Heating method and device suitable for forming pipes with different wall thicknesses

Abstract

According to the heating method and device suitable for forming of the pipes with the different wall thicknesses, the pipes are divided into different heating areas according to the wall thicknesses and the structural characteristics of different positions, and the temperature measurement result and the energy absorption block are used for measuring the temperature gradient between the different areas while partition electrification self-resistance heating is conducted; and feedback adjustment is carried out on the overall temperature field distribution of the pipe, so that the heating uniformity of the pipe can be effectively improved, and all local parts of a final pipe product can achieve preset mechanical properties, forming precision and durability in long-term use.

Description

Technical Field

[0001] The invention belongs to the technical field of metal pipe hot forming technology, and in particular relates to a heating method and a device suitable for forming pipes with unequal wall thicknesses. Background Art

[0002] With the development of high-end equipment manufacturing technologies such as aerospace and automobile manufacturing, the demand for special-shaped parts with both high strength and light weight in related fields has increased significantly, and higher requirements have been put forward for the forming indicators of unequal wall thickness tubes used in the processing of such parts. In the process of hot forming (such as hot bending and hot stamping) of unequal wall thickness tubes, there are still a series of heating control problems to be solved, including plastic flow instability, lack of dynamic phase change control, and mold thermal interaction interference. Due to the obvious difference in the local heat conduction efficiency of different wall thicknesses, it is easy to cause uneven temperature field distribution in various regions of the tube. Severe oxidation will occur at locations where the temperature is too high, affecting the surface quality and subsequent processing performance of the material; at locations where the temperature is too low, insufficient softening of the material and high hardness will occur, thereby reducing the forming adaptability and increasing the difficulty of processing; at the same time, the influence of inconsistent quenching effects in different regions of the component on the final mechanical properties cannot be ignored. Although some existing technologies have realized this technical problem and proposed a method of heating in different tube regions using several heaters separately, due to its heat conduction method and slow heating speed, it is still impossible to fundamentally solve the problem of heating uniformity and efficiency. Therefore, how to improve the heating method during the forming process of tubes with unequal wall thicknesses to improve temperature uniformity and reduce the possibility of process defects is a technical problem that urgently needs to be solved in this field. Summary of the invention

[0003] In view of this, in view of the technical problems existing in the art, the present invention provides a heating method suitable for forming tubes with unequal wall thicknesses, which specifically includes the following steps:

[0004] Step 1: Divide the pipe to be processed into different heating areas based on the wall thickness and shape structure of each local area, and arrange the low-temperature area and the high-temperature area to be heated on the pipe at intervals;

[0005] Step 2: Heating electrodes are respectively arranged at both ends of the high temperature zone to form a conductive connection with an external heating power source, and a corresponding temperature sensor is respectively arranged for each zone to measure its temperature; an energy absorbing block that can contact and separate from the outer surface of the low temperature zone is arranged for the low temperature zone to absorb heat and reduce the temperature of the low temperature zone;

[0006] Step 3: Turn on the external heating power supply to energize the high-temperature zones separated from each other, and use their own resistance for heating; during the heating process, use the temperature sensor to monitor the temperature of each zone and the temperature difference between different zones, feedback-adjust the heating current based on the temperature monitoring results, and adjust the contact time between the energy-absorbing block and the outer surface of the low-temperature zone according to the temperature difference, so that the temperature gradient between different zones remains stable;

[0007] Step 4: Continue the heating and energy absorbing block adjustment process of step 3 until the entire pipe reaches a predetermined temperature field distribution.

[0008] Furthermore, the energy absorbing block is specifically made of any one of non-conductive materials such as ceramics, composite carbon materials, etc.

[0009] Furthermore, in the heating process of step three, cold and hot gas spraying, non-contact radiation heaters, etc. are used to adjust and optimize the real-time temperature field distribution of the pipe.

[0010] Accordingly, the present invention also provides a heating device for performing the above method and suitable for forming tubes of unequal wall thickness, comprising: a heating electrode, an energy absorbing block, a temperature sensor and a heating control unit;

[0011] Among them, the heating electrode is used to form a conductive connection between the pipe and its high-temperature zone to be heated and the external heating power supply; the energy-absorbing block is arranged on the outside of the low-temperature zone, and is used to contact with the outer surface of the low-temperature zone to absorb excess heat; the temperature sensor is used to monitor the temperature of each area and provide the monitoring signal to the heating control unit; the heating control unit adjusts the corresponding heating power of each area based on the temperature sensor signal; and calculates the temperature difference between adjacent areas, and adjusts the contact time between the energy-absorbing block and the outer surface of the low-temperature zone according to the result, thereby realizing feedback adjustment of the overall temperature field distribution of the pipe.

[0012] The heating method and device provided by the present invention, which is suitable for forming tubes with unequal wall thicknesses, divides the tubes into different heating areas according to the wall thicknesses and structural characteristics at different positions, and while the zones are powered on for self-resistance heating, uses temperature measurement results and energy-absorbing blocks to perform feedback adjustment on the temperature gradient between different areas and the overall temperature field distribution of the tubes, which can effectively improve the uniformity of tube heating and enable all parts of the final tube product to achieve the predetermined mechanical properties, forming accuracy and durability in long-term use. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 Schematic diagram of the division of different areas of the pipe and the setting of energy absorbing blocks;

[0014] Figure 2 Schematic diagram of the zone heating process using heating electrodes. DETAILED DESCRIPTION

[0015] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] The present invention provides a heating method suitable for forming pipes of unequal wall thickness, which specifically comprises the following steps:

[0017] Step 1: Divide the pipe to be processed into different heating areas based on the wall thickness and shape structure of each local area, and arrange the low-temperature area and high-temperature area to be heated on the pipe at intervals, such as Figure 1 , 2 As shown;

[0018] Step 2: Heating electrodes are respectively arranged at both ends of the high temperature zone to form a conductive connection with an external heating power source, and a corresponding temperature sensor is respectively arranged for each zone to measure its temperature; an energy absorbing block that can contact and separate from the outer surface of the low temperature zone is arranged for the low temperature zone to absorb heat and reduce the temperature of the low temperature zone;

[0019] Step 3: Turn on the external heating power supply to energize the high-temperature zones separated from each other, and use their own resistance for heating; during the heating process, use the temperature sensor to monitor the temperature of each zone and the temperature difference between different zones, feedback-adjust the heating current based on the temperature monitoring results, and adjust the contact time between the energy-absorbing block and the outer surface of the low-temperature zone according to the temperature difference, so that the temperature gradient between different zones remains stable;

[0020] Step 4: Continue the heating and energy absorbing block adjustment process in step 3 until the entire pipe reaches a predetermined temperature field distribution.

[0021] In a preferred embodiment of the present invention, the energy absorbing block is specifically made of any one of non-conductive materials such as ceramics, composite carbon materials, etc.

[0022] In a preferred embodiment of the present invention, during the heating process of step three, hot and cold gas spraying, non-contact radiation heaters, etc. are used to adjust and optimize the real-time temperature field distribution of the pipe.

[0023] Accordingly, the present invention also provides a heating device for performing the above method and suitable for forming tubes of unequal wall thickness, comprising: a heating electrode, an energy absorbing block, a temperature sensor and a heating control unit;

[0024] Among them, the heating electrode is used to form a conductive connection between the pipe and its high-temperature zone to be heated and the external heating power supply; the energy-absorbing block is arranged on the outside of the low-temperature zone, and is used to contact with the outer surface of the low-temperature zone to absorb excess heat; the temperature sensor is used to monitor the temperature of each area and provide the monitoring signal to the heating control unit; the heating control unit controls and adjusts the corresponding heating power of each area based on the temperature sensor signal; and calculates the temperature difference between adjacent areas, and adjusts the contact time between the energy-absorbing block and the outer surface of the low-temperature zone according to the result, thereby realizing feedback adjustment of the overall temperature field distribution of the pipe.

[0025] It should be understood that the size of the serial numbers of the steps in the embodiment of the present invention does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present invention.

[0026] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A heating method suitable for forming tubes with unequal wall thicknesses, characterized in that: The specific steps include: Step 1: Divide the pipe to be processed into different heating areas based on the wall thickness and shape structure of each local area, and arrange the low-temperature area and the high-temperature area to be heated on the pipe at intervals; Step 2: Heating electrodes are respectively arranged at both ends of the high temperature zone to form a conductive connection with an external heating power source, and a corresponding temperature sensor is respectively arranged for each zone to measure its temperature; an energy absorbing block that can contact and separate from the outer surface of the low temperature zone is arranged for the low temperature zone to absorb heat and reduce the temperature of the low temperature zone; Step 3: Turn on the external heating power supply to energize the high-temperature zones separated from each other, and use their own resistance for heating; during the heating process, use the temperature sensor to monitor the temperature of each zone and the temperature difference between different zones, feedback-adjust the heating current based on the temperature monitoring results, and adjust the contact time between the energy-absorbing block and the outer surface of the low-temperature zone according to the temperature difference, so that the temperature gradient between different zones remains stable; Step 4: Continue the heating and energy absorbing block adjustment process of step 3 until the entire pipe reaches a predetermined temperature field distribution.

2. The method according to claim 1, characterized in that: The energy absorbing block is specifically made of any one of ceramics and composite carbon materials.

3. The method according to claim 1, characterized in that: During the heating process of step three, hot and cold gas spraying and / or non-contact radiation heaters are used to adjust and optimize the real-time temperature field distribution of the pipe.

4. A heating device for forming tubes of unequal wall thicknesses for executing the method according to any one of claims 1 to 3, characterized in that: It includes a heating electrode, an energy absorbing block, a temperature sensor and a heating control unit; Among them, the heating electrode is used to form a conductive connection between the pipe and its high-temperature zone to be heated and the external heating power supply; the energy-absorbing block is arranged on the outside of the low-temperature zone, and is used to contact with the outer surface of the low-temperature zone to absorb excess heat; the temperature sensor is used to monitor the temperature of each area and provide the monitoring signal to the heating control unit; the heating control unit adjusts the corresponding heating power of each area based on the temperature sensor signal; and calculates the temperature difference between adjacent areas, and adjusts the contact time between the energy-absorbing block and the outer surface of the low-temperature zone according to the result, thereby realizing feedback adjustment of the overall temperature field distribution of the pipe.

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