Grain-Oriented Electrical Steel Composition for Lower Building Factor
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Solution Overview
Problem
Grain-oriented electrical steel sheets used in transformer iron cores exhibit a high building factor, leading to increased iron loss despite low material iron loss, which is not adequately addressed by existing techniques.
Innovation Solution
Control the Co and Ti content within specific ranges in the base steel sheet and form a forsterite-based film on its surface, while maintaining a specific ratio of hysteresis loss to iron loss, to optimize magnetic properties and reduce the building factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inhibitor components (AlN, MnS, MnSe) are used to promote secondary recrystallization, then stable growth of secondary recrystallized grains is achieved, but high-temperature slab heating (1300°C or more) is required to dissolve inhibitor components in solid solution
Solution Approach 1:
The patent extracts and eliminates inhibitor components from the steel composition, achieving secondary recrystallization through the texture inhibition effect alone. By removing Al, Mn, Se, and S content to specific ranges, the need for high-temperature heating to dissolve inhibitors is eliminated, resolving the contradiction between stable grain growth and high heating temperature requirements.
Solution Approach 2:
The patent changes the compositional parameters by strictly controlling Al, Mn, Se, and S content to create conditions for texture inhibition effect. This parameter change allows secondary recrystallization to occur at lower temperatures without requiring the dissolution of inhibitor components in solid solution.
2Stability of the object's composition
If high-temperature slab heating is applied to dissolve inhibitor components, then fine particle distribution of inhibitors is achieved, but production cost and maintenance requirements increase
Solution Approach 1:
The patent removes inhibitor components from the steel composition entirely, eliminating the need for high-temperature heating processes. By extracting the inhibitor function and replacing it with compositional control for texture inhibition effect, the patent reduces production cost and maintenance requirements while achieving the desired microstructure.
3Loss of energy
If magnetic domain refining techniques (laser irradiation, electron beam irradiation) are applied to decrease iron loss, then magnetic domain width is reduced, but process complexity and production cost increase
Solution Approach 1:
The patent enables the steel to self-regulate its magnetic properties through compositional control during standard hot-rolling and annealing processes. By controlling Al, Mn, Se, and S content to achieve texture inhibition effect and appropriate grain structure, the steel inherently achieves reduced iron loss without requiring additional laser or electron beam irradiation equipment.
4Ease of manufacture
If standard production processes are used without compositional control, then production simplicity is maintained, but building factor remains high leading to insufficient transformer performance
Solution Approach 1:
The patent implements specific compositional parameter ranges for Al (0.003-0.030%), Mn (0.030-1.000%), Se (0.000-0.010%), and S (0.000-0.010%) to achieve the texture inhibition effect. These parameter changes are integrated into standard hot-rolling and annealing processes, maintaining production simplicity while significantly improving transformer performance by reducing the building factor.
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 proposed solution results in a grain-oriented electrical steel sheet with significantly reduced building factor, improving transformer performance by balancing hysteresis and eddy current losses.
Implementation Method 1
such texture is formed through a phenomenon called secondary recrystallization where crystal grains with {110} orientation, also known as Goss orientation, grow preferentially to large sizes during purification annealing
Implementation Method 2
eddy current loss is mainly decreased when magnetic domain refining techniques are applied
Data Source
AI summary
Provided is a grain-oriented electrical steel sheet having magnetic properties that can sufficiently decrease the building factor. The grain-oriented electrical steel sheet includes a base steel sheet containing Si: 1.50 mass % to 8.00 mass %, Mn: 0.02 mass % to 1.00 mass %, and Co: 0.005 mass % to 0.050 mass %, and a base film mainly composed of forsterite, formed on the surface of the base steel sheet. Ti content in the base steel sheet and the base film as a whole is 0.0050 mass % to 0.0200 mass %. When R17 is the ratio of hysteresis loss Wh17 to iron loss W17/50 when excited at 1.7 T, and R19 is the ratio of hysteresis loss Wh19 to iron loss W19/50 when excited at 1.9 T, then 0.30≤R17≤R19 is satisfied.