Variable Frequency Heating for Steel Pipe Weld Zone Temperature Control
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Solution Overview
Problem
Existing heating technologies for steel pipes face challenges in achieving precise temperature distribution and weld quality due to variations in material shape and properties, leading to inefficiencies and weld defects during continuous heating and welding processes.
Innovation Solution
A steel pipe weld zone heating apparatus and method utilizing a variable frequency alternating current power supply, coupled with imaging and measurement systems to dynamically adjust the frequency of the alternating current based on real-time temperature and melt shape data, ensuring accurate heat distribution and weld frequency control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fixed frequency alternating current is used for heating, then the heating process is simple and stable, but the temperature distribution cannot be precisely controlled when material shape or properties vary
Solution Approach 1:
The patent applies dynamics by transitioning from fixed frequency to variable frequency alternating current. The heating apparatus dynamically adjusts the frequency of the alternating current based on real-time feedback from temperature distribution detection, allowing the system to adapt to variations in material shape and properties while maintaining precise temperature control at the weld zone.
Solution Approach 2:
The patent changes the frequency parameter of the alternating current to optimize heating effectiveness. By varying the frequency within a predetermined range, the system can control the penetration depth and distribution of induced currents, thereby achieving desired temperature distributions in the weld zone regardless of material variations.
2Manufacturing precision
If variable frequency alternating current is used to control temperature distribution, then temperature control precision improves, but the device complexity and control difficulty increase
Solution Approach 1:
The patent implements feedback control by detecting the actual temperature distribution in the weld zone and using this information to adjust the frequency of the alternating current. This closed-loop control system automatically maintains the desired temperature distribution, simplifying operation while achieving high precision.
Solution Approach 2:
The heating apparatus performs self-adjustment by automatically modifying the current frequency based on detected temperature conditions. The system serves itself by detecting its own performance status and making necessary corrections without external intervention, thereby maintaining ease of operation despite the complexity of variable frequency control.
3Temperature
If high frequency is used for surface heating, then surface temperature increases, but the penetration depth decreases making through-thickness heating difficult
Solution Approach 1:
The patent utilizes parameter changes by varying the frequency of alternating current within a predetermined range. By adjusting the frequency, the system can control the balance between surface heating intensity and penetration depth, optimizing both surface temperature and through-thickness heat distribution according to specific welding requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables higher accuracy and efficiency in temperature distribution and weld quality, irrespective of the steel pipe's shape or material properties, thereby enhancing the consistency and quality of the weld zone during continuous heating and welding.
Implementation Method 1
uses a variable frequency alternating current power supply, whose frequency is variable within a predetermined frequency range, to generate joule heat by passing alternating current near end faces of the steel pipe material
Implementation Method 2
first imaging means installed opposite an end face weld zone of the steel pipe material that detects self-emitted light of the weld zone
Data Source
Figure 1(a)~1(b)
Figure 2(a)
Figure 2(b)
AI summary
This invention provides a steel pipe material weld zone heating method and apparatus for melting and welding the weld zone of a steel pipe material that during continuous induction heating and welding of moving steel pipe material as the material being heated controls temperature distribution and molten steel shape and weld frequency fluctuation with high accuracy and high efficiency, irrespective of the shape of the heated region of material being heated or the material properties of the material being heated, which comprises a first imaging step in which first imaging means 3 installed opposite an end face weld zone of the steel pipe material is used to detect self-emitted light of the weld zone and output a brightness image, a weld zone temperature distribution computation step in which image processing is performed based on the brightness image and emitted light temperature measurement is applied to compute the plate-thickness direction temperature distribution of the weld zone, a heating control step in which a criterion defined in advance for the relationship between alternating current frequency and plate-thickness direction temperature distribution is used to determine the frequency of the alternating current based on the plate-thickness direction temperature distribution, and a step in which the variable frequency alternating current power supply 1 is used to pass through the steel pipe material 10 alternating current of the frequency determined in the heating control step.