Multifunctional heat treatment furnace and heat treatment method

Abstract

The invention discloses a multifunctional heat treatment furnace and a heat treatment method.The heat treatment furnace comprises a furnace shell, a hearth and a heating system arranged in the hearth and further comprises a gas inlet system communicated with the hearth and used for introducing first gas and second gas into the hearth. And the emptying system is communicated with the hearth, can exhaust gas in the hearth and can form a vacuum environment. The heat treatment method comprises the steps of feeding, rubber discharging, gas replacement, sintering, cooling, discharging and the like. By arranging the gas inlet system and the emptying system which are communicated with the hearth, the hearth can be controllably filled with the first gas or the second gas respectively according to process requirements, and the gas in the hearth can be controllably discharged, so that gas replacement can be realized in the same hearth, and the requirements of two processes of rubber discharging and annealing are met respectively; and therefore, different process treatments can be completed in the same heat treatment furnace, and the step of transferring metal materials can be omitted.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of metal heat treatment, and in particular to a multifunctional heat treatment furnace and a heat treatment method. Background Art

[0002] Debinding and annealing are two important process steps in metal heat treatment. Debinding refers to the process of removing the binder gas generated by evaporation in the metal material by the flow of gas (such as air) under high temperature environment; annealing refers to the high-temperature sintering of the metal material in a protective atmosphere (such as argon environment). At present, the debinding and annealing of metal materials are handled by two different equipments, that is, the metal material is first debinded in one set of equipment, and then it is transferred to another equipment for annealing. This method of using different equipment for debinding and annealing has obvious defects. For example, between the two processes of debinding and annealing, the metal material must first be cooled, and then the cooled metal material must be transported out of the heat treatment furnace for debinding and loaded into the heat treatment furnace for annealing to heat up and sinter again. The transfer steps between the heat treatment furnaces are cumbersome, which not only affects the production efficiency, but also increases the energy consumption in the process of cooling and heating.

[0003] Therefore, it is necessary to transform the heat treatment furnace and develop a heat treatment method that is compatible with it. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a multifunctional heat treatment furnace and a heat treatment method.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: A multifunctional heat treatment furnace comprises a furnace shell, a furnace chamber, and a heating system arranged in the furnace chamber. It also comprises an intake system connected to the furnace chamber and used to introduce a first gas and a second gas therein respectively, and an exhaust system connected to the furnace chamber and capable of exhausting the gas therein and forming a vacuum environment.

[0006] As a further improvement of the above technical solution: The heat treatment furnace also includes a waste gas incineration system for purifying air, wherein the outlet end of the waste gas incineration system is connected to the air intake system, and the inlet end of the waste gas incineration system is connected to the exhaust system.

[0007] The air intake system includes a first air intake mechanism for introducing a first gas into the furnace and a second air intake mechanism for introducing a second gas into the furnace, which are independent of each other; the outlet end of the waste gas incineration system is only connected to the first air intake mechanism.

[0008] A refractory insulation layer is arranged inside the furnace shell, and an isolation layer for preventing glue gas from entering the refractory insulation layer from the furnace is arranged inside the refractory insulation layer. The isolation layer and the furnace shell are enclosed to form a closed interlayer space.

[0009] The interlayer space is communicated with the air intake system and the exhaust system respectively.

[0010] Sensors for acquiring air pressure data are arranged in the furnace and the interlayer space.

[0011] The pressure difference between the furnace and the interlayer space is no more than 2 kPa.

[0012] The heat treatment furnace also includes a circulating cooling system, and an inlet end and an outlet end of the circulating cooling system are respectively connected to the furnace.

[0013] Then, the present invention discloses a heat treatment method suitable for the above heat treatment furnace, comprising the following steps: Step S1, feeding, feeding the metal material to be heat treated into the furnace; Step S2, debinding, separating the binder gas from the metal material by heating, and letting the binder gas flow out of the furnace along with the other gas; Step S3, gas replacement, exhausting the first gas in the furnace and refilling it with the second gas; Step S4, sintering, heat treating the metal material by increasing the temperature; Step S5, cooling, reducing the temperature in the furnace through heat exchange between the gas and the outside; Step S6, discharging, removing the heat-treated metal material from the furnace.

[0014] As a further improvement of the above technical solution: The step S3 specifically includes: Step S31, exhausting the first gas in the furnace and the interlayer space synchronously through the exhaust system, so that the furnace and the interlayer space are in a vacuum state at the same time; Step S32, the second gas is synchronously charged into the furnace and the interlayer space through the air intake system.

[0015] Compared with the prior art, the advantages of the present invention are: Normally, the first gas (usually air) is filled into the furnace during the debinding process, while the second gas (usually argon) needs to be filled into the furnace during the annealing process. Therefore, the gas in the furnace needs to be replaced during the conversion of the two processes. By setting up an air intake system and an exhaust system connected to the furnace, the first gas or the second gas can be controllably filled into the furnace according to process requirements, and the gas in the furnace can be controllably discharged, so that gas replacement can be achieved in the same furnace, thereby meeting the requirements of the two processes of debinding and annealing, and then different process treatments can be completed in the same heat treatment furnace, so the step of transferring metal materials can be avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of a heat treatment furnace.

[0017] The numbers in the figure represent: 1. furnace shell; 2. furnace chamber; 3. heating system; 4. air intake system; 401. first air intake mechanism; 402. second air intake mechanism; 5. exhaust system; 6. waste gas incineration system; 7. refractory insulation layer; 8. isolation layer; 9. interlayer space; 10. circulating cooling system; 11. valve. DETAILED DESCRIPTION

[0018] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] Example like Figure 1 As shown, the multifunctional heat treatment furnace of this embodiment includes a furnace shell 1, a furnace chamber 2, and a heating system 3 arranged in the furnace chamber 2, and also includes an intake system 4 connected with the furnace chamber 2 and used for respectively introducing a first gas and a second gas therein, and an exhaust system 5 connected with the furnace chamber 2 and capable of exhausting the gas therein and forming a vacuum environment.

[0020] Normally, the first gas (usually air) is filled into the furnace during the debinding process, while the second gas (usually argon) needs to be filled into the furnace during the annealing process. Therefore, during the conversion of the two processes, the gas in the furnace 2 needs to be replaced. By setting up an air intake system 4 and an exhaust system 5 connected to the furnace 2, the first gas or the second gas can be controllably filled into the furnace 2 according to the process requirements, and the gas in the furnace 2 can be controllably discharged, so that the gas replacement can be achieved in the same furnace 2, thereby meeting the requirements of the two processes of debinding and annealing, and then different process treatments can be completed in the same heat treatment furnace, so the step of transferring metal materials can be avoided.

[0021] In the prior art, in order to achieve gas replacement, the second gas is usually continuously introduced, and the first gas is squeezed out of the furnace by the second gas. This method has at least the following disadvantages: First, as the replacement process progresses, the replacement effect is significantly reduced. In order to discharge the small amount of first gas remaining in the furnace, a long replacement is required, which is inefficient. Second, due to the complex structure and dead corners in the furnace 2, the first gas at some bends or corners is difficult to be squeezed out by the process gas, resulting in the second gas purity not meeting the standard during the sintering process. Third, some second gases (such as argon) are expensive, and this replacement method consumes a large amount of second gas, so the production cost is high. In the present application, the emptying system 5 can basically discharge the gas in the furnace 2 (that is, evacuate it), so when performing gas replacement, one of the gases in the furnace 2 can be basically completely extracted (the furnace reaches a vacuum state at this time), and then the second gas is added, so that the replacement efficiency can be effectively accelerated, and the purity of the second gas after replacement can be improved, and the amount of the second gas can be reduced.

[0022] In this embodiment, the heat treatment furnace further includes a waste gas incineration system 6 for purifying air. The outlet end of the waste gas incineration system 6 is connected to the air intake system 4 , and the inlet end thereof is connected to the exhaust system 5 .

[0023] During the debinding stage, the mixed gas containing glue gas is discharged from the furnace 2 under the action of the emptying system 5. If it is discharged directly to the outside, it will have an impact on the environment on the one hand, and will also cause a large amount of heat energy loss on the other hand. The present application sets up a waste gas incineration system 6, and connects its inlet end with the emptying system 5, so that the mixed gas discharged from the furnace 2 directly enters the waste gas incineration system 6 and is incinerated and purified there. At the same time, the outlet end of the waste gas incineration system 6 is connected to the air intake system 4, and the high-temperature and pure gas obtained after purification is introduced into the furnace 2 again through the air intake system 4 to participate in debinding, thereby forming a gas circuit cycle. By setting up the waste gas incineration system 6, the present application can recycle the gas during the debinding stage, thereby reducing the environmental pollution caused by external discharge, and can also recycle heat energy and reduce energy consumption to a certain extent.

[0024] In this embodiment, the air intake system 4 includes a first air intake mechanism 401 for introducing the first gas into the furnace 2 and a second air intake mechanism 402 for introducing the second gas into the furnace 2, and the two are independent of each other; the outlet end of the waste gas incineration system 6 is only connected to the first air intake mechanism 401.

[0025] In this embodiment, the first gas is air, and the second gas is argon. When the heat treatment furnace in this embodiment is used to heat treat the metal material, the air is mainly used to take the glue gas out of the furnace body in the debinding stage, and the argon is mainly used to provide a protective atmosphere for the heat treatment of the metal material in the sintering stage. In this embodiment, the first air intake mechanism 401 and the second air intake mechanism 402 are set as independent structures, which can effectively avoid the mixing of air and argon in the pipeline, thereby being more conducive to improving the purity of the argon in the furnace during the sintering stage. At the same time, in order to facilitate the recycling of air in the debinding stage, the inlet end of the first air intake mechanism 401 is connected to the outlet end of the waste gas incineration system 6, so that the high-temperature, pure air purified by the waste gas incineration system 6 can be re-filled into the furnace 2 under the action of the first air intake mechanism 401.

[0026] Further, in this embodiment, the second air intake mechanism 402 is connected to the exhaust system 5, and a valve 11 is provided on the connecting pipeline between the two. When necessary, the valve 11 can be opened to connect the second air intake mechanism 402 with the exhaust system 5, so that the second air intake mechanism 402 can be used to provide a protective atmosphere for the exhaust system 5.

[0027] In this embodiment, a refractory insulation layer 7 is provided on the inner side of the furnace shell 1, and an isolation layer 8 is provided on the inner side of the refractory insulation layer 7 for preventing glue gas from entering the refractory insulation layer 7 from the furnace 2. The isolation layer 8 and the furnace shell 1 are enclosed to form a closed interlayer space 9.

[0028] In order to reduce heat energy loss and avoid overheating damage to the furnace shell, this heat treatment furnace with both debinding and annealing functions needs to be provided with a refractory insulation layer 7 in the furnace body. However, since the insulation layer is often made of porous materials, during the debinding process, the glue gas is easy to diffuse into the refractory insulation layer 7. After the temperature drops, it will condense and tightly combine with the refractory insulation layer 7. When the temperature in the furnace 2 rises again, the glue gas will evaporate again and overflow for a second time. The residual glue gas has little effect on the heat treatment furnace used only for debinding in the prior art, because when the furnace temperature rises again and the glue gas overflows for a second time, the glue gas in the metal material is also in a gaseous state, so the glue gas overflowing for the second time can be mixed with the glue gas in the metal material and discharged together, so that the cleanliness in the furnace 2 will not be seriously affected. However, in the heat treatment furnace developed by the applicant with both debinding and annealing functions, the secondary overflow of this glue gas is difficult to meet the process requirements, because when entering the annealing process, the gas in the furnace 2 no longer flows outward in large quantities and continuously, so the glue gas cannot be discharged in time through the flow of gas, and the temperature rises again, causing the glue gas remaining in the refractory insulation layer 7 to enter the furnace 2 in a gaseous state and pollute the metal material, thereby seriously affecting the quality of heat treatment and may even cause the metal material to be scrapped. Therefore, in this embodiment, an isolation layer 8 is provided on the inner side of the refractory insulation layer 7, and the isolation layer 8 can effectively block the oil and gas from entering the refractory insulation layer 7 from the furnace 2, thereby avoiding the condensation and secondary overflow of the oil and gas in the refractory insulation layer 7, ensuring the cleanliness of the furnace 2 during the annealing process, and improving the heat treatment quality of the metal material.

[0029] In this embodiment, the interlayer space 9 is respectively connected to the air intake system 4 and the exhaust system 5. Sensors for obtaining air pressure data are provided in the furnace 2 and the interlayer space 9. The pressure difference between the furnace 2 and the interlayer space 9 is not greater than 2 kPa.

[0030] Since the first gas in the furnace 2 needs to be replaced by the second gas during the conversion process between the debinding process and the sintering process, the replacement means adopted in this embodiment is to first extract the first gas in the furnace 2 to make the furnace 2 in a vacuum state, and then fill the furnace 2 with the second gas. In addition, because the isolation layer 8 and the furnace shell 1 enclose a closed interlayer space 9, if the furnace 2 is in a vacuum state and there is gas in the interlayer space 9, the excessive pressure difference in the two spaces will squeeze and deform the isolation layer 8, or even damage it, so that the glue gas cannot be effectively isolated. Therefore, in this embodiment, the air intake system 4 and the emptying system 5 are connected to the interlayer space 9 respectively. When the furnace 2 is emptied or inflated, the interlayer space 9 is synchronously emptied or inflated by the air intake system 4 and the emptying system 5, so that the pressure difference on both sides of the isolation layer 8 can be effectively balanced, and then the isolation layer 8 can be effectively prevented from being deformed and damaged due to the pressure difference. In order to realize real-time monitoring of the pressure in the furnace 2 and the interlayer space 9, air pressure sensors are respectively installed in the two spaces.

[0031] In this embodiment, the heat treatment furnace further includes a circulating cooling system 10 , and an inlet end and an outlet end of the circulating cooling system 10 are respectively connected to the furnace 2 .

[0032] After the strip is sintered, the metal material needs to be cooled before it can be taken out of the furnace 2. In this embodiment, a circulating cooling system 10 is provided, and the high-temperature gas in the furnace 2 is first drawn into the circulating cooling system 10 for heat exchange and cooling, and then the cooled gas is re-introduced into the furnace 2 to form a circulating air path. After continuous heat exchange, the temperature of the metal material in the furnace 2 is reduced.

[0033] Then, the present invention also discloses a heat treatment method applicable to the above heat treatment furnace, which in one embodiment comprises the following steps: Step S1, feeding, feeding the metal material to be heat treated into the furnace; Step S2, debinding, separating the binder gas from the metal material by heating, and letting the binder gas flow out of the furnace along with the other gas; Step S3, gas replacement, exhausting the first gas in the furnace and refilling it with the second gas; Step S4, sintering, heat treating the metal material by increasing the temperature; Step S5, cooling, reducing the temperature in the furnace through heat exchange between the gas and the outside; Step S6, discharging, removing the heat-treated metal material from the furnace.

[0034] The above-mentioned heat treatment furnace has both debinding and sintering functions. Usually, the first gas (usually air) is filled into the furnace during the debinding process, and the second gas (usually argon) needs to be filled into the furnace during the annealing process. Therefore, during the conversion of the two processes, the gas in the furnace 2 needs to be replaced. By setting up an intake system 4 and an exhaust system 5 connected to the furnace 2, the first gas or the second gas can be controllably filled into the furnace 2 according to process requirements, and the gas in the furnace 2 can be controllably discharged, so that gas replacement can be achieved in the same furnace 2, thereby meeting the requirements of the two processes of debinding and annealing, respectively, and then different process treatments can be completed in the same heat treatment furnace, so the step of transferring metal materials can be avoided.

[0035] In this embodiment, step S3 specifically includes: Step S31, exhausting the first gas in the furnace and the interlayer space synchronously through the exhaust system, so that the furnace and the interlayer space are in a vacuum state at the same time; Step S32, the second gas is synchronously charged into the furnace and the interlayer space through the air intake system.

[0036] The first gas can be quickly and completely evacuated by vacuuming, thereby effectively accelerating the replacement efficiency, while also improving the purity of the second gas after replacement and reducing the amount of the second gas used.

[0037] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the technical content disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention should fall within the scope of protection of the technical solution of the present invention.

Claims

1. A multifunctional heat treatment furnace, characterized in that: The invention comprises a furnace shell (1), a furnace chamber (2), and a heating system (3) arranged in the furnace chamber (2), and is characterized in that it also comprises an intake system (4) connected to the furnace chamber (2) and used to introduce a first gas and a second gas therein respectively, and an exhaust system (5) connected to the furnace chamber (2) and capable of exhausting the gas therein and forming a vacuum environment.

2. The multifunctional heat treatment furnace according to claim 1, characterized in that: The heat treatment furnace further comprises a waste gas incineration system (6) for purifying air, wherein the outlet end of the waste gas incineration system (6) is connected to the air intake system (4), and the inlet end thereof is connected to the exhaust system (5).

3. The multifunctional heat treatment furnace according to claim 2, characterized in that: The air intake system (4) comprises a first air intake mechanism (401) for introducing a first gas into the furnace (2) and a second air intake mechanism (402) for introducing a second gas into the furnace (2), the two being independent of each other; the outlet end of the waste gas incineration system (6) is only connected to the first air intake mechanism (401).

4. The multifunctional heat treatment furnace according to claim 1, characterized in that: A refractory heat-insulating layer (7) is provided on the inner side of the furnace shell (1), and an isolation layer (8) is provided on the inner side of the refractory heat-insulating layer (7) for preventing glue gas from entering the refractory heat-insulating layer (7) from the furnace chamber (2). The isolation layer (8) and the furnace shell (1) are enclosed to form a closed interlayer space (9).

5. The multifunctional heat treatment furnace according to claim 4, characterized in that: The interlayer space (9) is respectively connected to the air intake system (4) and the exhaust system (5).

6. The multifunctional heat treatment furnace according to claim 5, characterized in that: Sensors for acquiring air pressure data are provided in the furnace (2) and in the interlayer space (9).

7. The multifunctional heat treatment furnace according to claim 6, characterized in that: The pressure difference between the furnace (2) and the interlayer space (9) is no greater than 2 kPa.

8. The multifunctional heat treatment furnace according to claim 1, characterized in that: The heat treatment furnace further comprises a circulating cooling system (10), wherein an inlet end and an outlet end of the circulating cooling system (10) are respectively connected to the furnace (2).

9. A heat treatment method suitable for the heat treatment furnace according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step S1, feeding, feeding the metal material to be heat treated into the furnace; Step S2, debinding, separating the binder gas from the metal material by heating, and letting the binder gas flow out of the furnace along with the other gas; Step S3, gas replacement, exhausting the first gas in the furnace and refilling it with the second gas; Step S4, sintering, heat treating the metal material by increasing the temperature; Step S5, cooling, reducing the temperature in the furnace through heat exchange between the gas and the outside; Step S6, discharging, removing the heat-treated metal material from the furnace.

10. The heat treatment method according to claim 9, characterized in that: The step S3 specifically includes: Step S31, exhausting the first gas in the furnace and the interlayer space synchronously through the exhaust system, so that the furnace and the interlayer space are in a vacuum state at the same time; Step S32, the second gas is synchronously charged into the furnace and the interlayer space through the air intake system.

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