Roller hearth protective atmosphere bright solution annealing furnace isolated from oxidizing atmosphere

Abstract

This utility model discloses a roller hearth type protective atmosphere bright solution furnace that effectively isolates oxidizing atmospheres. The roller hearth type protective atmosphere bright solution furnace of this utility model includes, along the material flow direction, a gas exchange section, a heating section, a rapid cooling section, and a slow cooling section that are interconnected. The gas exchange section includes a sealing section and a preheating section connected in sequence. The preheating section is connected to the heating section. The top of the sealing section and / or the preheating section is equipped with several isolation boxes that isolate the oxidizing atmosphere by sealing the steel with sealant.

Description

Technical Field

[0001] This utility model relates to the field of metal heat treatment, and in particular to a roller hearth type protective atmosphere bright solution furnace that isolates oxidizing atmosphere. Background Technology

[0002] Stainless steel pipe brightening and solution treatment equipment is used in the "solution heat treatment" process of stainless steel pipe production. After the "solution heat treatment" process, the stainless steel pipe needs to achieve the following characteristics: bright finish, excellent corrosion resistance, and good microstructure and properties.

[0003] "Solution treatment" refers to a heat treatment process in which an alloy is heated to a high-temperature single-phase region and held at that temperature, allowing the excess phase to fully dissolve into the solid solution, followed by rapid cooling to obtain a supersaturated solid solution. During solution heat treatment, carbon atoms on the steel pipe surface react with the oxidizing atmosphere in the medium, causing decarburization. The surface layer of the steel part becomes a decarburized layer with low carbon content, affecting properties such as hardness. The key to preventing decarburization lies in controlling the oxidizing atmosphere within the furnace. Among oxidizing atmospheres, water vapor has the strongest decarburizing ability, followed by O2.

[0004] Regarding the rapid cooling in the solution treatment process, early equipment used water to rapidly cool the steel pipes. The steel pipes, reaching temperatures as high as 950–1150℃, generated a large amount of water vapor under the jet cooling effect. A small amount of this water vapor would flow from the rapid cooling section to the heating section, affecting the furnace temperature, heating elements, and insulation layer in the heating section. Furthermore, it would cause oxidation on the steel pipe surface, affecting the product's surface gloss. Current technology has improved this by using a pure hydrogen atmosphere introduced into the furnace as the cooling medium. In terms of gas cooling characteristics, hydrogen has superior cooling properties. However, the properties of hydrogen pose a significant challenge to the equipment's sealing performance, and hydrogen also presents safety risks during daily operation.

[0005] The term "bright" refers to the use of a protective atmosphere to prevent the formation of an oxide layer (skin) on the material surface, or to the appropriate removal of any existing oxide layer (skin). The "bright" process gives stainless steel a superior industrial aesthetic appeal, with its glossy, reflective surface creating a strong visual impact.

[0006] Existing bright solution furnaces use a protective atmosphere as the cooling medium for the rapid cooling section. The protective atmosphere is generally introduced into the furnace in the rapid cooling section, where the pressure is the highest. The pressure decreases as you move further away from the rapid cooling section, resulting in a lower barrier to outside air. This makes it difficult to isolate the effective oxidizing atmosphere. Furthermore, the stainless steel tubes are directly fed into the heating section after exiting the feeding section, causing the stainless steel tubes to heat up rapidly and instantly. There is still room for improvement in the solution treatment effect.

[0007] Therefore, there is an urgent need for a roller hearth protective atmosphere bright solution furnace that can effectively isolate oxidizing atmospheres to overcome the above-mentioned defects. Utility Model Content

[0008] The purpose of this invention is to provide a roller hearth type protective atmosphere bright solution furnace that effectively isolates oxidizing atmospheres from the outside.

[0009] To achieve the above objectives, this utility model provides a roller hearth type protective atmosphere bright solution furnace for isolating oxidizing atmospheres, comprising an air exchange section, a heating section, a rapid cooling section and a slow cooling section connected in sequence along the material flow direction. The air exchange section includes a sealing section and a preheating section connected in sequence. The preheating section is connected to the heating section. The top of the sealing section and / or the preheating section is equipped with several isolation boxes that isolate the oxidizing atmosphere by sealing the steel with seals.

[0010] Preferably, the cross-sectional area of ​​the inner cavity of the sealing section is smaller than that of the inner cavity of the preheating section; the spacing between the isolation boxes in the sealing section is smaller than that between the isolation boxes in the preheating section; the cross-sectional area of ​​the cavity of the ventilation section is smaller than that of the cavity of the heating section; the connection between the ventilation section and the heating section is constricted relative to the cavity space; the cross-sectional area of ​​the cavity of the heating section is smaller than that of the cavity of the rapid cooling section; the connection between the heating section and the rapid cooling section is constricted relative to the cavity space; the cross-sectional area of ​​the cavity of the slow cooling section is smaller than that of the cavity of the rapid cooling section; the connection between the slow cooling section and the rapid cooling section is constricted relative to the cavity space.

[0011] Preferably, the top of the slow cooling section is also equipped with several isolation boxes that isolate the oxidizing atmosphere by sealing the steel with seals.

[0012] Preferably, the roller hearth type protective atmosphere bright solution furnace of this utility model further includes a feeding section and a discharging section. The feeding section, ventilation section, heating section, rapid cooling section, slow cooling section and discharging section are arranged sequentially along the material flow direction. Conveying roller groups arranged along the material flow direction for conveying steel are passed through the feeding section, ventilation section, heating section, rapid cooling section, slow cooling section and discharging section. The isolation boxes on the sealed section are centrally arranged at one end of the sealed section near the feeding section.

[0013] Preferably, the isolation boxes on the preheating section are distributed throughout the preheating section, the temperature of the inner cavity of the sealed section is lower than that of the inner cavity of the preheating section, and the temperature of the inner cavity of the preheating section is arranged to increase in a gradient along the material flow direction.

[0014] Preferably, a first exhaust port is provided at the top of the sealed section near the feeding section, and several isolation boxes are arranged on the side of the first exhaust port away from the feeding section. A second exhaust port is provided at the top of the preheating section near the sealed section, and several isolation boxes are arranged on the side of the second exhaust port away from the sealed section.

[0015] Preferably, the top of the preheating section is also provided with a gas extraction port for connection to gas monitoring equipment and / or dew point detection equipment.

[0016] Preferably, the isolation box includes a box body, a driver, a drive component, and a mounting base. The box body has a sealed cavity with a bottom opening. The driver is mounted on the box body, and the drive component is located in the sealed cavity. The drive component is connected to the output end of the driver. The driver drives the drive component to move up and down within the sealed cavity. The mounting base is mounted on the lower end of the drive component and extends downward beyond the opening end of the sealed cavity. The mounting base is used to load a sealing component that is pressed tightly against the steel. The driver drives the drive component to move up and down, which in turn drives the mounting base to move up and down synchronously, so that the sealing component is pressed tightly against the steel.

[0017] Preferably, the isolation box includes a transmission gear, a guide wheel, and a fixed seat mounted on the top of the box. The fixed seat has a receiving cavity. The transmission gear is rotatably mounted in the receiving cavity. The driver drives the transmission gear to rotate. The guide wheel is rotatably disposed in the receiving cavity and offset to one side of the transmission gear. The guide wheel and the transmission gear form a motion channel. The driving member passes through the motion channel. One side of the driving member has a rack arranged in the vertical direction. The meshing transmission between the transmission gear and the rack drives the driving member to perform vertical linear motion. The guide wheel is rolledly connected to the other side of the driving member opposite to the rack.

[0018] Preferably, the isolation box also includes a protective sleeve mounted on the fixed base and covering the upper end of the drive unit, the upper end of the drive unit being isolated from the external environment by means of the protective sleeve.

[0019] Compared with existing technologies, the roller hearth type protective atmosphere bright solution furnace of this utility model includes a gas exchange section, which comprises a sealing section and a preheating section connected in sequence. Several isolation boxes are installed at the top of the sealing section and the preheating section, which isolate the oxidizing atmosphere by sealing the steel with seals. These isolation boxes isolate the oxidizing atmosphere in the gas exchange section, preventing it from entering the heating section, rapid cooling section, or even slow cooling section, thus avoiding decarburization of the stainless steel tubes caused by the oxidizing atmosphere entering the furnace. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the roller-bottom type protective atmosphere bright solution furnace of this utility model, which isolates oxidizing atmosphere.

[0021] Figure 2 This is a front view of the ventilation section of this utility model.

[0022] Figure 3 This is a top view of the ventilation section of this utility model.

[0023] Figure 4 This is a perspective view of the isolation box of this utility model when it is installed on the slow cooling section.

[0024] Figure 5 This is a perspective view of the isolation box of this utility model.

[0025] Figure 6 This is a left view of the isolation box of this utility model.

[0026] Figure 7 This utility model is an isolation box edge Figure 6 The sectional view obtained after cutting along line segment AA.

[0027] Figure 8 This is a perspective view of the isolation box of this utility model after it has been separated from the box body. Detailed Implementation

[0028] To explain the technical content and structural features of this utility model in detail, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0029] This invention provides a roller-bottom type protective atmosphere bright solution furnace that isolates oxidizing atmosphere.

[0030] Solution treatment refers to a heat treatment process in which an alloy is heated to a high-temperature single-phase region and held at that temperature, allowing the excess phase to fully dissolve into the solid solution, followed by rapid cooling to obtain a supersaturated solid solution. Specifically in the field of stainless steel, taking austenitic stainless steel as an example, the solution treatment process typically involves heating the austenitic stainless steel to approximately 950-1150°C, causing all or most of the carbide phase to dissolve, with carbon dissolved in the austenite. Then, rapid cooling is performed to achieve a supersaturated state of the carbon. Once the carbon is stabilized, it has no ability or opportunity to form high-chromium carbides with chromium, thus strengthening the solid solution, improving toughness and corrosion resistance, eliminating stress and softening, and facilitating further processing or shaping. This heat treatment method is called solution heat treatment.

[0031] In the stainless steel industry, the influence of carbon is mainly manifested in two aspects. Firstly, it is a crucial element for stabilizing austenite, playing a role approximately 30 times that of nickel. Secondly, due to its strong affinity for chromium, carbon can form a series of complex carbides with chromium. Therefore, special attention must be paid to decarburization and carbon enrichment during the solution treatment process. Decarburization primarily refers to the process where, during solution heat treatment of stainless steel, carbon atoms on the steel pipe surface gain sufficient energy to escape from the surface into the furnace, passively reducing the carbon content of the material and resulting in decreased and uneven hardness. Decarburization is the reaction of carbon with the oxidizing atmosphere in the medium, causing surface decarburization. Decarburization is a diffusion process. On one hand, oxygen in the furnace gas diffuses into the steel, and on the other hand, carbon in the steel diffuses outward. The result is a decarburized layer with low carbon content on the surface of the steel. Therefore, controlling the decarburization phenomenon hinges on controlling the oxidizing atmosphere within the furnace. Oxidizing atmospheres cause decarburization in steel, with water (H2O) being the most potent decarburizing medium, followed by oxygen (O2). Therefore, it is essential to isolate the oxidizing atmosphere as much as possible to prevent it from entering the furnace. Traditionally, water is used as a cooling medium, but its strong oxidizing properties lead to decarburization on the steel surface. Furthermore, the oxygen in the cooling water negatively impacts the steel's shine. Consequently, cooling solutions using gas instead of water have emerged. This invention uses process gas as the cooling medium, primarily composed of hydrogen (H2) and nitrogen (N2), but is not limited to hydrogen and nitrogen; other substances can be used depending on the specific application requirements. This solution uses 70%~80% N2 and 20%~30% H2. Nitrogen acts as an inert atmosphere, isolating oxygen and preventing oxidation, while hydrogen acts as a reducing atmosphere, reducing the oxide layer on the steel surface to achieve a "bright" finish. In the embodiments provided by this utility model, the steel is a stainless steel pipe, but it should be understood that it is not limited to stainless steel pipes; steel plates, steel bars, etc., can be used depending on actual needs.

[0032] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the roller hearth type protective atmosphere bright solution furnace 1000 of this utility model, which isolates oxidizing atmosphere, includes, in sequence along the material flow direction, a feeding section 100, a ventilation section 200, a heating section 300, a rapid cooling section 400, a slow cooling section 500, and a discharging section 600, all interconnected. The ventilation section 200 includes a sealing section 210 and a preheating section 220 connected in sequence. The preheating section 220 is connected to the heating section 300. Several isolation boxes 700 are installed on the top of the sealing section 210 and the preheating section 220, which isolate the oxidizing atmosphere by sealing the steel with sealing elements (see below).

[0033] The roller hearth type protective atmosphere bright solution furnace 1000 of this utility model includes a gas exchange section 200, which includes a sealing section 210 and a preheating section 220 connected in sequence. Several isolation boxes 700 are installed on the top of the sealing section 210 and the preheating section 220, which isolate the oxidizing atmosphere by sealing the steel with seals. The isolation boxes 700 isolate the oxidizing atmosphere in the gas exchange section 200, preventing it from entering the heating section 300, the rapid cooling section 400, or even the slow cooling section 500, thus avoiding the decarburization of the stainless steel tubes caused by the oxidizing atmosphere entering the furnace.

[0034] The feeding section 100, ventilation section 200, heating section 300, rapid cooling section 400, slow cooling section 500, and discharge section 600 are interconnected. Process gas is introduced in the rapid cooling section 400 and enters the heating section 300 and ventilation section 200 through the gaps between the sections. Positive pressure is generated in the heating section 300 and ventilation section 200. Combined with the installed seals, this limits the amount of oxidizing atmosphere entering the furnace and blocks most of the oxidizing atmosphere at the inlet of the ventilation section 200, preventing the oxidizing atmosphere from contacting the stainless steel tubes and causing decarburization. On the other hand, it prevents most of the oxidizing atmosphere from entering the higher-temperature heating section 400, avoiding increasing the activity of the oxidizing atmosphere and causing rapid decarburization of the stainless steel tubes. Moreover, since the above sections are interconnected, process gas can be injected into the rapid cooling section 400 to achieve full coverage of process gas throughout the entire line.

[0035] Furthermore, the cross-sectional area of ​​the inner cavity of the sealing section 210 is smaller than that of the inner cavity of the preheating section 220. The process gas flowing out of the rapid cooling section 400 flows into the preheating section 220 and then into the sealing section 210. The cross-sectional area of ​​the inner cavity of the sealing section 210 is relatively small, while the cross-sectional area of ​​the inner cavity of the preheating section 220 is relatively large. This helps to limit the outflow velocity of the process gas and is more conducive to the pressure holding of the sealing section 210 and the preheating section 220.

[0036] Furthermore, in this invention, the cross-sectional area of ​​the ventilation section 200 is smaller than that of the heating section 300, the connection between the ventilation section 200 and the heating section 300 is constricted relative to the internal space, the cross-sectional area of ​​the heating section 300 is smaller than that of the rapid cooling section 400, the connection between the heating section 300 and the rapid cooling section 400 is constricted relative to the internal space, the cross-sectional area of ​​the slow cooling section 500 is smaller than that of the rapid cooling section 400, and the connection between the slow cooling section 500 and the rapid cooling section 400 is constricted relative to the internal space.

[0037] Low-temperature process gas is injected from the rapid cooling section 400 and splits into two opposing flows to maintain the air pressure of the roller hearth protective atmosphere bright solution furnace, blocking the entry of oxidizing atmosphere and effectively preventing decarburization. Additionally, the low-temperature process gas washes the surface of the stainless steel tube in the gas exchange section 200, drying the lubricant on the surface into powder. This powdered lubricant is then carried out of the furnace by the airflow, effectively trapping and removing carbon sources from the stainless steel tube surface. The installed seals prevent most of the carbon source from entering the higher-temperature heating section 300, reducing the temperature at which the carbon atmosphere contacts the stainless steel tube and solving the problem of carbon buildup on the stainless steel tube surface.

[0038] like Figure 1 , Figure 2 and Figure 3 As shown, the spacing between the isolation boxes 700 in the sealed section 210 is smaller than the spacing between the isolation boxes 700 in the preheating section 220. Process gas is input into the furnace body in the rapid cooling section 400. The pressure is higher closer to the rapid cooling section 400; that is, the pressure in the heating section 300 is greater than that in the gas exchange section 200, and the pressure in the preheating section 220 is greater than that in the sealed section 210. Due to the pressure difference, external oxidizing atmospheres tend to flow into the sealed section 210 more easily than into the preheating section 220 and the heating section 300. To better prevent external oxidizing atmospheres from flowing into the furnace body, the spacing between the isolation boxes 700 in the sealed section 210 is relatively small, while the spacing between the isolation boxes 700 in the preheating section 220 is relatively large. A smaller spacing between the isolation boxes 700 results in better isolation of the oxidizing atmosphere.

[0039] Figure 1 , Figure 2 and Figure 3The material flow direction is shown. Conveying roller sets 800, arranged along the material flow direction, are installed throughout the feeding section 100, ventilation section 200, heating section 300, rapid cooling section 400, slow cooling section 500, and discharge section 600 to automatically transport the steel. Oxidizing atmosphere flows into the furnace body along with the stainless steel pipes. Isolation boxes 700 on the sealing section 210 are concentrated at one end of the sealing section 210 near the feeding section 100, while isolation boxes 700 on the preheating section 200 are distributed throughout the preheating section 200. By concentrating the isolation boxes 700 on the sealing section 210 at one end near the feeding section 100, the oxidizing atmosphere is isolated from the furnace body as much as possible from the front end, preventing the inflow of oxidizing gases. Since the isolation chamber 700 on the sealed section 210 has effectively isolated a considerable portion of the oxidizing atmosphere, the amount of oxidizing atmosphere flowing into the preheating section 220 is relatively small. Therefore, the isolation chambers 700 on the preheating section 220 are distributed throughout the preheating section 220, which helps to isolate the oxidizing atmosphere flowing into the preheating section 220 segment by segment, thereby improving the isolation effect of the oxidizing atmosphere.

[0040] The ventilation section 200 includes a sealing section 210 connected in sequence. The sealing section 210 and the preheating section 220 are heated to heat the stainless steel pipe flowing into them. The temperature of the inner cavity of the sealing section 210 is lower than that of the preheating section 220, and the temperature of the inner cavity of the preheating section 220 is arranged in a gradient along the flow direction. This allows the temperature of the stainless steel pipe to rise slowly and gradually as it flows through the ventilation section 200, so that it enters the heating section 300 at a temperature closer to that of the inner cavity of the heating section 300. This results in a smooth temperature rise for the stainless steel pipe, improves the solid solution quality, and avoids a rapid temperature rise when the stainless steel pipe enters the heating section 300.

[0041] In order to better isolate the oxidizing atmosphere from entering the furnace, the top of the slow cooling section 500 is also equipped with several isolation boxes 700 that are sealed to the steel to isolate the oxidizing atmosphere, thus preventing the external oxidizing atmosphere from entering the slow cooling section 500 and the fast cooling section 400.

[0042] like Figure 1 , Figure 2 and Figure 3As shown, a first exhaust port 230 is provided at the top of the sealed section 210 near the feeding section 100. Several isolation boxes 700 are located on the side of the first exhaust port 230 away from the feeding section 100. A second exhaust port 240 is provided at the top of the preheating section 220 near the sealed section 210. Several isolation boxes 700 are located on the side of the second exhaust port 240 away from the sealed section 210. The process gas (containing hydrogen and nitrogen) flowing into the sealed section 210 can be discharged from the first exhaust port 230. An ignition gun can be installed outside the first exhaust port 230 to dissipate the discharged hydrogen. In case of excessive pressure inside the furnace, some of the process gas can be discharged through the second exhaust port 240 to relieve pressure.

[0043] Furthermore, the top of the preheating section 220 is also provided with a gas extraction port 250 for connection to gas monitoring equipment and / or dew point detection equipment, so as to monitor the operating conditions of the process gas in the furnace and detect the dew point. Preferably, there are two gas extraction ports 250, but it is not limited to this number.

[0044] like Figures 2 to 8 As shown, the isolation box 700 includes a box body 710, a driver 720, a driving component 730, and a mounting base 740. The box body 710 has a sealed cavity 711 with a bottom opening. The driver 720 is mounted on the box body 710, and the driving component 730 is located in the sealed cavity 711. The driving component 730 is connected to the output end of the driver 720. The driver 720 drives the driving component 730 to move up and down within the sealed cavity 711. The mounting base 740 is mounted on the lower end of the driving component 730, extending downwards beyond the opening end of the sealed cavity 711. The mounting base 740 is used to hold a sealing component 750 that is pressed tightly against the steel. The driver 720 drives the driving component 730 to move up and down, causing the mounting base 740 to move up and down synchronously, so that the sealing component 750 is pressed tightly against the steel. When the roller hearth type protective atmosphere bright solution furnace 1000 is running, the conveyor roller group 800 continuously feeds in stainless steel tubes. As the stainless steel tubes flow into the sealing section 210 and the preheating section 220, the sealing element 750 remains tightly pressed against the stainless steel tube, preventing external oxidizing atmospheres from entering the ventilation section 200, heating section 300, rapid cooling section 400, and slow cooling section 500, ensuring effective isolation from oxidizing agents and thus guaranteeing the quality of the stainless steel tube heat treatment. When the stainless steel tube wears down due to prolonged contact with the sealing element 750, the driver 720 drives the driving component 730 downwards, causing the mounting base 740 to move downwards, keeping the sealing element 750 in close contact with the stainless steel tube, thereby ensuring the isolation effect against the oxidizing atmosphere.

[0045] Preferably, the seal 750 can be made of cloth, such as fiber cloth, or soft rubber, etc. The seal 750 can be installed on the mounting base 740 by clamping, snapping, locking, etc. Preferably, the mounting base 740 is a plate-shaped piece with three slots at the bottom. The seal 750 can be inserted into the slots and fixed with screws. The three seals 750 are arranged sequentially and spaced apart along the material conveying direction, which is equivalent to setting multiple layers of seals 750, improving the isolation effect against oxidizing atmospheres.

[0046] like Figures 4 to 8 As shown, the isolation box 700 also includes a transmission gear 760, a guide wheel 770, and a fixed seat 780 mounted on the top of the box body 710. The fixed seat 780 has a receiving cavity 781. The transmission gear 760 is rotatably mounted in the receiving cavity 781. The driver 720 drives the transmission gear 760 to rotate. The guide wheel 770 is rotatably disposed in the receiving cavity 781 and offset to one side of the transmission gear 760. The guide wheel 770 and the transmission gear 760 form a motion channel. The driving member 730 passes through the motion channel. A rack 731 arranged in the vertical direction is provided on one side of the driving member 730. The meshing transmission between the transmission gear 760 and the rack 731 drives the driving member 730 to perform vertical linear motion. The guide wheel 770 is rolledly connected to the other side of the driving member 730 relative to the rack 731. The guide wheel 770 guides the lifting and lowering of the drive component 730 to prevent the drive component 730 from tilting. Moreover, the guide wheel 770 is rolled to the other side of the drive component 730 relative to the rack 731, which makes the transmission between the two stable and has low resistance.

[0047] Preferably, the guide wheel 770 is an I-beam wheel, but it is not limited to this. The I-beam wheel can better restrict and guide the drive component 730. Preferably, there are two guide wheels 770 that are positioned opposite each other, one above the other. The two guide wheels 770 and the transmission gear 760 form a "triangular structure" that can stably support the drive component 730.

[0048] like Figures 4 to 8 As shown, the isolation box 700 also includes a protective sleeve 790 mounted on the fixed base 780 and covering the upper end of the drive unit 730. The upper end of the drive unit 730 is isolated from the external environment by means of the protective sleeve 790 to prevent the entry of oxidizing atmosphere. Preferably, the protective sleeve 790 can be a round tube or a square tube.

[0049] like Figures 4 to 8As shown, preferably, two spaced-apart fixed seats 780 are provided. Each fixed seat 780 contains the aforementioned transmission gear 760 and guide wheel 770. The two transmission gears 760 are coaxially arranged and connected by a transmission shaft 791. The transmission shaft 791 is mounted at the output end of the driver 720. The driver 720 drives the two transmission gears 760 to rotate synchronously by rotating the transmission shaft 791. Correspondingly, two driving members 730 are provided. The lower ends of both driving members 730 are fixed to the mounting base 740, providing better support for the mounting base 740. Furthermore, the two driving members 730 move up and down synchronously. A flange structure 712 is formed at the bottom of the housing 710. The flange structure 712 facilitates the installation of the isolation box 700 onto the sealing section 210, the preheating section 220, and the slow cooling section 500, and also helps to enhance sealing.

[0050] The following is a brief description of the working process of the roller hearth protective atmosphere bright solution furnace 1000 of this utility model, which isolates an oxidizing atmosphere: Stainless steel pipes are placed on the conveying roller group 800, which transports the stainless steel pipes along the material flow direction. The stainless steel pipes flow sequentially through the feeding section 100, the ventilation section 200, the heating section 300, the rapid cooling section 400, the slow cooling section 500, and the discharge section 600. Low-temperature process gas is introduced into the rapid cooling section 400. Part of the low-temperature process gas in the rapid cooling section 400 flows into the heating section 300 and the ventilation section 200. When the process gas flows into the ventilation section 200, it vents the residual air inside the ventilation section 200, evaporates the residual moisture on the surface of the stainless steel pipe, removes residual carbonaceous substances from the surface of the stainless steel pipe, and raises the temperature in the ventilation section 200 (below 950℃), preheating the stainless steel pipe. Isolation boxes 700 in the sealing section 210 and preheating section 220, as well as in the slow cooling section 500, isolate the stainless steel tube from the external oxidizing atmosphere, preventing its inflow. Next, the conveyor roller assembly 800 feeds the stainless steel tube into the heating section 300, where the temperature rises to 950-1150°C, causing all or most of the carbides in the stainless steel tube to dissolve, with the carbon dissolved in the austenite. The conveyor roller assembly 800 then feeds the stainless steel tube into the rapid cooling section 400 for rapid cooling, lowering the temperature from 1150°C to the designated temperature. The conveyor roller assembly 800 then feeds the cooled stainless steel tube into the slow cooling section 500, where the temperature is gradually reduced to the discharge temperature. Finally, it is conveyed to the discharge section 600 for output and packaging.

[0051] The above-disclosed examples are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of the present utility model. Therefore, any equivalent variations made in accordance with the claims of the present utility model shall fall within the scope of the present utility model.

Claims

1. A roller hearth type protective atmosphere bright solution furnace for isolating oxidizing atmosphere, characterized in that: It includes an interconnected ventilation section, heating section, rapid cooling section and slow cooling section along the logistics direction. The ventilation section includes a sealed section and a preheating section connected in sequence. The preheating section is connected to the heating section. The top of the sealed section and / or the preheating section is equipped with several isolation boxes that isolate the oxidizing atmosphere by sealing the steel with seals.

2. The roller hearth type protective atmosphere bright solution furnace according to claim 1, characterized in that, The cross-sectional area of ​​the inner cavity of the sealing section is smaller than that of the inner cavity of the preheating section. The spacing between the isolation boxes on the sealing section is smaller than that between the isolation boxes on the preheating section. The cross-sectional area of ​​the cavity of the ventilation section is smaller than that of the cavity of the heating section. The connection between the ventilation section and the heating section is constricted relative to the cavity space. The cross-sectional area of ​​the cavity of the heating section is smaller than that of the cavity of the rapid cooling section. The connection between the heating section and the rapid cooling section is constricted relative to the cavity space. The cross-sectional area of ​​the cavity of the slow cooling section is smaller than that of the cavity of the rapid cooling section. The connection between the slow cooling section and the rapid cooling section is constricted relative to the cavity space.

3. The roller hearth type protective atmosphere bright solution furnace according to claim 1, characterized in that, The top of the slow cooling section is also equipped with several isolation boxes that isolate the oxidizing atmosphere by sealing the steel with seals.

4. The roller hearth type protective atmosphere bright solution furnace according to claim 1, characterized in that, It also includes a feeding section and a discharging section. The feeding section, the ventilation section, the heating section, the rapid cooling section, the slow cooling section, and the discharging section are arranged sequentially along the material flow direction. Conveying roller groups for conveying steel are arranged along the material flow direction and pass through the feeding section, the ventilation section, the heating section, the rapid cooling section, the slow cooling section, and the discharging section. The isolation boxes on the sealed section are centrally located at one end of the sealed section near the feeding section.

5. The roller hearth type protective atmosphere bright solution furnace according to claim 1, characterized in that, The isolation boxes on the preheating section are distributed throughout the preheating section. The temperature of the inner cavity of the sealing section is lower than that of the inner cavity of the preheating section. The temperature of the inner cavity of the preheating section increases in a gradient along the material flow direction.

6. The roller hearth type protective atmosphere bright solution furnace according to claim 4, characterized in that, A first exhaust port is provided at the top of the sealed section near the feeding section, and several isolation boxes are arranged on the side away from the feeding section from the first exhaust port. A second exhaust port is provided at the top of the preheating section near the sealed section, and several isolation boxes are arranged on the side away from the sealed section from the second exhaust port.

7. The roller hearth type protective atmosphere bright solution furnace according to claim 1, characterized in that, The top of the preheating section is also provided with a gas extraction port for connection to gas monitoring equipment and / or dew point detection equipment.

8. The roller hearth type protective atmosphere bright solution furnace according to claim 1, characterized in that, The isolation box includes a box body, a driver, a driving component, and a mounting base. The box body has a sealed cavity with an opening at the bottom. The driver is mounted on the box body, and the driving component is located in the sealed cavity. The driving component is connected to the output end of the driver. The driver drives the driving component to move up and down within the sealed cavity. The mounting base is mounted on the lower end of the driving component and extends downward beyond the opening end of the sealed cavity. The mounting base is used to load a sealing component that is pressed tightly against the steel. The driver drives the driving component to move up and down, which in turn causes the mounting base to move up and down synchronously, so that the sealing component is pressed tightly against the steel.

9. The roller hearth type protective atmosphere bright solution furnace according to claim 8, characterized in that, The isolation box includes a transmission gear, a guide wheel, and a fixed base mounted on the top of the box. The fixed base has a receiving cavity. The transmission gear is rotatably mounted in the receiving cavity. The driver drives the transmission gear to rotate. The guide wheel is rotatably disposed in the receiving cavity and offset to one side of the transmission gear. The guide wheel and the transmission gear form a movement channel. The driving member passes through the movement channel. One side of the driving member has a rack arranged in a vertical direction. The meshing transmission between the transmission gear and the rack drives the driving member to perform vertical linear motion. The guide wheel is rolledly connected to the other side of the driving member opposite to the rack.

10. The roller hearth type protective atmosphere bright solution furnace according to claim 9, characterized in that, The isolation box also includes a protective sleeve installed on the fixed base and covering the upper end of the drive component, wherein the upper end of the drive component is isolated from the external environment by means of the protective sleeve.

Images