rolling and heat treatment process, the rolling temperature and final rolling temperature are not accurately controlled, and the grains cannot be fully refined to improve performance; in the heat treatment process, the quenching and tempering parameters are not set reasonably, such as the quenching temperature, time and tempering temperature, time are not appropriate, which makes the steel either strong but not tough enough, prone to brittle fracture, or toughness is improved but strength is insufficient, unable to withstand the complex alternating loads during the pumping process, unable to meet the dual requirements of high strength and fatigue resistance of the pumping rod, and reducing the working reliability and service life. The machining accuracy is also low, the matching accuracy of the pumping rod and other pumping equipment is poor, the surface quality is rough, and there are many stress concentration points, which not only increases wear and energy loss, but also further weakens its fatigue resistance, making it unable to efficiently serve oil extraction operations, limiting the development of the oil extraction industry. Summary of the invention

[0005] The object of the present invention is to provide a sucker rod made of high-strength fatigue-resistant steel and a manufacturing process thereof, so as to solve the problems raised in the above-mentioned background technology.

[0006] To solve the above technical problems, the technical solution provided by the present invention is: a sucker rod made of high-strength fatigue-resistant steel, whose chemical composition, by weight percentage, includes: C: 0.35-0.45%, Si: 0.8-1.2%, Mn: 1.2-1.6%, Cr: 0.8-1.2%, Mo: 0.3-0.5%, V: 0.1-0.2%, Ni: 0.2-0.4%, and the balance is Fe.

[0007] Preferably, the C content is 0.38-0.42%.

[0008] Preferably, the Si content is 0.9-1.1%.

[0009] Preferably, the content of Mn is 1.3-1.5%.

[0010] A high-strength fatigue-resistant steel sucker rod, the manufacturing process of which comprises the following steps:

[0011] Step 1: preparing raw materials, preparing various raw materials according to the chemical composition ratio of claim 1, and smelting the raw materials in an electric furnace to obtain molten steel;

[0012] Step 2: Refining treatment, pouring the molten steel into a refining furnace for refining, controlling the temperature in the furnace at 1550-1600°C during the refining process, and refining time is 30-40 minutes, and deoxidation and desulfurization treatment is performed after refining;

[0013] Step 3: Continuous casting: the refined molten steel is continuously cast to obtain a continuous casting billet. During the continuous casting process, the billet drawing speed is controlled to be 0.8-1.2 m / min and the cooling intensity is 0.2-0.3 °C / s;

[0014] Step 4: rolling processing, heating the continuous casting billet to 1050-1100°C and then rolling it, and controlling the final rolling temperature at 850-900°C to obtain a sucker rod blank;

[0015] Step 5: Heat treatment: the sucker rod blank is first quenched at a temperature of 880-920°C, the quenching medium is oil, and the quenching time is 30-40 minutes, and then tempered at a temperature of 550-600°C and a tempering time of 60-90 minutes;

[0016] Step 6: Mechanical processing, mechanical processing the heat-treated sucker rod to the required size and precision to obtain a finished sucker rod. Preferably, the temperature in the refining furnace in step 2 is controlled at 1560-1580°C.

[0017] Preferably, the billet drawing speed during the continuous casting in step three is 0.9-1.1 m / min.

[0018] Preferably, during the rolling process in step 4, the continuous casting billet is heated to 1060-1080°C.

[0019] Preferably, the tempering time in step five is 70-80 minutes.

[0020] The advantages of the present invention are: in terms of chemical composition, the C content of 0.35-0.45% works synergistically with alloy elements such as Si and Mn. C provides strength, Si improves strength, hardness and oxidation resistance, Mn increases toughness, improves hardenability and reduces hot brittleness; Cr, Mo, V and Ni respectively enhance corrosion resistance, heat strength, refine grains, improve low-temperature toughness, etc. Each element is precisely formulated and impurities are strictly controlled to ensure that the steel is pure and dense, with good mechanical and fatigue resistance, can adapt to the complex stress of oil wells, extend service life, reduce costs, and reduce the risk of fatigue fracture.

[0021] In terms of manufacturing process, the refining temperature is 1550-1600℃ for 30-40 minutes, and the temperature is precisely controlled to remove impurities and make the composition uniform. After deoxidation and desulfurization, the internal structure is dense and uniform, which improves strength and toughness and prevents fatigue cracks. During continuous casting, the billet drawing speed is 0.8-1.2m / min and the cooling intensity is 0.2-0.3℃ / s to ensure stable solidification without defects, refine the grains, and provide high-quality billets for rolling. Rolling heating is 1050-1100℃, and final rolling is 850-900℃ to refine the grains; then oil quenching at 880-920℃ for 30-40 minutes and tempering at 550-600℃ for 60-90 minutes, which synergizes and enhances the effect, has high strength and toughness and fatigue resistance, withstands alternating loads, and improves reliability and life. Finally, the machining reaches high precision, ensures matching accuracy, excellent surface quality, reduces roughness and stress concentration, improves the reliability of use effect, and meets industry requirements. In short, the sucker rod has outstanding advantages in many aspects due to its optimized design and exquisite craftsmanship, has broad application prospects, high economic value, and can efficiently serve oil extraction. DETAILED DESCRIPTION

[0022] For the purpose of the following detailed description, it should be understood that the present invention may adopt various alternative changes and step sequences, unless expressly specified to the contrary. In addition, except in any operating examples, or otherwise indicated, all numbers representing the amount of ingredients used in the specification and claims should be understood to be modified by the term "about" in all cases. Therefore, unless otherwise indicated, the numerical parameters set forth in the following specification and the attached claims are approximate values ​​that vary according to the desired performance to be obtained by the present invention. At least it is not intended to limit the application of the doctrine of equivalents to the scope of the claims, and each numerical parameter should at least be interpreted according to the number of reported significant figures and by applying ordinary rounding techniques.

[0023] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values ​​set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0024] In addition, it should be understood that any numerical range described herein is intended to include all subranges subsumed therein. For example, a range of "1 to 10" is intended to include all subranges between (and including) the stated minimum value of 1 and the stated maximum value of 10, i.e., having a minimum value equal to or greater than 1 and a maximum value equal to or less than 10.

[0025] Embodiment 1:

[0026] Chemical composition: C: 0.40%, Si: 1.0%, Mn: 1.4%, Cr: 1.0%, Mo: 0.4%, V: 0.15%, Ni: 0.3%, and the balance is Fe.

[0027] Production process:

[0028] Raw material preparation: Prepare various raw materials accurately according to the above chemical composition ratio, put them into an electric furnace for smelting to obtain molten steel.

[0029] Refining treatment: Pour the molten steel into the refining furnace, control the temperature in the furnace at 1570℃, and refining for 35 minutes, followed by deoxidation and desulfurization treatment.

[0030] Continuous casting: The refined molten steel is continuously cast, the billet drawing speed is set to 1.0 m / min, and the cooling intensity is controlled at 0.25°C / s, thereby obtaining a continuously cast billet.

[0031] Rolling process: The continuous casting billet is heated to 1070℃ and then rolled to ensure that the final rolling temperature is 870℃ to make a sucker rod blank.

[0032] Heat treatment: firstly, the sucker rod blank is quenched at 900℃, oil is used as the quenching medium, and the quenching time is 35 minutes; then it is tempered at 570℃ and the tempering time is 75 minutes.

[0033] Machining: The heat-treated sucker rod is machined to meet the predetermined size and precision requirements, and finally a finished sucker rod is obtained.

[0034] Embodiment 2:

[0035] Chemical composition: C: 0.38%, Si: 0.9%, Mn: 1.3%, Cr: 0.8%, Mo: 0.3%, V: 0.1%, Ni: 0.2%, and the balance is Fe.

[0036] Production process:

[0037] Raw material preparation: Prepare raw materials according to the proportions and smelt molten steel in an electric furnace.

[0038] Refining treatment: The temperature of the molten steel in the refining furnace is controlled at 1560℃, and deoxidation and desulfurization are carried out after refining for 30 minutes.

[0039] Continuous casting: During continuous casting, the billet drawing speed is 0.9 m / min, the cooling intensity is 0.2 °C / s, and the continuous casting billet is obtained.

[0040] Rolling process: The continuous casting billet is heated to 1060℃ and then rolled. The final rolling temperature is 850℃ to obtain the sucker rod blank.

[0041] Heat treatment: quenching temperature 880℃, oil quenching for 30 minutes, tempering temperature 550℃, tempering time 60 minutes.

[0042] Machining: The heat-treated sucker rod is machined to the required specifications to produce finished sucker rods.

[0043] Embodiment 3:

[0044] Chemical composition: C: 0.42%, Si: 1.1%, Mn: 1.5%, Cr: 1.2%, Mo: 0.5%, V: 0.2%, Ni: 0.4%, and the balance is Fe.

[0045] Production process:

[0046] Raw material preparation: prepare the raw materials and smelt them in an electric furnace to obtain molten steel.

[0047] Refining treatment: The temperature of the molten steel in the refining furnace is maintained at 1580℃, and deoxidation and desulfurization treatment is carried out after refining for 40 minutes.

[0048] Continuous casting: The casting speed during the continuous casting process is 1.1m / min, the cooling intensity is 0.3℃ / s, and the continuous casting billet is produced.

[0049] Rolling process: The continuous casting billet is heated to 1080℃ for rolling, and the final rolling temperature is 900℃ to obtain the sucker rod blank.

[0050] Heat treatment: quenching temperature 920℃, oil quenching for 40 minutes, tempering temperature 600℃, tempering time 90 minutes.

[0051] Machining: The sucker rod is processed to the specified size and accuracy through machining to make a finished sucker rod.

[0052] Embodiment 4:

[0053] Chemical composition: C: 0.45%, Si: 1.2%, Mn: 1.6%, Cr: 1.1%, Mo: 0.45%, V: 0.18%, Ni: 0.35%, and the balance is Fe.

[0054] Production process:

[0055] Raw material preparation: Prepare raw materials according to the chemical composition ratio, and melt them in an electric furnace to obtain molten steel.

[0056] Refining treatment: The molten steel is poured into the refining furnace at a temperature of 1600°C. After refining for 35 minutes, it is deoxidized and desulfurized.

[0057] Continuous casting: The continuous casting billet drawing speed is 1.0m / min, the cooling intensity is 0.25℃ / s, and the continuous casting billet is obtained.

[0058] Rolling process: The continuous casting billet is heated to 1090℃ and rolled, and the final rolling temperature is 880℃ to obtain the sucker rod blank.

[0059] Heat treatment: quenching temperature 910℃, oil quenching for 35 minutes, tempering temperature 580℃, tempering time 80 minutes.

[0060] Machining: The heat-treated sucker rod is machined to meet the size and precision requirements to obtain a finished sucker rod.

[0061] Example 5

[0062] Chemical composition:

[0063] C: 0.36%, Si: 0.85%, Mn: 1.25%, Cr: 0.9%, Mo: 0.35%, V: 0.12%, Ni: 0.25%, and the balance is Fe.

[0064] Production process:

[0065] Raw material preparation: According to the chemical composition ratio determined above, accurately weigh each raw material and put it into an electric furnace for smelting to fully melt the raw materials and obtain uniform molten steel.

[0066] Refining treatment: The smelted molten steel is transferred to a refining furnace, and the temperature in the furnace is controlled at 1555°C. It is refined at this temperature for 32 minutes, followed by detailed deoxidation and desulfurization treatment to remove impurities in the molten steel and improve its quality.

[0067] Continuous casting: Continuous casting is carried out on the refined molten steel. During the continuous casting process, the billet drawing speed is controlled to 0.85m / min, and the cooling intensity is set to 0.22℃ / s to ensure that the molten steel solidifies smoothly and obtains a continuously cast billet.

[0068] Rolling process: The continuous casting billet is heated to 1055℃. When this temperature is reached, rolling process is immediately carried out. During the process, the final rolling temperature is strictly controlled at 860℃ to obtain the sucker rod blank.

[0069] Heat treatment: First, the sucker rod blank is quenched, the quenching temperature is set to 890℃, oil is selected as the quenching medium, and the blank is quenched in the oil for 32 minutes; then tempering is carried out, the tempering temperature is controlled at 560℃, and the tempering time is set to 65 minutes, and the material properties are further improved through tempering.

[0070] Mechanical processing: Use mechanical processing equipment to carry out fine processing on the heat-treated sucker rod, accurately process it to the required size and accuracy standard according to the design requirements, and finally obtain the finished sucker rod.

[0071] Example 6

[0072] Chemical composition:

[0073] C: 0.44%, Si: 1.15%, Mn: 1.55%, Cr: 1.15%, Mo: 0.48%, V: 0.19%, Ni: 0.38%, and the balance is Fe.

[0074] Production process:

[0075] Raw material preparation: Prepare the raw materials according to the given chemical composition ratio and put them into the electric furnace for smelting until the raw materials are completely converted into molten steel.

[0076] Refining treatment: Pour the molten steel into the refining furnace, accurately control the temperature in the furnace at 1590℃, maintain this temperature for 38 minutes of refining operation, and then carry out deoxidation and desulfurization treatment to ensure the purity of the molten steel.

[0077] Continuous casting: Carry out the continuous casting process, set the billet drawing speed during the continuous casting process to 1.15m / min, and adjust the cooling intensity to 0.28℃ / s, so that the molten steel gradually solidifies into a continuous casting billet.

[0078] Rolling process: The continuous casting billet is heated to 1095℃ and then rolled. During the rolling process, the final rolling temperature is always paid attention to and stabilized at 895℃ to obtain the sucker rod blank.

[0079] Heat treatment: First, the sucker rod blank is quenched at 915°C, using oil as the quenching medium for 38 minutes; then tempering is carried out, the tempering temperature is determined to be 590°C, and the tempering time is set to 85 minutes to optimize material properties.

[0080] Machining: The heat-treated sucker rods are machined in accordance with the specified size and precision requirements to produce finished sucker rods that meet the standards.

[0081] Example 7

[0082] Chemical composition:

[0083] C: 0.39%, Si: 0.95%, Mn: 1.35%, Cr: 0.95%, Mo: 0.32%, V: 0.14%, Ni: 0.28%, and the balance is Fe.

[0084] Production process:

[0085] Raw material preparation: Prepare raw materials according to the corresponding chemical composition ratio, smelt them in an electric furnace to obtain molten steel.

[0086] Refining treatment: The molten steel is introduced into the refining furnace, and the temperature in the furnace is controlled at 1565℃. Refining is continued at this temperature for 33 minutes, and then a strict deoxidation and desulfurization process is carried out.

[0087] Continuous casting: In the continuous casting process, the billet drawing speed is set to 0.95m / min and the cooling intensity is set to 0.24℃ / s, so that the molten steel can be smoothly formed into continuous casting billets.

[0088] Rolling process: The continuous casting billet is heated to 1065℃ and then rolled. During the process, the final rolling temperature is ensured to be 875℃ to obtain the sucker rod blank.

[0089] Heat treatment: firstly, the sucker rod blank is quenched at 905℃, with oil as the quenching medium and the quenching time of 33 minutes; then the sucker rod blank is tempered at 575℃ and the tempering time of 70 minutes.

[0090] Mechanical processing: Use mechanical processing methods to process the heat-treated sucker rods to achieve the predetermined dimensional accuracy requirements and finally make finished sucker rods.

[0091] Example 8

[0092] Chemical composition:

[0093] C: 0.41%, Si: 1.05%, Mn: 1.45%, Cr: 1.05%, Mo: 0.42%, V: 0.17%, Ni: 0.32%, and the balance is Fe.

[0094] Production process:

[0095] Raw material preparation: Prepare various raw materials according to the specified chemical composition ratio, put them into the electric furnace for full melting to obtain molten steel.

[0096] Refining treatment: The molten steel is transferred to the refining furnace, and the temperature in the furnace is controlled at 1575℃. This temperature is maintained for 37 minutes of refining operation, followed by deoxidation and desulfurization treatment to ensure the quality of the molten steel.

[0097] Continuous casting: During the continuous casting process, the billet drawing speed was set to 1.05 m / min and the cooling intensity was set to 0.26 °C / s to promote the solidification of the molten steel to form a continuous casting billet.

[0098] Rolling process: heat the continuous casting billet to 1075℃ and then start rolling. During rolling, the final rolling temperature is controlled at 885℃ to obtain the sucker rod blank.

[0099] Heat treatment: firstly, the sucker rod blank is quenched at 910℃, with oil as the quenching medium and the quenching time is 37 minutes; then it is tempered at 585℃ and the tempering time is 75 minutes.

[0100] Machining: The heat-treated sucker rod is machined according to the required size and precision requirements to finally obtain a qualified finished sucker rod.

[0101] The following is an explanation of the advantages of the high-strength fatigue-resistant steel sucker rod technology solution:

[0102] Chemical composition optimization

[0103] Alloy element synergistic strengthening: In the carefully formulated chemical composition, the C element content is between 0.35-0.45% (preferably 0.38-0.42%), which synergizes with alloy elements such as Si, Mn, Cr, Mo, V, and Ni to significantly improve the comprehensive performance of steel. The C element provides basic strength, the Si element (0.8-1.2%, preferably 0.9-1.1%) can effectively improve the strength and hardness of steel, while enhancing oxidation resistance; the Mn element (1.2-1.6%, preferably 1.3-1.5%) improves the toughness and hardenability of steel while improving strength, and reduces hot brittleness; the Cr element enhances the corrosion resistance and oxidation resistance of steel, the Mo element improves the thermal strength and tempering stability of steel, the V element refines the grains, improves strength and toughness, and the Ni element improves the low-temperature toughness and corrosion resistance of steel. These elements work together to make the sucker rod excel in high strength and fatigue resistance, and better adapt to harsh working environments, such as withstanding long-term complex stresses such as tension, compression, bending and torsion in oil wells, effectively extending the service life of the sucker rod, reducing the frequency of replacement and reducing mining costs.

[0104] Precise control of impurity content: strictly control the content range of each element to ensure that the impurity content is at an extremely low level, ensuring the purity and quality stability of the steel. The balance is Fe, which avoids the adverse effects of excessive impurity elements on the performance of the steel, making the organizational structure of the steel more uniform and dense, further improving its mechanical properties and fatigue resistance, reducing internal defects and stress concentration caused by impurities, thereby reducing the risk of fatigue fracture of the sucker rod during use.

[0105] Exquisite craftsmanship

[0106] Precise control of refining treatment: In the refining step, the molten steel is poured into the refining furnace, and the temperature in the furnace is precisely controlled at 1550-1600℃ (preferably 1560-1580℃), and the refining time is 30-40 minutes. This precise temperature and time control can effectively remove harmful impurities in the molten steel, such as sulfur and phosphorus, while homogenizing the composition of the molten steel, further improving the purity and quality stability of the steel. After refining, deoxidation and desulfurization treatment are carried out to minimize the oxygen and sulfur content in the steel, reduce the formation of inclusions, make the internal structure of the steel more dense and uniform, significantly improve its strength and toughness, enhance the reliability and durability of the sucker rod under complex stress conditions, and effectively prevent the initiation and expansion of fatigue cracks caused by internal defects.

[0107] Optimization of continuous casting parameters: During the continuous casting process, the billet drawing speed (0.8-1.2m / min, preferably 0.9-1.1m / min) and cooling intensity (0.2-0.3℃ / s) are finely controlled to ensure that the solidification process of the continuous casting billet is uniform and stable, to avoid defects such as internal cracks and looseness, and to ensure the quality and performance consistency of the continuous casting billet. Appropriate billet drawing speed and cooling intensity help to form a good billet structure, refine the grains, improve the comprehensive performance of steel, and provide high-quality billets for subsequent rolling processing, thereby laying a solid foundation for the production of high-strength, fatigue-resistant sucker rods, improving the overall quality and performance stability of the sucker rods, and enabling them to maintain a good working condition during long-term use.

[0108] Rolling and heat treatment process synergistically enhance efficiency: During rolling, the continuous casting billet is heated to 1050-1100℃ (preferably 1060-1080℃) and then rolled. The final rolling temperature is controlled at 850-900℃. Through a reasonable rolling process, the grains of the steel are further refined to improve its strength and toughness. In the subsequent heat treatment process, a quenching treatment at 880-920℃ (the quenching medium is oil, and the quenching time is 30-40 minutes) is first performed to allow the steel to obtain a martensitic structure, significantly improving its hardness and strength; followed by a tempering treatment at 550-600℃ (tempering time is 60-90 minutes, preferably 70-80 minutes), which effectively eliminates quenching stress, improves the toughness and plasticity of the steel, and maintains a high level of strength. The synergistic effect of this rolling and heat treatment process enables the sucker rod to have high strength while having good toughness and fatigue resistance. It can withstand repeated alternating loads during the pumping process and is not prone to fatigue damage. This greatly improves the working reliability and service life of the sucker rod and provides a strong guarantee for oil extraction operations.

[0109] Machining ensures precision: In the final machining step, the heat-treated sucker rod is precisely machined to achieve the required size and precision requirements, ensuring the matching accuracy and working performance of the sucker rod in actual use. High-precision machining can not only ensure the good matching of the sucker rod with other pumping equipment, reduce wear and energy loss caused by poor matching, but also further optimize the surface quality of the sucker rod, reduce surface roughness, reduce stress concentration points, and improve its fatigue resistance, thereby improving the overall use effect and reliability of the sucker rod and meeting the oil extraction industry's requirements for high precision and high performance of the sucker rod.

[0110] In summary, the sucker rod made of this high-strength fatigue-resistant steel has significant advantages in strength, toughness, fatigue resistance, quality stability and dimensional accuracy through optimized chemical composition design and exquisite manufacturing process. It can effectively meet the high performance requirements of sucker rods in fields such as oil extraction, and has broad application prospects and important economic value.

[0111] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A sucker rod made of high-strength fatigue-resistant steel, characterized in that: Its chemical composition by weight percentage includes: C: 0.35- 0.45%, Si: 0.8-1.2%, Mn: 1.2-1.6%, Cr: 0.8-1.2%, Mo: 0.3-0.5%, V: 0.1-0.2%, Ni: 0.2-0.4%, and the balance is Fe.

2. The sucker rod made of high-strength fatigue-resistant steel according to claim 1, wherein the C content is 0.38-0.42%.

3. The sucker rod made of high-strength fatigue-resistant steel according to claim 1, wherein the Si content is 0.9-1.1%.

4. The sucker rod made of high-strength fatigue-resistant steel according to claim 1, wherein the content of Mn is 1.3-1.5%.

5. The manufacturing process of the high-strength fatigue-resistant steel sucker rod according to claim 1 comprises the following steps: Step 1: preparing raw materials, preparing various raw materials according to the chemical composition ratio of claim 1, and smelting the raw materials in an electric furnace to obtain molten steel; Step 2: Refining treatment, pouring the molten steel into a refining furnace for refining, controlling the temperature in the furnace at 1550-1600°C during the refining process, and refining time is 30-40 minutes, and deoxidation and desulfurization treatment is performed after refining; Step 3: Continuous casting: the refined molten steel is continuously cast to obtain a continuous casting billet. During the continuous casting process, the billet drawing speed is controlled to be 0.8-1.2 m / min and the cooling intensity is 0.2-0.3 °C / s; Step 4: rolling processing, heating the continuous casting billet to 1050-1100°C and then rolling it, and controlling the final rolling temperature at 850-900°C to obtain a sucker rod blank; Step 5: Heat treatment: the sucker rod blank is first quenched at a temperature of 880-920°C, the quenching medium is oil, and the quenching time is 30-40 minutes, and then tempered at a temperature of 550-600°C and a tempering time of 60-90 minutes; Step 6: Machining: machining the heat-treated sucker rod to the required size and accuracy to obtain a finished sucker rod.

6. The process for manufacturing a sucker rod made of high-strength fatigue-resistant steel according to claim 5, wherein the temperature in the refining furnace in step 2 is controlled at 1560-1580°C.

7. The manufacturing process of the pumping rod of high-strength fatigue-resistant steel according to claim 5, wherein the billet drawing speed during the continuous casting process in step 3 is 0.9-1.1 m / min.

8. The process for manufacturing a pump rod made of high-strength fatigue-resistant steel according to claim 5, wherein the continuous casting billet is heated to 1060-1080°C during the rolling process in step 4.

9. The manufacturing process of the sucker rod made of high-strength fatigue-resistant steel according to claim 5, wherein the tempering time in step 5 is 70-80 minutes.