A bimetallic composite sucker rod steel wire rod and its production method

Abstract

The present invention provides a bimetallic composite sucker rod steel wire rod and a production method thereof, and the method steps are as follows: S1, large round billet assembly: a large round billet using a first metal material as a core material and a stainless steel pipe using a second metal material as a cladding material are assembled to form a composite large round billet, i.e., a bimetallic large round billet; S2, the welded bimetallic large round billet is sent into a heating furnace for heating; S3, the heated bimetallic large round billet is subjected to billet rolling to obtain a bimetallic composite square billet; S4, the bimetallic composite square billet is sent into a heating furnace for heating; S5, the heated bimetallic composite square billet is subjected to billet rolling; S6, air cooling is performed after rolling, heat treatment is performed after air cooling, and oil cooling is performed to room temperature after heat treatment to obtain a bimetallic composite sucker rod steel wire rod, and further packaging is provided to provide a downstream processing end. The present invention can smoothly roll out a bimetallic composite sucker rod steel wire rod, and solve the problem of steel sticking.

Description

Technical Field

[0001] The invention relates to the technical field of rolling, and in particular to a bimetallic composite sucker rod steel wire rod and a production method thereof. Background Art

[0002] With the development of industry, the application environment of various steel materials has become increasingly harsh, especially in the field of oil field mining. The high temperature, high load and high corrosion working environment have greatly shortened the service life of the materials. Every year, oil production plants spend a huge amount of money on the renewal of sucker rods and supporting oil well operations. Therefore, bimetallic composite sucker rods came into being, which have the advantages of high mechanical properties of core materials and excellent corrosion resistance of cladding materials.

[0003] However, during the research process, it was found that the rolling process is one of the most critical issues in the development of bimetallic composite sucker rods. During the test, it was difficult to ensure the coordinated deformation of the bimetal using the original single metal material rolling process. During the rolling process, ear and shelling problems frequently occurred. Figure 1 Then, a thermal simulation test was carried out in the laboratory. Figure 2 These are the stress-strain curves of the two materials at different temperatures in the experiment. It can be seen that there are significant differences in the deformation characteristics of the two metal materials, and the normal rolling process of a single metal material cannot meet the needs of bimetallic forming.

[0004] And because the developed product is a bimetallic composite profile, the deformation process is determined by the cooperation of the hole type and the rolling process, and the material is subjected to forces in multiple directions, which is different from the deformation characteristics of composite plates subjected to unidirectional forces. Therefore, there is currently no rolling experience to draw on. There are some rolling processes used in other fields, such as:

[0005] In a steel-aluminum bimetallic rolling composite method with embedded groove interlocking (CN112275799A), the steel plate to be rolled is designed to be processed with embedded grooves, and the aluminum plate is embedded to achieve the interlocking effect for rolling. The invention is cleverly designed and interlocking is formed by processing the original billet, but the invention has high requirements on the processing accuracy of the material, and the method is only suitable for the rolling of composite plate materials with simple structure, and is not suitable for the rolling of composite sucker rods.

[0006] In a mosaic bimetallic rolled high-efficiency fin tube for an evacuated air cooler (CN201266041Y), the materials are also assembled by slotting and rolled, but the patent does not specify the rolling process.

[0007] In the semi-solid copper-lead bearing alloy / steel bimetal rolling composite process (CN100553811C), a method of casting a semi-solid alloy on a preheated steel plate and feeding it into a rolling mill for rolling composite was invented. This method is relatively complicated to operate and is only suitable for the rolling of composite plates.

[0008] In a silicon carbide aluminum-copper clad material and rolling process (US20020006526A1), a composite rolling method of stacking and rolling three metal layers is invented. An intermediate bonding reinforcement layer is coated on the metal layer to improve the composite effect between the materials. In terms of rolling process, it is also only applicable to plate rolling.

[0009] A method and apparatus for rolling composite materials (BRPI1402296A2) invents an apparatus for laminating a composite strip onto a substrate using a stand so that the strip laminating head moves along the length of the substrate. The invention fails to describe the rolling process and is not suitable for the rolling of bimetallic composite sucker rods.

[0010] At present, there is no report on the bimetallic rolling process for processing wire rods in this field. Therefore, it is urgent to develop a production method for bimetallic composite sucker rod steel wire rod, which is particularly important for the development of bimetallic composite sucker rods, and also has important reference value for the development and preparation of other bimetallic composite profiles. Summary of the invention

[0011] In response to the technical problems raised above, a bimetallic composite sucker rod steel wire rod and a production method thereof are provided.

[0012] The technical means adopted by the present invention are as follows:

[0013] A bimetallic composite sucker rod steel wire rod comprises a core material arranged in the center and a cladding material coated on the outer surface of the core material, wherein the core material is made of 20CrMo and the cladding material is made of 06Cr18Ni11Nb stainless steel.

[0014] The present invention also provides a method for producing a bimetallic composite sucker rod steel wire rod, comprising the following steps:

[0015] S1. Billet assembly: Billets made of the first metal material are used as core materials, and stainless steel pipes made of the second metal material are used as cladding materials to form composite billets, i.e., bimetallic billets.

[0016] S2, sending the bimetallic round billet welded in step S1 into a heating furnace for heating;

[0017] S3, performing blanking and rolling on the bimetallic round billet heated in step S2 to obtain a bimetallic composite square billet;

[0018] S4, sending the bimetallic composite billet obtained in step S3 into a heating furnace for heating;

[0019] S5, performing blanking and rolling on the bimetallic composite square billet heated in step S4;

[0020] S6. After the rolling in step S5 is completed, air cooling is performed, heat treatment is performed after air cooling, and oil cooling is performed to room temperature after heat treatment to obtain bimetallic composite sucker rod steel wire rod, which is further packaged and provided to downstream processing ends.

[0021] Furthermore, in step S1, the large round billet and the stainless steel pipe are assembled into a composite large round billet with a size of φ232 mm to φ382 mm by vacuuming and welding, and the cross-sectional area ratio of the core to the cladding is (3.2-4.3):1; when vacuuming, the vacuum degree is less than 5×10 -2 Pa.

[0022] Furthermore, in step S2, the welded bimetallic round billet is heated in the range of 1150°C to 1240°C, and the heating time = coating thickness / 3, in units of h; the first metal material is 20CrMo, and the second metal material is 06Cr18Ni11Nb stainless steel.

[0023] Furthermore, in step S3, the billet rolling temperature is controlled at 1150°C to 1200°C, and the billet rolling is performed for 9 to 13 passes to a 180mm×180mm / 160mm×160mm billet, and the bimetallic composite billet is obtained after air cooling.

[0024] Furthermore, in the rolling process, non-hole rolling and box-type hole rolling are adopted, wherein the last 6 passes adopt box-type hole rolling, and the hole parameters are as follows:

[0025] Groove bottom width bk = B + (2 to 8);

[0026] Notch width Bk = Δh × β / 2 + B + (1 to 5);

[0027] The slope of the hole side wall is tanψ = [Δh×β / 2+(-7~3)] / (H-Δh);

[0028] Groove bottom fillet radius r1 = (0.1 ~ 0.3) B;

[0029] The radius of the notch corner r2 = (0.05-0.2) B;

[0030] Roll gap s = (0.02 ~ 0.05) D0;

[0031] Hole height h≤H-Δh;

[0032] Groove depth hp = (hs) / 2;

[0033] In the formula: B is the width of the incoming material; H is the height of the incoming material; Δh is the pass reduction; β is the width expansion coefficient; D0 is the nominal diameter of the roll.

[0034] Furthermore, in order to ensure smooth biting of the billet and to ensure h / b<1.6, where b is the width of the billet and h is the height of the billet, the first and second pass reductions are both controlled at 2-10%; the third and fourth pass reductions are 10-15% respectively; the fifth and sixth pass reductions are 15-22% respectively; the subsequent pass reductions are all 10-25%; and the last pass reduction is 5-15%.

[0035] Furthermore, in step S4, the bimetallic composite square billet is fed into a heating furnace for heating in the range of 1100°C to 1180°C, including: first heating at 780°C to 840°C, second heating at 1120°C to 1220°C, a soaking section at 1100°C to 1180°C, a heating time of 2 to 3 hours, and the billet rolling temperature is controlled at 1080°C to 1150°C.

[0036] Furthermore, in step S5, during the rolling process, the first four passes are all rolled using a box-type hole, and the fifth pass and thereafter use an elliptical-circular hole system to roll the finished product, and the hole design formula is as follows:

[0037] The box hole design uses the following formula:

[0038] Groove bottom width b k =B+(5-15);

[0039] Slot width B k =Δh×β+B+(6~13);

[0040] The slope of the hole side wall is tanψ = [Δh×β+(-9~8)] / (H-Δh-s);

[0041] Groove bottom fillet radius r1 = (0.15 ~ 0.25) B;

[0042] The radius of the notch corner r2 = (0.12-0.15) B;

[0043] Roll gap s = (0.01 ~ 0.2) D0;

[0044] Hole height h = H-Δh;

[0045] Groove depth hp = (hs) / 2;

[0046] Groove bottom convexity f = (0.02 ~ 0.04) B;

[0047] In the formula: B is the material width; H is the material height; Δh is the pass reduction; β is the width expansion coefficient; D0 is the nominal diameter of the roll;

[0048] The elliptical hole design adopts the following formula:

[0049] Ellipse radius R = [(hs) 2 +B k 2 ] / 4(hs);

[0050] The blunt side of the ellipse is m=s+1;

[0051] Groove width B k =(1.088~1.11)(A+β×Δh);

[0052] Slot fillet radius r = (0.08 ~ 0.12) B k ;

[0053] Roll gap s = (0.2 ~ 0.3) h;

[0054] Where: A is the side length of the incoming billet; h is the hole height; Δh is the pass reduction; β is the width expansion coefficient;

[0055] To ensure smooth rolling bite, the first four passes h / b ≤ 1.5, the elongation coefficient is controlled at 1-1.3, the first pass reduction is controlled at 20%-25%, the second to fourth passes reduction is controlled at 30%-40%, and the fifth pass reduction is controlled at 15%-20%.

[0056] Furthermore, in step S6, the heat treatment adopts a quenching and tempering heat treatment process, with water quenching at 780°C to 820°C and tempering at 490°C to 550°C for 0.5h.

[0057] Compared with the prior art, the present invention has the following advantages:

[0058] 1. The bimetallic composite sucker rod steel wire rod and its production method provided by the present invention have the excellent corrosion resistance of the original coating and the mechanical properties of the core material. The method can be used to smoothly roll out the bimetallic composite sucker rod steel wire rod to solve the problem of steel sticking.

[0059] 2. The bimetallic composite sucker rod steel wire rod and its production method provided by the present invention have strong operability and good composite effect, which can solve key problems in the development of bimetallic composite sucker rods, provide assistance, and provide guarantee for the subsequent application of sucker rods in oil production plants.

[0060] Based on the above reasons, the present invention can be widely promoted in the fields of corrosion-resistant products for oil production and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0062] Figure 1 Schematic diagram of ears produced by uncoordinated deformation rolling in bimetallic rolling.

[0063] Figure 2 Figure 2 is the stress-strain curve of alloy steel and stainless steel, where (a) is the stress-strain curve of alloy steel and (b) is the stress-strain curve of stainless steel.

[0064] Figure 3 It is a process flow chart of the present invention.

[0065] Figure 4 This is the metallographic detection image of the present invention. DETAILED DESCRIPTION

[0066] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments 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.

[0067] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0068] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0069] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0070] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0071] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. 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 figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0072] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0073] The invention provides a bimetallic composite sucker rod steel wire rod, which consists of a core material arranged in the center and a cladding material coated on the outer surface of the core material, wherein the core material is made of 20CrMo and the cladding material is made of 06Cr18Ni11Nb stainless steel.

[0074] like Figure 3 As shown, the present invention also provides a method for producing bimetallic composite sucker rod steel wire rod, which belongs to the field of corrosion-resistant products for oil production, and relates to a production process method of a bimetallic composite material, which is mainly used for the preparation of bimetallic composite sucker rod steel wire rod. The present invention has the characteristics of strong operability, applicability to current production lines, good molding, and good composite. The product composite rolling process is relatively difficult, and problems such as steel sticking and ears often occur. The present invention mainly solves the problem of composite rolling, that is, how to roll out a composite product, which is currently the most difficult problem.

[0075] The main process route adopted by the present invention is: large round billet assembly-blank rolling-hot rolling forming-packaging.

[0076] The specific steps are as follows:

[0077] 1. Use the mature 20CrMo round billet as the core material (the 20CrMo used is low-cost, for example, it can reduce costs compared to 30CrMo), and 06Cr18Ni11Nb stainless steel pipe as the cladding material. Through the "vacuuming + welding" method, the vacuum degree of the billet assembly can be guaranteed, which is beneficial to the composite rolling effect and the quality of the composite billet, and assembled into φ232mm~φ382mm composite round billets. Ensure that the cross-sectional area ratio of the core and the cladding is controlled at (3.2-4.3):1, avoid the composite layer being too thin or too thick, and avoid the phenomenon of "skin cracking" of the finished product.

[0078] 2. Use the method of "vacuuming + welding sealing" to assemble the blank. The vacuum degree is controlled to be less than 5×10 -2 Pa is enough, and within this numerical range, the lower the value, the better the vacuum effect, the less residual air, and the better the composite effect. The welded bimetallic round billet is sent into the heating furnace and heated in the range of 1150℃~1240℃ (the purpose of heating is rolling. And the rolling composite effect is good in this temperature range, and the bimetal is deformed in a coordinated manner. After heating in this temperature range, the structure is austenite. During the rolling process, the grains will be elongated or broken, and the high-temperature heating and rolling of the bimetal will cause diffusion, which promotes the bimetal composite), heating time = coating thickness / 3 (h).

[0079] 3. The rolling temperature is controlled at 1150℃~1200℃ (i.e. the rolling temperature after heating and heat dissipation), and 9 to 13 passes of billet rolling are performed (according to the accumulation of the reduction in each pass, 9 to 13 passes are obtained, and this value is based on the previously set reduction combined with the actual situation), and the billet is rolled to 180mm×180mm / 160mm×160mm. The bimetallic composite billet is obtained by air cooling. In the rolling process, hole-free rolling + box-type hole rolling are adopted, and the last 6 passes are box-type hole rolling. The rolling of the billet changes from hole-free type to hole-containing type, which is conducive to rolling forming. Some hole type parameters are as follows:

[0080] Groove bottom width bk = B + (2 to 8);

[0081] Notch width Bk = Δh × β / 2 + B + (1 to 5);

[0082] The slope of the hole side wall is tanψ = [Δh×β / 2+(-7~3)] / (H-Δh);

[0083] Groove bottom fillet radius r1 = (0.1 ~ 0.3) B;

[0084] The radius of the notch corner r2 = (0.05-0.2) B;

[0085] Roll gap s = (0.02 ~ 0.05) D0;

[0086] Hole height h≤H-Δh;

[0087] Groove depth hp = (hs) / 2.

[0088] In the formula: B-incoming material width; H-incoming material height; Δh-pass reduction; β-width expansion coefficient; D0-nominal diameter of the roll.

[0089] Rolling is divided into 9-13 passes; to ensure that the billet bites smoothly, it is necessary to ensure that h / b<1.6, b is the width of the billet, h is the height of the billet, the first pass reduction and the second pass reduction are both controlled at 2-10%; the third pass reduction and the fourth pass reduction are 10-15% respectively; the fifth pass reduction and the sixth pass reduction are 15-22% respectively; the subsequent pass reduction is 10-25%; the last pass reduction is 5-15%. The purpose of this step is to ensure smooth biting, rolling and forming, and forming is the key to compounding.

[0090] 4. For the next step of rolling forming, the bimetallic composite square billet is sent to the heating furnace again for heating in the range of 1100℃~1180℃, the first heating is 780℃~840℃, the second heating is 1120℃~1220℃, the soaking section is 1100℃~1180℃, the heating time is 2~3h, and the rolling start temperature is controlled at 1080℃~1150℃ (i.e. the rolling start temperature after heating and heat dissipation).

[0091] 5. The heated bimetallic composite square billet is subjected to blank rolling (rolling forming). In the product rolling process, the first few rough rolling passes are the key to ensure the uniform deformation of the bimetallic material. In order to ensure the rolling quality of the bimetallic product, the rolling hole type and process need to be redesigned. The first four passes are designed to use box holes, and the elliptical-circular hole type system is used for the 5th pass and thereafter to obtain the finished product. The design formulas of some hole types are as follows:

[0092] Box hole design:

[0093] Groove bottom width b k =B+(5-15);

[0094] Slot width B k =Δh×β+B+(6~13);

[0095] The slope of the hole side wall is tanψ = [Δh×β+(-9~8)] / (H-Δh-s);

[0096] Groove bottom fillet radius r1 = (0.15 ~ 0.25) B;

[0097] The radius of the notch corner r2 = (0.12-0.15) B;

[0098] Roll gap s = (0.01 ~ 0.2) D0;

[0099] Hole height h = H-Δh;

[0100] Groove depth hp = (hs) / 2;

[0101] Groove bottom convexity f = (0.02 ~ 0.04) B.

[0102] In the formula: B-incoming material width; H-incoming material height; Δh-pass reduction; β-width expansion coefficient; D0-nominal diameter of the roll.

[0103] The formula used for elliptical hole design is as follows:

[0104] Ellipse radius R = [(hs) 2 +B k 2 ] / 4(hs);

[0105] The blunt side of the ellipse is m=s+1;

[0106] Groove width B k =(1.088~1.11)(A+β×Δh);

[0107] Slot fillet radius r = (0.08 ~ 0.12) B k ;

[0108] Roll gap s = (0.2 ~ 0.3) h.

[0109] In the formula: A is the side length of the incoming billet; h is the hole height; Δh is the reduction per pass; β is the width expansion coefficient.

[0110] The rough rolling process is designed as follows: to ensure smooth rolling bite, the first four passes require h / b≤1.5, the elongation coefficient is controlled at 1-1.3, the first pass reduction is slightly smaller, controlled at 20%-25%, the next three passes reduction are controlled at 30%-40%, and the fifth pass reduction is controlled at 15%-20%.

[0111] 6. After air cooling, the quenching + tempering heat treatment process is adopted (this post-treatment is to ensure that the coating is austenitic stainless steel), water quenching at 780℃~820℃, tempering at 490℃~550℃ for 0.5h, oil cooling to room temperature, and packaging for downstream processing ends.

[0112] 7. During use, the coil is uncoiled directly using an uncoiler, which reduces the number of ends, reduces the risk of corrosion, speeds up the project progress, and is convenient and quick to use.

[0113] The above rolling temperature is set to make the bimetals deform in a coordinated manner and make their stress-strain curves similar. The setting of the pass number and the amount of reduction is also to coordinate the deformation, reduce the sliding of the bimetals, and facilitate the composite.

[0114] The product of the invention has the excellent corrosion resistance of the original cladding layer and the mechanical properties of the core material. The method can be used to smoothly roll out a bimetallic composite pumping rod steel wire rod to solve the problem of steel sticking.

[0115] Data collection was performed on the coating thickness adjustment process of the bimetallic material, as shown in Table 1.

[0116] Table 1 Billet rolling reduction data

[0117]

[0118]

[0119] The implementation of bimetallic round billet to square billet is shown in Table 2.

[0120] Table 2 Billet rolling reduction data

[0121]

[0122]

[0123] The implementation of the heating process and the starting rolling temperature of the bimetallic composite square billet is shown in Table 3.

[0124] Table 3 Composite billet heating furnace

[0125]

[0126] The implementation of the rolling process for bimetallic composite sucker rod steel is shown in Table 4.

[0127] Table 4 Continuous rolling rough rolling reduction data

[0128]

[0129]

[0130] The composite sucker rod steel wire rod is subjected to subsequent heat treatment, and the implementation status is shown in Table 5.

[0131] Table 5 Heat treatment data

[0132]

[0133] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for producing a bimetallic composite sucker rod steel wire rod, characterized in that: The bimetallic composite sucker rod steel wire rod is composed of a core material arranged in the center and a cladding material coated on the outer surface of the core material, the core material is made of 20CrMo, and the cladding material is made of 06Cr18Ni11Nb stainless steel; The method for producing the bimetallic composite sucker rod steel wire rod comprises the following steps: S1. Billet assembly: Billets made of the first metal material are used as core materials, and stainless steel pipes made of the second metal material are used as cladding materials to form composite billets, i.e., bimetallic billets. S2, sending the bimetallic round billet welded in step S1 into a heating furnace for heating; S3, performing blanking and rolling on the bimetallic round billet heated in step S2 to obtain a bimetallic composite square billet; S4, sending the bimetallic composite billet obtained in step S3 into a heating furnace for heating; S5, performing blanking and rolling on the bimetallic composite square billet heated in step S4; S6, after the rolling in step S5 is completed, air cooling is performed, heat treatment is performed after air cooling, and oil cooling is performed to room temperature after heat treatment to obtain a bimetallic composite sucker rod steel wire rod, which is further packaged to provide a downstream processing end; In the step S2, the welded bimetallic round billet is heated in the range of 1150° C. to 1240° C., and the heating time is equal to the coating thickness / 3, and the unit is h; the first metal material is 20CrMo, and the second metal material is 06Cr18Ni11Nb stainless steel; In the step S3, the billet rolling temperature is controlled at 1150°C to 1200°C, and the billet is rolled for 9 to 13 passes to a 180mm×180mm / 160mm×160mm billet, and a bimetallic composite billet is obtained after air cooling; during the rolling process, holeless rolling and box-type hole rolling are adopted, wherein the last 6 passes adopt box-type hole rolling; to ensure that the billet is smoothly bitten into the billet, h / b<1.6 is ensured, b is the width of the billet, h is the height of the billet, the first pass reduction and the second pass reduction are both controlled at 2-10%; the third pass reduction and the fourth pass reduction are 10-15% respectively; the fifth pass reduction and the sixth pass reduction are 15-22% respectively; the subsequent pass reductions are all 10-25%; and the last pass reduction is 5-15%; In the step S4, the bimetallic composite square billet is sent into a heating furnace for heating in the range of 1100°C to 1180°C, including: first heating at 780°C to 840°C, second heating at 1120°C to 1220°C, a soaking section at 1100°C to 1180°C, a heating time of 2 to 3 hours, and the billet rolling temperature is controlled at 1080°C to 1150°C; In step S5, during the rolling process, the first four passes are all rolled using a box-type hole, and the fifth pass and thereafter use an elliptical-circular hole system to roll to obtain a finished product. The hole design formula is as follows: The box hole design uses the following formula: Groove bottom width b k =B+(5-15); Slot width B k =Δh×β+B+(6~13); The slope of the hole side wall is tanψ = [Δh×β+(-9~8)] / (H-Δh-s); Groove bottom fillet radius r1 = (0.15 ~ 0.25) B; The radius of the notch corner r2 = (0.12-0.15) B; Roll gap s = (0.01 ~ 0.2) D0; Hole height h = H-Δh; Groove depth hp = (hs) / 2; Groove bottom convexity f = (0.02 ~ 0.04) B; In the formula: B is the width of the incoming material; H is the height of the incoming material; Δh is the pass reduction; β is the width expansion coefficient; D0 is the nominal diameter of the roll; The elliptical hole design adopts the following formula: Ellipse radius R = [(hs) 2 +B k 2 ] / 4(hs); The blunt side of the ellipse is m=s+1; Groove width B k =(1.088~1.11)(A+β×Δh); Slot fillet radius r = (0.08 ~ 0.12) B k ; Roll gap s = (0.2 ~ 0.3) h; Where: A is the side length of the incoming billet; h is the hole height; Δh is the pass reduction; β is the width expansion coefficient; To ensure smooth rolling bite, the first four passes h / b ≤ 1.5, the elongation coefficient is controlled at 1-1.3, the first pass reduction is controlled at 20%-25%, the second to fourth passes reduction is controlled at 30%-40%, and the fifth pass reduction is controlled at 15%-20%.

2. The method for producing bimetallic composite sucker rod steel wire rod according to claim 1, characterized in that: In the step S1, the large round billet and the stainless steel pipe are assembled into a composite large round billet with a size of φ232 mm to φ382 mm by vacuuming and welding, and the cross-sectional area ratio of the core to the cladding is (3.2-4.3):1; when vacuuming, the vacuum degree is less than 5×10 -2 Pa.

3. The method for producing bimetallic composite sucker rod steel wire rod according to claim 1, characterized in that: In step S3, the hole parameters of the box hole rolling are as follows: Groove bottom width bk = B + (2 to 8); Notch width Bk = Δh × β / 2 + B + (1 to 5); The slope of the hole side wall is tanψ = [Δh×β / 2+(-7~3)] / (H-Δh); Groove bottom fillet radius r1 = (0.1 ~ 0.3) B; The radius of the notch corner r2 = (0.05-0.2) B; Roll gap s = (0.02 ~ 0.05) D0; Hole height h≤H-Δh; Groove depth hp = (hs) / 2; In the formula: B is the width of the incoming material; H is the height of the incoming material; Δh is the pass reduction; β is the width expansion coefficient; D0 is the nominal diameter of the roll.

4. The method for producing bimetallic composite sucker rod steel wire rod according to claim 1, characterized in that: In step S6, the heat treatment adopts a quenching and tempering heat treatment process, with water quenching at 780° C. to 820° C. and tempering at 490° C. to 550° C. for 0.5 h.

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