Grain-Oriented Electrical Steel Annealing for β-Angle Control
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Solution Overview
Problem
Existing methods for manufacturing grain-oriented electrical steel sheets struggle to achieve optimal magnetic properties, particularly in reducing iron loss, due to challenges in controlling the β angle during secondary recrystallization annealing.
Innovation Solution
The development of a grain-oriented electrical steel sheet with a specific chemical composition and manufacturing process, including secondary recrystallization orientation control using coil annealing, to achieve favorable magnetic properties by controlling the deviation angles and area ratios of secondary recrystallized grains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If secondary recrystallization annealing is performed to achieve Goss orientation texture, then magnetic flux density is improved, but iron loss increases due to uncontrollable β angle deviation
Solution Approach 1:
The invention changes the chemical composition parameters (adding 0.003-0.030% C, controlling Si at 3.0-3.8%, Mn at 0.05-0.20%, and adding grain boundary segregation elements Sb 0.003-0.020% or Sn 0.003-0.020%) to control the β angle deviation during secondary recrystallization, thereby reducing iron loss while maintaining magnetic flux density
Solution Approach 2:
The invention introduces grain boundary segregation elements (Sb or Sn) as intermediaries that segregate to grain boundaries during secondary recrystallization annealing, controlling the β angle deviation and preventing excessive iron loss while allowing Goss orientation development
2Loss of energy
If the β angle is controlled to reduce iron loss, then energy efficiency improves, but manufacturing complexity increases due to multiple composition constraints
Solution Approach 1:
The invention simplifies manufacturing by establishing specific compositional ranges (C: 0.003-0.030%, Si: 3.0-3.8%, Mn: 0.05-0.20%, Sb or Sn: 0.003-0.020%) that automatically control β angle during secondary recrystallization, eliminating the need for complex post-annealing β angle adjustment processes
3Loss of energy
If chemical composition is optimized to control β angle, then iron loss is reduced, but manufacturing cost increases due to stricter material requirements
Solution Approach 1:
The invention balances composition optimization by adding small amounts of cost-effective elements (Sb or Sn at 0.003-0.020%, C at 0.003-0.030%) to control β angle, achieving iron loss reduction without requiring expensive rare earth elements or complex alloying systems
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 results in a grain-oriented electrical steel sheet with improved magnetic flux density and reduced iron loss, while also enhancing productivity in the manufacturing process.
Implementation Method 1
Such texture is formed through secondary recrystallization annealing of preferentially causing the growth of giant crystal grains in (110)[001] orientation which is called Goss orientation
Implementation Method 2
secondary recrystallization orientation control using coil annealing
Data Source
AI summary
Provided is a method for manufacturing a grain-oriented electrical steel sheet. A steel slab having a specific chemical composition is heated and hot rolled. A hot-rolled steel sheet thus obtained is subjected to hot band annealing to obtain a cold-rolled steel sheet, which is then subjected to primary recrystallization annealing to obtain a primary recrystallized steel sheet. An annealing separator is applied to the primary recrystallized steel sheet, which is then coiled. The coil is subjected to secondary recrystallization annealing to obtain a grain-oriented electrical steel sheet having an average value of a deviation angle (α2+β2)1/2 calculated from a deviation angle α from ideal Goss orientation around an ND rotation axis and a deviation angle β from ideal Goss orientation around a TD rotation axis of 4.5° or less, and an area ratio Rβ of crystal grains with β≤0.50° of 15% or less.