Grain-Oriented Steel Forsterite Adhesion via Alloying
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Solution Overview
Problem
The existing production methods for grain-oriented electrical steel strips face challenges in achieving reliable adhesion of the forsterite layer to the steel substrate, which affects the magnetic properties and leads to defects in the laminated stacks used in electric motors and transformers, with current methods requiring lengthy high-temperature annealing and resulting in compromised magnetic performance.
Innovation Solution
A grain-oriented electrical steel sheet with a cold-rolled steel core layer containing specific alloy elements and a forsterite layer, where the forsterite layer is formed with optimized adhesion by controlling the dew point and annealing time during primary recrystallization, ensuring anchorages protrude into the steel core for enhanced bonding without deteriorating magnetic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional high-temperature annealing is used to form the forsterite layer, then adhesion is improved, but magnetic properties deteriorate and production time increases
Solution Approach 1:
The patent changes the chemical composition parameters of the steel substrate by adding specific alloying elements (Ti: 0.01-0.06 wt.%, Nb: 0.01-0.06 wt.%, V: 0.01-0.06 wt.%, Al: 0.01-0.06 wt.%) to modify the interaction between the steel and forsterite layer, achieving improved adhesion without requiring excessive annealing temperature that would harm magnetic properties
Solution Approach 2:
The patent creates a composite structure with the steel substrate containing specific alloying elements combined with the forsterite (MgO·SiO2) insulating layer, where the alloying elements form a transition layer that enhances interfacial bonding while preserving the magnetic characteristics of the base steel
2Reliability
If traditional production methods are used, then forsterite layer is formed, but adhesion is insufficient and defects occur in laminated stacks
Solution Approach 1:
The patent modifies the chemical composition parameters of the steel substrate by adding specific alloying elements (Ti: 0.01-0.06 wt.%, Nb: 0.01-0.06 wt.%, V: 0.01-0.06 wt.%, Al: 0.01-0.06 wt.%) to modify the interaction between the steel and forsterite layer, achieving improved adhesion without requiring excessive annealing temperature that would harm magnetic properties
Solution Approach 2:
The alloying elements (Ti, Nb, V, Al) act as intermediary substances that facilitate bonding between the steel substrate and the forsterite layer, forming a transition zone that enhances interfacial adhesion and prevents defects in laminated stacks
3Strength
If lengthy high-temperature annealing is performed, then forsterite layer adhesion is improved, but energy consumption increases and production is delayed
Solution Approach 1:
The patent incorporates alloying elements (Ti, Nb, V, Al) into the steel substrate before the forsterite layer formation process, preparing the chemical environment in advance to facilitate adhesion during a shortened annealing cycle, thereby reducing production time while maintaining adhesion quality
Solution Approach 2:
The patent changes the chemical composition parameters of the steel substrate by adding specific alloying elements (Ti: 0.01-0.06 wt.%, Nb: 0.01-0.06 wt.%, V: 0.01-0.06 wt.%, Al: 0.01-0.06 wt.%) to modify the interaction between the steel and forsterite layer, achieving improved adhesion without requiring excessive annealing temperature that would harm magnetic properties
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 solution achieves improved adhesion of the forsterite layer with excellent magnetic properties, including peak magnetic polarization of ≥ 1.3 T at 100 A/m and 1000 Hz, and increased peel strength in laminated stacks, suitable for electric motors and transformers, while reducing energy consumption and production delays.
Implementation Method 1
controlling the dew point and annealing time during primary recrystallization
Implementation Method 2
a forsterite layer, formed thereon
Implementation Method 3
GOES is a soft magnetic material, which typically exhibits high silicon contents. GOES has a high permeability to the magnetic field and can be magnetized and demagnetized easily.
Implementation Method 4
a peak magnetic polarization of ≥ 1.3 T at an external field of 100 A/m and an excitation of 1000 Hz
Data Source
Figure 1
AI summary
The invention relates to a grain-oriented electrical steel sheet having a peak magnetic polarization of ≥ 1.3 T at an external field of 100 A/m and an excitation of 1000 Hz and comprising: a cold-rolled steel core layer consisting of Fe, Si and optionally further alloying elements, the steel core layer having two outer surfaces, a forsterite layer on at least one of the two outer surfaces of the cold-rolled steel core layer wherein the grain-oriented electrical steel sheet has a bending radius of 9 mm or less, determined using a taper mandrel bending device and bending a specimen of the grain oriented electrical steel continuously 180° around a taper mandrel with a taper base of 30 mm and a taper tip of 5 mm, the bending radius being the radius at which visible cracks appear in the grain-oriented electrical steel sheet. The invention further relates to a method of producing a grain-oriented electrical steel sheet of the invention, to laminated stacks of grain-oriented electrical steel sheets, wherein the stack comprises at least two grain-oriented electrical steel sheets according to the invention laminated together with a resin and to the use of the grain-oriented electrical steel sheet of the invention as material for the production of parts for electric motors, for electric transformers or for other electric devices.