Intelligent gas protection system for magnesium alloy heat treatment

Abstract

The application discloses a magnesium alloy heat treatment intelligent gas protection system, and belongs to the field of metal material heat treatment, which is composed of a heat treatment furnace, a gas source, a control system and a gas protection system. Carbon dioxide gas is used to protect the heat treatment furnace in the whole process, the carbon dioxide gas concentration in the furnace is monitored in real time, and dynamic air supplement is conducted according to the carbon dioxide gas concentration in the furnace. Through real-time monitoring of the atmosphere in the furnace and dynamic air supplement, closed-loop control is realized to maintain the constant carbon dioxide concentration in the heat treatment furnace, the gas protection effect is achieved, in addition, the heat treatment furnace does not need to be vacuumized before heat treatment, and the use of expensive inert gas is avoided, the heat treatment cost is low, rapid cooling can be realized after heat treatment, the precipitation of alloy elements is avoided, the precipitation strengthening effect is reduced, and the magnesium alloy product with high strength and high toughness is of great significance.

Description

Technical Field

[0001] This invention relates to the field of heat treatment of metallic materials, and in particular to an intelligent gas protection system for heat treatment of magnesium alloys. Background Technology

[0002] Magnesium and magnesium alloys exhibit high chemical reactivity at high temperatures, posing risks of oxidation and combustion. This is particularly true in the aerospace field, where complex, thin-walled magnesium alloy castings are predominant. These castings inevitably contain microburrs and residual magnesium powder after polishing, further increasing the risk of oxidation and combustion during solution heat treatment. Therefore, protective measures during the heat treatment of magnesium alloy castings are crucial. A traditional method involves placing pyrite (FeS2) in the furnace. At high temperatures, FeS2 reacts with O2 to form Fe2O3 and SO2 gas. The SO2 gas then reacts with Mg to form a MgS.MgO composite film, preventing further oxidation of the magnesium alloy casting and mitigating the risk of combustion.

[0003] However, in traditional existing technologies, the use of FeS2 has problems such as environmental pollution, corrosion, and impact on the health of on-site operators. Therefore, gas protection has gradually been adopted for the protection of magnesium alloy heat treatment. Usually, the heat treatment furnace is first evacuated, and then CO2, SO2 or Ar2 or other gases are introduced for protection. However, the main problems are as follows: (1) Inability to dynamically replenish gas. Existing technologies all fill the required gas at once after evacuation, and then shut down the gas supply system for heat treatment. During the heat treatment process, the atmosphere concentration in the furnace is in dynamic change and cannot be monitored in real time. Even if the local atmosphere concentration decreases, there is still a risk of combustion. (2) High cost. The use of vacuum heat treatment furnaces and inert gases increases the cost of heat treatment. (3) Inability to force cooling. Gas needs to be released before unloading. The furnace door can only be opened when the pressure inside the furnace is the same as the atmospheric pressure, which takes a long time. Cast magnesium alloys can be strengthened by heat treatment and have a high content of alloying elements. Since the solid solubility of alloying elements in the magnesium matrix decreases significantly with decreasing temperature, a large amount of alloying elements will precipitate during the cooling process, thereby reducing the subsequent age hardening effect and hindering the improvement of alloy strength and plasticity.

[0004] To address this, we propose an intelligent gas protection system for magnesium alloy heat treatment. This system can dynamically replenish gas based on the carbon dioxide concentration in the furnace under low-cost control, avoiding the combustion risk caused by the reduction of protective gas concentration during heat treatment and preventing the waste of CO2 gas. Summary of the Invention

[0005] 1. Technical problems to be solved

[0006] To address the problems existing in the prior art, the present invention aims to provide an intelligent gas protection system for magnesium alloy heat treatment. This system uses carbon dioxide gas to provide gas protection for the heat treatment furnace throughout the entire process. By monitoring the atmosphere inside the furnace in real time and dynamically replenishing the gas, closed-loop control is achieved to maintain a constant carbon dioxide concentration inside the heat treatment furnace.

[0007] 2. Technical Solution

[0008] To solve the above problems, the present invention adopts the following technical solution.

[0009] A smart gas protection system for magnesium alloy heat treatment includes a heat treatment furnace, a gas source, a control system, and a gas protection system. The gas source includes a CO2 gas storage tank and an SF6 gas storage tank.

[0010] The control system includes an electrical control system, a pneumatic control system, and an atmosphere sampling system;

[0011] The surface of the heat treatment furnace is equipped with a gas protection system, which includes an inlet pipe, a pressure gauge, a safety valve, and a gas detection system interface. The surface of the heat treatment furnace has 12 SF6 emergency gas inlet pipes in three directions (upper, middle, and lower). The surface of the heat treatment furnace is equipped with three safety valves in three directions (upper, middle, and lower). The safety valves are located on the surface of the pipes connected to the heat treatment furnace. The heat treatment furnace uses resistance heating. The gas detection system interface is connected to the inlet pipe, and the pressure gauge is installed inside the inlet pipe.

[0012] The output end of the CO2 gas storage tank is connected to a control system via a pipeline, and the output end of the SF6 gas storage tank is connected to a gas protection system via a pipeline. The output ends of the control system and the gas protection system are connected to a heat treatment furnace via pipelines.

[0013] Furthermore, the output end of the CO2 gas storage tank is connected to a gas drying device via a pipeline. The output end of the gas drying device is connected to a manual air intake and flow monitoring system and a pressure and flow monitoring system via pipelines. The output end of the pressure and flow monitoring system is connected to a furnace atmosphere acquisition device. The surface of the furnace atmosphere acquisition device is equipped with a furnace atmosphere monitoring and control system and an air intake valve group that are electrically connected to the furnace atmosphere acquisition device. The air intake valve group is electrically connected to the furnace atmosphere monitoring and control system. The output end of the air intake valve group is connected to the heat treatment furnace via a pipeline. The output end of the manual air intake and flow monitoring system is connected to one of the gas detection system interfaces on the surface of the heat treatment furnace via a pipeline.

[0014] Furthermore, the CO2 gas in the CO2 gas storage tank is used to control the atmosphere concentration in the heat treatment furnace in real time, and the SF6 gas in the SF6 gas storage tank is used for emergency handling.

[0015] Furthermore, the gas drying device consists of two sets of spaced-apart drying alarm units and a preheating device. The preheating device is installed on the surface of the pipe at the output end of the CO2 gas storage tank and is located in front of the two sets of drying alarm units. Each set of alarm drying units includes a molecular sieve, an electric micro-rod, a humidity sensor, and a drying alarm display. The molecular sieve is installed on the inner wall of the pipe at the output end of the CO2 gas storage tank. A drying alarm display is installed on the surface of the pipe at the output end of the CO2 gas storage tank, and the two sets of drying alarm displays are electrically connected. The bottom end of the drying alarm display is connected to an electric micro-rod that passes through the pipe at the output end of the CO2 gas storage tank. When the electric micro-rod is extended, it enters the interior of the molecular sieve. The tail end of the electric micro-rod is connected to a humidity sensor. A regulating valve that is electrically connected to the drying alarm display is installed between the preheating device and the molecular sieve at the front end.

[0016] Furthermore, the output end of the SF6 gas storage tank is connected to a manual entry and flow monitoring system and an emergency safety control system. The output ends of the manual entry and flow monitoring system and the emergency safety control system are connected to the heat treatment furnace through pipelines.

[0017] Furthermore, the electrical control system includes a host computer, a slave computer, a carbon dioxide content analyzer, and analog signal acquisition channels. The host computer uses a Siemens touch screen to set control parameters and process parameters, as well as monitor the working process in real time. The slave computer uses a Siemens PLC to collect data inside the furnace and control the switching of combination valves to control the atmosphere inside the furnace. The carbon dioxide content analyzer monitors the atmosphere inside the furnace in real time. All analog signal acquisition channels use shielded twisted-pair cables to prevent signal interference.

[0018] Furthermore, the pneumatic control system consists of four sets of imported SMC digital combination valves, which linearly adjust the carbon dioxide gas flow rate.

[0019] Furthermore, the pressure gauge is used for real-time monitoring of pressure and oxygen partial pressure, and the gas detection system interface is used for real-time monitoring and control of carbon dioxide gas content and gas flow rate in the heat treatment furnace.

[0020] Furthermore, the atmosphere sampling system is connected to a cooling device via pipeline, and the output of the cooling device is connected to a carbon dioxide content analyzer.

[0021] Furthermore, the operating procedures for the heat treatment gas protection system for this magnesium alloy casting are as follows:

[0022] S1. Clean the heat treatment furnace and put the magnesium alloy casting to be treated into the heat treatment furnace.

[0023] S2. Set the heat treatment temperature, heat treatment time, and target value for carbon dioxide concentration in the furnace chamber of the heat treatment furnace;

[0024] S3. Sequentially open the furnace atmosphere acquisition device, the air inlet valve group, the furnace atmosphere monitoring and control system, the pressure and flow monitoring system, the gas drying device, and the CO2 gas storage tank.

[0025] S4. Open the emergency safety control system and SF6 gas storage tank;

[0026] S5. Start the heat treatment furnace and start timing when the furnace temperature and CO2 gas concentration in the furnace reach the set value in S2.

[0027] S6. After the heat treatment time in S2 is completed, open the furnace door and take out the magnesium alloy casting.

[0028] S7. Shut down the gas source and the heat treatment furnace.

[0029] 3. Beneficial effects

[0030] Compared with the prior art, the advantages of this invention are:

[0031] (1) The present invention does not require vacuuming of the heat treatment furnace before heat treatment, and also avoids the use of expensive inert gases, resulting in lower heat treatment costs.

[0032] (2) The present invention adopts real-time monitoring of carbon dioxide gas concentration in the furnace and dynamically replenishes gas according to the carbon dioxide gas concentration in the furnace, instead of filling the furnace with excessive carbon dioxide gas at one time. This avoids the risk of combustion caused by the decrease in protective gas concentration during heat treatment, and also avoids the waste of CO2 gas caused by filling with excessive CO2 gas at one time.

[0033] (3) The present invention employs a gas preheating system before the gas enters the heat treatment furnace, thereby avoiding the entry of water vapor.

[0034] (4) The technical solution of the present invention can achieve rapid cooling after heat treatment, which avoids the large amount of alloying elements precipitating out and reducing the precipitation strengthening effect, which is of great significance for the preparation of high strength and high toughness magnesium alloy products.

[0035] (5) The present invention also uses sulfur hexafluoride gas for emergency treatment, which plays a "double insurance" role in the fire prevention effect.

[0036] (6) The present invention, through the gas drying device, can not only achieve a full and complete drying effect, but also can automatically adjust and alarm when the adsorption is saturated, so that the operator can take timely and targeted measures. Attached Figure Description

[0037] Figure 1 This is a system diagram of the present invention;

[0038] Figure 2This is a system workflow diagram of the present invention;

[0039] Figure 3 This is a cross-sectional view of the gas drying apparatus of the present invention;

[0040] Figure 4 This is an internal view of the gas drying apparatus of the present invention;

[0041] Figure 5 This is a state diagram of CO2 gas being completely dried in the preheating device of the gas drying apparatus of the present invention;

[0042] Figure 6 This is a state diagram of CO2 gas completely dried by the front-end molecular sieve in the gas drying device of the present invention;

[0043] Figure 7 The diagram shows the state of the regulating valve before and after activation when the front molecular sieve in the gas drying device of the present invention fails to completely dry the CO2 gas.

[0044] Figure 8 This is a surface condition diagram of ZM5 magnesium alloy before heat treatment;

[0045] Figure 9 This is a diagram showing the state of the ZM5 magnesium alloy surface after heat treatment with pyrite protection.

[0046] Figure 10 This is a diagram showing the surface state of the ZM5 magnesium alloy after heat treatment according to the present invention.

[0047] Figure 11 (a) and (c) are microstructure images of ZM5 magnesium alloy castings after heat treatment with pyrite, and (b) and (d) are microstructure images of ZM5 magnesium alloy castings after heat treatment using the technology of this invention.

[0048] Explanation of the labels in the diagram:

[0049] 1. Heat treatment furnace; 2. CO2 gas storage tank; 3. SF6 gas storage tank; 4. Gas drying device; 5. Manual air intake and flow monitoring system; 6. Pressure and flow monitoring system; 7. Furnace atmosphere monitoring and control system; 8. Furnace atmosphere acquisition device; 9. Air intake valve group; 10. Manual air intake and flow monitoring system; 11. Emergency safety control system; 12. Molecular sieve; 13. Electric micro-reduction rod; 14. Humidity detection sensor; 15. Drying alarm display. Detailed Implementation

[0050] This embodiment 1 will be described clearly and completely with reference to the accompanying drawings, making the purpose, technical solution, and beneficial effects of the embodiments of this disclosure clearer. Obviously, the described embodiments are only a part of the embodiments of this disclosure, not all of them. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0051] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the conventional meaning as understood by those skilled in the art. The terms "first," "second," and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "above," "below," "inner," and "outer" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0052] Example:

[0053] Please refer to the following: A smart gas protection system for magnesium alloy heat treatment. Figure 1 and Figure 11 It includes a heat treatment furnace 1, a gas source, a control system and a gas protection system. The gas source includes a CO2 gas storage tank 2 and an SF6 gas storage tank 3.

[0054] The control system includes an electrical control system, a pneumatic control system, and an atmosphere sampling system;

[0055] The surface of the heat treatment furnace 1 is equipped with a gas protection system, which includes an inlet pipe, a pressure gauge, a safety valve, and a gas detection system interface. The surface of the heat treatment furnace 1 has 12 SF6 emergency gas inlet pipes in three directions (upper, middle, and lower). The surface of the heat treatment furnace 1 is equipped with three safety valves in three directions (upper, middle, and lower). The safety valves are located on the surface of the pipes connected to the heat treatment furnace 1. The heat treatment furnace 1 uses resistance heating. The gas detection system interface is connected to the inlet pipe, and the pressure gauge is installed inside the inlet pipe.

[0056] The output end of CO2 gas storage tank 2 is connected to a control system via a pipeline, the output end of SF6 gas storage tank 3 is connected to a gas protection system via a pipeline, and the output ends of the control system and the gas protection system are connected to heat treatment furnace 1 via pipelines.

[0057] Specifically, the internal microstructure of magnesium alloy parts that have undergone heat treatment in this system and magnesium alloy parts that have undergone pyrite heat treatment is identical, therefore it will not interfere with the performance of magnesium alloys.

[0058] The output end of CO2 gas storage tank 2 is connected to gas drying device 4 via a pipeline. The output end of gas drying device 4 is connected to manual air intake and flow monitoring system 5 and pressure and flow monitoring system 6 via a pipeline. The output end of pressure and flow monitoring system 6 is connected to furnace atmosphere acquisition device 8. The surface of furnace atmosphere acquisition device 8 is equipped with furnace atmosphere monitoring and control system 7 and air intake valve group 9, which are electrically connected to furnace atmosphere acquisition device 8. Air intake valve group 9 is electrically connected to furnace atmosphere monitoring and control system 7. The output end of air intake valve group 9 is connected to heat treatment furnace 1 via a pipeline. The output end of manual air intake and flow monitoring system 5 is connected to one of the gas detection system interfaces on the surface of heat treatment furnace 1 via a pipeline.

[0059] Specifically, the furnace is monitored in real time for carbon dioxide concentration, and gas is dynamically replenished based on the concentration, rather than filling the furnace with excessive carbon dioxide gas at once. This avoids the risk of combustion caused by a decrease in the concentration of protective gas during heat treatment, and also avoids the waste of CO2 gas caused by filling the furnace with excessive CO2 gas at once.

[0060] The CO2 gas in CO2 gas storage tank 2 is used to control the atmosphere concentration in the heat treatment furnace 1 in real time, and the SF6 gas in SF6 gas storage tank 3 is used for emergency handling.

[0061] The CO2 gas in the CO2 gas storage tank 2 can enter the heat treatment furnace 1 through two paths after passing through the gas drying device 4. One path is that the CO2 gas passes through the pressure and flow monitoring system 6 and then enters the furnace atmosphere monitoring and control system 7, and finally enters the heat treatment furnace 1 through the inlet valve group 9. The other path is that the CO2 gas enters the heat treatment furnace 1 through the manual inlet and flow monitoring system 5.

[0062] Please see Figures 3-10 The gas drying device 4 consists of two sets of spaced-apart drying alarm units and a preheating device. The preheating device is installed on the surface of the pipe at the output end of the CO2 gas storage tank 2 and is located at the front end of the two sets of drying alarm units. Each set of alarm drying units includes a molecular sieve 12, an electric miniature rod 13, a humidity sensor 14, and a drying alarm display 15. The molecular sieve 12 is installed on the inner wall of the pipe at the output end of the CO2 gas storage tank 2. The drying alarm display 15 is installed on the surface of the pipe at the output end of the CO2 gas storage tank 2, and the two sets of drying alarm displays 15 are electrically connected. The bottom end of the drying alarm display 15 is connected to an electric miniature rod 13 that passes through the pipe at the output end of the CO2 gas storage tank 2. When the electric miniature rod 13 is extended, it enters the interior of the molecular sieve 12. The tail end of the electric miniature rod 13 is connected to the humidity sensor 14. A regulating valve that is electrically connected to the drying alarm display 15 is installed between the preheating device and the front molecular sieve 12.

[0063] Specifically, the CO2 gas is dried by a preheating device to prevent water vapor from entering and maintain its normal metallic luster. The drying is supplemented by a molecular sieve 12 at the front end to ensure that the CO2 gas is fully and completely dried.

[0064] While the molecular sieve 12 at the front end is continuously drying, the electric micro-rod 13 intermittently extends and retracts into the interior of the molecular sieve 12, thereby regularly detecting the humidity index inside the molecular sieve 12. When the molecular sieve 12 at the front end is not saturated with adsorption, the value displayed on the screen of the drying alarm display 15, which is electrically connected to the front end, is in a state of dynamic and continuous increase. At this time, the value displayed on the drying alarm display 15 at the rear end is a constant value of 0, indicating that the CO2 gas that finally enters the heat treatment furnace 1 is in a completely dry state.

[0065] When the molecular sieve 12 at the front end is in a state of adsorption saturation, the value displayed by the front-end drying alarm display 15 remains constant, while the value displayed by the rear-end drying alarm display 15 continuously increases. This activates the regulating valve electrically connected to it, reducing the flow rate of CO2 gas after passing through the preheating device. Consequently, the gas flow rate through the two sets of molecular sieves 12 decreases, promoting the absorption of water vapor by the rear-end molecular sieve 12. Simultaneously, the rear-end drying alarm display 15 alerts the operator to abnormal drying, prompting them to take targeted measures.

[0066] The output end of the SF6 gas storage tank 3 is connected to a manual entry and flow monitoring system 10 and an emergency safety control system 11. The output ends of the manual entry and flow monitoring system 10 and the emergency safety control system 11 are connected to the heat treatment furnace 1 through pipelines.

[0067] Specifically, the SF6 gas in the SF6 gas storage tank 3 enters the heat treatment furnace 1 through two paths. One path is through the manual entry and flow monitoring system 10, and the other path is through the emergency safety control system 11. The use of SF6 gas for emergency handling plays a supplementary protective role in terms of fire prevention.

[0068] The electrical control system includes a host computer, a slave computer, a carbon dioxide content analyzer, and analog signal acquisition channels. The host computer uses a Siemens touch screen to set control parameters and process parameters, as well as monitor the working process in real time. The slave computer uses a Siemens PLC to collect data inside the furnace and control the switching of combination valves to control the atmosphere inside the furnace. The carbon dioxide content analyzer monitors the atmosphere inside the furnace in real time. All analog signal acquisition channels use shielded twisted-pair cables to prevent signal interference.

[0069] The pneumatic control system consists of four sets of imported SMC digital combination valves, which linearly adjust the carbon dioxide gas flow rate.

[0070] The pressure gauge is used for real-time monitoring of pressure and oxygen partial pressure, and the gas detection system interface is used for real-time monitoring and control of carbon dioxide gas content and gas flow rate in heat treatment furnace 1.

[0071] The atmosphere sampling system is connected to a cooling device via pipeline, and the output of the cooling device is connected to a carbon dioxide content analyzer.

[0072] Specifically, the use of a cooling device can achieve rapid cooling after heat treatment, avoiding the precipitation of a large amount of alloying elements and reducing the precipitation strengthening effect, which is of great significance for the preparation of high-strength and high-toughness magnesium alloy products.

[0073] Please see Figure 2 The operating steps of the heat treatment gas protection system for this magnesium alloy casting are as follows:

[0074] S1. Clean the heat treatment furnace 1 and put the magnesium alloy casting to be treated into the heat treatment furnace 1.

[0075] S2. Set the heat treatment temperature, heat treatment time, and target value for carbon dioxide concentration in the furnace chamber of heat treatment furnace 1.

[0076] S3. Sequentially open the furnace atmosphere acquisition device 8, the air inlet valve group 9, the furnace atmosphere monitoring and control system 7, the pressure and flow monitoring system 6, the gas drying device 4, and the CO2 gas storage tank 2.

[0077] S4. Open the emergency safety control system 11 and SF6 gas storage tank 3;

[0078] S5. Start the heat treatment furnace 1. Start timing when the furnace temperature and CO2 gas concentration in the furnace chamber of the heat treatment furnace 1 reach the set value in S2.

[0079] S6. After the heat treatment time in S2 is completed, open the furnace door of heat treatment furnace 1 and take out the magnesium alloy casting.

[0080] S7. Shut down the gas source and heat treatment furnace 1.

[0081] Specifically, there is no need to vacuum the heat treatment furnace before heat treatment, and the use of expensive inert gases is avoided, resulting in lower heat treatment costs.

[0082] Example 1: Heat treatment of ZM5 magnesium alloy castings

[0083] S1. Clean the heat treatment furnace 1 and put the ZM5 magnesium alloy casting to be treated into the heat treatment furnace 1.

[0084] S2. Set the heat treatment temperature to 420℃, the heat treatment time to 24h, and the target value of carbon dioxide concentration in the furnace to 5%;

[0085] S3. Sequentially open the furnace atmosphere acquisition device 8, the air inlet valve group 9, the furnace atmosphere monitoring and control system 7, the pressure and flow monitoring device 6, the gas drying device 4, and the CO2 gas storage tank 2.

[0086] S4. Open the emergency safety control system 11 and SF6 gas storage tank 3;

[0087] S5. Start the heat treatment furnace 1. Start timing when the furnace temperature and CO2 gas concentration in the furnace chamber of the heat treatment furnace 1 reach the set value.

[0088] S6. After heat treatment is completed, open the furnace door of heat treatment furnace 1 and take out the magnesium alloy casting.

[0089] S7. Shut down the gas source and heat treatment furnace 1.

[0090] Example 2: Heat treatment of ZM6 magnesium alloy castings

[0091] S1. Clean the heat treatment furnace 1 and put the ZM6 magnesium alloy casting to be treated into the heat treatment furnace 1.

[0092] S2. Set the heat treatment temperature to 410℃, the heat treatment time to 24h, and the target value of carbon dioxide concentration in the furnace to 10%;

[0093] S3. Sequentially open the furnace atmosphere acquisition device 8, the air inlet valve group 9, the furnace atmosphere monitoring and control system 7, the pressure and flow monitoring device 6, the gas drying device 4, and the CO2 gas storage tank 2.

[0094] S4. Open the emergency safety control system 11 and SF6 gas storage tank 3;

[0095] S5. Start the heat treatment furnace 1. Start timing when the furnace temperature and CO2 gas concentration in the furnace chamber of the heat treatment furnace 1 reach the set value.

[0096] S6. After heat treatment is completed, open the furnace door of heat treatment furnace 1 and take out the magnesium alloy casting.

[0097] S7. Shut down the gas source and heat treatment furnace 1.

[0098] Example 3: Heat Treatment of ZM7 Magnesium Alloy Castings

[0099] S1. Clean the heat treatment furnace and place the ZM7 magnesium alloy casting into the heat treatment furnace.

[0100] S2. Set the heat treatment temperature to 405℃, the heat treatment time to 24h, and the target value of carbon dioxide concentration in the furnace to 15%.

[0101] S3. Sequentially open the furnace atmosphere acquisition device 8, the air inlet valve group 9, the furnace atmosphere monitoring and control system 7, the pressure and flow monitoring device 6, the gas drying device 4, and the CO2 gas storage tank 2.

[0102] S4. Open the emergency safety control system 11 and SF6 gas storage tank 3;

[0103] S5. Start the heat treatment furnace 1. Start timing when the furnace temperature and CO2 gas concentration in the furnace chamber of the heat treatment furnace 1 reach the set value.

[0104] S6. After heat treatment is completed, open the furnace door of heat treatment furnace 1 and take out the magnesium alloy casting.

[0105] S7. Shut down the gas source and heat treatment furnace 1.

[0106] Example 4: Heat Treatment of WE43 Magnesium Alloy Castings

[0107] S1. Clean the heat treatment furnace and place the WE43 magnesium alloy casting into the heat treatment furnace.

[0108] S2. Set the heat treatment temperature to 500℃, the heat treatment time to 48h, and the target value of carbon dioxide concentration in the furnace to 20%.

[0109] S3. Sequentially open the furnace atmosphere acquisition device 8, the air inlet valve group 9, the furnace atmosphere monitoring and control system 7, the pressure and flow monitoring device 6, the gas drying device 4, and the CO2 gas storage tank 2.

[0110] S4. Open the emergency safety control system 11 and SF6 gas storage tank 3;

[0111] S5. Start the heat treatment furnace 1. Start timing when the furnace temperature and CO2 gas concentration in the furnace chamber of the heat treatment furnace 1 reach the set value.

[0112] S6. After heat treatment is completed, open the furnace door of heat treatment furnace 1 and take out the magnesium alloy casting.

[0113] S7. Shut down the gas source and heat treatment furnace 1.

[0114] Example 5: Heat Treatment of VW63 Magnesium Alloy Castings

[0115] S1. Clean the heat treatment furnace and place the VW63 magnesium alloy casting to be treated into the heat treatment furnace.

[0116] S2. Set the heat treatment temperature to 500℃, the heat treatment time to 24h, and the target value of carbon dioxide concentration in the furnace to 30%.

[0117] S3. Sequentially open the furnace atmosphere acquisition device 8, the air inlet valve group 9, the furnace atmosphere monitoring and control system 7, the pressure and flow monitoring device 6, the gas drying device 4, and the CO2 gas storage tank 2.

[0118] S4. Open the emergency safety control system 11 and SF6 gas storage tank 3;

[0119] S5. Start the heat treatment furnace 1. Start timing when the furnace temperature and CO2 gas concentration in the furnace chamber of the heat treatment furnace 1 reach the set value.

[0120] S6. After heat treatment is completed, open the furnace door of heat treatment furnace 1 and take out the magnesium alloy casting.

[0121] S7. Shut down the gas source and heat treatment furnace 1.

[0122] Example 6: Heat Treatment of VW100Z Magnesium Alloy Castings

[0123] S1. Clean the heat treatment furnace and place the VW63 magnesium alloy casting to be treated into the heat treatment furnace.

[0124] S2. Set the heat treatment temperature to 500℃, the heat treatment time to 24h, and the target value of carbon dioxide concentration in the furnace to 35%.

[0125] S3. Sequentially open the furnace atmosphere acquisition device 8, the air inlet valve group 9, the furnace atmosphere monitoring and control system 7, the pressure and flow monitoring device 6, the gas drying device 4, and the CO2 gas storage tank 2.

[0126] S4. Open the emergency safety control system 11 and SF6 gas storage tank 3;

[0127] S5. Start the heat treatment furnace 1. Start timing when the furnace temperature and CO2 gas concentration in the furnace chamber of the heat treatment furnace 1 reach the set value.

[0128] S6. After heat treatment is completed, open the furnace door of heat treatment furnace 1 and take out the magnesium alloy casting.

[0129] S7. Shut down the gas source and heat treatment furnace 1.

[0130]

[0131] A comparison of the mechanical properties of ZM5 magnesium alloy castings treated with pyrite heat treatment and those treated with this system technology shows that the mechanical properties of ZM5 magnesium alloys treated with this patented technology are higher than those of traditional pyrite-protected heat treatment.

[0132] The above are merely preferred embodiments of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concept, should be covered within the scope of protection of the present invention.

Claims

1. A smart gas protection system for magnesium alloy heat treatment, comprising a heat treatment furnace (1), a gas source, a control system, and a gas protection system, characterized in that: The gas source includes a CO2 gas storage tank (2) and an SF6 gas storage tank (3). The control system includes an electrical control system, a pneumatic control system, and an atmosphere sampling system; The surface of the heat treatment furnace (1) is equipped with a gas protection system, which includes an inlet pipe, a pressure gauge, a safety valve, and a gas detection system interface. The surface of the heat treatment furnace (1) is pre-set with 12 SF6 emergency gas inlet pipes in three directions (upper, middle, and lower). The surface of the heat treatment furnace (1) is equipped with three safety valves in three directions (upper, middle, and lower). The safety valves are installed on the surface of the pipes connected to the heat treatment furnace (1). The heat treatment furnace (1) uses resistance heating. The gas detection system interface is connected to the inlet pipe. The pressure gauge is installed inside the inlet pipe. The output end of the CO2 gas storage tank (2) is connected to a control system via a pipeline, the output end of the SF6 gas storage tank (3) is connected to a gas protection system via a pipeline, and the output ends of the control system and the gas protection system are connected to a heat treatment furnace (1) via pipelines. The CO2 gas in the CO2 gas storage tank (2) is used to control the atmosphere concentration in the heat treatment furnace (1) in real time, and the SF6 gas in the SF6 gas storage tank (3) is used for emergency handling. The output end of the CO2 gas storage tank (2) is connected to a gas drying device (4) via a pipeline. The gas drying device (4) consists of two sets of spaced-apart drying alarm units and a preheating device. The preheating device is installed on the surface of the pipeline at the output end of the CO2 gas storage tank (2) and located in front of the two sets of drying alarm units. Each set of alarm drying units includes a molecular sieve (12), an electric micro-rod (13), a humidity detection sensor (14), and a drying alarm display (15). The molecular sieve (12) is installed on the inner wall of the pipeline at the output end of the CO2 gas storage tank (2). A dryness alarm display (15) is installed on the surface of the output pipe of the gas storage tank (2), and two sets of dryness alarm displays (15) are electrically connected. The bottom end of the dryness alarm display (15) is connected to an electric micro-rod (13) that passes through the output pipe of the CO2 gas storage tank (2). When the tail end of the electric micro-rod (13) is in the extended state, it enters the interior of the molecular sieve (12). The tail end of the electric micro-rod (13) is connected to a humidity detection sensor (14), and a regulating valve that is electrically connected to the dryness alarm display (15) is installed between the preheating device and the front molecular sieve (12).

2. The intelligent gas protection system for magnesium alloy heat treatment according to claim 1, characterized in that: The output end of the gas drying device (4) is connected to a manual air intake and flow monitoring system (5) and a pressure and flow monitoring system (6) via a pipeline. The output end of the pressure and flow monitoring system (6) is connected to an in-furnace atmosphere acquisition device (8). The surface of the in-furnace atmosphere acquisition device (8) is equipped with an in-furnace atmosphere monitoring and control system (7) and an air intake valve group (9) that are electrically connected to the in-furnace atmosphere acquisition device (8). The air intake valve group (9) is electrically connected to the in-furnace atmosphere monitoring and control system (7). The output end of the air intake valve group (9) is connected to a heat treatment furnace (1) via a pipeline. The output end of the manual air intake and flow monitoring system (5) is connected to one of the gas detection system interfaces on the surface of the heat treatment furnace (1) via a pipeline.

3. The intelligent gas protection system for magnesium alloy heat treatment according to claim 1, characterized in that: The output end of the SF6 gas storage tank (3) is connected to a manual entry and flow monitoring system (10) and an emergency safety control system (11). The output ends of the manual entry and flow monitoring system (10) and the emergency safety control system (11) are connected to the heat treatment furnace (1) through pipelines.

4. The intelligent gas protection system for magnesium alloy heat treatment according to claim 1, characterized in that: The electrical control system includes a host computer, a slave computer, a carbon dioxide content analyzer, and analog signal acquisition channels. The host computer uses a Siemens touch screen to set control parameters and process parameters, as well as monitor the working process in real time. The slave computer uses a Siemens PLC to collect data inside the furnace and control the combination valve to control the atmosphere inside the furnace. The carbon dioxide content analyzer monitors the atmosphere inside the furnace in real time. All analog signal acquisition channels use shielded twisted-pair cables to prevent signal interference.

5. The intelligent gas protection system for magnesium alloy heat treatment according to claim 1, characterized in that: The pneumatic control system consists of four sets of imported SMC digital combination valves, which linearly adjust the carbon dioxide gas flow rate.

6. The intelligent gas protection system for magnesium alloy heat treatment according to claim 1, characterized in that: The pressure gauge is used for real-time monitoring of pressure and oxygen partial pressure, and the gas detection system interface is used for real-time monitoring and control of carbon dioxide gas content and gas flow rate in the heat treatment furnace (1).

7. The intelligent gas protection system for magnesium alloy heat treatment according to claim 1, characterized in that: The atmosphere sampling system is connected to a cooling device via a pipeline, and the output end of the cooling device is connected to a carbon dioxide content analyzer.

8. A smart gas protection system for magnesium alloy heat treatment according to any one of claims 1-7, characterized in that, The operating steps of this system are as follows: S1. Clean the heat treatment furnace (1) and put the magnesium alloy casting to be treated into the heat treatment furnace (1); S2. Set the heat treatment temperature, heat treatment time, and target value of carbon dioxide concentration in the furnace (1). S3. Sequentially open the furnace atmosphere acquisition device (8), the air inlet valve group (9), the furnace atmosphere monitoring and control system (7), the pressure and flow monitoring system (6), the gas drying device (4), and the CO2 gas storage tank (2). S4. Open the emergency safety control system (11) and the SF6 gas storage tank (3). S5. Start the heat treatment furnace (1) and start timing when the furnace temperature and CO2 gas concentration in the furnace reach the set value in S2. S6. After the heat treatment time in S2 is completed, open the furnace door of the heat treatment furnace (1) and take out the magnesium alloy casting. S7. Shut down the gas source and the heat treatment furnace (1).

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