Etching Resist Coating for Grain-Oriented Steel Groove Formation
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Solution Overview
Problem
Conventional etching resist coatings on grain-oriented electrical steel sheets suffer from discoloration and poor removability during electrolytic etching, leading to decreased resist property and ease of removal.
Innovation Solution
A method involving hot rolling, annealing, and multiple cold rolling stages followed by application of a coating agent for etching resist coating formation, with specific baking and etching treatments to create non-coated regions and grooves, resulting in an etching resist coating with a surface insulation resistance coefficient of 20 Ω·cm²/sheet or more and pencil hardness of H or more and 8H or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional etching resist coating is applied to grain-oriented electrical steel sheet, then the coating provides basic etching resistance, but the coating becomes discolored during electrolytic etching indicating decreased resist property
Solution Approach 1:
The patent specifies precise parameter ranges for the coating agent composition (resin type, pigment content, solvent ratio) and baking conditions (temperature: 100-200°C, time: 10-60 seconds) to optimize the etching resist coating properties. These parameter changes ensure the coating maintains appropriate resistivity during electrolytic etching without discoloration, directly resolving the contradiction between resist property and discoloration prevention.
2Productivity
If strong alkaline aqueous solution is used to strip the etching resist coating, then the coating should be removed efficiently, but portions of the coating do not strip off indicating poor removability
Solution Approach 1:
The patent optimizes the coating agent formulation with specific resin types and additives that balance etching resistance and removability. The coating is designed to be removable by strong alkaline aqueous solutions while ensuring complete strip-off, resolving the contradiction between ease of removal and actual removability performance.
3Reliability
If the etching resist coating is made more resistant to electrolytic etching, then the resist property improves, but the ease of removing the coating after etching deteriorates
Solution Approach 1:
The coating is designed with differentiated properties: it exhibits high resistivity and protection during the etching process in the non-coated regions, while maintaining uniform compositional quality that ensures complete removability in coated regions. This local quality differentiation resolves the contradiction between resist property and ease of removal.
Solution Approach 2:
The patent specifies precise compositional parameters of the coating agent including resin type, pigment content, and solvent ratio, along with controlled baking parameters, to achieve the optimal balance between etching resistance and removability. These parameter changes enable the coating to provide sufficient protection during etching while ensuring complete removal afterward, resolving the contradiction between resist property and ease of removal.
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 produces a grain-oriented electrical steel sheet with an etching resist coating that maintains excellent resist property and removability, preventing discoloration and ensuring effective groove formation for reduced iron loss.
Implementation Method 1
a subsequent process of applying a baking treatment to the specified steel sheet to bake the coating agent for etching resist coating formation to form an etching resist coating
Implementation Method 2
there are cases where a portion of the surface of the etching resist coating is discolored, causing a change in appearance. The change in color tone of the etching resist coating suggests that the resistance of the etching resist coating to the electrolytic etching solution
Data Source
Figure 1
AI summary
Provided is a method of producing a grain-oriented electrical steel sheet including an etching resist coating that has an excellent resist property and removability, and an etching resist coated grain-oriented electrical steel sheet using the etching resist coating. The method of producing a grain-oriented electrical steel sheet includes: applying a coating agent for etching resist coating formation to a surface of a specified steel sheet selected from the group consisting of a hot-rolled steel sheet, a hot-rolled annealed steel sheet, a cold-rolled steel sheet, a primary recrystallization annealed steel sheet, and a secondary recrystallization annealed steel sheet, leaving a plurality of non-coated regions where the coating agent for etching resist coating formation is not applied linearly along a direction intersecting the rolling direction of the specified steel sheet; then applying a baking treatment to the specified steel sheet to bake the coating agent for etching resist coating formation to form an etching resist coating; and then applying an etching treatment to the specified steel sheet to form grooves on the surface of the specified steel sheet in the non-coated regions. The etching resist coating has a surface insulation resistance coefficient of 20 Ω·cm2/sheet or more and a pencil hardness of H or more and 8H or less.