Heat treatment process and heat treatment equipment for deep-hole drill rod

Abstract

The invention discloses a heat treatment process and heat treatment equipment for a deep-hole drill rod. The heat treatment process for the deep hole drill rod comprises the following steps: selecting high-speed tool steel, and manufacturing the high-speed tool steel into a pipe with a required specification; and the prototype drill rod is heated to a first preset temperature, then the prototype drill rod is naturally cooled in a gas environment to achieve quenching, first tempering and second tempering are achieved, and the deep hole drill rod is obtained. The whole drill rod is made of high-speed tool steel, the heat treatment step of carburizing can be omitted, and the deep hole drill rod has the structural characteristics of thin wall and slender structure, so that air-blast quenching can be directly performed after heating to the quenching temperature, quenching cooling liquid is not needed, and chemical reagents such as carburizing agents and quenching cooling liquid are not needed in the whole step; and compared with single tempering in the prior art, a secondary tempering process is carried out, and the mechanical property of the deep hole drill rod is further improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of deep hole drill rod processing, and particularly relates to a deep hole drill rod heat treatment process and a deep hole drill rod heat treatment equipment. BACKGROUND

[0002] The deep hole processing process is widely used in the manufacturing industry, and a deep hole drill rod needs to be used to realize deep hole processing, and the mechanical properties of the drill rod have high standards. Therefore, a series of heat treatments are performed on the prototype drill rod to improve the mechanical properties, but the heat treatment process in the related art is more serious in polluting the environment. SUMMARY

[0003] The present application aims to at least solve one of the technical problems in the prior art. To this end, the present application provides a deep hole drill rod heat treatment process, which can ensure the mechanical properties of the deep hole drill rod while reducing pollution to the environment.

[0004] The present application also provides a heat treatment equipment for implementing the above deep hole drill rod heat treatment process.

[0005] The deep hole drill rod heat treatment process according to the first aspect embodiment of the present application comprises the following steps. S1: selecting high-speed tool steel, manufacturing the high-speed tool steel into a pipe material of a required specification, processing the pipe material into a prototype drill rod before heat treatment, and vertically hanging the prototype drill rod and hanging a counterweight at the bottom end of the prototype drill rod for straightening. S2: heating the prototype drill rod to a first preset temperature, and then naturally cooling the prototype drill rod in a gas environment below the martensite start temperature corresponding to the high-speed tool steel to achieve quenching. S3: heating the prototype drill rod to a second preset temperature, and keeping warm for a first preset time, and then naturally cooling the prototype drill rod in a gas environment to achieve first tempering. S4: heating the prototype drill rod after the first tempering to a third preset temperature, and keeping warm for a second preset time, and then naturally cooling the prototype drill rod in a gas environment to achieve second tempering, to obtain the deep hole drill rod.

[0006] According to the deep hole drill rod heat treatment process of the embodiment of the present application, at least the following beneficial effects are achieved: the deep hole drill rod in the prior art is mostly made of carburizing steel, the hardness is improved by surface carburizing, and the internal strength and toughness are maintained to achieve the performance of external hardness and internal toughness, but carburizing agents such as kerosene and methanol are used in the carburizing process of the carburizing steel, which pollutes the environment, and a cooling liquid is also used in the quenching process to rapidly cool the workpiece to meet the requirement of mechanical properties, and the quenching cooling liquid also pollutes the environment to a certain extent. In the embodiment of the present application, the whole drill rod is made of high-speed tool steel, so that the carburizing heat treatment step can be omitted, and because the deep hole drill rod has the structural characteristics of thin wall and elongated, the drill rod can be directly air-cooled quenched after being heated to the quenching temperature, without the need for quenching cooling liquid, so that chemical reagents such as carburizing agents and quenching cooling liquids are not needed in the whole process, the pollution to the environment is reduced, and compared with the single tempering process in the prior art, the secondary tempering process is further performed, the mechanical properties of the deep hole drill rod are further improved, and the pollution to the environment is improved while the mechanical properties of the deep hole drill rod are ensured.

[0007] According to some embodiments of the present application, the effective thickness of the prototype drill rod is D, the first preset time is T1, and the second preset time is T2, T1=(a+b)D, T2=(a+b)D, a=20 min / mm, 10 min / mm≤b≤20 min / mm, and T2>T1.

[0008] According to some embodiments of the present application, in step S2, the gas for naturally cooling the prototype drill rod in the gas environment is nitrogen; in step S3, the gas for naturally cooling the prototype drill rod in the gas environment to achieve the first tempering is nitrogen; and in step S4, the gas for naturally cooling the prototype drill rod in the gas environment to achieve the second tempering is nitrogen.

[0009] According to some embodiments of the present application, the material of the high-speed tool steel is W18Cr4V.

[0010] According to some embodiments of the present application, 850℃≤the first preset temperature≤1280℃.

[0011] According to some embodiments of the present application, 550℃≤the second preset temperature≤650℃.

[0012] According to some embodiments of the present application, 650℃≤the third preset temperature≤800℃.

[0013] According to some embodiments of the present application, the third preset temperature is greater than the second preset temperature.

[0014] The heat treatment device according to the second aspect of the present application is used to implement the deep hole drill rod heat treatment process according to any one of the first aspect of the present application, and comprises a quenching furnace, a cooling furnace and a tempering furnace. The quenching furnace is used to perform the process of heating the prototype drill rod to a first preset temperature in step S2. The cooling furnace is used to perform the process of naturally cooling the prototype drill rod to below the martensite start temperature of the high-speed tool steel in a gas environment in step S2. The tempering furnace is used to perform steps S3 and S4.

[0015] The heat treatment device according to the embodiments of the present application has at least the following beneficial effects: by using high-speed tool steel to manufacture the whole drill rod, the heat treatment step of carburizing can be avoided, and since the deep hole drill rod has the structural characteristics of thin wall and elongated, after being heated to the quenching temperature, air cooling quenching can be directly performed, without quenching coolant, so that no chemical reagent such as carburizing agent and quenching coolant is needed in the whole process, the pollution to the environment is reduced, and compared with the single tempering process in the prior art, the secondary tempering process is further performed, the mechanical properties of the deep hole drill rod are further improved, the cooling furnace in the heat treatment device does not need to be configured with coolant, and the carburizing furnace and other devices are also avoided, so that the mechanical properties of the deep hole drill rod after heat treatment can be ensured, and the pollution to the environment is improved.

[0016] According to some embodiments of the present application, the heat treatment device further comprises a nitrogen making device, which is connected to the quenching furnace, the tempering furnace and the cooling furnace, and is used to provide nitrogen to the quenching furnace, the tempering furnace and the cooling furnace.

[0017] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0018] The present application will be further described below in conjunction with the drawings and embodiments, wherein: Figure 1 A step diagram of the deep hole drill rod heat treatment process in an embodiment of the present application; Figure 2 A structural schematic diagram of a prototype drill rod in multiple embodiments of the present application; Figure 3 A process curve diagram of the deep hole drill rod heat treatment process in an embodiment of the present application; Figure 4 A whole schematic diagram of the heat treatment device in an embodiment of the present application.

[0019] Reference signs: first drill rod 100, second drill rod 200, third drill rod 300, heat treatment device 400, quenching furnace 401, cooling furnace 402, tempering furnace 403, nitrogen making device 404. DETAILED DESCRIPTION

[0020] Embodiments of the present application are described in detail below with reference to the attached drawing figures, wherein the same or like component have the same or similar designations. The embodiments described below are presented by way of example only and are not intended to limit the present application as defined by the appended claims and their equivalents.

[0021] In the description of the present application, it is to be understood that the orientation description, such as upper, lower, front, back, left, right, and the like, or the orientation or positional relationship indicated by the orientation or position relationship shown in the drawings, is for the purpose of facilitating the description of the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0022] In the description of the present application, if the meaning of several is more than one, the meaning of multiple is more than two, greater than, less than, more than, and the like are understood as not including the number, above, below, and the like are understood as including the number. If it is described as first, second, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of technical features indicated.

[0023] In the description of the present application, unless otherwise explicitly limited, the words such as setting, installing, connecting, and the like should be broadly understood, and those skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.

[0024] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the exemplary description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0025] Reference Figure 1 and Figure 3According to the deep hole drill rod heat treatment process of the first aspect of the present application, the following steps are included. S1: Selecting high-speed tool steel, manufacturing the high-speed tool steel into a pipe material of a required specification, processing the pipe material into a prototype drill rod before heat treatment, and vertically hanging the prototype drill rod, and hanging a counterweight at the bottom end of the prototype drill rod for straightening. S2: Heating the prototype drill rod to a first preset temperature, and then naturally cooling the prototype drill rod in a gas environment to below the start of transformation temperature of the martensite corresponding to the high-speed tool steel to achieve quenching. S3: Heating the prototype drill rod to a second preset temperature, and keeping the temperature for a first preset time, and then naturally cooling the prototype drill rod in a gas environment to achieve first tempering. S4: Heating the prototype drill rod after the first tempering to a third preset temperature, and keeping the temperature for a second preset time, and then naturally cooling the prototype drill rod in a gas environment to achieve second tempering, to obtain a deep hole drill rod.

[0026] The deep hole drill rod in the prior art is mostly made of carburizing steel, which improves the hardness by carburizing the surface, and keeps the inside with good strength and toughness to achieve the performance of hard outside and tough inside. However, the carburizing process of the carburizing steel uses carburizing agents such as kerosene and methanol, which pollute the environment. In the quenching process, a cooling liquid is also used to quickly cool the workpiece to meet the mechanical performance requirements, and the quenching cooling liquid also pollutes the environment. The embodiment of the present application uses high-speed tool steel to manufacture the whole drill rod, which can eliminate the carburizing heat treatment step. Since the deep hole drill rod has the structural characteristics of thin wall and elongated, it can be directly air-cooled quenched after being heated to the quenching temperature, without the need for quenching cooling liquid. Therefore, the whole process does not need chemical reagents such as carburizing agents and quenching cooling liquids, reducing the pollution to the environment, and compared with the single tempering of the prior art, the present application further performs a second tempering process, further improving the mechanical properties of the deep hole drill rod, so that the deep hole drill rod heat treatment process of the present application can ensure the mechanical properties of the deep hole drill rod while improving the pollution to the environment.

[0027] It should be noted that the prototype drill rod mentioned above refers to a deep hole drill rod that has not been completely heat treated, which is equivalent to an embryo. Both essentially refer to the same workpiece.

[0028] It should be noted that the "martensite start temperature" in the S2 step is referred to as Ms temperature, which refers to the temperature at which the austenite starts to transform into martensite. Only when the temperature is lower than Ms, the austenite will start to transform into martensite, triggering the martensite phase change so as to obtain a higher hardness of the prototype drill pipe. Moreover, the quenching must be cooled quickly to avoid the prototype drill pipe staying at a higher temperature for too long during the cooling process, so that the austenite will have a diffusion phase change to form structures such as pearlite, sorbite, bainite and the like. The hardness of these structures is much lower than that of the martensite, which cannot meet the requirements of high hardness and high wear resistance of the deep hole drill pipe. Therefore, the temperature must be cooled quickly to pass through these regions and reach below Ms temperature to avoid the non-martensite phase change and ensure the formation of martensite. For this reason, the cooling process of quenching in the prior art usually uses a cooling liquid to shorten the cooling time. However, in the field of the deep hole drill pipe applied in the present application, the drill pipe has the characteristics of thin wall and elongated shape, so the air cooling in the environment of air or inert gas can meet the requirement of rapid cooling, and the cooling liquid is not needed, thereby reducing the pollution to the environment.

[0029] Reference Figure 2 and Figure 3 In some embodiments of the present application, the effective thickness of the prototype drill pipe is D, the first preset time is T1, the second preset time is T2, T1= (a+b)D, T2= (a+b)D, a=20min / mm, 10min / mm≤b≤20min / mm, and T2>T1. The first preset time is the first tempering holding time, and the second preset time is the second tempering holding time. For example, Figure 2As shown, the cross section of the prototype drill pipe is basically in the form of rectangle, circle and ring. When the prototype drill pipe is in the form of the rectangular cross section shown in the first drill pipe 100, the effective thickness D is the width of the rectangle. When the prototype drill pipe is in the form of the circular cross section shown in the second drill pipe 200, the effective thickness D is the diameter of the circle. When the prototype drill pipe is in the form of the ring cross section shown in the third drill pipe 300, the effective thickness D is equal to the diameter d1 of the large circle minus the diameter d2 of the small circle, i.e. D=(d1-d2). The prototype drill pipe is an elongated tubular metal part, and the tempering process thereof requires heating the whole pipe body to a set tempering temperature and keeping for a certain time, so as to homogenize the structure, release the stress and optimize the performance. Therefore, the effective thickness of the prototype drill pipe determines the time required for heat conduction from the surface to the internal center, and the effective thickness of the ring drill pipe needs to subtract the diameter of the internal hollow circle. If the holding time is insufficient, the internal part of the prototype drill pipe can not reach the target tempering temperature or the temperature is not uniform, resulting in incomplete structure transformation. The above formula is used to calculate the tempering holding time required by the prototype drill pipe, and b is an adjustable range value. For example, when the effective thickness is 3 mm, the minimum value of T1 and T2 is: (20 min / mm+10 min / mm)×3 mm=90 min, and the maximum value of T1 and T2 is: (20 min / mm+20 min / mm)×3 mm=120 min. Specifically, T1 and T2 can be any value in the range of 90 min, 95 min, 100 min, 105 min, 110 min, 115 min, 120 min and 90 min-120 min. Further, the holding time of the second tempering is greater than that of the first tempering, which can further relax the residual stress in the microstructure, make the structure more stable, and thus improve the size accuracy and long-term stability of the drill pipe. Moreover, the longer tempering holding time of the second time can further promote the dispersion and distribution of carbides, so that the prototype drill pipe has better toughness and stronger impact resistance while maintaining high strength.

[0030] In some embodiments of the present application, the gas in the step S2 of naturally cooling the prototype drill pipe in a gas environment is nitrogen; the gas in the step S3 of naturally cooling the prototype drill pipe in a gas environment to achieve the first tempering is nitrogen; and the gas in the step S4 of naturally cooling the prototype drill pipe in a gas environment to achieve the second tempering is nitrogen. Air contains oxygen, and although cooling in an air environment can further reduce the cost, when the prototype drill pipe is cooled in air at high temperature, the oxygen will react with the surface of the drill pipe to form various oxides, which affects the surface quality, size accuracy and subsequent processing or use of the workpiece. Nitrogen is an inert gas with stable chemical properties and is not easy to react with most metals and their oxides. The use of nitrogen can effectively isolate oxygen and avoid oxidation of the high-temperature workpiece during the cooling stage, improve the controllability of the cooling process, prevent oxidation and decarburization, reduce heat treatment defects and improve the quality of the workpiece.

[0031] It should be noted that nitrogen is not required in steps S2, S3 and S4, and some steps can be adjusted to air cooling according to cost or actual demand. Further, helium, argon and other inert gases can be used for cooling and protection.

[0032] It should be noted that in some embodiments of the present application, the cooling in the nitrogen environment can also be provided with an oxygen detection probe in the cooling furnace 402, so as to determine whether nitrogen needs to be supplemented by detecting the content of oxygen. Since nitrogen is essentially used to isolate the influence of oxygen on the prototype drill pipe, directly detecting the oxygen content is more direct and effective than simply controlling the nitrogen flow. By detecting the oxygen concentration in real time, the nitrogen supply is increased once the set threshold is exceeded, so as to rapidly reduce the oxygen concentration. The use of the oxygen detection probe can also be suitable for different process requirements, and only the set value of the oxygen concentration needs to be adjusted to adapt to the nitrogen protection requirements of different materials and different temperatures.

[0033] Further, in some embodiments of the present application, a controllable nitrogen release device can be provided in the cooling furnace 402, so as to more accurately control the cooling rate and uniformity by adjusting the flow, pressure, flow direction and other parameters of the nitrogen, thereby improving the stability and consistency of the workpiece quality during heat treatment and cooling.

[0034] In some embodiments of the present application, the material of the high-speed tool steel is W18Cr4V. W18Cr4V is a tungsten-based high-speed steel, which has high wear resistance and can resist severe friction during deep hole drilling, and can still maintain hardness at high temperature, is suitable for long time continuous drilling, avoids softening of the drill pipe caused by heating, and has high hardness and impact resistance after heat treatment into a deep hole drill pipe, and meets the use requirements of various complex working conditions.

[0035] In some embodiments of the present application, 850℃≤ the first preset temperature≤1280℃. The first preset temperature, i.e., the quenching heating temperature, can be specifically 850℃, 855℃, 900℃, 950℃, 980℃, 1000℃, 1080℃, 1120℃, 1180℃, 1200℃, 1240℃, 1250℃, 1260℃, 1270℃, 1280℃, or any temperature value in the range of 850℃-1280℃. The selection of the quenching temperature directly affects the hardness, toughness, wear resistance, and final use performance of the drill pipe. A suitable quenching temperature can ensure that the steel material obtains high hardness, good wear resistance, and sufficient high-temperature hardness, while avoiding excessive brittleness or uneven structure. When the first preset temperature is lower than 850℃, the quenching temperature is too low, the alloying elements and carbon are not fully dissolved, and poor wear resistance and insufficient high-temperature hardness are also generated. The heat generated during deep hole drilling easily causes the drill pipe to soften and fail, and the overall performance consistency is also low. When the first preset temperature is higher than 1280℃, the quenching heating temperature is too high, which easily generates coarse grain structure, increases the brittleness of the drill pipe, and reduces the toughness, and accidents such as fracture are easily caused. In addition, the excessively high temperature can directly damage the material structure, excessively dissolve the carbide, and easily cause the workpiece to deform or directly quench crack. Therefore, selecting a suitable temperature is beneficial to improving the internal performance of the prototype drill pipe.

[0036] In some embodiments of the present application, 550℃≤ the second preset temperature≤650℃. The second preset temperature, i.e., the heating and holding temperature of the first tempering, can be specifically 550℃, 560℃, 570℃, 580℃, 590℃, 600℃, 610℃, 620℃, 630℃, 640℃, 650℃, or any temperature value in the range of 550℃-650℃. A suitable tempering temperature can eliminate quenching stress, stabilize the structure, adjust the hardness and toughness, and finally obtain good comprehensive mechanical properties. When the second preset temperature is lower than 550℃, the tempering temperature is too low, the stress generated during quenching is not fully eliminated, and the toughness and wear resistance of the drill pipe cannot be well improved, and the comprehensive performance is not up to standard. When the second preset temperature is higher than 650℃, the tempering temperature is too high, the hardness and strength of the material will decrease, and the problem of impact toughness decrease is also easily caused. Therefore, selecting a suitable tempering temperature can obtain good comprehensive mechanical properties.

[0037] In some embodiments of the present application, 650℃≤ third preset temperature ≤ 800℃. The third preset temperature, i.e. the heating and holding temperature of the second tempering, can be specifically any temperature value in the range of 650℃, 660℃, 670℃, 680℃, 690℃, 700℃, 710℃, 720℃, 730℃, 740℃, 750℃, 780℃, 800℃ and 650℃-800℃. The second tempering can further eliminate residual stress, optimize the microstructure, improve the comprehensive performance of hardness and toughness, enhance the wear resistance and hot hardness, and improve the fatigue life and dimensional stability on the basis of the first tempering, and is particularly suitable for workpieces with high performance and reliability requirements. The adverse effects caused by too high or too low second tempering temperature and too large deviation from the first tempering temperature are similar, and will not be described here.

[0038] In some embodiments of the present application, the third preset temperature is greater than the second preset temperature. After the first tempering, the hardness of the material is relatively high, and only the part of the drill rod head has reached the requirement. However, the present application is to heat treat the entire high-speed tool steel drill rod to form a deep hole drill rod, so the heating temperature of the second tempering is increased at the same time, part of the tempered martensite is converted into sorbite, and part of the residual austenite is retained to reduce the hardness, so that the strength and toughness of the entire drill rod are improved by more than 70% on the basis of the existing process, and the good comprehensive mechanical properties of the gun drill rod are ensured.

[0039] Reference Figure 4 According to the heat treatment equipment 400 of the second aspect of the present application, the heat treatment equipment 400 is used to implement the deep hole drill rod heat treatment process of any one of the first aspect of the present application, and includes a quenching furnace 401, a cooling furnace 402 and a tempering furnace 403. The quenching furnace 401 is used to perform the process of heating the prototype drill rod to the first preset temperature in step S2. The cooling furnace 402 is used to perform the process of naturally cooling the prototype drill rod to below the martensite start temperature of the high-speed tool steel in a gas environment in step S2. The tempering furnace 403 is used to perform steps S3 and S4.

[0040] By using high-speed tool steel to manufacture the entire drill rod, the heat treatment step of carburizing can be eliminated, and since the deep hole drill rod has the structural characteristics of thin wall and elongated, it can be directly air-cooled after being heated to the quenching temperature, without the need for quenching coolant, so that the chemical reagents such as carburizing agent and quenching coolant are not needed in the overall process, reducing the pollution to the environment, and compared with the single tempering of the prior art, the second tempering process is also performed, further improving the mechanical properties of the deep hole drill rod. The cooling furnace 402 in the heat treatment equipment 400 does not need to be configured with a cooling liquid, and the carburizing furnace and other devices are also eliminated, so that the mechanical properties of the deep hole drill rod after heat treatment can be ensured while the pollution to the environment is improved.

[0041] Reference Figure 4In some embodiments of the present application, the heat treatment device 400 further comprises a nitrogen generator 404, which is connected to the quenching furnace 401, the tempering furnace 403 and the cooling furnace 402, and is used to provide nitrogen to the quenching furnace 401, the tempering furnace 403 and the cooling furnace 402. The nitrogen generator 404 is arranged and can provide nitrogen protection to the quenching furnace 401, the tempering furnace 403 and the cooling furnace 402 respectively, which improves the process quality of heat treatment in each furnace, reduces the influence of oxygen on the surface of the drill pipe during heat treatment, and has no environmental pollution, and in combination with the oxygen detection probe, the nitrogen content in each furnace can be adjusted in real time.

[0042] The following are some specific embodiments of the deep hole drill pipe heat treatment process of the present application.

[0043]

[0044] The deep hole drill pipe in Example One is a circular ring drill pipe with an outer diameter of 8mm, and the hardness before heat treatment is 25HRC and the tensile strength is 460Mpa. After quenching and twice tempering, the hardness is improved to 50~54HRC and the tensile strength is improved to 800~900Mpa.

[0045] The deep hole drill pipe in Example Two is also a circular ring drill pipe with an outer diameter of 20mm, and the hardness before heat treatment is 25HRC and the tensile strength is 460Mpa. After quenching and twice tempering, the hardness is also greatly improved, and the hardness is improved to 50~54HRC and the tensile strength is improved to 800~900Mpa.

[0046] The heat treatment process of the present application can greatly improve the performance of different sizes of prototype drill pipes.

[0047] The embodiments of the present application are described in detail above in combination with the drawings, but the present application is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the purpose of the present application. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

Claims

1. A heat treatment process for deep hole drill pipes, characterized in that, The process includes the following steps: S1: Select high-speed tool steel, make the high-speed tool steel into pipes of the required specifications, process the pipes into prototype drill rods before heat treatment, and hang the prototype drill rods vertically, with a counterweight attached to the bottom of the prototype drill rods for straightening. S2: Heat the prototype drill rod to a first preset temperature, and then allow the prototype drill rod to cool naturally in a gas environment to below the martensite transformation temperature corresponding to the high-speed tool steel to achieve quenching; S3: Heat the prototype drill rod to a second preset temperature and keep it at that temperature for a first preset time, then allow the prototype drill rod to cool naturally in a gas environment to achieve the first tempering. S4: After the first tempering, the prototype drill rod is heated to a third preset temperature and held at that temperature for a second preset time. Then, the prototype drill rod is allowed to cool naturally in a gas environment to achieve a second tempering, thus obtaining the deep hole drill rod.

2. The heat treatment process for deep hole drill pipe according to claim 1, characterized in that, The effective thickness of the prototype drill pipe is D, the first preset time is T1, the second preset time is T2, T1=(a+b)D, T2=(a+b)D, a=20min / mm, 10min / mm≤b≤20min / mm, T2>T1.

3. The heat treatment process for deep hole drill pipe according to claim 1, characterized in that, In step S2, the gas used for natural cooling of the prototype drill pipe in a gas environment is nitrogen; in step S3, the gas used for the first tempering of the prototype drill pipe in a gas environment is nitrogen; in step S4, the gas used for the second tempering of the prototype drill pipe in a gas environment is nitrogen.

4. The heat treatment process for deep hole drill pipe according to claim 1, characterized in that, The high-speed tool steel is made of W18Cr4V.

5. The heat treatment process for deep hole drill pipe according to claim 1, characterized in that, 850℃≤First preset temperature≤1280℃.

6. The heat treatment process for deep hole drill pipe according to claim 1, characterized in that, 550℃≤Second preset temperature≤650℃.

7. The heat treatment process for deep hole drill pipe according to claim 1, characterized in that, 650℃≤the third preset temperature≤800℃.

8. The heat treatment process for deep hole drill pipe according to claim 1, characterized in that, The third preset temperature is greater than the second preset temperature.

9. Heat treatment equipment, characterized in that, The process for implementing the deep hole drill pipe heat treatment process according to any one of claims 1 to 8 includes: A quenching furnace, which is used to perform the step S2 of heating the prototype drill rod to a first preset temperature; A cooling furnace is used to perform the step S2 process of naturally cooling the prototype drill pipe in a gaseous environment to below the martensite transformation temperature corresponding to the high-speed tool steel. A tempering furnace, used for steps S3 and S4.

10. The heat treatment equipment according to claim 9, characterized in that, The heat treatment equipment also includes a nitrogen generator connected to the quenching furnace, the tempering furnace, and the cooling furnace. The nitrogen generator is used to supply nitrogen to the quenching furnace, the tempering furnace, and the cooling furnace.

Images