High-strength trolley drill rod quenching process and isothermal quenching furnace thereof

Abstract

The invention relates to the field of trolley drill rod quenching, in particular to a high-strength trolley drill rod quenching process and an isothermal quenching furnace thereof.The high-strength trolley drill rod quenching process comprises the steps that a trolley drill rod is subjected to carburizing treatment and then cooled to the preset temperature, the preset time is maintained, and the trolley drill rod is cooled to the set temperature within the set time through flowing inert gas; and the trolley drill rod is controlled to move in the flowing inert gas. According to the isothermal quenching process of the trolley drill rod, a uniform granular bainite structure can be obtained on a trolley drill rod base body, first-grade retained austenite martensite and carbide structures are obtained on the carburized surface, the toughness and strength of the trolley drill rod are enhanced, the fatigue performance is improved, and the rock drilling service life can be prolonged by 30%-60%. The hardness uniformity of the trolley drill rod is improved, an automatic straightening machine does not need to be adopted for straightening the trolley drill rod, equipment investment is reduced, and cost is reduced. Heat energy in cooling water can be extracted through the heat energy pump, heat energy recovery in the trolley drill rod isothermal quenching process is fully utilized, and the purpose of saving energy is achieved.

Description

Technical Field

[0001] The present application relates to the field of trolley drill pipe quenching, and in particular to a high-strength trolley drill pipe quenching process and an isothermal quenching furnace thereof. Background Art

[0002] As an important mining and construction tool, the performance of trolley drill rods directly affects work efficiency and safety. With the development of industrial technology, the manufacturing process of trolley drill rods is also constantly improving. In the traditional production process of trolley drill rods, oil quenching or air cooling quenching methods are usually used. Although these methods are low-cost, they are easy to cause deformation and uneven hardness of trolley drill rods during the quenching process, which in turn affects their performance.

[0003] In recent years, in order to improve the quality and performance of trolley drill pipes, protective atmosphere austempering technology has gradually received attention. This technology can not only effectively control the deformation of trolley drill pipes by austempering in a controlled atmosphere, but also significantly improve their hardness and toughness, thereby extending their service life. Summary of the invention

[0004] In order to perform isothermal quenching in a controlled atmosphere, the present application provides a high-strength trolley drill pipe quenching process and an isothermal quenching furnace thereof.

[0005] In the first aspect, the present application provides a high-strength trolley drill pipe quenching process, which adopts the following technical solution: A high-strength trolley drill pipe quenching process, comprising: After carburizing, the drill pipe is cooled to a predetermined temperature and maintained for a predetermined time. The flow of inert gas is used to cool the drill pipe on the trolley to the set temperature within the set time.

[0006] By adopting the above technical scheme, the isothermal quenching process of the trolley drill pipe is completed, so that the trolley drill pipe matrix can obtain a uniform granular bainite structure, and the carburized surface obtains a level 1 residual austenite, martensite and carbide structure. The toughness and strength of the trolley drill pipe are enhanced, the fatigue performance is improved, and the rock drilling life can be increased by 30-60%.

[0007] The trolley drill pipe is not oxidized by air during the isothermal quenching process, so the surface of the trolley drill pipe is free of oxidation.

[0008] The trolley drill rod has good straightness and can be well controlled within 1.0 / 1000mm (the national standard stipulates 1.3 / 1000mm). There is no need to use an automatic straightening machine to straighten the trolley drill rod, which reduces equipment investment and reduces costs.

[0009] Preferably, the predetermined temperature is 820-880°C, and the predetermined time is 1H. The inert gas is nitrogen, the set time is 0.5H, and the set temperature is 320-380°C.

[0010] Preferably, it includes: The console truck moves the drill pipe in the flowing inert gas.

[0011] By adopting the above technical solution, each trolley drill rod is in uniform contact and heat exchange with the inert gas, so that the trolley drill rod is uniformly quenched. The hardness uniformity of the trolley drill rod is improved, and the tolerance of the base and surface hardness of the trolley drill rod is reduced from ±4HRC to within the range of ±1HRC.

[0012] In a second aspect, the present application provides an isothermal quenching furnace, which adopts the following technical solution: An isothermal quenching furnace comprises a furnace body, a nitrogen pipe, a finned tube and a fan. The furnace body is used for placing the trolley drill rod. The nitrogen pipe is used to fill the furnace with nitrogen. The fin tube extends into the furnace body, the interior of the fin tube is used for cooling liquid to flow, and the outer surface of the fin tube is used for nitrogen to contact. The fan is located in the furnace body, and is used to circulate the nitrogen in the furnace body.

[0013] By adopting the above technical solution, the trolley drill rod is placed into the furnace body to complete the isothermal quenching process.

[0014] Preferably, comprising a tray, The material tray is rotatably connected to the furnace body, and the material tray is used for placing the trolley drill rod.

[0015] By adopting the above technical solution, the material tray drives the trolley drill rod to move in the flowing inert gas.

[0016] Preferably, it comprises a planetary gear mechanism and a reciprocating screw, The ring gear of the planetary gear mechanism is fixedly connected to the furnace body. The reciprocating screw is coaxially connected to the center wheel of the planetary gear mechanism. The material tray is slidably connected to the planetary frame of the planetary gear mechanism, and the sliding direction is parallel to the reciprocating screw rod. A screw pair is formed between the reciprocating screw rod and the material tray.

[0017] By adopting the above technical solution, the material tray rotates and slides, so that the trolley drill rod and the inert gas are evenly contacted and heat exchanged.

[0018] Preferably, it comprises a furnace cover and a rotating shaft, The rotating shaft is rotatably connected to the furnace cover, and the rotating shaft is detachably connected to the central wheel of the planetary gear mechanism.

[0019] By adopting the above technical solution, it is convenient to take and put the trolley drill rod at the material tray, and it is convenient to put the material tray into the furnace body.

[0020] Preferably, the furnace body comprises a furnace shell and an air guide tube. The air guide cylinder is used for placing the trolley drill rod. The air guide tube is located in the furnace shell, and a ventilation layer is formed between the inner wall of the furnace shell and the outer wall of the air guide tube. The air guide tube and the ventilation layer are used for nitrogen circulation. The fin tube is located in the ventilation layer.

[0021] By adopting the above technical solution, nitrogen exchanges heat with the finned tube in the ventilation layer, and nitrogen exchanges heat with the trolley drill pipe in the air guide tube, which is conducive to stable heat exchange and realizes the isothermal quenching process.

[0022] In summary, the present application includes at least one of the following beneficial technical effects: 1. The isothermal quenching process of the trolley drill pipe enables the trolley drill pipe matrix to obtain a uniform granular bainite structure, and the carburized surface obtains a level 1 residual austenite, martensite and carbide structure. The toughness and strength of the trolley drill pipe are enhanced, the fatigue performance is improved, and the rock drilling life can be increased by 30-60%; 2. The trolley drill pipe is not oxidized by air during the isothermal quenching process, so the surface of the trolley drill pipe is free of oxidation; 3. The straightness of the trolley drill rod is good and can be well controlled within 1.0 / 1000mm (the national standard stipulates 1.3 / 1000mm). There is no need to use an automatic straightening machine to straighten the trolley drill rod, which reduces equipment investment and reduces costs; 4. The hardness uniformity of the trolley drill pipe is improved, and the tolerance of the base and surface hardness of the trolley drill pipe is reduced from ±4HRC to ±1HRC; 5. The heat energy in the cooling water can be extracted through a heat pump, and the heat energy recovery during the isothermal quenching process of the trolley drill pipe can be fully utilized to achieve the purpose of energy saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the overall structure of the isothermal quenching furnace.

[0024] Figure 2 This is a schematic diagram of the distribution of finned tubes.

[0025] Figure 3 It is a schematic diagram of the reciprocating screw, rotating frame and other components.

[0026] Explanation of the accompanying reference numerals: 1. furnace body; 11. furnace shell; 12. air guide tube; 2. furnace cover; 3. nitrogen pipe; 31. air inlet pipe; 32. ring pipe; 4. fin tube; 41. water pipe; 42. fin; 5. rotating shaft; 6. fan; 7. material tray; 8. planetary gear mechanism; 9. reciprocating screw; 01. rotating seat; 02. swivel; 03. support rod. DETAILED DESCRIPTION

[0027] The present application is further described in detail below in conjunction with the accompanying drawings.

[0028] Reference Figure 1 The embodiment of the present application discloses an isothermal quenching furnace, including a furnace body 1, a furnace cover 2, a nitrogen pipe 3, a fin tube 4, a rotating shaft 5 and a fan 6.

[0029] The furnace body 1 includes a furnace shell 11 and an air guide 12. The upper end of the furnace shell 11 is open, and the furnace shell 11 is provided with a water cooling layer, and the water cooling layer is used for cooling liquid to flow. The air guide 12 is used for the trolley drill rod to be placed. The air guide 12 is located in the furnace shell 11, and a ventilation layer is formed between the inner wall of the furnace shell 11 and the outer wall of the air guide 12.

[0030] The furnace cover 2 is used to seal the opening of the furnace shell 11 .

[0031] The nitrogen pipe 3 is used to fill the furnace body 1 with nitrogen. Specifically, the nitrogen pipe 3 includes an air inlet pipe 31 and an annular pipe 32. The air inlet pipe 31 extends from the bottom of the furnace shell 11 into the furnace shell 11. The annular pipe 32 is connected to the air inlet pipe 31 and is sleeved outside the air guide tube 12. The annular pipe 32 is provided with an air outlet. Nitrogen circulates in the air guide tube 12 and the ventilation layer.

[0032] The fin tube 4 extends into the furnace body 1, the fin tube 4 is used for the coolant to flow, and the outer surface of the fin tube 4 is used for the nitrogen to contact. Specifically: the fin tube 4 includes a water pipe 41 and a fin 42; the water pipe 41 extends from the outer wall of the furnace shell 11 into the furnace shell 11, and the water pipe 41 extends into the ventilation layer, the water pipe 41 is used for the coolant to flow; the fin 42 is connected to the outer wall of the water pipe 41.

[0033] Reference Figure 2 A plurality of fin tubes 4 are arranged at equal intervals along the circumferential direction of the furnace body 1 .

[0034] Reference Figure 1 The rotating shaft 5 is rotatably connected to the furnace cover 2, and the lower end of the rotating shaft 5 is used to extend into the furnace body 1. The fan 6 is connected to the rotating shaft 5, and the fan 6 is used to circulate the nitrogen in the furnace body 1.

[0035] The trolley drill pipe that has been carburized and cooled to a predetermined temperature of 820-880℃ and kept at a predetermined temperature for 1 hour is lifted out of the pit carburizing furnace and transferred to the isothermal water quenching furnace. The furnace cover 2 is closed, nitrogen is introduced, the motor drives the shaft 5 to rotate, the fan 6 works, and the nitrogen in the air guide 12 flows into the ventilation layer through the fan 6 to form a rapid cycle. The nitrogen in the air guide 12 absorbs the heat of the trolley drill pipe and heats up, and the nitrogen in the ventilation layer transfers the heat to the fin tube 4 (circulating coolant) to cool down.

[0036] When the temperature drops to the specified temperature of 320-380°C within the set time of 30 minutes, the control valve is automatically adjusted to control the speed of the fan 6, the flow rate and flow of water into the fin tube 4 and the furnace shell 11, so that the nitrogen temperature is stabilized at the set temperature of 320-380°C, and the trolley drill pipe is subjected to isothermal quenching treatment.

[0037] Reference Figure 1 and Figure 3 The austempering furnace further includes a material tray 7 , a planetary gear mechanism 8 and a reciprocating screw 9 .

[0038] The material tray 7 is used for placing the drill rod of the trolley.

[0039] The ring gear of the planetary gear mechanism 8 is fixedly connected to the furnace body 1 or the furnace cover 2. The reciprocating screw 9 is detachably coaxially connected to the center wheel of the planetary gear mechanism 8, and the center wheel is detachably connected to the rotating shaft 5, and the center wheel is used to be coaxially fixedly connected to the rotating shaft 5.

[0040] The material tray 7 is slidably connected to the planetary frame of the planetary gear mechanism 8, and the sliding direction is parallel to the reciprocating screw rod 9. A screw pair is formed between the reciprocating screw rod 9 and the material tray 7.

[0041] In this embodiment: a rotating seat 01 is provided in the furnace shell 11, and the rotating seat 01 is rotatably connected to the furnace shell 11. The rotating seat 01 is provided with an embedding groove for the lower end of the reciprocating screw rod 9 to be embedded; the reciprocating screw rod 9 can be lifted out of the furnace shell 11 together with the material tray 7; It should be noted that the lower part of the reciprocating screw rod 9 is a smooth rod, and the upper outer circumference of the reciprocating screw rod 9 has threads; The gear ring is fixedly connected to the furnace cover 2, the planet carrier is rotatably connected to the furnace cover 2, and the rotating shaft 5 passes through the center wheel and is used for detachable coaxial connection to the upper end of the reciprocating screw 9; for example, the end face of the rotating shaft 5 is provided with a spline groove, and the outer periphery of the upper end of the reciprocating screw 9 is provided with a matching external spline; it should be noted that nitrogen can still flow upward to the fan 6 through the gap of the planetary gear mechanism 8; A rotating frame is also rotatably connected in the furnace shell 11, and the rotating frame includes a rotating ring 02 and a support rod 03; the rotating ring 02 is rotatably connected to the furnace shell 11, and the support rod 03 is fixedly connected to the rotating ring 02; the support rod 03 is used to penetrate the material tray 7; The planet carrier is used to be detachably connected to the upper end of the support rod 03. The planet carrier and the support rod 03 may be a simple planet carrier with a circular hole, and the upper end of the support rod 03 is embedded in the circular hole.

[0042] The implementation principle of an isothermal quenching furnace in the embodiment of the present application is as follows: the trolley drill pipe that has been carburized and cooled to a predetermined temperature of 820-880°C and kept warm for a predetermined time of 1 hour is lifted out of the pit-type carburizing furnace, and transferred into the isothermal water quenching furnace, the furnace cover 2 is closed, nitrogen is introduced, the motor drives the rotating shaft 5 to rotate, the fan 6 works, and the nitrogen in the air guide 12 flows into the ventilation layer through the fan 6 to form a rapid circulation. The nitrogen in the air guide 12 absorbs the heat of the trolley drill pipe and heats up, and the nitrogen in the ventilation layer transfers the heat to the fin tube 4 (circulating coolant) and cools down.

[0043] When the temperature drops to the specified temperature of 320-380°C within the set time of 30 minutes, the control valve is automatically adjusted to control the speed of the fan 6, the flow rate and flow of water into the finned tube 4 and the furnace shell 11, so that the nitrogen temperature is stabilized at the set temperature of 320-380°C, and the trolley drill pipe is subjected to isothermal quenching treatment, so that the trolley drill pipe matrix can obtain a uniform granular bainite structure, and the carburized surface obtains a level 1 residual austenite martensite and carbide structure, the toughness and strength of the trolley drill pipe are enhanced, the fatigue performance is improved, and the rock drilling life can be increased by 30-60%.

[0044] The present application also discloses a high-strength trolley drill pipe quenching process, including: After carburizing, the drill pipe is cooled to a predetermined temperature and maintained for a predetermined time. Use flowing inert gas to cool the drill pipe to the set temperature within the set time. The console truck moves the drill pipe in the flowing inert gas.

[0045] The preset temperature is 820-880°C, the preset time is 1H, the inert gas is nitrogen, the set time is 0.5H, and the set temperature is 320-380°C.

[0046] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A high-strength trolley drill pipe quenching process, characterized in that: include: After carburizing, the drill pipe is cooled to a predetermined temperature and maintained for a predetermined time. The flow of inert gas is used to cool the drill pipe on the trolley to the set temperature within the set time.

2. The high-strength trolley drill pipe quenching process according to claim 1 is characterized in that: The predetermined temperature is 820-880°C, the predetermined time is 1H, The inert gas is nitrogen, the set time is 0.5H, and the set temperature is 320-380°C.

3. The high-strength trolley drill pipe quenching process according to claim 1 is characterized in that: include: The console truck moves the drill pipe in the flowing inert gas.

4. An isothermal quenching furnace, characterized in that: It comprises a furnace body (1), a nitrogen pipe (3), a finned tube (4) and a fan (6), The furnace body (1) is used for placing the trolley drill rod. The nitrogen pipe (3) is used to fill nitrogen into the furnace body (1). The finned tube (4) extends into the furnace body (1), the interior of the finned tube (4) is used for cooling liquid to flow, and the outer surface of the finned tube (4) is used for nitrogen to contact. The fan (6) is located inside the furnace body (1), and the fan (6) is used to circulate the nitrogen inside the furnace body (1).

5. The isothermal quenching furnace according to claim 4, characterized in that: Including a tray (7), The material tray (7) is rotatably connected to the furnace body (1), and the material tray (7) is used for placing the drilling rod of the trolley.

6. The isothermal quenching furnace according to claim 5, characterized in that: It includes a planetary gear mechanism (8) and a reciprocating screw (9), The ring gear of the planetary gear mechanism (8) is fixedly connected to the furnace body (1). The reciprocating screw (9) is coaxially connected to the center wheel of the planetary gear mechanism (8). The material tray (7) is slidably connected to the planetary frame of the planetary gear mechanism (8), and the sliding direction is parallel to the reciprocating screw rod (9). A screw pair is formed between the reciprocating screw rod (9) and the material tray (7).

7. The isothermal quenching furnace according to claim 6, characterized in that: It comprises a furnace cover (2) and a rotating shaft (5), The rotating shaft (5) is rotatably connected to the furnace cover (2), and the rotating shaft (5) is detachably connected to the reciprocating screw (9) or the center wheel of the planetary gear mechanism (8).

8. The isothermal quenching furnace according to claim 4, characterized in that: The furnace body (1) comprises a furnace shell (11) and an air guide tube (12). The air guide tube (12) is used for placing the trolley drill rod. The air guide tube (12) is located inside the furnace shell (11), and a ventilation layer is formed between the inner wall of the furnace shell (11) and the outer wall of the air guide tube (12). The inside of the air guide tube (12) and the ventilation layer are used for nitrogen to circulate. The finned tube (4) is located in the ventilation layer.

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