A heat treatment salt bath isothermal tempering device

Abstract

The utility model relates to the technical field of heat treatment isothermal tempering, concretely is a kind of heat treatment salt bath isothermal tempering device, including shell, outer insulating layer, salt bath system, guide salt subassembly, salt supplement pipeline, air cooling system, temperature measuring thermocouple, liquid level control system, basket and heating system;Shell is set on horizontal plane, and the head end of shell is provided with air inlet pipeline, and tail end is provided with air outlet pipeline;Outer insulating layer is set to the outer wall of shell;Salt bath system is provided with salt bath tank, and salt bath tank is set in shell, and stirring subassembly is set in salt bath tank. It is unique to utilize the special thermal physical property of molten salt medium, overcome the inherent defect of traditional tempering method, realize the tempering treatment under accurate, uniform, constant temperature, to obtain more optimal, more stable, more reliable metal material performance.

Description

Technical Field

[0001] This utility model relates to the technical field of isothermal tempering in heat treatment, specifically to a salt bath isothermal tempering device for heat treatment. Background Technology

[0002] In traditional air furnaces, oil furnaces, or nitrate furnaces (non-isothermal) tempering processes, a temperature gradient exists within the furnace chamber. Uneven heating of different parts of the workpiece, as well as between the surface and the core, leads to inconsistent tempering degrees, affecting the uniformity of the final hardness and properties.

[0003] Reaching the target temperature requires a certain heating time. During the heating process, tempering transformation begins, making it difficult to accurately control the actual holding time.

[0004] Some steels develop temper brittleness when slowly cooled within a specific temperature range. Traditional furnace cooling methods struggle to quickly avoid these dangerous zones.

[0005] For workpieces that have undergone isothermal quenching of bainitic material, or if a more uniform and stable tempered structure is desired, a precise and uniform isothermal transformation is required at a specific temperature.

[0006] The purpose of isothermal tempering after heat treatment quenching includes eliminating internal stress, adjusting mechanical properties, and stabilizing microstructure. Currently, the most commonly used tempering equipment is the air-fired electric furnace. The disadvantages of air-fired tempering furnaces are significant temperature overshoot, ineffective temperature control, and poor temperature uniformity. Therefore, a dedicated system for tempering after quenching was developed, using industrial salt as the medium in the isothermal tempering tank. Utility Model Content

[0007] In view of the deficiencies of the prior art, this utility model provides a heat treatment salt bath isothermal tempering device, which utilizes the unique thermophysical properties of the molten salt medium to overcome the inherent defects of traditional tempering methods, and realizes tempering treatment at a precise, uniform and constant temperature, thereby obtaining better, more stable and more reliable metallic material properties.

[0008] To achieve the above objectives, the present invention provides a heat treatment salt bath isothermal tempering device: comprising a shell, an outer insulation layer, a salt bath system, a salt guiding component, a salt replenishment pipe, an air cooling system, a temperature measuring thermocouple, a liquid level control system, a hanging basket, and a heating system; the shell is disposed on a horizontal plane, with an air inlet pipe at the front end and an air outlet pipe at the rear end; the outer insulation layer is disposed on the outer wall of the shell; the salt bath system includes a salt bath tank disposed inside the shell, and the salt bath... A stirring assembly is installed inside the tank; the stirring assembly is used to accelerate the circulation of the salt solution in the salt bath tank; the stirring assembly is connected to the outer insulation layer, and the stirring assembly extends into the guide tube; one end of the connector is connected to the guide tube, and the other end abuts against one end of the U-shaped channel steel of the guide layer; the other end of the U-shaped channel steel of the guide layer communicates with the operating position, and the operating position is located above the U-shaped channel steel of the guide layer; the salt guiding assembly passes through the outer insulation layer and the outer shell, and connects to the inside of the salt bath tank. The salt assembly is connected to the salt pump for pumping salt solution into or out of the salt bath tank; the salt replenishment pipe passes through the outer insulation layer and the outer shell, connecting to the inside of the salt bath tank; the air-cooling system is equipped with a snail fan and a bend, one end of the bend is connected to the snail fan, and the other end is connected to the air inlet pipe; a ventilation channel is formed between the salt bath tank and the inner wall of the outer shell, and a U-shaped channel steel air duct layer is provided between the bottom of the salt bath tank and the inner wall of the outer shell; the air-cooling system is used to cool the salt solution in the salt bath tank. The temperature-measuring thermocouple passes through the outer insulation layer and the outer shell, connecting to the salt bath tank, and is used to monitor the temperature of the salt solution in the salt bath tank; the liquid level control system passes through the outer insulation layer and the outer shell, connecting to the salt bath tank, and is used to monitor the liquid level in the salt bath tank; the workpiece is installed inside the basket and is hoisted into the operating position by a hoisting device, forming a sealed contact with the outer shell and the outer insulation layer; the heating system is equipped with a heater, one end of which is connected to a terminal block, and the other end extends into the bottom of the basket.

[0009] Furthermore, the stirring assembly is equipped with a stirring motor, the output end of which is connected to a power shaft. The power shaft is connected to a pulley via a belt, the pulley being located at one end of a drive shaft, and the other end of the drive shaft being connected to a fan blade. The stirring motor rotates the fan blade via the drive shaft, causing the salt solution in the guide tube to be stirred and circulated.

[0010] Furthermore, the stirring assembly is provided with a connecting seat, which is connected to the outer insulation layer.

[0011] Furthermore, the number of operating stations is at least three.

[0012] Furthermore, the snail-shaped fan is placed on a fan support, and the fan support is placed on a horizontal surface.

[0013] Furthermore, the suspended basket is equipped with a base frame and a hoisting column. One end of the hoisting column is connected to the base frame, and the other end is connected to the insulation cover. The insulation cover is equipped with a hoisting handle, which is used in conjunction with hoisting equipment. The insulation cover and the outer insulation layer form a sealed protection for the salt bath tank.

[0014] Furthermore, a protective cover is provided outside the heater.

[0015] Furthermore, a filter screen is installed on the salt replenishment pipe.

[0016] The method of using the aforementioned heat treatment salt bath isothermal tempering apparatus includes the following steps: S100. Transfer the workpiece and material tray to the basket, and use the hoisting equipment to place the basket into the operating position for a 180-230℃ salt bath. S200. When the level control system detects that the salt solution level is lower than the workpiece surface, solid liquid is added to the salt bath through the salt replenishment pipe to ensure that the salt solution level is higher than the workpiece surface. The freezing point of solid salt is 147℃. It is liquid above this temperature and solidifies below this temperature. S300. Turn on the stirring assembly to allow the salt solution in the salt bath to circulate through the guide tube, the U-shaped channel steel of the guide layer, the operating station, and the guide tube. S400. When the temperature of the brine in the salt bath is too low as detected by the thermocouple, turn on the heating system. S500 When the temperature of the salt solution in the salt bath is higher than the set value by the temperature measuring thermocouple, the air cooling system will be turned on to allow air to circulate through the air inlet pipe, ventilation pipe, U-shaped channel steel of the air duct layer, and air outlet pipe. After the S600 tempering time is completed, the basket is removed using hoisting equipment. Furthermore, in the event of a malfunction in the salt bath, the salt solution is extracted from the bath via a salt pump connected to the salt guiding assembly for repair.

[0017] The beneficial effects of this utility model are: (1) Extremely high heating rate and heat transfer efficiency: Molten salt has a large heat capacity and good thermal conductivity, which enables the workpiece to reach the bath temperature in a very short time, greatly shortening the residence time at non-target temperatures and solving the problem of non-uniform tempering during the heating process.

[0018] (2) Excellent temperature uniformity: The molten salt is heated by convection, and the temperature distribution in the bath is extremely uniform (usually controllable within ±3℃). All parts of the workpiece reach the target temperature almost simultaneously and remain constant, ensuring the uniformity and consistency of the tempering transformation.

[0019] (3) Precise temperature control: The temperature control system of the salt bath furnace is mature and can accurately set and maintain the target tempering temperature, realizing a true isothermal tempering process. Attached Figure Description

[0020] Figure 1 This is a front view of the present invention; Figure 2 This is a top view of the present invention; Figure 3 This is the left view of the present invention; Figure 4 This is the right view of the present invention; Figure 5 for Figure 1 A magnified view of part A; Figure 6 This is a schematic diagram of the salt bath system of this utility model; In the diagram: 100, outer casing; 110, air inlet duct; 120, air outlet duct. 200. External insulation layer 300. Salt bath system; 310. Salt bath tank; 320. Agitator assembly; 321. Agitator motor; 322. Power shaft; 323. Angle belt; 324. Angle belt pulley; 325. Drive shaft; 326. Fan blade; 330. U-shaped channel steel for guide layer; 340. Operating station; 350. Connecting seat; 360. Guide cylinder; 370. Connecting component. 400. Salt conduction assembly. 500. Salt replenishment pipeline. 600. Air-cooled system; 610. Snail fan; 620. Pipe bend; 630. U-shaped channel steel for air duct layer; 640. Fan bracket. 700. Temperature measuring thermocouple. 800. Suspended platform; 810. Base frame; 820. Lifting column; 830. Insulation cover; 840. Lifting handle. 900. Heating system; 910. Heater; 920. Terminal block; 930. Protective cover. 1000. Liquid level control system. Detailed Implementation

[0021] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0022] like Figure 1-6 As shown, an embodiment of the present invention provides a heat treatment salt bath isothermal tempering device, comprising a shell 100, an outer insulation layer 200, a salt bath system 300, a salt guiding component 400, a salt replenishment pipe 500, an air cooling system 600, a temperature measuring thermocouple 700, a liquid level control system 1000, a hanging basket 800, and a heating system 900. The shell 100 is disposed on a horizontal plane, with an air inlet pipe 110 at the head end and an air outlet pipe 120 at the tail end. The outer insulation layer 200 is disposed on the outer wall of the shell 100. The salt bath system 300 includes a salt bath tank 310, which is disposed inside the shell 100, and a stirring device is provided inside the salt bath tank 310. A stirring assembly 320 is used to accelerate the circulation of salt solution in the salt bath tank 310. The stirring assembly 320 is connected to the outer insulation layer 200 and extends into the guide tube 360. One end of the connector 370 is connected to the guide tube 360, and the other end abuts against one end of the U-shaped channel steel 330 of the guide layer. The other end of the U-shaped channel steel 330 of the guide layer is connected to the operating station 340, which is located above the U-shaped channel steel 330. A salt guiding assembly 400 passes through the outer insulation layer 200 and the outer shell 100, connecting to the salt bath tank 310. The salt guiding assembly 400 is connected to a salt pump for pumping salt out or into the salt bath tank 310. The salt solution; the salt replenishment pipe 500 passes through the outer insulation layer 200 and the outer shell 100, connecting to the inside of the salt bath tank 310; the air-cooling system 600 is equipped with a snail fan 610 and a bend 620, the bend 620 being made of stainless steel, the snail fan 610 providing air energy, automatically starting when the actual temperature of the isothermal tempering tank exceeds the set value deviation, reducing it to the set temperature; one end of the bend 620 is connected to the snail fan 610, and the other end is connected to the air inlet pipe 110; a ventilation channel is formed between the salt bath tank 310 and the inner wall of the outer shell 100, and a U-shaped channel steel 630 is installed between the bottom of the salt bath tank 310 and the inner wall of the outer shell 100, the air-cooling system 600 using The system is designed to cool the salt solution in the salt bath 310; a temperature-measuring thermocouple 700 passes through the outer insulation layer 200 and the outer shell 100, and is connected to the inside of the salt bath 310 to monitor the temperature of the salt solution in the salt bath 310; a liquid level control system 1000 passes through the outer insulation layer 200 and the outer shell 100, and is connected to the inside of the salt bath 310 to monitor the liquid level in the salt bath 310; a basket 800 contains a workpiece, which is hoisted into the operating position 340 by a hoisting device, forming a sealed contact with the outer shell 100 and the outer insulation layer 200; a heating system 900 is equipped with a heater 910, one end of which is connected to a terminal 920, and the other end extends into the bottom of the basket 800.

[0023] It should be noted that the salt guiding component 400 is normally fixed with screws using a cover plate. When the equipment malfunctions and needs maintenance, the liquid salt at 180-230℃ inside the equipment must be pumped to another container using a salt pump. At the ends of the air inlet pipe 110 and the air outlet pipe 120, the diameter of the end pipe is doubled to ensure that the air velocity is not affected. The air duct system is a sealed interlayer and is sealed and welded to the outer shell 100 and the salt bath tank 310. The liquid level detection system uses a proximity switch to detect high and low levels, and alarms are triggered when the levels are too high or too low.

[0024] In one embodiment, the stirring assembly 320 is equipped with a stirring motor 321. The output end of the stirring motor 321 is connected to a power shaft 322. The power shaft 322 is connected to a pulley 324 via a belt 323. The pulley 324 is located at one end of a transmission shaft 325, and the other end of the transmission shaft 325 is connected to a fan blade 326. The stirring motor 321 rotates the fan blade 326 via the transmission shaft 325, causing the salt solution in the guide tube 360 ​​to be stirred and circulated. This can evenly distribute the temperature in the isothermal tempering tank, allowing the workpiece to be heated uniformly.

[0025] In one embodiment, the stirring assembly 320 is provided with a connecting seat 350, which is connected to the outer insulation layer 200.

[0026] In one embodiment, there are at least three operating stations 340.

[0027] In one embodiment, the snail fan 610 is placed on the fan bracket 640, which is placed on a horizontal surface; the lower end is fixed to the horizontal ground, and its function is to support the fan.

[0028] In one embodiment, the suspended basket 800 is provided with a base frame 810 and a lifting column 820. One end of the lifting column 820 is connected to the base frame 810, and the other end is connected to the insulation cover 830. The insulation cover 830 is provided with a lifting handle 840, which is used in conjunction with lifting equipment. The insulation cover 830 and the outer insulation layer 200 form a sealed protection for the salt bath tank 310. The insulation cover 830 is tightly fitted to the tank body and relatively sealed, which reduces the heat loss caused by direct contact between industrial salt and air, thus saving energy.

[0029] In one embodiment, a protective cover 930 is provided outside the heater 910.

[0030] In one embodiment, a filter screen is provided on the salt replenishment pipe 500.

[0031] This application involves rapidly immersing the workpiece in and maintaining it at a specific tempering temperature of 180-230℃, allowing it to complete the expected microstructure transformation at this constant temperature. Because the temperature is constant and uniform throughout the process, the resulting tempered microstructure is more uniform, and the fluctuation range of hardness and mechanical properties is significantly reduced, resulting in good consistency. For steels prone to temper brittleness, after isothermal holding in a salt bath, the workpiece can be rapidly transferred to a cooling tank (usually water or oil) for quenching, quickly traversing the brittle temperature range and effectively suppressing the occurrence of temper brittleness. Uniform tempering helps to more fully eliminate quenching stress and stabilize the microstructure, reducing dimensional changes during subsequent use.

[0032] A method for using a heat treatment salt bath isothermal tempering apparatus includes the following steps: S100: Transfer the workpiece and material tray to the basket 800, and use the hoisting equipment to place the basket 800 into the operating position 340 for a 180-230℃ salt bath. S200. When the level control system 1000 monitors that the salt solution level is lower than the workpiece surface, the solid liquid is introduced into the salt bath tank 310 through the salt replenishment pipe 500 to ensure that the salt solution level is higher than the workpiece surface. The freezing point of solid salt is 147℃. It is liquid above this temperature and solidifies below this temperature. S300, turn on the stirring assembly 320 to allow the salt solution in the salt bath tank 310 to circulate through the guide tube 360, the guide layer U-shaped channel steel 330, the operating station 340, and the guide tube 360. S400 When the temperature measuring thermocouple 700 detects that the temperature of the salt solution in the salt bath 310 is too low, the heating system 900 will be turned on. S500 When the temperature measuring thermocouple 700 detects a deviation value of the salt solution temperature in the salt bath 310 that is higher than the set value, the air cooling system 600 is turned on to allow air to circulate through the air inlet pipe 110, ventilation pipe, air duct layer U-shaped channel steel 630, and air outlet pipe 120. After the S600 tempering time is completed, the basket 800 is removed using hoisting equipment.

[0033] Furthermore, when a malfunction occurs in the salt bath 310, the salt solution in the salt bath 310 is extracted through a salt pump connected to the salt guiding assembly 400 for repair.

[0034] It should be noted that this application pertains to the post-quenching process of the workpiece. The salt bath 310 contains industrial salt, and the temperature is generally set between 175-230℃ depending on the process. This application has three workstations. The base frame 810 and the workpiece are driven to the basket 800 by a motor, and a robotic arm places the basket 800 into the designated position. Tempering is then performed, and after the time is up, the robotic arm removes the workpiece, which is then driven to the corresponding position by a motor. The stirring motor 321 can be set to a corresponding speed to ensure the industrial salt flows and maintains a uniform temperature. Each workstation is equipped with a heater 910 and a cooling snail fan 610 for temperature control.

[0035] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to 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 utility model.

[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0037] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0038] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature. It should be noted that when an element is referred to as "fixed to" or "set on" another element, it can be directly on the other element or there may be an intermediate element present. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element present. The terms "vertical," "horizontal," "above," "below," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible embodiments.

Claims

1. A heat treatment salt bath isothermal tempering apparatus, characterized in that: The system includes an outer shell, positioned on a horizontal plane, with an air inlet duct at one end and an air outlet duct at the other; an outer insulation layer, disposed on the outer wall of the outer shell; and a salt bath system, comprising a salt bath tank disposed within the outer shell, containing a stirring assembly. The stirring assembly accelerates the circulation of the salt solution within the salt bath tank. The stirring assembly is connected to the outer insulation layer and extends into a guide tube. One end of a connector is connected to the guide tube, and the other end abuts against one end of a U-shaped channel steel in the guide layer. The other end of the U-shaped channel steel in the guide layer communicates with an operating station, which is located within the U-shaped channel steel in the guide layer. Above the channel steel; a salt guiding assembly, passing through the outer insulation layer and the outer shell, connecting to the salt bath tank; the salt guiding assembly is connected to a salt pump for pumping salt solution out or into the salt bath tank; a salt replenishment pipe, passing through the outer insulation layer and the outer shell, connecting to the salt bath tank; an air-cooling system, equipped with a snail fan and a bend, one end of the bend connected to the snail fan and the other end connected to the air inlet pipe; a ventilation channel is formed between the salt bath tank and the inner wall of the outer shell, and an air duct layer U is provided between the bottom of the salt bath tank and the inner wall of the outer shell. The system includes a channel steel section, an air-cooling system for cooling the salt solution in the salt bath, a thermocouple passing through the outer insulation layer and the outer shell to monitor the temperature of the salt solution, a level control system passing through the outer insulation layer and the outer shell to monitor the level of the solution, a basket containing the workpiece which is hoisted into the operating position by a hoisting device and forms a sealed contact with the outer shell and the outer insulation layer, and a heating system with a heater, one end of which is connected to a terminal and the other end of which extends into the bottom of the basket.

2. The isothermal tempering apparatus for salt bath heat treatment according to claim 1, characterized in that: The stirring assembly is equipped with a stirring motor, the output end of which is connected to a power shaft. The power shaft is connected to a pulley via a belt, and the pulley is located at one end of a drive shaft. The other end of the drive shaft is connected to a fan blade. The stirring motor rotates the fan blade via the drive shaft, thereby stirring and circulating the salt solution in the guide tube.

3. A heat treatment salt bath isothermal tempering apparatus according to claim 1 or 2, characterized in that: The stirring assembly is provided with a connecting seat, which is connected to the outer insulation layer.

4. The isothermal tempering apparatus for heat treatment salt bath according to claim 1, characterized in that: The number of operating stations is at least three.

5. The isothermal tempering apparatus for heat treatment salt bath according to claim 1, characterized in that: The snail-shaped fan is placed on a fan support, and the fan support is placed on a horizontal surface.

6. The isothermal tempering apparatus for heat treatment salt bath according to claim 1, characterized in that: The suspended basket is equipped with a base frame and a hoisting column. One end of the hoisting column is connected to the base frame, and the other end is connected to the insulation cover. The insulation cover is equipped with a hoisting handle, which is used in conjunction with hoisting equipment. The insulation cover and the outer insulation layer form a sealed protection for the salt bath tank.

7. The isothermal tempering apparatus for heat treatment salt bath according to claim 1, characterized in that: The heater is equipped with a protective cover.

8. The isothermal tempering apparatus for heat treatment salt bath according to claim 1, characterized in that: A filter screen is installed on the salt replenishment pipe.

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