Induction Heated Roll Build-Up Welding
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Solution Overview
Problem
Conventional methods for providing a secondary conductor on the inner circumferential surface of an induction heated roll apparatus require multiple complex processes, are not suitable for high-speed rotation, and result in reduced thermal conductivity due to thermal expansion differences and inadequate adhesion.
Innovation Solution
A secondary conductor made of aluminum bronze is formed on the inner surface of the roll main body using build-up welding, eliminating the need for additional processes like plating and fitting, and ensuring integration and stability during high-speed rotation by forming a protective oxide coating that prevents oxidation and corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional methods (brazing, press-fitting, shrink-fitting) are used to provide a secondary conductor on the inner circumferential surface of the roll main body, then the secondary conductor can be provided, but the number of working processes increases and thermal conductivity decreases due to mechanical contact only and thermal expansion differences
Solution Approach 1:
The patent combines the secondary conductor and roll main body into a single integrated structure through build-up welding, eliminating the need for separate fitting processes (brazing, press-fitting, or shrink-fitting). This merging approach reduces the number of working processes while ensuring continuous thermal contact, thereby maintaining thermal conductivity without the loosening issues that arise from thermal expansion differences in mechanically fitted structures.
2Strength
If brazing is used to fit the secondary conductor, then adhesion is enhanced, but it is difficult to perform brazing over the entire outer circumferential surface and the method is inappropriate for high-speed rotation
Solution Approach 1:
The patent replaces the thermal joining process (brazing) with build-up welding, which creates a stronger and more reliable bond suitable for high-speed rotation. Build-up welding allows for complete coverage of the outer circumferential surface and creates a rigid connection that can withstand the centrifugal forces and vibrations associated with high-speed operation, overcoming the limitations of brazing.
3Ease of manufacture
If press-fitting or shrink-fitting is used to provide the secondary conductor, then the fitting process is simplified, but the roll main body and secondary conductor are only mechanically in close contact and thermal expansion differences cause loosening
Solution Approach 1:
The patent merges the secondary conductor and roll main body into a single welded structure, eliminating the mechanical contact interface that causes loosening due to thermal expansion differences. Build-up welding creates a permanent, rigid connection that maintains stable contact under varying temperature conditions, preventing the loosening issues inherent in press-fitted or shrink-fitted structures.
4Reliability
If a plating process is performed on the secondary conductor for rust prevention, then corrosion resistance is improved, but the number of working processes increases
Solution Approach 1:
The patent uses aluminum bronze, which is an inherently corrosion-resistant copper alloy, as the material for the secondary conductor. This composite material approach eliminates the need for additional plating processes while maintaining or improving corrosion resistance. The aluminum bronze material provides both the electrical conductivity needed for induction heating and the corrosion resistance that would otherwise require separate protective coatings.
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 reduces the number of working processes, maintains thermal conductivity, and allows for efficient induction heating with improved power factor and temperature control, making it suitable for high-speed applications.
Implementation Method 1
an induction coil for allowing the roll main body to inductively generate heat, and allowing the roll main body to inductively generate heat by applying alternating current (AC) voltage having a commercial frequency to the induction coil
Implementation Method 2
allows the roll main body to inductively generate heat
Implementation Method 3
a secondary conductor is formed by build-up welding
Implementation Method 4
a protective oxide coating film is formed on the surface of aluminum bronze, and therefore aluminum bronze is characterized by preventing oxidation at high temperatures
Data Source
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AI summary
The present invention is one that intends to reduce the number of working processes necessary to provide a secondary conductor on the inner circumferential surface of a roll main body, and an induction heated roll apparatus including: a roll main body that is rotatably supported, and an induction heating mechanism that is provided inside the roll main body and has an induction coil for allowing the roll main body to inductively generate heat. In addition, on the inner circumferential surface of the roll main body, the secondary conductor is formed by build-up welding.