Extruded full-jacketed sucker rod

Abstract

The present application relates to a kind of extruded full-coated sucker rod, including sucker rod base body and metal sleeve, the middle part of the sucker rod base body is rod body, the end part is rod head and the both ends are symmetrically arranged, the rod head from the end of sucker rod base body towards rod body is in turn threaded joint, unloading groove, shoulder, wrench square and flange, the outer surface of the rod body is covered with anticorrosive non-metallic material layer, the metal sleeve is extruded and closely fitted to the outer surface of the shoulder, wrench square and flange, and completely covers the shoulder, wrench square and flange, and the anticorrosive non-metallic material layer is covered, and the shape formed at the corresponding position of the outer surface of the metal sleeve and the shoulder, wrench square and flange is same with the shape of the outer surface of the shoulder, wrench square and flange.The present application can reduce the cost and workload of machining, and facilitate on-site operation, improve operation efficiency.

Description

Technical Field

[0001] The invention relates to the field of oil drilling and production, and in particular to an extruded fully-covered sucker rod. Background Art

[0002] The sucker rod is an important component required in the process of oil drilling and production. At present, most of my country's oil fields have entered the middle and late stages of development, with increasingly high water content. Water injection and other production-increasing measures are often used, and the oil field reinjection water is basically sewage directly reinjected, resulting in a very harsh working environment for the sucker rod. Highly mineralized well fluids contain various corrosive media and corrosive microorganisms, especially those rich in Cl - , which greatly increases the corrosion rate of the pump rod. At the same time, the associated gas contains corrosive gases such as CO2 and H2S, which make the well fluid weakly acidic. As we all know, the treatment of Cl - Corrosion caused by CO2, H2S, and other factors has always been a global challenge in oil production. Furthermore, friction between the sucker rod and the inner wall of the tubing generates heat, activating the rod's surface. Under the influence of corrosive produced fluids, the rate of corrosion on the rod surface is significantly accelerated. Furthermore, factors such as sand content, wax and scaling in the well, and produced fluid viscosity can also contribute to corrosion and eccentric wear on the rod surface. In short, the long-term exposure of sucker rods to alternating loads and the combined effects of oil, gas, water, and corrosive media, coupled with eccentric wear, makes them the least reliable equipment in mechanical oil production and prone to breakage accidents.

[0003] Research has shown that when the water content of an oil well exceeds 74.02%, the produced fluid undergoes a phase shift, switching from oil-in-water to water-in-oil. The tubing and rod surfaces lose the protection of crude oil, and the produced water comes into direct contact with the metal, accelerating corrosion. As the lubricant changes from crude oil to produced water, the oil's lubricating properties are lost. As the water content of the well fluid increases, its specific gravity also increases, significantly reducing the lubrication coefficient at the tubing-rod interface. This significantly increases upward loads and invisibly increases downward resistance, exacerbating the stress and deformation of the sucker rod, increasing frictional resistance and accelerating tubing and rod wear. Eccentric wear of tubing and rods generates heat, activating the surface. Under the influence of the highly corrosive produced fluid, the eccentric wear areas are preferentially corroded, increasing surface roughness, friction resistance, and further aggravating wear. Furthermore, factors such as sand content, wax and scale deposits in the well, and the viscosity of the produced fluid can also contribute to corrosion and eccentric wear on the sucker rod surface. Corrosion and mechanical wear are not simply additive; rather, they interact and reinforce each other, making their combined destructive nature even more destructive. Anti-eccentric wear measures such as centralizers, anti-wear pairs, and weighted rods are widely used in oil fields. Although they can extend the service life of pipes and rods, they cannot completely solve the problem.

[0004] In response to the problem of corrosion resistance and wear resistance, the current preventive measures for sucker rods mainly include using conventional methods such as electroplating or chemical plating to process chrome-plated sucker rods, nickel-plated sucker rods, tungsten-plated sucker rods, semi-coated anti-corrosion and wear-resistant sucker rods, and fully coated anti-corrosion and wear-resistant sucker rods.

[0005] Conventional wear-resistant and anti-corrosion coatings on sucker rods are limited by the large-diameter ratio of the rod head to the rod body and the complex shape of the upset-forged sucker rod. The bonding strength between the coating and the substrate is low. When used in the above-mentioned complex well conditions, the coating is prone to peeling, falling off, and wearing, forming a shortcoming in corrosion resistance and wear resistance. The effect is not very ideal, and the cost is relatively high. For example, a corrosion-resistant and wear-resistant polished rod disclosed in Chinese invention patent application CN108798537A includes a rod body, a first external threaded joint and a second external threaded joint are provided at both ends of the rod body, an anti-corrosion and wear-resistant alloy coating is provided on the outside of the rod body, and a cathodic protection anti-corrosion alloy coating is provided on the non-upset portion of the rod body near the second external threaded joint; another example is a new type of corrosion-resistant and wear-resistant spray-welded sucker rod disclosed in Chinese invention patent application CN108798538A, including a rod body, one end of the rod body is connected outwardly with a first rod head upset portion and a first rod head threaded section in sequence, and the other end of the rod body is provided with a first external threaded joint. A second rod head upset portion and a second rod head threaded section are connected outward in sequence, a first arc transition zone and a first flange are provided between the rod body and the first rod head upset portion, a first thrust surface shoulder and a first unloading groove are provided between the first rod head upset portion and the first rod head threaded section, a second arc transition zone and a second flange are provided between the rod body and the second rod head upset portion, a second thrust surface shoulder and a second unloading groove are provided between the second rod head upset portion and the second rod head threaded section, and the outer sides of the rod body, the first rod head upset portion and the second rod head upset portion are provided with an anti-corrosion and wear-resistant alloy coating. Both of the above-mentioned patent applications enhance the corrosion and wear resistance of the sucker rod by plating, but they also inevitably have the problems of low bonding strength between the plating and the substrate, easy falling off and wear.

[0006] The bonding strength between the spray-welded coating and the substrate of the semi-coated anti-corrosion and wear-resistant sucker rod is greatly improved, and it has good anti-corrosion and wear-resistant properties. However, after the rod head is spray-welded with the anti-corrosion alloy coating, secondary solid solution strengthening is required. High temperature will substantially reduce the substrate performance of the coated anti-corrosion and wear-resistant sucker rod head, which substantially reduces the overall anti-corrosion and wear-resistant performance and reliability of the sucker rod, and the cost is relatively high.

[0007] Fully covered sucker rods, by completely covering the rod head and rod body, have excellent corrosion resistance and wear resistance. For example, Chinese utility model patent CN210564384U discloses an improved fully covered sucker rod, comprising a sucker rod base and a clamp. The sucker rod base comprises shoulders and a rod body at both ends, extending from the outside to the inside. The shoulders are provided with thrust blocks and clamp threads, which are used to tightly fit the clamp. The connection between the shoulder and the rod body comprises a wrench square and a flange, the wrench square and flange having a reduced diameter, while the shoulder has a larger diameter than the flange. The connection between the shoulder and the rod body and the outer wall of the rod body are provided with an anti-corrosion polymer plastic layer. The clamp includes a joint, the inner ring of which is provided with a thrust hole and internal threads corresponding to the shoulder, so that the clamp fits tightly against the sucker rod base. An injection channel is formed between the sucker rod base, which is coated with the anti-corrosion polymer plastic layer, and the inner cavity of the clamp, and the polymer plastic is high-pressure injection molded. The aforementioned patent forms a full covering of the sucker rod by the clamp and the polymer plastic layer as well as the polymer plastic injected under high pressure inside the clamp. The patent has good corrosion resistance and wear resistance, but it requires the thrust platform and clamp thread processing on the shoulder of the sucker rod base, the thrust port and internal thread processing on the clamp, and the high-pressure injection molding of the inner cavity of the clamp. The increase in processing steps leads to a corresponding increase in processing cost and workload. Another example is a new sucker rod disclosed in Chinese utility model patent CN212454282U, which includes a sucker rod base and a threaded sleeve. The two ends of the sucker rod base are symmetrically arranged. The sucker rod base is provided with a first external thread joint, a relief groove, a second external thread shoulder, a wrench square and a rod body in sequence from the end to the center; the threaded sleeve is sleeved on the second external thread shoulder of the sucker rod base and partially covers the rod body; the ends where the second external thread shoulder and the threaded sleeve abut are respectively provided with a thrust platform and a thrust port; the outer wall of the rod body is covered with an anti-corrosion polymer plastic layer, and the outer surface of the threaded sleeve is provided with an anti-corrosion Wear-resistant coating; Chinese utility model patent CN212454283U discloses a new type of sucker rod, including a sucker rod base and a tapered sleeve, the two ends of the sucker rod base are symmetrically arranged, and the sucker rod base is sequentially provided with an external threaded joint, a unloading groove, a tapered shoulder, a wrench square and a rod body from the end to the center; the tapered sleeve is sleeved on the tapered shoulder of the sucker rod base and partially covers the rod body; the ends of the tapered shoulder and the tapered sleeve where they abut are respectively provided with a tapered thrust platform and a tapered thrust port, the outer wall of the rod body is covered with an anti-corrosion polymer plastic layer, and the outer surface of the tapered sleeve is provided with an anti-corrosion and wear-resistant coating. The above two patents are similar to CN210564384U in that the rod head is covered by a clamp / sleeve and the rod body is covered by a polymer plastic layer. However, both patents require the sleeve and shoulder to be threaded, thrust ports and thrust platforms processed, thereby increasing the machining workload and cost.In addition, the square wrench of the standard API sucker rod is designed so that there is no direction selection for on-site operations, and the wrench can be used to quickly align in any direction. However, in the aforementioned Chinese utility model patents CN210564384U, CN212454282U, and CN212454283U, since the square wrench is covered with a clamp / sleeve, and the clamp / sleeve is circular in shape, two symmetrical 180-degree square wrench grooves are milled on the outer surface of the clamp / sleeve for the convenience of on-site operations. This results in a directional selection, which causes inconvenience to on-site operations. Moreover, due to the wall thickness of the clamp / sleeve, the milling depth of the square wrench groove is very small, which in turn affects the efficiency of on-site operations.

[0008] In view of this, the present invention provides an extruded fully covered sucker rod, which solves the technical problems of high machining cost and workload caused by the need to process threads, thrust blocks and thrust ports of fully covered sucker rods in the prior art by improving the sleeve structure and the sleeve and rod head covering method, and ensures that the rod head part of the fully covered sucker rod still forms the API standard four-sided wrench square, thereby improving the efficiency of on-site operations. Summary of the Invention

[0009] The present invention is intended to provide an extruded fully covered sucker rod to address the deficiencies in the prior art. The technical problem to be solved by the present invention is achieved through the following technical solutions.

[0010] A fully-covered extruded sucker rod comprises a sucker rod base and a metal sleeve, wherein the improvement is that the middle portion of the sucker rod base is a rod body, the two end portions are rod heads, and the two ends are symmetrically arranged; the rod head comprises a threaded joint, a unloading groove, a shoulder, a wrench square and a flange in sequence from the end of the sucker rod base toward the rod body; the outer surface of the rod body is covered with a corrosion-resistant non-metallic material layer; the metal sleeve is tightly fitted to the outer surfaces of the shoulder, wrench square and flange after extrusion and completely covers the shoulder, wrench square and flange and covers part of the corrosion-resistant non-metallic material layer; and the shape formed at the corresponding position of the outer surface of the metal sleeve to the shoulder, wrench square and flange is the same as the shape of the outer surface of the shoulder, wrench square and flange.

[0011] Preferably, the metal sleeve is tightly fitted to the outer surfaces of the shoulder, the wrench square and the flange by hot extrusion and completely covers the shoulder, the wrench square and the flange.

[0012] Preferably, the metal sleeve is partially covered with an anti-corrosion non-metallic material layer by cold extrusion.

[0013] Preferably, the metal sleeve is a stainless steel sleeve.

[0014] Preferably, the end surface of the metal sleeve adjacent to the end of the sucker rod base is flush with the end surface of the shoulder adjacent to the unloading groove.

[0015] Preferably, the anti-corrosion non-metallic material layer is an anti-corrosion polymer plastic layer.

[0016] Preferably, at least one groove is provided on the inner wall of the metal sleeve near the end.

[0017] Preferably, the outer diameter of the threaded joint is smaller than the outer diameter of the shoulder.

[0018] Preferably, the outer diameter of the flange is equal to the outer diameter of the shoulder.

[0019] Preferably, the outer diameter of the wrench square is smaller than the outer diameters of the shoulder and the flange.

[0020] The present invention forms a layer of corrosion-resistant non-metallic material on the outer surface of the rod and uses a metal sleeve to cover the rod head and partially cover the corrosion-resistant non-metallic material layer, thereby forming a fully covered corrosion protection for a single sucker rod. Multiple sucker rods are connected through joints and threaded joints such as standard spray-welded ferrules. The pre-tightening force is used to achieve an extrusion seal between the joint and the metal sleeve, which can effectively prevent corrosive media from entering the interior of the rod head. Compared with the existing technology, the present invention uses an extruded metal sleeve to cover the shoulder, wrench square and flange of the rod head and partially cover the corrosion-resistant non-metallic material layer, thereby eliminating the need to process threads, thrust blocks and thrust ports, thereby reducing machining costs and workload. At the same time, because the outer surface of the metal sleeve is formed in the same shape as the shoulder, wrench square and flange, that is, the metal sleeve still retains the API standard four-sided wrench square structure, it facilitates on-site operations and improves work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the present invention;

[0022] Figure 2 Schematic diagram of the structure of the sucker rod base body in the present invention;

[0023] Figure 3 Schematic diagram of the structure of the metal sleeve in the present invention (the metal sleeve shown in the figure is a schematic diagram of the structure when it is not extruded and coated on the sucker rod base);

[0024] The reference numerals in the accompanying drawings are: 1. sucker rod base, 11. threaded joint, 12. unloading groove, 13. shoulder, 14. wrench square, 15. flange, 16. rod body, 2. metal sleeve, 21. groove, 3. anti-corrosion non-metallic material layer. DETAILED DESCRIPTION

[0025] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0026] Example 1:

[0027] Reference Figures 1 to 3 As shown, an extruded fully covered sucker rod includes a sucker rod base 1 and a metal sleeve 2, the improvement of which is that the middle part of the sucker rod base 1 is a rod body 16, the two end parts are rod heads and the two ends are symmetrically arranged, the rod head is composed of a threaded joint 11, a unloading groove 12, a shoulder 13, a wrench square 14 and a flange 15 from the end of the sucker rod base 1 toward the rod body 16, the outer surface of the rod body 16 is covered with an anti-corrosion non-metallic material layer 3, the metal sleeve 2 is extruded to tightly fit the outer surfaces of the shoulder 13, the wrench square 14 and the flange 15 and completely cover the shoulder 13, the wrench square 14 and the flange 15 and cover part of the anti-corrosion non-metallic material layer 3, and the shape formed at the corresponding position of the outer surface of the metal sleeve 2 and the shoulder 13, the wrench square 14 and the flange 15 is the same as the shape of the outer surface of the shoulder 13, the wrench square 14 and the flange 15.

[0028] In this embodiment, the two ends of the sucker rod base 1 are symmetrically arranged, firstly to facilitate processing and production; secondly, to facilitate assembly. The structures at both ends are the same, and there is no need to specify the direction during assembly, which saves time and effort. After the threaded joint 11 is threadedly connected to the butt joint (not shown in the figure), the butt joint and the metal sleeve 2 are tightly abutted, and a sealing effect is achieved through pre-tightening force. The setting of the unloading groove 12 can reduce the stress on the sucker rod base 1. The outer surface of the rod body 16 is covered with an anti-corrosion non-metallic material layer 3, which can prevent the corrosive medium from corroding the rod body 16. The metal sleeve 2 completely covers the shoulder 13, the wrench square 14 and the flange 15, and can seal the shoulder 13, the wrench square 14 and the flange 15, thereby preventing the corrosive medium from corroding the shoulder 13, the wrench square 14 and the flange 15. The metal sleeve 2 covers part of the anti-corrosion non-metallic material layer 3 to achieve a sealed connection between the two, which can prevent the corrosive medium from corroding the sucker rod base 1.

[0029] It is worth noting that the reason why the shape formed by the outer surface of the metal sleeve 2 is the same as the shape of the outer surfaces of the shoulder 13, the wrench square 14 and the flange 15 after the metal sleeve 2 is provided to cover the shoulder 13, the wrench square 14 and the flange 15 in this embodiment is because the setting of the wrench square 14 on the sucker rod base 1 is to facilitate on-site operations. The standard API sucker rod is designed with a four-sided wrench square so that there is no direction selection for on-site operations, and a wrench can be used to quickly align it in any direction. The fully covered sucker rods in the prior art mostly use a circular clamp / sleeve to cover the rod head part of the sucker rod, which makes it impossible to effectively correct the sucker rod during on-site operations. In order to solve this problem, the prior art mills two symmetrical wrench square grooves of 180 degrees on the outer surface of the clamp / sleeve, thereby resulting in directional selection, which causes inconvenience to on-site operations. In addition, due to the wall thickness of the clamp / sleeve, the milling depth of the wrench square groove is very small, which in turn affects the efficiency of on-site operations. In this embodiment, the metal sleeve 2 is extruded so that the shape of its outer surface is consistent with the shape of the rod head of the sucker rod, so that the fully covered sucker rod still retains the square structure of the API standard four-sided wrench, thereby facilitating on-site operations and improving operating efficiency.

[0030] This embodiment forms an anti-corrosion non-metallic material layer 3 on the outer surface of the rod body 16 and uses a metal sleeve 2 to cover the rod head, partially covering the anti-corrosion non-metallic material layer 3. This fully encapsulates and protects a single sucker rod. Multiple sucker rods are connected using butt joints, such as standard spray-welded ferrules, and threaded joints 11. Preload is used to create a squeeze seal between the butt joints and the metal sleeve 2, effectively preventing corrosive media from entering the rod head.

[0031] Compared with the prior art, this embodiment achieves the purpose of covering the shoulder 13, wrench square 14 and flange 15 of the rod head and covering part of the anti-corrosion non-metallic material layer 3 by extruding the metal sleeve 2, thereby eliminating the need to process threads, thrust blocks and thrust ports, thereby reducing machining costs and workload. At the same time, since the outer surface of the metal sleeve 2 forms the same shape as the shoulder 13, wrench square 14 and flange 15, that is, the API standard four-sided wrench square structure is still retained on the metal sleeve 2, it is convenient for on-site operations and improves work efficiency.

[0032] Furthermore, the end surface of the metal sleeve 2 adjacent to the end of the sucker rod base 1 is flush with the end surface of the shoulder 13 adjacent to the unloading groove 12 .

[0033] In this embodiment, the end face of the metal sleeve 2 is flush with the end face of the shoulder 13. When the joint is tightly abutted against the metal sleeve 2, a sealing effect can be achieved through pre-tightening force, thereby preventing the corrosive medium from corroding the unloading groove 12, the threaded joint 11 and the inside of the joint.

[0034] Furthermore, the anti-corrosion non-metallic material layer 3 is an anti-corrosion polymer plastic layer.

[0035] The anti-corrosion polymer plastic layer of this embodiment can be formed as a coating on the outer surface of the rod body 16 by heating the polymer plastic, performing low-medium pressure injection molding, and curing processes. Polymer plastic has high chemical stability, high toughness, a certain degree of wear resistance, and self-lubricating properties. Its main advantages include high mechanical strength, good toughness, impact resistance, fatigue resistance, smooth surface, low friction coefficient, heat resistance (long-term use within 180°C), corrosion resistance, light weight, easy molding, and reliable dimensional stability. Coating the rod body 16 of the sucker rod base 1 with the anti-corrosion polymer plastic layer can isolate the rod body 16 from the corrosive medium, thereby ensuring that the rod body 16 is not damaged by the corrosive medium and enhancing the fatigue strength of the rod body 16.

[0036] Furthermore, at least one groove 21 is provided on the inner wall of the metal sleeve 2 near the end. In this embodiment, the provision of the groove 21 can squeeze the anti-corrosion non-metallic material layer 3 when the metal sleeve 2 partially covers the anti-corrosion non-metallic material layer 3, thereby sealing the two together, achieving both a sealing effect and ensuring its firmness.

[0037] Furthermore, the outer diameter of the threaded joint 11 is smaller than the outer diameter of the shoulder 13 , the outer diameter of the flange 15 is equal to the outer diameter of the shoulder 13 , and the outer diameter of the wrench square 14 is smaller than the outer diameters of the shoulder 13 and the flange 15 .

[0038] Example 2:

[0039] On the basis of Example 1, the metal sleeve 2 is tightly fitted to the outer surfaces of the shoulder 13 , the wrench square 14 and the flange 15 by hot extrusion and completely covers the shoulder 13 , the wrench square 14 and the flange 15 .

[0040] In this embodiment, the metal sleeve 2 is first heated during hot extrusion, and then the metal sleeve 2 is extruded by a press to ensure that the metal sleeve 2 is tightly fitted to the outer surfaces of the shoulder 13, the wrench square 14 and the flange 15 and completely covers the shoulder 13, the wrench square 14 and the flange 15, thereby sealing the shoulder 13, the wrench square 14 and the flange 15 to prevent the corrosive medium from corroding the shoulder 13, the wrench square 14 and the flange 15.

[0041] Furthermore, the metal sleeve 2 is partially covered with the anti-corrosion non-metallic material layer 3 by cold extrusion.

[0042] In this embodiment, after the metal sleeve 2 is extruded to fit tightly against the outer surfaces of the shoulder 13, the wrench square 14 and the flange 15 and completely covers the shoulder 13, the wrench square 14 and the flange 15, the portion of the metal sleeve 2 covering the anti-corrosion non-metallic material layer 3 is cold extruded, so that it is deformed and necked and then tightly pressed against the anti-corrosion non-metallic material layer 3, thereby achieving a sealed connection to prevent the corrosive medium from corroding the sucker rod base 1.

[0043] Furthermore, the metal sleeve 2 is a stainless steel sleeve.

[0044] This embodiment uses stainless steel for the sleeve because of its excellent corrosion resistance. Conventional clamps / sleeves typically spray-weld nickel-based alloy powder onto their outer surfaces to enhance their corrosion resistance, imparting comprehensive properties such as wear resistance, corrosion resistance, and friction reduction. However, the use of a stainless steel sleeve eliminates the need for spray-welding with alloy powder.

[0045] It should be noted that the above detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which this application belongs.

[0046] It should be noted that the terms used herein are intended only to describe specific embodiments and are not intended to limit the exemplary embodiments described herein. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0047] It should be noted that the terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, such that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0048] In addition, the terms "comprises" and "comprising" and any variations thereof are intended to cover a non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, product, or apparatus.

[0049] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be subsequently positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways, such as rotated 90 degrees or in other orientations, and the spatially relative descriptions used herein are interpreted accordingly.

[0050] In the above detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless the context dictates otherwise. The illustrated embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be used, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein.

[0051] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. An extruded fully covered sucker rod, comprising a sucker rod base (1) and a metal sleeve (2), characterized in that: The middle part of the sucker rod base (1) is a rod body (16), and the two ends are rod heads, and the two ends are symmetrically arranged. The rod head is composed of a threaded joint (11), a relief groove (12), a shoulder (13), a wrench square (14) and a flange (15) from the end of the sucker rod base (1) toward the rod body (16). The outer surface of the rod body (16) is covered with an anti-corrosion non-metallic material layer (3). The metal sleeve (2) is tightly fitted to the shoulder (13), the wrench square (14) and the flange (15) by hot extrusion. and the outer surface of the flange (15) and completely covers the shoulder (13), the wrench square (14) and the flange (15) and covers part of the anti-corrosion non-metallic material layer (3); and the shape formed at the position corresponding to the outer surface of the metal sleeve (2) and the shoulder (13), the wrench square (14) and the flange (15) is the same as the shape of the outer surface of the shoulder (13), the wrench square (14) and the flange (15), and the metal sleeve (2) is covered with part of the anti-corrosion non-metallic material layer (3) by cold extrusion During hot extrusion, the metal sleeve (2) is first heated, and then the metal sleeve (2) is extruded by a press to ensure that the metal sleeve (2) is tightly fitted to the outer surface of the shoulder (13), the wrench square (14) and the flange (15) and completely covers the shoulder (13), the wrench square (14) and the flange (15), thereby sealing the shoulder (13), the wrench square (14) and the flange (15) to prevent corrosive media from damaging the shoulder (13), the wrench square (14) and the flange (15). After the metal sleeve (2) is squeezed and tightly fits the outer surfaces of the shoulder (13), the wrench square (14) and the flange (15) and completely covers the shoulder (13), the wrench square (14) and the flange (15), the portion of the metal sleeve (2) covering the anti-corrosion non-metallic material layer (3) is cold extruded, so that the portion is deformed and necked and then tightly pressed onto the anti-corrosion non-metallic material layer (3), thereby achieving a sealed connection to prevent the corrosive medium from corroding the sucker rod base (1).

2. The extruded fully covered sucker rod according to claim 1, characterized in that: The metal sleeve (2) is a stainless steel sleeve.

3. The extruded fully covered sucker rod according to claim 1, characterized in that: The end surface of the metal sleeve (2) adjacent to the end of the sucker rod base (1) is flush with the end surface of the shoulder (13) adjacent to the unloading groove (12).

4. The extruded fully covered sucker rod according to claim 1, characterized in that: The anti-corrosion non-metallic material layer (3) is an anti-corrosion polymer plastic layer.

5. The extruded fully covered sucker rod according to claim 1, characterized in that: At least one groove (21) is provided on the inner wall of the metal sleeve (2) at a position close to the end.

6. The extruded fully covered sucker rod according to claim 1, characterized in that: The outer diameter of the threaded joint (11) is smaller than the outer diameter of the shoulder (13).

7. The extruded fully covered sucker rod according to claim 1, characterized in that: The outer diameter of the flange (15) is equal to the outer diameter of the shoulder (13).

8. The extruded fully covered sucker rod according to claim 1, characterized in that: The outer diameter of the wrench square (14) is smaller than the outer diameters of the shoulder (13) and the flange (15).

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