Grain-Oriented Electrical Steel Sheet Te-N Composition Control
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Solution Overview
Problem
The existing manufacturing methods for grain-oriented electrical steel sheets face challenges in achieving both good magnetic properties and a satisfactory appearance of the glass coating film, particularly when Te is added, as it can lead to defects in the coating film.
Innovation Solution
A manufacturing method involving specific composition ranges of elements like Si, C, Mn, Al, N, S, P, and Te, along with controlled nitridation annealing and finish annealing processes, to set the N content between 0.0150 and 0.0250 mass % and maintain the relationship 2×[Te]+[N]≦0.0300 mass %, ensuring a good magnetic property and appearance of the glass coating film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Te is contained in the grain-oriented electrical steel sheet to improve magnetic property, then the magnetic property is improved, but defects are caused on the appearance of the glass coating film
Solution Approach 1:
The patent applies parameter changes by precisely controlling the Te content within 0.0005-0.0050 mass % and establishing a specific relationship between Te and N contents (2×[Te]+[N]≦0.0300 mass %). This quantitative parameter control allows the steel sheet to achieve improved magnetic properties while preventing defects in the glass coating film appearance
Solution Approach 2:
The patent creates a composite material system by combining multiple elements (Si, C, Mn, Al, N, S, P, and Te) in specific proportions. The synergistic interaction between these elements, particularly the controlled combination of Te with N and other alloying elements, enables simultaneous achievement of good magnetic properties and coating film quality
2Reliability
If N content is increased to strengthen inhibitors for secondary recrystallization, then the magnetic property is improved, but the glass coating film appearance deteriorates when Te is present
Solution Approach 1:
The patent applies parameter changes by establishing a specific relationship between Te and N contents (2×[Te]+[N]≦0.0300 mass %) and controlling N content within 0.002-0.012 mass %. This coordinated parameter control allows N to effectively strengthen inhibitors for secondary recrystallization while preventing deterioration of the glass coating film appearance
Solution Approach 2:
The patent uses the controlled interaction between Te and N as an intermediary mechanism. By maintaining the specific relationship 2×[Te]+[N]≦0.0300 mass %, the combination of Te and N acts as a mediator that enables N to strengthen inhibitors while Te's harmful effect on coating appearance is suppressed
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 method effectively achieves a grain-oriented electrical steel sheet with enhanced magnetic properties and a defect-free glass coating film, optimizing the balance of Te and N content during nitridation annealing.
Implementation Method 1
The control of the orientation of the crystal grains is performed by using an abnormal grain growth phenomenon called secondary recrystallization
Implementation Method 2
in a nitridation annealing step performed after cold rolling, fine dispersed precipitates such as AlN, (Al.Si)N being inhibitors are precipitated
Implementation Method 3
performing decarburization annealing and nitridation annealing of the cold-rolled steel sheet
Implementation Method 4
performing decarburization annealing and nitridation annealing of the cold-rolled steel sheet
Implementation Method 5
performing finish annealing of the decarburized nitrided steel sheet to form a glass coating film
Data Source
AI summary
A predetermined steel containing Te: 0.0005 mass % to 0.0050 mass % is heated to 1320° C. or lower to be subjected to hot rolling, and is subjected to annealing, cold rolling, decarburization annealing, and nitridation annealing, and thereby a decarburized nitrided steel sheet is obtained. Further, an annealing separating agent is applied on the surface of the decarburized nitrided steel sheet and finish annealing is performed, and thereby a glass coating film is formed. The N content of the decarburized nitrided steel sheet is set to 0.0150 mass % to 0.0250 mass % and the relationship of 2×[Te]+[N]≦0.0300 mass % is set to be established. Note that [Te] represents the Te content and [N] represents the N content.