Grain-Oriented Steel Sheet Grooves for Stable Magnetic Domain Refinement
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Solution Overview
Problem
Existing methods for refining magnetic domains in grain-oriented electrical steel sheets, such as etching, rolling, and laser techniques, face challenges in uniformly controlling iron loss characteristics, stability, and environmental friendliness, particularly in maintaining low magnetic flux density degradation and high energy conversion efficiency.
Innovation Solution
A grain-oriented electrical steel sheet with grooves and a solidified alloy layer containing recrystallized particles of specific sizes, formed using a continuous wave laser with controlled cooling speeds and oxide layers, to enhance magnetic domain refinement and reduce iron loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a groove is formed on the surface of the steel sheet by selective electrochemical reaction (etching method), then magnetic domain refinement is achieved, but it is difficult to uniformly control groove shape and secure iron loss characteristics in the width direction
Solution Approach 1:
The patent replaces the electrochemical etching method with a mechanical rolling method that uses a roller with protrusions to directly form grooves on the steel sheet surface. This mechanical approach provides precise control over groove dimensions and uniformity across the width direction, eliminating the variability inherent in electrochemical processes.
Solution Approach 2:
The patent changes the fundamental parameter of groove formation from chemical reaction control to mechanical dimensional control. By using a roller with specifically designed protrusion geometry, the groove width, depth, and spacing can be precisely controlled and uniformly replicated across the entire steel sheet width, ensuring consistent iron loss characteristics.
2Manufacturing precision
If the roll method is used to form grooves by processing a protrusion shape on the roll, then magnetic domain miniaturization is achieved, but stability in machine processing and reliability to obtain stable iron loss depending on thickness is poor
Solution Approach 1:
The patent applies local quality by creating grooves with specific dimensional characteristics at precise locations on the steel sheet surface. The roller protrusions are designed to form grooves with controlled width and depth that vary locally to optimize magnetic domain refinement while maintaining overall process stability and consistent iron loss characteristics across different thicknesses.
3Shape
If a laser of pulse and non-Gaussian mode is used to form grooves, then solidified alloy layer is formed at the side wall, but excessive deformation occurs at the bottom part of the groove
Solution Approach 1:
The patent replaces the laser-based thermal process with a mechanical rolling process that forms grooves through direct contact pressure. This eliminates the thermal effects and excessive deformation associated with laser processing, while still achieving the desired groove shape and solidified alloy layer formation through controlled mechanical deformation during rolling.
4Shape
If continuous wave laser is used to form grooves, then solidified alloy layer is formed entirely or partially, but it is difficult to control recrystallized particles' grain size through thickness control
Solution Approach 1:
The patent changes the control parameter for grain size from thermal thickness control (laser method) to mechanical pressure and rolling speed control. By adjusting the roller protrusion geometry, rolling force, and rolling speed, the groove dimensions and subsequent recrystallized particle grain size can be precisely controlled throughout the steel sheet thickness, achieving uniform grain structure without the limitations of laser-based thermal processing.
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
The method effectively reduces magnetic flux density degradation and improves iron loss characteristics, allowing for efficient energy conversion and stable performance in transformers after heat treatment.
Implementation Method 1
a groove forming step of irradiating a continuous wave laser having a Gaussian energy distribution to a steel sheet surface
Implementation Method 2
forms a solidified alloy layer of the groove part only at the side wall
Implementation Method 3
forms a solidified alloy layer of the groove part only at the side wall or does not uniformly form the groove
Implementation Method 4
a stress relaxation annealing step of performing stress relaxation annealing after the groove formation
Data Source
AI summary
A grain-oriented electrical steel sheet incudes a groove formed on a surface and a solidified alloy layer formed under the groove, wherein the solidified alloy layer includes particles of a certain average diameter.