Heat treatment method for weld joint of super-thick-wall drill rod

Abstract

The invention relates to the technical field of petroleum drill rods, in particular to an ultra-thick-wall drill rod weld joint heat treatment method which comprises the steps that the outer side of a weld joint area of a pre-machined drill rod is heated through a medium-frequency heating device, the inner side of the weld joint area of the pre-machined drill rod is heated through an internal heating device, and a hot drill rod is obtained. And the outer side of the weld joint area of the hot drill rod is cooled through spraying equipment, the inner side of the weld joint area of the hot drill rod is cooled through an internal cooling device, and the cold drill rod is obtained. And the outer side of the weld joint area of the cold drill rod is heated through the medium-frequency heating device, the inner side of the weld joint area of the cold drill rod is heated through the internal heating device, and the tempered drill rod is obtained. And naturally cooling the tempered drill rod at normal temperature to obtain a finished drill rod. The welding seam heating uniformity is improved, the heating time is shortened, and the overburning phenomenon of the outer surface of the welding seam due to overlong heating time is effectively prevented.

Description

Technical Field

[0001] This application relates to the field of oil drill pipe technology, and more specifically, to a heat treatment method for weld seams of ultra-thick-walled drill pipes. Background Technology

[0002] Deep and ultra-deep oil and gas resources account for a significant proportion of my country's remaining oil and gas reserves and represent a strategic area for future development. With advancements in exploration technology, my country's drilling and completion depths have reached over 9,000 meters, but progressing to 10,000-meter deep wells remains challenging. To meet the demands of these deep wells, there is an urgent need to develop high-end drilling and completion equipment, particularly focusing on improving the performance of drill pipe, a critical component.

[0003] Drill pipe, as a crucial tool connecting surface equipment and the bottom-hole power system, plays a vital role in drilling deep wells at depths of tens of thousands of meters. However, due to the enormous tensile, internal and external pressures, torques, bending, and vibrations that drill pipes must withstand, their overall tensile and torsional resistance is increasingly insufficient, leading to frequent fatigue failures and becoming a major challenge in drilling deep wells at depths of tens of thousands of meters.

[0004] To meet the requirements of casing installation in ultra-deep wells, the overall tensile strength of the drill pipe needs to be increased to over 900t. To achieve this, the thickness of the weld area must reach 28-35mm to meet the overall tensile strength requirements. However, the commonly used medium-frequency coil heating method in the industry has several shortcomings. First, this method results in excessively long weld heating times, easily leading to overheating on the outer surface of the weld and affecting weld quality. Second, the heat-affected zone of the weld is prone to overlap with the joint diameter change location, creating a superposition of two danger zones and further reducing the overall safety of the drill pipe. Furthermore, due to the thick weld wall and long temperature conduction time, the quenching uniformity of the weld in both radial and circumferential directions is poor, resulting in excessive differences in the uniformity of the physicochemical properties of the weld in these two directions, failing to meet the requirements of the finished drill pipe.

[0005] Therefore, there is an urgent need for a new heat treatment method for the weld seams of ultra-thick-walled drill pipes to solve the above problems, improve the overall performance of the drill pipes, and meet the needs of ultra-deep well drilling operations. Summary of the Invention

[0006] This application provides a heat treatment method for weld seams of ultra-thick-walled drill pipes, aiming to solve the problems that excessive heating time in the weld seam area of ​​thicker drill pipes can easily lead to overheating of the outer surface and poor uniformity of weld quenching.

[0007] The first aspect of this application provides a method for heat treatment of weld seams in ultra-thick-walled drill pipes, comprising:

[0008] A hot drill rod is obtained by heating the outer side of the weld area of ​​the pre-processed drill rod using a medium-frequency heating device and heating the inner side of the weld area of ​​the pre-processed drill rod using an internal heating device.

[0009] A cold drill rod is obtained by cooling the outer side of the weld area of ​​the hot drill rod through a spraying device and cooling the inner side of the weld area of ​​the hot drill rod through an internal cooling device.

[0010] The spraying equipment is used to cool the outer side of the weld area of ​​the hot drill rod by spraying quenching liquid, and the internal cooling device is used to cool the inner side of the weld area of ​​the hot drill rod by spraying high-pressure water mist.

[0011] The cold drill rod is heated by the medium-frequency heating device to heat the outer side of the weld area, and by the internal heating device to heat the inner side of the weld area, to obtain a tempered drill rod.

[0012] The medium-frequency heating device is used to heat the outer side of the pre-processed drill rod and the outer side of the tempered drill rod, and the internal heating device is used to heat the inner side of the pre-processed drill rod and the inner side of the tempered drill rod.

[0013] The tempered drill rod is left to cool naturally at room temperature to obtain the finished drill rod.

[0014] Optionally, a hot drill rod is obtained by heating the weld area inside and outside the pre-processed drill rod using a medium-frequency heating device and an internal heating device, including:

[0015] During the first outer heating period, the medium frequency heating device is heated to the outer quenching temperature to heat the outer side of the weld area of ​​the pre-machined drill rod.

[0016] During the first inner heating period, the internal heating device is heated to the inner quenching temperature to heat the inner side of the weld area of ​​the pre-processed drill rod.

[0017] The medium-frequency heating device and the internal heating device heat simultaneously, so that the weld area of ​​the pre-processed drill rod is heated and heated by both the internal heating device and the medium-frequency heating device at the same time.

[0018] After the internal heating device is heated to the internal quenching temperature for the first internal heating period, the internal heating device is turned off.

[0019] After the medium-frequency heating device heats the outer quenching temperature to the outer temperature for the first outer heating time, the medium-frequency heating device maintains the outer quenching temperature for the first holding time.

[0020] After the temperature of the medium-frequency heating device is maintained for the first heat preservation time, the medium-frequency heating device is turned off to obtain the hot drill rod.

[0021] Optionally, the outer quenching temperature is 898°C to 902°C, the first outer heating time is 27s, and the first holding time is 100s.

[0022] The inner quenching temperature is 680°C to 720°C, and the first inner heating time is 60 seconds.

[0023] Optionally, the weld area of ​​the cold drill rod is heated inside and outside by the medium-frequency heating device and the internal heating device to obtain a tempered drill rod, including:

[0024] During the second outer heating period, the medium frequency heating device is heated to the outer tempering temperature to temper the outer side of the weld area of ​​the cold drill rod.

[0025] During the second inner heating period, the internal heating device is heated to the inner tempering temperature, and the inner side of the weld area of ​​the cold drill rod is tempered and heated.

[0026] The medium-frequency heating device and the internal heating device heat simultaneously, so that the weld area of ​​the cold drill rod is simultaneously tempered and heated by the internal heating device and the medium-frequency heating device.

[0027] After the internal heating device is heated to the internal tempering temperature for the second internal heating period, the internal heating device is turned off.

[0028] After the medium-frequency heating device heats the outer tempering temperature to the outer tempering temperature for the second outer heating time, the medium-frequency heating device maintains the outer tempering temperature for the second holding time.

[0029] After the temperature of the medium-frequency heating device is maintained for the second holding time, the medium-frequency heating device is turned off to obtain the tempered drill rod.

[0030] Optionally, the outer tempering temperature is 698°C to 702°C, the second outer heating time is 20s, and the second holding time is 200s;

[0031] The inner tempering temperature is 480°C to 520°C, and the second inner heating time is 50 seconds.

[0032] Optionally, the internal heating device includes an electric heating mechanism and an assembly rod, wherein the electric heating mechanism is located at one end of the assembly rod;

[0033] The assembly rod is used to send the electric heating mechanism into the weld seam inside the drill rod, and the electric heating mechanism is used to heat the weld seam inside the drill rod.

[0034] Optionally, a first centering device is provided on the outer side of the assembly rod;

[0035] The first centering device includes at least four first support rods and at least four first movable wheels. The first support rods are fixedly mounted on the assembly rod, and each first support rod has a first movable wheel at its end away from the assembly rod. Each first support rod is equidistantly distributed circumferentially on the outer side of the assembly rod.

[0036] The first support rod and the first movable wheel are used to support the assembly rod on the axis of the drill rod.

[0037] Optionally, the internal cooling device includes a cooling pipe, one end of which has multiple through holes;

[0038] The cooling pipe is used to deliver water mist to the inside of the drill rod, and the through hole is used to guide the water mist to the weld on the inside of the drill rod.

[0039] A second centering device is provided on the outside of the cooling pipe;

[0040] The second centering device includes at least four second support rods and at least four second moving wheels. The second support rods are fixedly mounted on the cooling pipe, and each second support rod has a second moving wheel at its end away from the cooling pipe. Each second support rod is equidistantly distributed circumferentially on the outer side of the assembly rod.

[0041] The second support rod and the second movable wheel are used to support the cooling pipe on the axis of the drill rod.

[0042] Optionally, the cooling pipe has multiple water channels inside its wall;

[0043] The water trough enters the cooling pipe from the end away from the through hole and forms a U-shaped loop inside the cooling pipe, exiting from the end away from the through hole.

[0044] The water trough is used to inject cooling water to cool the water mist in the cooling pipe.

[0045] Optionally, the inlet and outlet portions of the U-shaped water trough are superimposed along the diameter direction of the cooling pipe, and the inlet portion of the water trough is closer to the center of the cooling pipe. The inlet portion of the water trough is used to inject cooling water, and the outlet portion of the water trough is used to discharge cooling water.

[0046] Beneficial effects:

[0047] This application provides a heat treatment method for weld seams of ultra-thick-walled drill pipes. The method uses a medium-frequency heating device to heat the outer side of the weld seam and an internal heating device to heat the inner side of the weld seam, which improves the uniformity of weld seam heating and shortens the heating time, effectively preventing overheating of the outer surface of the weld seam due to excessive heating time.

[0048] Meanwhile, this internal heating method solves the problem of uneven temperature between the inner and outer surfaces of the weld caused by the skin effect, and avoids the dual risks of overheating of the outer surface of the weld and overlap between the heat-affected zone of the weld and the joint diameter change position caused by extending the heating time.

[0049] By combining external quenching fluid and internal high-pressure water mist for dual cooling during weld quenching, the quenching uniformity of the weld in both the radial and circumferential directions is significantly improved. This simultaneous internal and external cooling method ensures consistent hardenability on both the inner and outer surfaces of the weld, thereby reducing the difference in physical and chemical properties between the two directions and meeting the high performance requirements of the finished drill pipe. Attached Figure Description

[0050] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0051] Figure 1 This is a flowchart of a heat treatment method for weld seams of ultra-thick-walled drill pipes according to an embodiment of this application;

[0052] Figure 2 This is a schematic diagram of the weld area of ​​an ultra-thick-walled drill pipe according to an embodiment of the present application, illustrating a heat treatment method for the weld seam of such a drill pipe.

[0053] Figure 3 This is a schematic diagram of a medium-frequency heating device for heating the weld area of ​​an ultra-thick wall drill pipe, according to an embodiment of this application, in a heat treatment method for ultra-thick wall drill pipe welds.

[0054] Figure 4 This is a schematic diagram of the rotation of the weld area of ​​an ultra-thick wall drill pipe using a medium-frequency heating device in an embodiment of the heat treatment method for ultra-thick wall drill pipe welds proposed in this application.

[0055] Figure 5 This is a schematic diagram of the internal heating of the weld area of ​​an ultra-thick wall drill rod according to an embodiment of the present application for a heat treatment method of weld seam of ultra-thick wall drill rod;

[0056] Figure 6This is a schematic diagram of the cooling of the weld area of ​​an ultra-thick wall drill pipe according to an embodiment of the present application for a heat treatment method of weld seam of ultra-thick wall drill pipe;

[0057] Figure 7 This is a front view of the internal heating device of a heat treatment method for ultra-thick wall drill pipe welds according to an embodiment of this application;

[0058] Figure 8 This is a side view of the internal heating device of a heat treatment method for ultra-thick wall drill pipe welds according to an embodiment of this application;

[0059] Figure 9 This is a front view of the internal cooling device of a heat treatment method for ultra-thick wall drill pipe welds according to an embodiment of this application;

[0060] Figure 10 This is a side view of the internal cooling device of a heat treatment method for ultra-thick wall drill pipe welds according to an embodiment of this application;

[0061] Explanation of reference numerals in the attached drawings: medium frequency heating device 100, electric heating mechanism 101, assembly rod 102, cooling pipe 201, through hole 202, water channel 203, first support rod 301, first moving wheel 302, second support rod 401, second moving wheel 402, connecting sleeve 501, positioning ring 502. Detailed Implementation

[0062] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0063] like Figure 1 As shown, a heat treatment method for weld seams of ultra-thick-walled drill pipes is provided, the method comprising:

[0064] Step S11: The outer side of the weld area of ​​the pre-processed drill rod is heated by the medium frequency heating device 100, and the inner side of the weld area of ​​the pre-processed drill rod is heated by the internal heating device to obtain a hot drill rod.

[0065] like Figure 3 , Figure 4 and Figure 5 As shown, specifically, the internal heating device includes an electric heating mechanism 101 and an assembly rod 102, with the electric heating mechanism 101 located at one end of the assembly rod 102. The assembly rod 102 is used to insert the electric heating mechanism 101 into the weld seam inside the drill pipe, and the electric heating mechanism 101 is used to heat the weld seam inside the drill pipe.

[0066] When aligning the internal heating device with the inside of the weld area of ​​the pre-machined drill rod, the heating mechanism 101 is inserted into the pre-machined drill rod by the assembly rod 102, aligning the heating mechanism 101 with the inside of the weld area of ​​the pre-machined drill rod. The heating mechanism 101 is a structure that can be electrically heated, such as a heating wire.

[0067] like Figure 5 , Figure 7 and Figure 8 As shown, furthermore, the weld area of ​​the pre-processed drill rod is entirely annular to allow the heating mechanism 101 to heat the inner side of the weld area of ​​the pre-processed drill rod more evenly. A first centering device is provided on the outer side of the assembly rod 102. The first centering device includes at least four first support rods 301 and at least four first moving wheels 302. The first support rods 301 and first moving wheels 302 are arranged in a one-to-one correspondence, with the first support rods 301 fixedly mounted on the assembly rod 102, and each first support rod 301 having a first moving wheel 302 at its end away from the assembly rod 102. Each first support rod 301 is equidistantly distributed circumferentially on the outer side of the assembly rod 102. The one-to-one correspondence of the first support rods 301 and first moving wheels 302 is used to support the assembly rod 102 on the axis of the drill rod. The first movable wheel 302 directly contacts the inner wall of the pre-processed drill rod, and the first movable wheel 302 can roll. When the assembly rod 102 feeds the pre-processed drill rod into the heating mechanism 101, the rolling first movable wheel 302 reduces friction, making the feeding operation easier. At least four equidistantly distributed first support rods 301 and first movable wheels 302 provide support for the assembly rod 102 on all four sides. This ensures that the assembly rod 102 is blocked from approaching the inner wall of the drill rod from any direction, guaranteeing that the assembly rod 102 remains on the axis of the drill rod. Thus, when the heating mechanism 101 is used to heat the inner side of the weld area of ​​the pre-processed drill rod, uniform heating of the entire annular weld area can be ensured.

[0068] Specifically, the pre-processed drill rod requiring quenching is placed in the processing position, and then the heating element of the medium-frequency heating device 100 is aligned with the outer side of the weld area of ​​the pre-processed drill rod. The medium-frequency heating device 100 is a drill rod processing heating device, and is an existing technology device that heats the drill rod from its outer surface, which will not be described in detail here. After the medium-frequency heating device 100 is aligned with the outer side of the weld area of ​​the pre-processed drill rod, the internal heating device is aligned with the inner side of the weld area of ​​the pre-processed drill rod.

[0069] After aligning the intermediate frequency heating device 100 with the outer side of the weld area of ​​the pre-machined drill rod, and aligning the internal heating device with the inner side of the weld area of ​​the pre-machined drill rod, the intermediate frequency heating device 100 is heated to the outer quenching temperature during the first outer heating duration, thus heating the outer side of the weld area of ​​the pre-machined drill rod. Then, the internal heating device is heated to the inner quenching temperature during the first inner heating duration, thus heating the inner side of the weld area of ​​the pre-machined drill rod. Furthermore, the intermediate frequency heating device 100 and the internal heating device heat simultaneously, ensuring that both the inner and outer sides of the weld area of ​​the pre-machined drill rod are heated by both the internal heating device and the intermediate frequency heating device 100.

[0070] Specifically, in this embodiment, the outer quenching temperature is 898°C to 902°C, the first outer heating time is 27 seconds, and the first holding time is 100 seconds. The inner quenching temperature is 680°C to 720°C, and the first inner heating time is 60 seconds. That is, the medium-frequency heating device 100 is activated to heat from room temperature to the outer quenching temperature of 898°C to 902°C during the 27 seconds of the first outer heating time. Simultaneously with the activation of the medium-frequency heating device 100, the electric heating mechanism 101 of the inner heating device is activated, allowing the electric heating mechanism 101 to heat from room temperature to the inner quenching temperature of 680°C to 720°C during the 60 seconds of the first inner heating time. During this process, the outer side of the weld area of ​​the pre-machined drill rod is also affected by the medium-frequency heating device 100 and heats up from room temperature as well.

[0071] After the heating mechanism 101 heats the inner side from room temperature to the inner quenching temperature of 680°C to 720°C for a first inner heating period of 60 seconds, the internal heating device is turned off. During this process, the inner side of the weld area of ​​the pre-machined drill rod is heated from room temperature by the heating mechanism 101, rather than relying solely on the medium-frequency heating device 100 to heat the weld area from the outside in. This increases the heating rate of the inner side of the weld area and shortens the heating time compared to using only the medium-frequency heating device 100. This ensures that the temperature difference between the inner and outer sides is not too large when heating the weld area of ​​the pre-machined drill rod, avoiding uneven temperature distribution on the inner and outer surfaces of the weld due to the skin effect. It also prevents the outer surface from overheating due to excessively long heating time in the weld area.

[0072] After the intermediate frequency heating device 100 heats the outer quenching temperature to 898°C to 902°C for 27 seconds during the first outer heating period, it continues to maintain the temperature at 898°C to 902°C for another 100 seconds for the first holding period. This ensures that the weld area of ​​the pre-machined drill rod is continuously heated to 898°C to 902°C and maintained for a certain duration to achieve the quenching purpose.

[0073] After the temperature of the medium-frequency heating device 100 is maintained for 100 seconds for the first heat preservation period, the medium-frequency heating device 100 is turned off to obtain the hot drill rod that has been quenched and heated.

[0074] Step S21: Cool the outer side of the weld area of ​​the hot drill rod using a spraying device, and cool the inner side of the weld area of ​​the hot drill rod using an internal cooling device to obtain a cold drill rod.

[0075] like Figure 6 , Figure 9 and Figure 10 As shown, specifically, the spraying equipment is an existing device capable of spraying liquid, used to spray quenching liquid onto the outer side of the weld area of ​​the hot drill rod for cooling, which will not be described in detail here. The internal cooling device includes a cooling pipe 201, one end of which has multiple through holes 202. The cooling pipe 201 is used to transport water mist to the inner side of the hot drill rod, and the through holes 202 are used to guide the water mist to spray onto the weld area on the inner side of the hot drill rod for cooling. That is, the spraying equipment is used to spray quenching liquid to cool the outer side of the weld area of ​​the hot drill rod, and the internal cooling device is used to spray high-pressure water mist to cool the inner side of the weld area of ​​the hot drill rod, so that the weld area of ​​the hot drill rod can be cooled from both inside and outside simultaneously, increasing the hardenability of the inner wall of the weld area. Moreover, the through holes 202 are inclined along the length of the cooling pipe 201. Multiple through holes 202 are equidistantly distributed circumferentially around the cooling pipe 201, and are arranged in multiple rows along the length of the cooling pipe 201. This ensures that water mist can be guided from each through hole 202 to spray out from the circumference of the cooling pipe 201, matching the annular weld seam area so that the inside of the annular weld seam area can be sprayed with water mist. The multiple rows of through holes 202 can further increase the coverage area of ​​the water mist spray. The water mist can cool the inside of the weld seam area of ​​the hot drill rod more quickly.

[0076] Furthermore, to allow the internal cooling device to cool the inside of the weld area of ​​the hot drill rod more evenly, a second centering device is provided on the outside of the cooling pipe 201.

[0077] The second alignment device includes at least four second support rods 401 and at least four second moving wheels 402, which are arranged in a one-to-one correspondence. The second support rods 401 are fixedly mounted on the cooling pipe 201, and each second support rod 401 has a second moving wheel 402 at its end away from the cooling pipe 201. The second support rods 401 are equidistantly distributed circumferentially on the outer side of the assembly rod 102. The second support rods 401 and the second moving wheels 402 are used to support the cooling pipe 201 onto the axis of the drill rod. The second moving wheels 402 are rollable and can directly contact the inner wall of the hot drill rod, reducing friction when the cooling pipe 201 is inserted into the hot drill rod. At least four second support rods 401 and at least four second moving wheels 402 are equidistantly distributed circumferentially on the outside of the cooling pipe 201, so that the cooling pipe 201 is supported by the second support rods 401 and the second moving wheels 402 on all four sides, ensuring that the cooling pipe 201 is on the axis of the hot drill rod, thereby ensuring uniform cooling.

[0078] Specifically, after obtaining the hot drill rod, the medium-frequency heating device 100 and the internal heating device are removed, and the hot drill rod is placed in a cooling processing position. The spraying equipment is aligned with the outer side of the weld area of ​​the hot drill rod, and the internal cooling device is pushed into the interior of the hot drill rod, aligning it with the inner side of the weld area, i.e., aligning the through-hole 202 on the cooling pipe 201 with the inner side of the weld area. Then, the spraying equipment is activated to spray quenching fluid onto the outer side of the weld area of ​​the hot drill rod, while simultaneously blowing high-pressure water mist into the cooling pipe 201. The quenching fluid sprayed by the spraying equipment cools both the inner and outer sides of the weld area, while the high-pressure water mist from the cooling pipe 201 sprays out from the through-hole 202 to cool the inner side of the weld area of ​​the hot drill rod. In this embodiment, the spraying time of the spraying equipment is 100 seconds, the flow rate is 350 L / min, and the high-pressure air-water mist in the cooling pipe 201 has a humidity of 70% RH, a temperature of 10 ± 2℃, and a flow rate of 5.3 m³ / min. 3 / min, blowing time 100s. After 100s of cooling by the spraying equipment and the internal cooling device, the cold drill rod is obtained.

[0079] like Figure 9As shown, furthermore, because the internal temperature of the hot drill rod is high, the cooling pipe 201 will also be heated when it enters the hot drill rod, causing the blown-in high-pressure water mist to also be heated. Therefore, multiple water channels 203 are formed inside the wall of the cooling pipe 201. The water channel 203 enters the wall of the cooling pipe 201 from the end away from the through hole 202, forming a U-shaped loop inside the wall of the cooling pipe 201 and exiting from the end away from the through hole 202. That is, the water channel 203 is essentially two straight channels, one for entry and one for exit, which are then connected at their ends in a U-shape. The water channel 203 is used to inject cooling water to cool the water mist in the cooling pipe 201 and prevent the water mist from being heated.

[0080] Furthermore, the insertion and exit portions of the U-shaped water trough 203 are superimposed along the diameter direction of the cooling pipe 201, with the insertion portion of the water trough 203 being closer to the center of the cooling pipe 201. The insertion portion of the water trough 203 is used to inject cooling water, and the exit portion is used to discharge cooling water. That is, the straight groove of the insertion portion, the straight groove of the exit portion, and the axis of the cooling pipe 201 are on the same plane, and the straight groove of the insertion portion is closer to the inner wall surface of the cooling pipe 201. In this way, the newly entering cooling water can better cool the water mist in the cooling pipe 201, and after the cooling water is heated, it is discharged from the straight groove of the exit portion, which is far away from the cooling pipe 201, reducing the impact on the water mist in the cooling pipe 201. In this embodiment, the cooling water temperature is controlled between 3°C and 7°C, and the total flow rate is 3.3 cubic meters per minute.

[0081] Step S31: The outer side of the weld area of ​​the cold drill rod is heated by the medium frequency heating device 100, and the inner side of the weld area of ​​the cold drill rod is heated by the internal heating device to obtain a tempered drill rod.

[0082] like Figure 5 , Figure 7 and Figure 8 As shown, specifically, after obtaining the cold drill rod, the cold drill rod is placed in the tempering area, and the heating component of the medium frequency heating device 100 is aligned with the outside of the weld area of ​​the cold drill rod, while the internal heating device is aligned with the inside of the weld area of ​​the cold drill rod.

[0083] Then, during the second outer heating period, the intermediate frequency heating device 100 is heated to the outer tempering temperature, tempering the outer side of the weld area of ​​the cold drill rod. During the second inner heating period, the internal heating device is heated to the inner tempering temperature, tempering the inner side of the weld area of ​​the cold drill rod. The intermediate frequency heating device 100 and the internal heating device heat simultaneously, so that the weld area of ​​the cold drill rod is simultaneously tempered and heated by both the internal heating device and the intermediate frequency heating device 100. After the intermediate frequency heating device 100 is heated to the outer tempering temperature during the second outer heating period, the intermediate frequency heating device 100 maintains the outer tempering temperature for the second holding period.

[0084] After the internal heating device is heated to the internal tempering temperature for the second internal heating period, the internal heating device is turned off. After the temperature of the medium-frequency heating device 100 is maintained for the second holding period, the medium-frequency heating device 100 is turned off, and the tempered drill rod is obtained.

[0085] Specifically, in this embodiment, the outer tempering temperature is 698°C to 702°C, the second outer heating time is 20s, and the second holding time is 200s. The inner tempering temperature is 480°C to 520°C, and the second inner heating time is 50s.

[0086] Step S41: Place the tempered drill rod at room temperature to cool naturally, and obtain the finished drill rod.

[0087] After obtaining the tempered drill rod, place it at room temperature to cool naturally until it reaches room temperature, thus completing the entire quenching process and obtaining the finished drill rod.

[0088] Furthermore, during the heating process, specifically during S11 quenching and S31 tempering, to ensure uniform heating of the intermediate frequency heating device 100 and the internal heating device, the drill rod and the intermediate frequency heating device 100 are rotated simultaneously, with opposite rotation directions and a rotation speed of 5° / s. After rotating 180°, they rotate in opposite directions. For example, if the intermediate frequency heating device 100 initially rotates clockwise, the drill rod rotates counterclockwise. After rotating 180°, the intermediate frequency heating device 100 begins to rotate counterclockwise, and the drill rod rotates clockwise. After rotating 180°, they reverse direction again, and this process repeats until the heating is complete.

[0089] like Figure 3As shown, furthermore, to prevent the drill rod from shifting during rotation, thus causing the intermediate frequency heating device 100 and the internal heating device to become misaligned with the weld area, a positioning device is provided. The positioning device includes a connecting sleeve 501 and a positioning ring 502. The connecting sleeve 501 is threadedly connected to the external threaded joint of the drill rod. The positioning ring 502 is located at the end of the connecting sleeve 501 away from the drill rod, and is used to fix or adjust the position of the drill rod. By limiting the position of the positioning ring 502 along the length of the drill rod during rotation, the displacement of the drill rod can be limited, thereby preventing displacement.

[0090] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0091] It should also be noted that, in this document, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations, nor should they be construed as indicating or implying relative importance. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements, but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. In the absence of further restrictions, an element defined by the phrase "includes a..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes the element.

[0092] The technical solutions provided in this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand this application, and the content of this specification should not be construed as a limitation of this application. Furthermore, for those skilled in the art, there will be different forms of changes in the specific implementation methods and application scope based on this application. It is neither necessary nor possible to exhaustively list all implementation methods here, and obvious changes or modifications derived therefrom are still within the protection scope of this application.

Claims

1. A heat treatment method for weld seams of ultra-thick-walled drill pipes, characterized in that, The method includes: A hot drill rod is obtained by heating the outer side of the weld area of ​​the pre-processed drill rod using a medium-frequency heating device and heating the inner side of the weld area of ​​the pre-processed drill rod using an internal heating device. A cold drill rod is obtained by cooling the outer side of the weld area of ​​the hot drill rod through a spraying device and cooling the inner side of the weld area of ​​the hot drill rod through an internal cooling device. The spraying equipment is used to cool the outer side of the weld area of ​​the hot drill rod by spraying quenching liquid, and the internal cooling device is used to cool the inner side of the weld area of ​​the hot drill rod by spraying high-pressure water mist. The cold drill rod is heated by the medium-frequency heating device to heat the outer side of the weld area, and by the internal heating device to heat the inner side of the weld area, to obtain a tempered drill rod. The medium-frequency heating device is used to heat the outer side of the pre-processed drill rod and the outer side of the tempered drill rod, and the internal heating device is used to heat the inner side of the pre-processed drill rod and the inner side of the tempered drill rod. The tempered drill rod is left to cool naturally at room temperature to obtain the finished drill rod.

2. The heat treatment method for weld seams of ultra-thick-walled drill pipes according to claim 1, characterized in that, A hot drill rod is obtained by heating the weld area inside and outside the pre-processed drill rod using a medium-frequency heating device and an internal heating device, including: During the first outer heating period, the medium frequency heating device is heated to the outer quenching temperature to heat the outer side of the weld area of ​​the pre-machined drill rod. During the first inner heating period, the internal heating device is heated to the inner quenching temperature to heat the inner side of the weld area of ​​the pre-processed drill rod. The medium-frequency heating device and the internal heating device heat simultaneously, so that the weld area of ​​the pre-processed drill rod is heated and heated by both the internal heating device and the medium-frequency heating device at the same time. After the internal heating device is heated to the internal quenching temperature for the first internal heating period, the internal heating device is turned off. After the medium-frequency heating device heats the outer quenching temperature to the outer temperature for the first outer heating time, the medium-frequency heating device maintains the outer quenching temperature for the first holding time. After the temperature of the medium-frequency heating device is maintained for the first heat preservation time, the medium-frequency heating device is turned off to obtain the hot drill rod.

3. The heat treatment method for weld seams of ultra-thick-walled drill pipes according to claim 2, characterized in that, The outer quenching temperature is 898℃ to 902℃, the first outer heating time is 27s, and the first holding time is 100s. The inner quenching temperature is 680°C to 720°C, and the first inner heating time is 60 seconds.

4. The heat treatment method for weld seams of ultra-thick-walled drill pipes according to claim 1, characterized in that, The cold drill rod is heated inside and outside the weld area by the medium-frequency heating device and the internal heating device to obtain a tempered drill rod, including: During the second outer heating period, the medium frequency heating device is heated to the outer tempering temperature to temper the outer side of the weld area of ​​the cold drill rod. During the second inner heating period, the internal heating device is heated to the inner tempering temperature, and the inner side of the weld area of ​​the cold drill rod is tempered and heated. The medium-frequency heating device and the internal heating device heat simultaneously, so that the weld area of ​​the cold drill rod is simultaneously tempered and heated by the internal heating device and the medium-frequency heating device. After the internal heating device is heated to the internal tempering temperature for the second internal heating period, the internal heating device is turned off. After the medium-frequency heating device heats the outer tempering temperature to the outer tempering temperature for the second outer heating time, the medium-frequency heating device maintains the outer tempering temperature for the second holding time. After the temperature of the medium-frequency heating device is maintained for the second holding time, the medium-frequency heating device is turned off to obtain the tempered drill rod.

5. The heat treatment method for weld seams of ultra-thick-walled drill pipes according to claim 4, characterized in that, The outer tempering temperature is 698°C to 702°C, the second outer heating time is 20s, and the second holding time is 200s. The inner tempering temperature is 480°C to 520°C, and the second inner heating time is 50 seconds.

6. The heat treatment method for weld seams of ultra-thick-walled drill pipes according to claim 1, characterized in that, The internal heating device includes an electric heating mechanism and an assembly rod, wherein the electric heating mechanism is located at one end of the assembly rod; The assembly rod is used to insert the heating mechanism into the weld seam inside the drill rod, and the heating mechanism is used to heat the weld seam inside the drill rod.

7. The heat treatment method for weld seams of ultra-thick-walled drill pipes according to claim 6, characterized in that, The assembly rod is provided with a first centering device on its outer side; The first centering device includes at least four first support rods and at least four first movable wheels. The first support rods are fixedly mounted on the assembly rod, and each first support rod has a first movable wheel at its end away from the assembly rod. Each first support rod is equidistantly distributed circumferentially on the outer side of the assembly rod. The first support rod and the first movable wheel are used to support the assembly rod on the axis of the drill rod.

8. The heat treatment method for weld seams of ultra-thick-walled drill pipes according to claim 1, characterized in that, The internal cooling device includes a cooling pipe, one end of which has multiple through holes; The cooling pipe is used to deliver water mist to the inside of the drill rod, and the through hole is used to guide the water mist to the weld on the inside of the drill rod. A second centering device is provided on the outside of the cooling pipe; The second centering device includes at least four second support rods and at least four second moving wheels. The second support rods are fixedly mounted on the cooling pipe, and each second support rod has a second moving wheel at its end away from the cooling pipe. Each second support rod is equidistantly distributed circumferentially on the outer side of the assembly rod. The second support rod and the second movable wheel are used to support the cooling pipe on the axis of the drill rod.

9. The heat treatment method for weld seams of ultra-thick-walled drill pipes according to claim 8, characterized in that, The cooling pipe has multiple water channels inside its wall; The water trough enters the cooling pipe from the end away from the through hole and forms a U-shaped loop inside the cooling pipe, exiting from the end away from the through hole. The water trough is used to inject cooling water to cool the water mist in the cooling pipe.

10. The heat treatment method for weld seams of ultra-thick-walled drill pipes according to claim 9, characterized in that, The U-shaped water trough has its inlet and outlet portions superimposed along the diameter of the cooling pipe, with the inlet portion closer to the center of the cooling pipe. The inlet portion is used to inject cooling water, and the outlet portion is used to discharge cooling water.

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