A brass annealing process using a natural gas annealing furnace

Abstract

This invention discloses a brass annealing process using a natural gas annealing furnace, aiming to solve the problem of water spots easily forming on the surface of brass products during heat treatment using a natural gas annealing furnace. The invention includes the following steps: S1, starting the blower of the natural gas annealing furnace; S2, igniting the natural gas annealing furnace; S3, when the furnace temperature reaches 500-600 degrees Celsius, extinguishing the furnace and stopping heating, and turning off the blower; S4, loading the brass product into the furnace for preheating, and allowing the brass product to stand still in the furnace; S5, restarting the blower, and then igniting the furnace; S6, holding the furnace at 350-450 degrees Celsius, and after the holding time, cooling the brass product in the furnace to 180-220 degrees Celsius before removing it from the furnace. The brass annealing process using a natural gas annealing furnace is not affected by power restrictions, and water spots do not appear during the brass annealing process, ensuring product quality.

Description

Technical Field

[0001] This invention relates to a brass heat treatment technology, and more specifically, to a brass annealing process using a natural gas annealing furnace. Background Technology

[0002] Brass rods, wires, and profiles are widely used due to their outstanding comprehensive properties such as conductivity, wear resistance, corrosion resistance, and machinability, especially in the refrigeration, automotive parts, and sanitary ware industries. Market demand for them in instruments, meters, electronic appliances, headphone jacks, pen tips, and communication equipment remains strong. The production process for brass products generally involves raw material smelting, casting copper ingots, heating the ingots, hot extrusion thermoplastic deformation, cold plastic deformation of billets, annealing heat treatment, and finishing. Annealing heat treatment is one of the key processes for controlling the performance of brass products, generally including recrystallization annealing and stress-relief annealing. However, traditional annealing heat treatment furnaces for brass products use electric heating furnaces. Due to the influence of the furnace load and electricity prices, the cost per ton of annealing heat treatment furnace remains high, especially during periods of high temperatures and power rationing, directly affecting the company's output and delivery. To avoid the shortcomings of electric heating furnaces, many companies use natural gas annealing furnaces for heat treatment. However, natural gas combustion produces water vapor, which easily penetrates the surface of brass products at high temperatures, causing white water spots. Customers generally require a bright, yellowish surface and cannot accept white oxidized spots. Therefore, pickling or peeling processes are usually added to ensure product surface quality. However, pickling is environmentally unfriendly and costly, while peeling typically requires multiple steps to completely remove the white oxidized spots, thus affecting the yield. Both pickling and peeling increase the production cycle and costs for copper processing companies. Companies urgently need to explore improvement methods to reduce overall production costs and increase profit margins. Summary of the Invention

[0003] To overcome the above shortcomings, the present invention provides a brass annealing process using a natural gas annealing furnace. The annealing heat treatment is carried out using a natural gas annealing furnace, which is not affected by power restrictions. Water spots will not appear during the brass annealing process, thus ensuring product quality.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a brass annealing process using a natural gas annealing furnace, comprising the following steps:

[0005] S1, start the blower of the natural gas annealing furnace to make the airflow inside the natural gas annealing furnace circulate in the furnace;

[0006] S2, ignition of the natural gas annealing furnace, which raises the temperature inside the furnace;

[0007] S3, when the temperature inside the furnace of the natural gas annealing furnace reaches 500-600 degrees Celsius, the furnace is shut down to stop heating and the blower is turned off;

[0008] S4. Load the brass products into the furnace and use the residual heat in the furnace to preheat the brass products. Let the brass products stand in the furnace for 1-2 hours.

[0009] S5, restart the fan, then ignite the ignition to heat the brass product;

[0010] S6: The furnace is kept at 350-450 degrees Celsius. After the holding time is up, the brass products are cooled to 180-220 degrees Celsius and then removed from the furnace.

[0011] The natural gas annealing furnace is ignited, raising the temperature inside the furnace to 500-600 degrees Celsius. Airflow is circulated by a fan to ensure uniform temperature throughout the furnace. Heating is then stopped by extinguishing the flame and shutting off the fan. At this point, most of the water vapor in the furnace has been expelled. The brass products are then placed back into the furnace for preheating. The residual heat in the furnace is transferred to the brass products, raising their temperature. When the surface temperature of the brass products reaches above 200 degrees Celsius, an oxide film forms on the surface, preventing water repellency. This prevents water vapor generated during the later annealing process from seeping into the surface of the brass products and causing white oxide spots. This eliminates product defects caused by white oxide spots on the annealed heat-treated products, ensuring product surface quality. It also eliminates the need for additional processing steps to remove white oxide spots, shortens the processing flow and cycle, and increases the yield of brass products, resulting in ideal practical effects.

[0012] The brass annealing process using a natural gas annealing furnace described in this application employs a natural gas annealing furnace for annealing heat treatment, which is not affected by power restrictions. Water spots will not appear during the brass annealing process, thus ensuring product quality.

[0013] Preferably, before the brass products are loaded into the furnace, S4 stacks the brass products on the transfer platform, and then the transfer platform is transported into the furnace.

[0014] Brass products are first stacked and then transferred into the furnace for easy handling.

[0015] As a preferred option, during step S5, the fan and ignition should be turned on only after the surface temperature of the brass product approaches 200 degrees Celsius.

[0016] The surface temperature of brass products is close to 200 degrees Celsius, which can form an oxide film on the surface and prevent water spots from forming.

[0017] As a preferred option, the heat preservation time is 4.5-5.5 hours for S6.

[0018] The heat preservation time is set reasonably to ensure the annealing effect of brass products.

[0019] Preferably, the brass product is heated to the holding temperature of S6 at S5.

[0020] The brass product is directly heated to the holding temperature, which facilitates the holding operation.

[0021] Preferably, several heat-conducting plates are installed inside the natural gas annealing furnace, forming a heating chamber between the heat-conducting plates and the inner wall of the natural gas annealing furnace. The opening end of the heating chamber is close to the top of the natural gas annealing furnace, and a natural gas burner is installed inside the heating chamber.

[0022] In S2, the natural gas burner is ignited, and the natural gas combustion generates heat, which is transferred into the furnace through the heat conduction plate. The water vapor and carbon dioxide generated during combustion are discharged to the top of the natural gas annealing furnace through the opening end of the heating chamber, avoiding water vapor residue in the furnace that could cause water spots to form on the surface of the brass products.

[0023] Preferably, a flame hole is provided at the lower part of the heat-conducting plate, and a movable cover plate is installed on the heat-conducting plate to cover the flame hole. The cover plate is connected to a lever. A gas channel switching head is installed on the natural gas flame head. The gas channel switching head is provided with an inlet pipe, an upper outlet pipe, a lower outlet pipe, and a valve plate. The inlet pipe is connected to the natural gas flame head, the upper outlet pipe is set upwards, and the lower outlet pipe is set towards the flame hole. A track groove is provided on the side wall of the natural gas annealing furnace, and the lever extends into the track groove. S4 stacks the brass products on the transfer platform and then transfers them into the natural gas annealing furnace. The transfer platform is provided with a guide rail. The guide rail slides in the guide rail groove, thereby pushing the lever, so that the cover plate moves to expose the flame hole. At the same time, it drives the valve plate to move, so that the gas channel switching head switches from connecting the inlet pipe and the upper outlet pipe to connecting the inlet pipe and the lower outlet pipe.

[0024] In S2, the cover plate closes the flame hole, the natural gas flame head is ignited, the inlet pipe is connected to the upper outlet pipe, the upper outlet pipe sprays flame upward to generate heat, and the heat is transferred into the furnace through the heat conduction plate. The water vapor and carbon dioxide generated during the combustion process are discharged to the top of the natural gas annealing furnace through the opening end of the heating chamber, so as to avoid water vapor remaining in the furnace and forming water spots on the surface of the brass products.

[0025] In step S4, the brass products are stacked and placed on the transfer platform before being transported to the natural gas annealing furnace. The guide rail slides in the guide groove, pushing the lever to move the cover plate, exposing the flame holes. Simultaneously, the valve plate moves, switching the gas flow switching head from connecting the inlet pipe and upper outlet pipe to connecting the inlet pipe and lower outlet pipe. In step S5, the lower outlet pipe sprays flames into the flame holes, generating heat. At this point, combustion occurs directly below the transfer platform, resulting in good heat transfer. After step S6, the transfer platform moves out of the furnace. Under gravity, the cover plate returns to its original position, closing the flame holes, and the valve plate returns to its original position, connecting the inlet pipe and upper outlet pipe.

[0026] Preferably, the heat-conducting plate is mounted on a rotating turntable, and the cover plate and lever are both connected to the turntable.

[0027] When the lever is moved, the turntable rotates, causing the cover plate to deviate from its position, resulting in smooth and reliable operation.

[0028] Preferably, the heat-conducting plate is provided with an installation groove, and the turntable and cover plate are both set in the installation groove. A limiting strip is installed in the installation groove, and a limiting groove is formed between the limiting strip and the bottom surface of the installation groove. A connecting rib is connected between the cover plate and the turntable, and the connecting rib is inserted into the limiting groove.

[0029] During the movement of the cover plate, the connecting rib is limited in the limiting groove to ensure that the cover plate can reliably cover the flame hole.

[0030] Preferably, the airway switching head is equipped with an upper air outlet baffle and a lower air outlet baffle. The upper air outlet baffle is located between the air inlet pipe and the upper air outlet pipe, and the lower air outlet baffle is located between the air inlet pipe and the lower air outlet pipe. Both the upper and lower air outlet baffles are provided with vent holes. A rotating shaft is installed at the connection position between the upper and lower air outlet baffles. A valve plate is fastened to the rotating shaft. The rotating shaft is connected to the turntable. The surface of the valve plate can seal and cover the vent holes on the upper or lower air outlet baffle.

[0031] As the lever is pushed, the turntable rotates. The rotating shaft is connected to the turntable, so the turntable also rotates, thereby realizing the rotation reversal of the valve plate.

[0032] Compared with the prior art, the beneficial effects of the present invention are: the brass annealing process using a natural gas annealing furnace of this application uses a natural gas annealing furnace for annealing heat treatment, which is not affected by power restrictions, and water spots will not appear during the brass annealing process, thus ensuring product quality. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the natural gas annealing furnace according to Embodiment 2 of the present invention;

[0034] Figure 2 This is a schematic diagram of the heat-conducting plate connection structure of Embodiment 2 of the present invention;

[0035] Figure 3 This is a schematic diagram of the airway switching head according to Embodiment 2 of the present invention;

[0036] In the diagram: 1. Natural gas annealing furnace, 2. Heat-conducting plate, 3. Fan, 4. Heating chamber, 5. Natural gas burner head, 6. Burner hole, 7. Cover plate, 8. Lever, 9. Gas duct switching head, 10. Inlet pipe, 11. Upper outlet pipe, 12. Lower outlet pipe, 13. Valve plate, 14. Track groove, 15. Mounting groove, 16. Limiting strip, 17. Limiting groove, 18. Connecting rib, 19. Upper outlet baffle, 20. Lower outlet baffle, 21. Vent hole, 22. Rotating shaft, 23. Sealing gasket. Detailed Implementation

[0037] The technical solution of the present invention will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings:

[0038] Example 1: A brass annealing process using a natural gas annealing furnace, comprising the following steps:

[0039] S1, start the blower of the natural gas annealing furnace to circulate the airflow inside the furnace. The blower is a variable frequency blower, and the air volume is adjusted by frequency conversion.

[0040] S2, ignition of the natural gas annealing furnace, which raises the temperature inside the furnace;

[0041] S3, when the temperature inside the furnace of the natural gas annealing furnace reaches 500-600 degrees Celsius, the furnace is shut down to stop heating and the blower is turned off;

[0042] S4. Load the brass products into the furnace and use the residual heat in the furnace to preheat the brass products. Let the brass products stand in the furnace for 1-2 hours.

[0043] S5, restart the fan, then ignite the ignition to heat the brass product;

[0044] S6: The furnace is kept at 350-450 degrees Celsius. After the holding time is up, the brass products are cooled to 180-220 degrees Celsius and then removed from the furnace.

[0045] In S4, before the brass products are loaded into the furnace, the brass products are stacked on the transfer platform, and then the transfer platform is moved into the furnace. In S5, after the surface temperature of the brass products approaches 200 degrees Celsius, the blower and ignition are turned on. In S6, the holding time is 4.5-5.5 hours.

[0046] This method is applicable to the operation of natural gas annealing heat treatment furnaces for brass bars, wires and profiles with a copper content of 55%-65%, such as HPb57-3, HPb58-3, HPb58-2, HPb59-3, HPb59-2, HPb59-1, H62, and H65.

[0047] The natural gas annealing furnace is ignited, raising the temperature inside the furnace to 500-600 degrees Celsius. Airflow is circulated by a fan to ensure uniform temperature throughout the furnace. Heating is then stopped by extinguishing the flame and shutting off the fan. At this point, most of the water vapor in the furnace has been expelled. The brass products are then placed back into the furnace for preheating. The residual heat in the furnace is transferred to the brass products, raising their temperature. When the surface temperature of the brass products reaches above 200 degrees Celsius, an oxide film forms on the surface, preventing water repellency. This prevents water vapor generated during the later annealing process from seeping into the surface of the brass products and causing white oxide spots. This eliminates product defects caused by white oxide spots on the annealed heat-treated products, ensuring product surface quality. It also eliminates the need for additional processing steps to remove white oxide spots, shortens the processing flow and cycle, and increases the yield of brass products, resulting in ideal practical effects.

[0048] Example 2: A brass annealing process using a natural gas annealing furnace. The process steps are similar to those in Example 1, with the main difference being that in this example, several heat-conducting plates 2 are installed inside the natural gas annealing furnace 1, and a fan 3 is installed between two adjacent heat-conducting plates. The fan installed on one side wall is positioned opposite to the heat-conducting plate installed on the opposite side wall. A heating chamber 4 is formed between the heat-conducting plates and the inner wall of the natural gas annealing furnace. The opening end of the heating chamber is close to the top of the natural gas annealing furnace, and a natural gas burner head 5 is installed inside the heating chamber. A flame hole 6 is provided at the lower part of the heat-conducting plate. A movable cover plate 7 is installed on the heat-conducting plate, which covers the flame hole. The cover plate is connected to a lever 8. A gas channel switching head 9 is installed on the natural gas flame head. The gas channel switching head is provided with an inlet pipe 10, an upper outlet pipe 11, a lower outlet pipe 12, and a valve plate 13. The inlet pipe is connected to the natural gas flame head. The upper outlet pipe is set upwards, and the lower outlet pipe is set towards the flame hole. A track groove 14 is provided on the side wall of the natural gas annealing furnace. The lever extends to the track groove. S4 stacks brass products on the transfer platform and then transfers them into the natural gas annealing furnace. The transfer platform is provided with a guide rail. The guide rail slides in the guide rail groove, thereby pushing the lever, so that the cover plate moves to expose the flame hole. At the same time, it drives the valve plate to move, so that the gas channel switching head switches from connecting the inlet pipe and the upper outlet pipe to connecting the inlet pipe and the lower outlet pipe. The heat-conducting plate has a mounting groove 15, in which the turntable and cover plate are both set. A limiting strip 16 is installed in the mounting groove, forming a limiting groove 17 between the limiting strip and the bottom surface of the mounting groove. A connecting rib 18 connects the cover plate and the turntable, and the connecting rib is inserted into the limiting groove. An upper air outlet baffle 19 and a lower air outlet baffle 20 are provided inside the airway switching head. The upper air outlet baffle is located between the inlet pipe and the upper air outlet pipe, and the lower air outlet baffle is located between the inlet pipe and the lower air outlet pipe. Both the upper and lower air outlet baffles have vent holes 21. A rotating shaft 22 is installed at the connection point between the upper and lower air outlet baffles. A valve plate is securely connected to the rotating shaft, and sealing gaskets 23 are installed on both sides of the valve plate. The rotating shaft is connected to the turntable, and the surface of the valve plate can seal and cover the vent holes on the upper or lower air outlet baffle. A torsion spring is installed between the rotating shaft and the airway switching head, so that the valve plate is initially attached to the lower air outlet baffle.

[0049] In S2, the cover plate closes the flame hole, the natural gas flame head is ignited, the inlet pipe is connected to the upper outlet pipe, the upper outlet pipe sprays flame upward to generate heat, and the heat is transferred into the furnace through the heat conduction plate. The water vapor and carbon dioxide generated during the combustion process are discharged to the top of the natural gas annealing furnace through the opening end of the heating chamber, so as to avoid water vapor remaining in the furnace and forming water spots on the surface of the brass products.

[0050] In step S4, the brass products are stacked and placed on the transfer platform before being transferred to the natural gas annealing furnace. The guide rail slides in the guide rail groove, pushing the lever to move the cover plate, exposing the flame holes. Simultaneously, the valve plate moves, switching the gas flow switching head from connecting the inlet pipe and the upper outlet pipe to connecting the inlet pipe and the lower outlet pipe. In step S5, the lower outlet pipe sprays flames into the flame holes, generating heat. At this point, combustion occurs directly below the transfer platform, resulting in good heat transfer. After step S6, the transfer platform moves out of the furnace chamber. Under gravity, the cover plate returns to its original position and closes the flame holes, and the valve plate returns to its original position, connecting the inlet pipe and the upper outlet pipe. Other process steps are the same as in Example 1.

[0051] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Other variations and modifications may be made without departing from the technical solutions described in the claims.

Claims

1. A brass annealing process using a natural gas annealing furnace, characterized in that, Includes the following steps: S1, start the blower of the natural gas annealing furnace to make the airflow inside the natural gas annealing furnace circulate in the furnace; S2, ignition of the natural gas annealing furnace, which raises the temperature inside the furnace; S3, when the temperature inside the furnace of the natural gas annealing furnace reaches 500-600 degrees Celsius, the furnace is shut down to stop heating and the blower is turned off; S4. Load the brass products into the furnace and use the residual heat in the furnace to preheat the brass products. Let the brass products stand in the furnace for 1-2 hours. S5, restart the fan, then ignite the ignition to heat the brass product; S6, the furnace is kept at 350-450 degrees Celsius. After the holding time is up, the brass products are cooled to 180-220 degrees Celsius in the furnace and then taken out of the furnace. Several heat-conducting plates are installed inside the natural gas annealing furnace, forming a heating chamber between the heat-conducting plates and the inner wall of the furnace. The opening of the heating chamber is close to the top of the furnace, and a natural gas burner is installed inside the chamber. A burner hole is provided at the bottom of the heat-conducting plate, and a movable cover plate is installed on the heat-conducting plate. In S2, the cover plate closes the burner hole, the natural gas burner is ignited, and the natural gas combustion generates heat, which is transferred to the furnace through the heat-conducting plate. In S4, the cover plate moves to expose the burner hole, and in S5, the burner injects gas into the burner hole to generate heat.

2. The brass annealing process using a natural gas annealing furnace according to claim 1, characterized in that, Before the brass products are loaded into the furnace, S4 stacks the brass products on the transfer platform, and then the transfer platform is transported into the furnace.

3. The brass annealing process using a natural gas annealing furnace according to claim 1, characterized in that, When using S5, wait until the surface temperature of the brass product approaches 200 degrees Celsius before turning on the fan and igniting.

4. The brass annealing process using a natural gas annealing furnace according to claim 1, characterized in that, For S6, the heat preservation time is 4.5-5.5 hours.

5. The brass annealing process using a natural gas annealing furnace according to claim 1, characterized in that, At step S5, the brass product is heated to the holding temperature of step S6.

6. The brass annealing process using a natural gas annealing furnace according to claim 1, characterized in that, The cover plate is connected to the lever; a gas channel switching head is installed on the natural gas burner head. The gas channel switching head is equipped with an inlet pipe, an upper outlet pipe, a lower outlet pipe, and a valve plate. The inlet pipe is connected to the natural gas burner head, the upper outlet pipe is set upwards, and the lower outlet pipe is set towards the burner hole; a track groove is set on the side wall of the natural gas annealing furnace, and the lever extends into the track groove. S4 stacks brass products on the transfer platform and then transfers them into the natural gas annealing furnace. The transfer platform is equipped with a guide rail. The guide rail slides in the track groove to push the lever, so that the cover plate moves to expose the burner hole. At the same time, it drives the valve plate to move so that the gas channel switching head switches from connecting the inlet pipe and the upper outlet pipe to connecting the inlet pipe and the lower outlet pipe.

7. The brass annealing process using a natural gas annealing furnace according to claim 6, characterized in that, The heat-conducting plate is mounted on a rotating turntable, and the cover plate and lever are all connected to the turntable.

8. The brass annealing process using a natural gas annealing furnace according to claim 7, characterized in that, The heat-conducting plate is provided with an installation groove, and the turntable and cover plate are both set in the installation groove. A limiting strip is installed in the installation groove, and a limiting groove is formed between the limiting strip and the bottom surface of the installation groove. A connecting rib is connected between the cover plate and the turntable, and the connecting rib is inserted into the limiting groove.

9. The brass annealing process using a natural gas annealing furnace according to claim 7, characterized in that, The airway switching head is equipped with an upper air outlet baffle and a lower air outlet baffle. The upper air outlet baffle is located between the air inlet pipe and the upper air outlet pipe, and the lower air outlet baffle is located between the air inlet pipe and the lower air outlet pipe. Both the upper and lower air outlet baffles are provided with vent holes. A rotating shaft is installed at the connection position between the upper and lower air outlet baffles. A valve plate is fastened to the rotating shaft. The rotating shaft is connected to the turntable. The surface of the valve plate can seal and cover the vent holes on the upper or lower air outlet baffle.

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