Heat treatment device for ductile iron castings

Abstract

The utility model provides a kind of nodular cast iron casting heat treatment device, belong to casting processing technical field, comprising: box and box door, the sidewall and top wall of box are provided with electric heating tube;The sidewall of box is equipped with turbine fan, and the fan blade of turbine fan is located inside the box;The top of one side of box is provided with exhaust port, exhaust port is connected with exhaust pipe by exhaust valve;The top of box is also provided with air inlet, air inlet is connected with the outlet of mixing bin by air inlet valve and pipeline, air inlet is provided with air inlet duct, and fan is installed in air inlet duct;The inlet of mixing bin is also connected with exhaust pipe by air guide pipe.The device strengthens the flow of hot air in the box by turbine fan, realizes the uniform distribution of heat in the box, improves the quality and effect of heat treatment;In the cooling process, the heat of hot air in the box and outside cold air is neutralized before being sent into the box, and the casting with qualified galvanizing quality is obtained, the rework is reduced, and the production cost is reduced.

Description

Technical Field

[0001] This utility model relates to the field of casting processing technology, and in particular to a heat treatment device for ductile iron castings. Background Technology

[0002] Galvanizing is a common metal surface treatment method, mainly used to form a dense, protective zinc layer on the metal surface. This zinc layer provides excellent corrosion protection for the steel, significantly extending the service life of castings and improving their corrosion resistance and durability. The galvanizing process typically includes casting surface treatment, molten zinc immersion, heat treatment, and finishing. It offers advantages such as corrosion resistance, uniformity, and cost-effectiveness, and is widely used in construction, automotive, power, shipbuilding, electronics, and machinery manufacturing, among other fields. The heat treatment step involves placing the zinc-plated casting in a furnace for heat treatment, causing the zinc layer to form an alloy layer with the casting surface. This significantly improves the microstructure and properties of the casting, enhancing its strength, hardness, toughness, and other mechanical properties, while also providing strong corrosion resistance, ensuring effective protection throughout the casting surface.

[0003] In the field of machinery manufacturing, the quality of galvanizing castings has a crucial impact on the performance and reliability of the entire mechanical product. Heat treatment, as a key step in the production process of galvanized castings, is also of paramount importance. In existing technologies, castings are statically heated during the heating process, and the internal heating equipment often relies on electric heating. This frequently leads to uneven heat or airflow distribution within the equipment, resulting in uneven heating of different parts of the casting during heat treatment. Some parts are heated sufficiently, while others are underheated, which reduces the quality and effectiveness of the heat treatment and may lead to problems such as poor coating adhesion, substandard corrosion resistance, and surface defects (blistering, peeling). Furthermore, during the cooling process after heat treatment, direct contact between the high-temperature casting and cold air can easily cause significant internal stress in the material, which can also negatively affect the casting quality. Therefore, these shortcomings need to be addressed to improve the quality and effectiveness of heat treatment after galvanizing, thereby obtaining castings with qualified galvanized quality, reducing rework, and lowering production costs. Utility Model Content

[0004] This utility model provides a heat treatment device for ductile iron castings to solve the problems in the prior art, such as uneven distribution of heat or hot air flow during heat treatment, uneven heating of castings, and easy influence of cold air on the cooling process, which result in poor heat treatment quality and effect.

[0005] This utility model provides a heat treatment device for ductile iron castings, including: a box body and a box door, the box door being installed on the box body via hinges; electric heating tubes for heating are provided on the side walls and top walls of the box body, and multiple sets of electric heating tubes are provided and connected in parallel; a first temperature sensor is fixed on the inner wall of the box body; a turbine fan is provided on the side wall of the box body away from the box door, and the blades of the turbine fan are located inside the box body; an exhaust port is provided on the top of one side of the box body, the exhaust port being connected to an exhaust pipe via an exhaust valve, and the exhaust pipe leading to a waste gas treatment unit; an air inlet is provided on the top of the box body away from the exhaust port, the air inlet being connected to the outlet of a mixing chamber via an air inlet valve and a pipe, an air inlet duct is provided at the inlet of the mixing chamber, and a fan is installed inside the air inlet duct; the inlet of the mixing chamber is also connected to the exhaust pipe via an air intake pipe, and a shut-off valve is provided on the air intake pipe.

[0006] In some technical solutions, spoilers are installed on both the upper and lower inner walls of the mixing chamber, and the spoilers on the upper and lower sides are arranged in an alternating manner.

[0007] In some technical solutions, an adsorption layer is installed at the outlet of the mixing chamber, and the adsorption layer is filled with activated carbon.

[0008] In some technical solutions, a second temperature sensor is installed on the pipe between the mixing chamber and the air inlet valve; a gas flow sensor is installed on the vent pipe.

[0009] In some technical solutions, a controller is installed on the outside of the box door. The controller is connected to the electric heating element, the first temperature sensor, the exhaust valve, the intake valve, the fan, the shut-off valve, the second temperature sensor, the gas flow sensor, and the motor of the turbine fan via wires.

[0010] In some technical solutions, the box is equipped with a support assembly, which includes a placement plate for placing ductile iron castings. The placement plate has multiple layers, and a connecting column is inserted between two adjacent layers of placement plates. Multiple sets of connecting columns are arranged side by side.

[0011] In some technical solutions, the placement plate is hollowed out; the bottom placement plate is placed inside the box by a support frame.

[0012] In some technical solutions, thermal insulation layers are provided between the side walls and top walls of the enclosure and the electric heating tubes; the thermal insulation layers are arranged from the outside to the inside as a nanoporous thermal insulation layer, a ceramic fiber thermal insulation layer, and a rock wool thermal insulation layer.

[0013] The heat treatment device for ductile iron castings provided by this utility model converts electrical energy into heat energy through an electric heating tube and transfers it to the castings through radiation. At the same time, the flow of hot air inside the chamber is enhanced by a turbine fan, which achieves uniform heat distribution within the chamber. This ensures that each casting is surrounded by uniform heat, providing an ideal heat treatment environment for the castings. As a result, the quality and effect of heat treatment are improved, avoiding problems such as poor heat treatment effect leading to poor coating adhesion, substandard corrosion resistance, and surface defects (blistering, peeling).

[0014] When the device is cooled after heat treatment, the heat of the hot air inside the chamber is neutralized with the heat of the cold air outside in the mixing chamber before being sent into the chamber. This avoids the high-temperature casting from directly contacting the cold air and generating internal stress. The cooling process is more stable. The turbine fan can also be used to increase the airflow velocity inside the chamber and accelerate the cooling speed, thereby obtaining castings with qualified galvanized quality, reducing rework and lowering production costs. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 A schematic diagram of the structure of the heat treatment device for ductile iron castings provided in one embodiment of this utility model; Figure 2 A schematic diagram of the heat treatment apparatus for ductile iron castings provided for another embodiment of this utility model; Figure 3 This is a schematic diagram of the structure of a support component provided in one embodiment of the present invention.

[0017] Explanation of reference numerals in the attached figures: 1. Box body, 2. Box door, 3. Electric heating element, 4. Turbine fan, 5. Mixing chamber, 6. Controller, 11. First temperature sensor, 12. Second temperature sensor, 13. Gas flow sensor, 51. Baffle plate, 52. Adsorption layer, 71. Exhaust valve, 72. Exhaust pipe, 73. Inlet valve, 74. Air inlet duct, 75. Fan, 76. Air duct, 77. Shut-off valve, 81. Placement plate, 82. Connecting column. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions in the embodiments of this utility model are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are also within the protection scope of this utility model.

[0019] like Figure 1 and Figure 2 This utility model provides a heat treatment device for ductile iron castings, comprising: a housing 1 and a door 2, the door 2 being hinged to the housing 1; electric heating tubes 3 for heating are provided on the side and top walls of the housing 1, with multiple sets of electric heating tubes 3 connected in parallel; a first temperature sensor 11 is fixed on the inner wall of the housing 1. The housing 1 and door 2 provide a closed space environment for the heat treatment process, protecting the internal temperature and the casting from external interference. The door 2 facilitates the opening and closing of the housing 1 by operators, mainly used for placing the casting to be treated into the housing 1 or removing the heat-treated casting from the housing 1. The electric heating tubes 3 convert electrical energy into heat energy, providing the required heat for the heat treatment process. The multiple sets of parallel-distributed electric heating tubes 3 ensure sufficient heat supply inside the housing 1 during use, meeting the temperature requirements for casting heat treatment. The specific arrangement of the electric heating tubes 3 can adopt commonly used arrangements in the art, and is not limited here.

[0020] like Figure 2 In a specific implementation scheme, a turbine fan 4 is installed on the side wall of the chamber 1 away from the door 2, and the blades of the turbine fan 4 are located inside the chamber 1. During the heat treatment process, the turbine fan 4 pushes and guides the flow of hot air inside the chamber 1, which can more quickly diffuse and circulate the hot air, making the distribution of hot air in the chamber 1 more uniform and dispersed. This achieves uniform heat distribution within the chamber 1, ensuring that each casting is surrounded by uniform heat, providing an ideal heat treatment environment for the casting, and thus improving the quality and effect of the heat treatment.

[0021] like Figure 1 and Figure 2In a specific implementation plan, an exhaust port is provided on the top side of the box 1. The exhaust port is connected to the exhaust pipe 72 through an exhaust valve 71, and the exhaust pipe 72 leads to the waste gas treatment unit. An air inlet is provided on the top of the box 1 away from the exhaust port. The air inlet is connected to the outlet of the mixing chamber 5 through an air inlet valve 73 and a pipe. An air inlet duct 74 is provided at the inlet of the mixing chamber 5, and a fan 75 is installed inside the air inlet duct 74. The inlet of the mixing chamber 5 is also connected to the exhaust pipe 72 through an air intake pipe 76, and a shut-off valve 77 is provided on the air intake pipe 76. During cooling after heat treatment, cold air from the outside is sequentially sent into the mixing chamber 5 and the housing 1 via the fan 75 and the air inlet duct 74. The hot air in the housing 1 is sent to the waste gas treatment unit through the exhaust valve 71 and the exhaust pipe 72. In order to avoid the high-temperature casting from directly contacting the cold air and generating internal stress, part of the hot air in the exhaust pipe 72 is introduced into the mixing chamber 5 through the air intake pipe 76 to mix and exchange heat with the cold air from the fan 75. The amount of hot air is controlled by the opening of the shut-off valve 77, so that the temperature of the air entering the housing 1 through the air inlet valve 73 is increased and adjustable, thereby allowing the casting to be cooled more smoothly and avoiding adverse results such as internal stress caused by sudden cooling.

[0022] This heat treatment device provides power to all electrical equipment via an external power supply. During operation, the ductile iron casting to be treated is placed into chamber 1, and chamber door 2 is closed. Power is supplied to the electric heating element 3, which converts electrical energy into heat energy, which is then transferred to the casting via radiation. Once the temperature inside chamber 1 reaches the specified temperature, it is maintained at that temperature for a certain period. A turbine fan 4 ensures a more uniform and dispersed distribution of heat within chamber 1, guaranteeing that each casting is uniformly surrounded by heat. Under high-temperature conditions, the zinc layer on the casting forms an alloy layer with the casting surface, enhancing the various properties of the galvanized casting. During cooling after heat treatment, the exhaust valve 71 and intake valve 73 are opened and the ventilation speed is adjusted. The cold air from the fan 75 mixes and exchanges heat with the hot air from the exhaust pipe 72 and the duct pipe 76 in the mixing chamber 5. Then the heated air is sent into the housing 1 to cool the casting, avoiding direct contact between the high-temperature casting and the cold air, which would cause large internal stress in the material and ensure the quality of the casting. The hot air in the housing 1 is sent to the exhaust gas treatment unit through the exhaust pipe 72. At this time, the rotating turbine fan 4 can also be used to increase the airflow speed in the housing 1 and accelerate the cooling speed.

[0023] The aforementioned heat treatment device enhances the flow of hot air within the chamber 1 via the turbine fan 4, achieving uniform heat distribution within the chamber 1. This ensures that each casting is uniformly surrounded by heat, providing an ideal heat treatment environment and improving the quality and effectiveness of the heat treatment. It avoids problems such as poor heat treatment results leading to poor coating adhesion, substandard corrosion resistance, and surface defects (blistering, peeling). In the subsequent cooling process, the heat from the hot air inside the chamber 1 is neutralized with the heat from the outside cold air in the mixing chamber 5 before being introduced into the chamber 1. This prevents the high-temperature casting from directly contacting the cold air and generating internal stress, resulting in a more stable cooling process. This leads to castings with qualified galvanized quality, reducing rework and lowering production costs.

[0024] like Figure 2 In the specific implementation plan, the upper and lower inner walls of the mixing chamber 5 are equipped with baffles 51, and the baffles 51 on the upper and lower sides are arranged alternately. The baffles 51 can make the hot and cold air mix more thoroughly and the heat neutralization effect is better, thereby increasing the temperature of the cold air and making it controllable and adjustable, so that the casting can be cooled more stably.

[0025] In a specific implementation scheme, an adsorption layer 52 is provided at the outlet of the mixing chamber 5, and the adsorption layer 52 is filled with activated carbon. The adsorption layer 52 can absorb impurities in the hot and cold air and moisture generated after heat exchange, so as to avoid adverse effects on the quality of the castings and improve the cleanliness and dryness of the air supplied to the chamber 1. Other materials with adsorption capacity can also be filled into the adsorption layer 52.

[0026] like Figure 2 In a specific implementation, a second temperature sensor 12 is installed on the pipe between the mixing chamber 5 and the air inlet valve 73; a gas flow sensor 13 is installed on the air intake pipe 76. The second temperature sensor 12 measures the temperature of the airflow after the hot and cold air are mixed, and the gas flow sensor 13 measures the flow rate of the hot air sent into the mixing chamber 5 by the air intake pipe 76. The flow rate of the hot air sent into the air intake pipe 76 is controlled by the temperature measured by the second temperature sensor 12, which also facilitates the control of the cooling rate and effect of the castings in the chamber 1.

[0027] In a specific implementation, a controller 6 is installed on the outside of the enclosure door 2. The controller 6 is connected via wires to the electric heating element 3, the first temperature sensor 11, the exhaust valve 71, the intake valve 73, the fan 75, the shut-off valve 77, the second temperature sensor 12, the gas flow sensor 13, and the motor of the turbine fan 4. The controller 6 and its control system program are common structures and methods in the art, and will not be described in detail here. The controller 6 can control the heating temperature of the electric heating element 3 inside the enclosure 1, control the temperature of the air supplied to the enclosure 1 for cooling, and control the start and stop of the turbine fan 4 to control the heating and cooling rates, etc. It can also significantly improve the automation level of the device and facilitate control and use.

[0028] like Figure 3 In a specific implementation scheme, the housing 1 is equipped with a support assembly, which includes placement plates 81 for placing ductile iron castings. The placement plates 81 are multi-layered, with connecting columns 82 inserted between adjacent layers of placement plates 81. Multiple sets of connecting columns 82 are arranged side-by-side. The castings are typically placed on the placement plates 81 for heat treatment. The number of placement plates 81 can be added or adjusted according to the quantity and specifications of the castings to adapt to different production needs, thereby improving the flexibility and versatility of the device. The upper and lower layers of placement plates 81 are supported by connecting columns 82 to enhance the stability between the placement plates 81.

[0029] In the specific implementation scheme, the placement plate 81 is hollowed out; the bottom placement plate 81 is placed inside the housing 1 by a support frame. The hollowed-out design of the placement plate 81 can reduce weight, and more importantly, it can ensure smooth heat flow between the placement plates 81, so that the placement plate 81 and all surfaces of the casting can be fully heated, reducing thermal stress differences and promoting more uniform heating of the casting. The support frame is a common structure in the art and is not specifically limited here. It is not shown in the attached figure. Casters can also be added to the bottom of the support frame to facilitate entry and exit from the housing 1.

[0030] In the specific implementation scheme, thermal insulation layers are provided between the side walls and top walls of the enclosure 1 and the electric heating tube 3. These thermal insulation layers, from the outside to the inside, are sequentially configured as a nanoporous thermal insulation layer, a ceramic fiber thermal insulation layer, and a rock wool thermal insulation layer (a standard configuration, not shown in the attached diagram). The thermal insulation layers are primarily used for thermal insulation of the enclosure 1. Each layer uses materials with extremely low thermal conductivity, effectively preventing heat transfer through radiation and convection. They possess excellent high-temperature resistance and insulation properties, enabling them to withstand high-temperature environments, protecting the enclosure 1, and ensuring the safety of the device.

[0031] In this utility model, the heat treatment device for ductile iron castings involves placing the ductile iron castings to be treated on a placement plate 81, with the number of layers on the placement plate 81 determined by the quantity and specifications of the castings. A movable support frame is used to move the placement plate 81 containing the ductile iron castings into the chamber 1, and the chamber door 2 is closed. A controller 6 controls the power switch to supply power to the electric heating tube 3, which converts electrical energy into heat energy and transfers it to the castings via radiation. Simultaneously, a turbine fan 4 is activated, driving and guiding the flow of hot air inside the chamber 1, enabling faster diffusion and circulation of the hot air, resulting in a more uniform and dispersed distribution of hot air within the chamber 1. Once the temperature inside the chamber 1 reaches the specified temperature, it is held at that temperature for a certain period. During heat treatment and holding, the heat insulation layer inside the chamber 1 provides high-temperature resistance and insulation, effectively isolating the chamber 1 from the external environment and ensuring the safety of the device.

[0032] After the heat preservation time is reached, during cooling, the exhaust valve 71 and intake valve 73 are opened and the ventilation speed is adjusted. The hot air in the chamber 1 is sent to the exhaust gas treatment unit through the exhaust valve 71 and exhaust pipe 72. The outside cold air is sent into the mixing chamber 5 through the fan 75 and air inlet duct 74. A portion of the hot air in the exhaust pipe 72 is introduced into the mixing chamber 5 through the air duct 76. The cold air from the fan 75 and the hot air from the air duct 76 mix and exchange heat in the mixing chamber 5. Then, the heated air is sent back into the chamber 1 to cool the casting. The flow rate of the hot air sent into the air duct 76 and the temperature of the mixed air are controlled by the temperature measured by the second temperature sensor 12 and the opening of the shut-off valve 77 to avoid the high-temperature casting directly contacting the cold air and causing large internal stress in the material. At the same time, the rotating turbine fan 4 can also be used to increase the airflow velocity in the chamber 1 and accelerate the cooling speed. Through the cooperation of various components, it is easy to control the cooling speed and effect of the casting in the chamber 1.

[0033] It should be noted that the detailed structure of some devices in this utility model is not described in detail, but belongs to the prior art known to those skilled in the art, and therefore will not be described again here. In addition, the parts of this device not described are the same as or can be implemented using existing technology.

[0034] It should be noted that pressure sensors, flow meters, or temperature sensors are installed on the conveying pipelines inside the system between different units, devices, or equipment. Various valves, such as pressure relief valves, pressure regulating valves, and safety valves, are also installed to regulate and stabilize the pressure of the entire system.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it; although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A heat treatment apparatus for ductile iron castings, characterized in that, include: The enclosure comprises a housing and a door, the door being hinged to the housing; electric heating elements for heating are installed on the side and top walls of the housing, with multiple sets of these elements connected in parallel; a first temperature sensor is fixed to the inner wall of the housing; a turbine fan is installed on the side wall of the housing away from the door, with the fan blades located inside the housing; an exhaust port is located on the top side of the housing, connected to an exhaust pipe via an exhaust valve, the exhaust pipe leading to a waste gas treatment unit; an air inlet is located on the top of the housing away from the exhaust port, connected to the outlet of the mixing chamber via an air inlet valve and a pipe, an air intake duct at the inlet of the mixing chamber containing a fan; the inlet of the mixing chamber is also connected to the exhaust pipe via an air intake pipe, the air intake pipe being equipped with a shut-off valve.

2. The heat treatment apparatus for ductile iron castings according to claim 1, characterized in that, The mixing chamber is equipped with baffles on both the upper and lower inner walls, and the baffles on the upper and lower sides are arranged in an alternating manner.

3. The heat treatment apparatus for ductile iron castings according to claim 1, characterized in that, An adsorption layer is provided at the outlet of the mixing chamber, and the adsorption layer is filled with activated carbon.

4. The heat treatment apparatus for ductile iron castings according to claim 1, characterized in that, A second temperature sensor is installed on the pipe between the mixing chamber and the air inlet valve; a gas flow sensor is installed on the air vent pipe.

5. The heat treatment apparatus for ductile iron castings according to claim 4, characterized in that, A controller is installed on the outside of the box door. The controller is connected to the electric heating tube, the first temperature sensor, the exhaust valve, the intake valve, the fan, the shut-off valve, the second temperature sensor, the gas flow sensor, and the motor of the turbine fan via wires.

6. The heat treatment apparatus for ductile iron castings according to claim 1, characterized in that, The box is equipped with a support assembly, which includes a placement plate for placing ductile iron castings. The placement plate has multiple layers, and a connecting column is inserted between two adjacent layers of the placement plate. Multiple sets of the connecting columns are arranged side by side.

7. The heat treatment apparatus for ductile iron castings according to claim 6, characterized in that, The placement plate is hollowed out; the bottom placement plate is placed inside the box by a support frame.

8. The heat treatment apparatus for ductile iron castings according to any one of claims 1-7, characterized in that, The side walls and top walls of the enclosure are all provided with heat insulation layers between them and the electric heating tubes; the heat insulation layers are arranged from the outside to the inside as a nanoporous heat insulation layer, a ceramic fiber heat insulation layer and a rock wool heat insulation layer.

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