Dynamic temperature control ceramic heating device and method for welding preheating of steel structure

Abstract

The invention discloses a dynamic temperature control ceramic heating device and method for welding preheating of a steel structure, and belongs to the technical field of metal welding process equipment. The technical problems that an existing ceramic heating belt temperature control system is poor in temperature control precision, poor in temperature uniformity, low in automation degree and lack of process recording traceability in the welding preheating process of a large steel structure are solved. The multi-loop heating unit comprises at least two mutually independent ceramic heating bands, and each ceramic heating band is connected with an independent power adjusting module; the multi-point multi-path temperature measuring unit comprises a plurality of temperature sensors for monitoring the surface temperature of the workpiece in real time; the input end of the controller is connected with the multi-point multi-path temperature measuring unit, the output end of the controller is connected with the power adjusting module of the multi-loop heating unit, and the controller is used for independently controlling the heating power of each heating belt according to the multi-path temperature feedback signals; and the human-computer interaction interface is electrically connected with the controller and is used for intensively displaying the real-time temperature of each area and setting control parameters.

Description

Technical Field

[0001] This invention relates to the field of metal welding process equipment technology, specifically to a dynamic temperature-controlled ceramic heating device and method for preheating large steel structural components, particularly watertight bulkheads of ships and transverse diaphragms of steel bridges, before welding. Background Technology

[0002] In the shipbuilding and bridge manufacturing industry, watertight bulkheads and box girder transverse diaphragms generally use medium-thick plate low-alloy high-strength steel to meet the comprehensive requirements of the structure for strength, weight and safety.

[0003] High-strength hull structural steels widely used in shipbuilding mainly include the 32 series, which is commonly used in the main hull and strong deck of large ships; the 36 series, which is currently the most mainstream high-strength steel for large bulk carriers, container ships and oil tankers; and the 40 series, which is suitable for special areas with higher requirements for weight reduction and load-bearing capacity.

[0004] In bridge construction, bridge structural steel conforming to specific standards is commonly used, such as Q345qC / D / E, Q370qC / D / E series steel, Q370qC / DE series steel, and Q420qC / D / E / F series steel. In addition, there are ultra-high strength bridge steels such as Q500q, Q550q, and Q690q; however, due to their high carbon equivalent and difficulty in welding, these types of steel are not yet widely used.

[0005] This type of steel is prone to defects such as hardened structure and cold cracks during welding. Therefore, the weld area must be preheated before welding and post-weld heat treatment to remove hydrogen must be performed. Strict requirements are placed on the preheating temperature, heating rate, isothermal temperature, and uniformity of the weld area.

[0006] Currently, common preheating methods include flame heating, induction heating, and resistance heating. Ceramic heating strips are widely used due to their flexibility, ability to conform to complex curved surfaces, and high thermal efficiency. However, most existing ceramic heating strip temperature control systems have the following drawbacks:

[0007] 1. Poor temperature control accuracy: Most systems use simple "on-off" control or PID fixed-point control. For workpieces with large heat capacity, the temperature overshoot or lag is serious, making it difficult to stabilize the workpiece temperature within the narrow range required by the process.

[0008] 2. Poor temperature uniformity: Single-point temperature measurement cannot reflect the true temperature distribution of the entire heating area, which can easily lead to local overheating or insufficient heating.

[0009] 3. Low level of automation: The preheating, heating, heat preservation and cooling processes rely heavily on manual adjustment based on workers' experience, making it impossible to achieve automated operation of the program. Human factors have a significant impact, resulting in poor process consistency.

[0010] 4. Lack of process records: It is impossible to record and trace the temperature profiles during preheating and welding in real time, which is not conducive to quality control and responsibility determination.

[0011] Therefore, there is an urgent need for a dynamic temperature control device and method that can achieve high precision, high uniformity, and automated program control. Summary of the Invention

[0012] To address the technical problems of existing ceramic heating belt temperature control systems in the preheating process of large steel structure welding, such as poor temperature control accuracy, poor temperature uniformity, low automation, and lack of process recording and traceability, this invention provides a dynamic temperature-controlled ceramic heating device and method for steel structure welding preheating.

[0013] In one aspect, the present invention provides a dynamic temperature-controlled ceramic heating device for preheating steel structure welding, comprising:

[0014] Multi-loop heating unit: includes at least two independent ceramic heating strips, each of which is connected to an independent power adjustment module;

[0015] Multi-point, multi-channel temperature measurement unit: includes several temperature sensors for real-time monitoring of the workpiece surface temperature;

[0016] Controller: Its input terminal is connected to the multi-point multi-channel temperature measurement unit, and its output terminal is connected to the power adjustment module of the multi-loop heating unit. It is used to independently control the heating power of each heating band according to the multi-channel temperature feedback signal.

[0017] Human-machine interface: electrically connected to the controller, used to centrally display the real-time temperature of each area and set control parameters;

[0018] Data storage module: Used to store historical data of the temperature control process.

[0019] Preferably, the controller is pre-loaded with a fuzzy adaptive PID control algorithm.

[0020] Preferably, the temperature sensor is a K-type armored thermocouple, which is fixed to the surface of the workpiece by a magnetic temperature measuring base.

[0021] Preferably, the surface of the ceramic heating belt has a high-performance ceramic coating.

[0022] Preferably, it also includes a wireless communication module for transmitting real-time temperature data and alarm information to a remote monitoring terminal.

[0023] In another aspect, the present invention provides a dynamic temperature-controlled ceramic heating method for preheating steel structure welding, comprising the following steps:

[0024] S1. Process parameter settings: Input the target preheating temperature, heating rate and holding time through the human-machine interface;

[0025] S2. Installation and Start-up: Arrange the ceramic heating belt in the area of ​​the workpiece to be welded, and evenly distribute and fix multiple temperature sensors; start the device.

[0026] S3. Dynamic temperature rise control: The controller dynamically adjusts the output power of each power adjustment module based on the temperature feedback from multiple temperature sensors, so that the workpiece is heated uniformly at a set rate.

[0027] S4 Intelligent heat preservation control: When the temperature at the measuring point reaches the target temperature and stabilizes, the heat preservation stage begins; the controller continuously compares the temperature at each measuring point and independently fine-tunes the power of the corresponding heating belt to achieve a balanced and stable regional temperature.

[0028] S5. Process monitoring and recording: Real-time display of temperature-time curves and recording of all temperature data;

[0029] S6. Alarm and linkage: If the temperature of any measuring point exceeds the limit or the sensor fails, the device will issue an alarm and automatically cut off the heating power.

[0030] S7. End: After the heat preservation time is reached, the device will automatically stop heating.

[0031] Preferably, in step S3, the control algorithm adopts a fuzzy adaptive PID algorithm.

[0032] Preferably, in step S2, for butt welds, the total width W of the ceramic heating band satisfies: Where H is the thickness of the base material, and the safe distance between the inner edge of the ceramic heating band and the center line of the weld is... Not less than 50mm.

[0033] Preferably, in step S2, for fillet welds, ceramic heating strips are symmetrically arranged on both sides of the joint, and the width of the ceramic heating strip on each side satisfies the following: Where H is the thickness of the base material, and the safe distance between the inner edge of the ceramic heating band and the weld toe. Not less than 50mm.

[0034] Preferably, the temperature fluctuation during the heat preservation stage is controlled within... Within this range, the accuracy of the heating rate control .

[0035] The beneficial effects of this invention are:

[0036] 1. High temperature control accuracy and good uniformity: Through multi-channel independent temperature control and multi-point multi-channel temperature measurement feedback, combined with intelligent control algorithms, it can compensate for thermal field differences in real time, effectively suppress overshoot, and ensure that the temperature is accurately and stably within the process requirements range.

[0037] 2. High degree of automation and intelligence: The entire process can be automatically controlled with a single setup, significantly reducing labor intensity and reliance on operator experience, and ensuring process consistency;

[0038] 3. Full-process traceability: The system fully records historical temperature data, providing a reliable basis for quality assessment and accountability.

[0039] 4. High safety and reliability: It integrates multiple hardware and software protection measures to fully ensure the safety of equipment and operation. Attached Figure Description

[0040] Figure 1 This is a system principle block diagram of the device of the present invention;

[0041] Figure 2 This is a flowchart of the dynamic temperature control method of the present invention;

[0042] Figure 3 This is a schematic diagram of the metal plate zone temperature control of the present invention;

[0043] Figure 4 This is a schematic diagram of the heating band arrangement for butt welds;

[0044] Figure 5 This is a schematic diagram of the arrangement of heating bands for fillet welds;

[0045] Figure 6 This is a schematic diagram of a specific example. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0048] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0049] Specific Implementation Method 1: The following is combined with... Figures 1 to 6This embodiment describes a dynamic temperature-controlled ceramic heating device for preheating steel structure welding, comprising a multi-loop heating unit: including at least two independent ceramic heating strips, each of which is connected to an independent power adjustment module;

[0050] Multi-point, multi-channel temperature measurement unit: includes several temperature sensors for real-time monitoring of the workpiece surface temperature;

[0051] Controller: Its input terminal is connected to the multi-point multi-channel temperature measurement unit, and its output terminal is connected to the power adjustment module of the multi-loop heating unit. It is used to independently control the heating power of each heating band according to the multi-channel temperature feedback signal.

[0052] Human-machine interface: electrically connected to the controller, used to centrally display the real-time temperature of each area and set control parameters;

[0053] Data storage module: Used to store historical data of the temperature control process.

[0054] The controller is pre-loaded with a fuzzy adaptive PID control algorithm.

[0055] The temperature sensor is a K-type armored thermocouple, which is fixed to the surface of the workpiece by a magnetic temperature measuring base.

[0056] The surface of the ceramic heating belt has a high-performance ceramic coating.

[0057] It also includes a wireless communication module for transmitting real-time temperature data and alarm information to a remote monitoring terminal.

[0058] Based on the above-mentioned device, the present invention provides a dynamic temperature-controlled ceramic heating method for preheating steel structure welding, the method comprising the following steps:

[0059] S1. Process parameter settings: Input the target preheating temperature, heating rate and holding time through the human-machine interface;

[0060] S2. Installation and Start-up: Arrange the ceramic heating belt in the area of ​​the workpiece to be welded, and evenly distribute and fix multiple temperature sensors; start the device.

[0061] For butt welds, the total width W of the ceramic heating band satisfies: Where H is the thickness of the base material, and the safe distance between the inner edge of the ceramic heating band and the center line of the weld is... Not less than 50mm.

[0062] For fillet welds, ceramic heating strips are symmetrically arranged on both sides of the joint, and the width of the ceramic heating strips on each side meets the following requirements: Where H is the thickness of the base material, and the safe distance between the inner edge of the ceramic heating band and the weld toe. Not less than 50mm.

[0063] S3. Dynamic heating control: The controller dynamically adjusts the output power of each power adjustment module based on the temperature feedback from multiple temperature sensors, so that the workpiece heats up uniformly at a set rate; the control algorithm adopts the fuzzy adaptive PID algorithm.

[0064] S4 Intelligent heat preservation control: When the temperature at the measuring point reaches the target temperature and stabilizes, the heat preservation stage begins; the controller continuously compares the temperature at each measuring point and independently fine-tunes the power of the corresponding heating belt to achieve a balanced and stable regional temperature.

[0065] S5. Process monitoring and recording: Real-time display of temperature-time curves and recording of all temperature data;

[0066] S6. Alarm and linkage: If the temperature of any measuring point exceeds the limit or the sensor fails, the device will issue an alarm and automatically cut off the heating power.

[0067] S7. End: After the heat preservation time is reached, the device will automatically stop heating.

[0068] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0069] Example 1: Preheating control for welding diaphragms of large steel structure bridges

[0070] This embodiment takes the preheating process of the butt weld of the box girder diaphragm (material Q370qD, plate thickness 25mm) of a large steel structure bridge as an example to illustrate the implementation of the device of the present invention.

[0071] 1. Device Configuration and Integration

[0072] refer to Figure 1 The system principle block diagram shown is illustrated below. The specific configuration of the device in this embodiment is as follows:

[0073] Multi-loop heating unit: Four flexible ceramic fiber heating strips are used, each with a rated power of 2kW and a length of 1.5 meters. Each heating strip is connected to an independent solid-state relay as a power regulation module.

[0074] Multi-point, multi-channel temperature measurement unit: Four K-type armored thermocouples are used as temperature sensors, connected via a strong magnetic temperature measuring base (magnetic...). It adheres firmly to the surface of the workpiece.

[0075] The core controller uses a main control board developed based on the STM32F407 microprocessor, which embeds a fuzzy adaptive PID control algorithm. Analog input ports connect to thermocouple signals, and four PWM output ports drive four solid-state relays after optocoupler isolation.

[0076] Human-Machine Interaction and Recording: A 7-inch industrial touchscreen is used as the human-machine interface, communicating with the controller via an RS485 interface. The controller is expanded with an SD card data storage module for full-cycle temperature data recording.

[0077] Key protective structure: The ceramic heating belt selected in this embodiment is coated with a high-performance ceramic coating. This coating, after sintering and curing, possesses resistance to high temperatures up to 1200℃, excellent high-temperature oxidation resistance, resistance to chemical corrosion from welding spatter, and good electrical insulation properties. These are crucial for ensuring the long-term reliable operation of the heating belt near the welding arc. The power-conducting parts of the device are integrated into an IP54-rated enclosure, and the heating belt is wrapped with a high-temperature resistant (… Ceramic fiber insulation blankets are used to reduce heat loss and ensure operational safety.

[0078] 2. Installation and Layout

[0079] refer to Figure 4 Schematic diagram of butt weld and installation based on quantitative specifications for base metal thickness (H=25mm):

[0080] Calculation parameters: The total heating width must meet the following requirements. Select Set a safe distance. ( Minimum value).

[0081] Physical installation: Select a 200mm wide heating strip and lay it in place, aligning its inner edge with a distance of 60mm from the weld centerline. The heating strip covers an area of ​​60mm to 260mm, and through heat conduction, heat can be applied to both sides of the weld centerline. The area has met the preheating requirements.

[0082] Temperature measurement point arrangement: Fix the thermocouple 135mm from the center line of the weld (edge ​​of the heating range). All sensor signal cables should be routed according to specifications and connected to the control box.

[0083] 3. Operation and Control Procedures

[0084] Combination Figure 2 The control method flowchart and operation steps are as follows:

[0085] S1. Parameter Settings: Set process parameters on the touchscreen: target preheating temperature. heating rate The heat preservation time is t=30 minutes. The over-temperature alarm threshold is set to... The low temperature alarm threshold is .

[0086] S2. Start-up: After confirming that the installation is correct, start the system. The controller will begin to read the temperatures of the four thermocouples in a loop.

[0087] S3. Dynamic Heating: The controller calculates the average temperature at four points and, based on its deviation from the set heating curve, runs a fuzzy adaptive PID algorithm to dynamically adjust the duty cycle of the PWM signal output to the four solid-state relays, thereby independently and precisely controlling the instantaneous power of each heating band. This process automatically compensates for differences in the thermal field caused by uneven workpiece thickness and different heat dissipation conditions, achieving stable and uniform heating of the entire area at a set rate.

[0088] S4, Intelligent Heat Preservation: When the temperature at all measuring points reaches... Once stabilized, the system automatically enters the heat preservation phase. The controller continuously compares the temperatures at four points. If a temperature at any point is too low, the power of the corresponding heating element is slightly increased; if a temperature at any point is too high, the power is reduced, achieving closed-loop balanced control and strictly controlling temperature fluctuations during the heat preservation period. Within.

[0089] S5. Monitoring and Recording: Throughout the entire heating and heat preservation process, the touchscreen displays four temperature readings in real time. Time curve. All temperature data is stored on an SD card at a frequency of 1 time per second, generating a traceable electronic record.

[0090] S6. Safety Protection: During welding, thanks to the protection of the high-performance ceramic coating, spattered weld spatter will not damage the heating element. Simultaneously, if the system detects that the temperature at any measuring point exceeds [a certain value], [further protection will be provided]. If the thermocouple breaks down, an audible and visual alarm will be triggered immediately, and the power supply to all heating circuits will be automatically cut off within 2 seconds.

[0091] S7. End: After 30 minutes of heat preservation, the system automatically stops heating and indicates that the preheating process is complete. The welder can remove the insulation blanket and perform welding operations directly next to the protected heating zone.

[0092] Example 2: Preheating control of fillet welds in watertight compartment walls of ships

[0093] This embodiment uses the T-shaped fillet weld of a watertight bulkhead (material EH36, web thickness 20mm) of a bulk carrier as an example to illustrate the application of the present invention in complex joints.

[0094] 1. Installation and layout

[0095] refer to Figure 5 and Figure 6 Schematic diagram of fillet weld heating band, based on quantitative specifications (web thickness) ):

[0096] Panel side: Select a 60mm wide heating strip and place its inner edge 50mm away from the weld toe;

[0097] Web side: Select a 120mm wide heating strip, placing its inner edge 50mm from the weld toe, ensuring it covers the entire thickness of the web. The symmetrical heating strip coverage areas are not marked in the figure.

[0098] Temperature monitoring: Install a thermocouple on each side of the panel and web, 110 mm from the weld toe.

[0099] Welding operation: The heating elements on both sides work simultaneously, and the intelligent temperature controller adjusts the temperature based on the combined temperature of both sides, allowing the welder to work in a safe area for fillet welds.

[0100] 2. Control characteristics

[0101] The controller treats the thermocouple signals from both sides of the panel and the web as two independent but coordinated control loops. The system uses the average temperature of both sides as the primary control target, while also considering the temperature difference between the two sides. Through a fuzzy adaptive PID algorithm, the power of the heating bands on both sides is intelligently allocated to ensure that, even with structural asymmetry and different heat dissipation conditions, the root of the fillet weld and the heat-affected zones on both sides can achieve a uniform preheating temperature that meets the process requirements.

[0102] The above embodiments fully demonstrate the flexibility, accuracy, and reliability of the device and method of the present invention. By comprehensively applying multi-loop independent temperature control, multi-point multi-path feedback, intelligent control algorithms, and high-temperature resistant protective coatings, key technical challenges in the preheating of large steel structure welding have been successfully solved, achieving standardization, automation, and traceability of the process.

[0103] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A dynamic temperature-controlled ceramic heating device for preheating steel structure welding, characterized in that, include: Multi-loop heating unit: includes at least two independent ceramic heating strips, each of which is connected to an independent power adjustment module; Multi-point, multi-channel temperature measurement unit: includes several temperature sensors for real-time monitoring of the workpiece surface temperature; Controller: Its input terminal is connected to the multi-point multi-channel temperature measurement unit, and its output terminal is connected to the power adjustment module of the multi-loop heating unit. It is used to independently control the heating power of each heating band according to the multi-channel temperature feedback signal. Human-machine interface: electrically connected to the controller, used to centrally display the real-time temperature of each area and set control parameters; Data storage module: Used to store historical data of the temperature control process.

2. The dynamic temperature-controlled ceramic heating device for preheating steel structure welding according to claim 1, characterized in that, The controller is pre-loaded with a fuzzy adaptive PID control algorithm.

3. The dynamic temperature-controlled ceramic heating device for preheating steel structure welding according to claim 1, characterized in that, The temperature sensor is a K-type armored thermocouple, which is fixed to the surface of the workpiece by a magnetic temperature measuring base.

4. The dynamic temperature-controlled ceramic heating device for preheating steel structure welding according to claim 1, characterized in that, The surface of the ceramic heating belt has a high-performance ceramic coating.

5. The dynamic temperature-controlled ceramic heating device for preheating steel structure welding according to claim 1, characterized in that, It also includes a wireless communication module for transmitting real-time temperature data and alarm information to a remote monitoring terminal.

6. A dynamic temperature-controlled ceramic heating method for preheating welding of steel structures, the method employing the apparatus as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Process parameter settings: Input the target preheating temperature, heating rate and holding time through the human-machine interface; S2. Installation and Start-up: Arrange the ceramic heating belt in the area of ​​the workpiece to be welded, and evenly distribute and fix multiple temperature sensors; start the device. S3. Dynamic temperature rise control: The controller dynamically adjusts the output power of each power adjustment module based on the temperature feedback from multiple temperature sensors, so that the workpiece is heated uniformly at a set rate. S4 Intelligent heat preservation control: When the temperature at the measuring point reaches the target temperature and stabilizes, the heat preservation stage begins; the controller continuously compares the temperature at each measuring point and independently fine-tunes the power of the corresponding heating belt to achieve a balanced and stable regional temperature. S5. Process monitoring and recording: Real-time display of temperature-time curves and recording of all temperature data; S6. Alarm and linkage: If the temperature of any measuring point exceeds the limit or the sensor fails, the device will issue an alarm and automatically cut off the heating power. S7. End: After the heat preservation time is reached, the device will automatically stop heating.

7. The dynamic temperature-controlled ceramic heating method for preheating steel structure welding according to claim 6, characterized in that, In step S3, the control algorithm adopts the fuzzy adaptive PID algorithm.

8. The dynamic temperature-controlled ceramic heating method for preheating steel structure welding according to claim 6, characterized in that, In step S2, for butt welds, the total width W of the ceramic heating band satisfies: Where H is the thickness of the base material, and the safe distance between the inner edge of the ceramic heating band and the center line of the weld is... Not less than 50mm.

9. The dynamic temperature-controlled ceramic heating method for preheating steel structure welding according to claim 6, characterized in that, In step S2, for fillet welds, ceramic heating strips are symmetrically arranged on both sides of the joint, and the width of the ceramic heating strip on each side satisfies the following: Where H is the thickness of the base material, and the safe distance between the inner edge of the ceramic heating band and the weld toe. Not less than 50mm.

10. A dynamic temperature-controlled ceramic heating method for preheating steel structure welding according to any one of claims 6 to 9, characterized in that, Temperature fluctuations during the insulation stage are controlled within Within this range, the accuracy of the heating rate control .

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