Insulating Coated Grain Oriented Steel Sheet Heat Resistance
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Solution Overview
Problem
The existing insulating coatings on grain oriented electrical steel sheets exhibit insufficient heat resistance, leading to sticking issues during stress relief annealing, which affects the magnetic properties and workability of the steel sheets.
Innovation Solution
A method involving a treatment solution with phosphates and colloidal silica, followed by baking and plasma treatment, to control the state of P-O bonds and achieve a P K-absorption edge XAFS spectrum with three absorption peaks between 2156 eV and 2180 eV, enhancing the heat resistance of the insulating coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional insulating coatings are used, then the steel sheet has basic insulation properties, but the coating exhibits insufficient heat resistance causing sticking during stress relief annealing
Solution Approach 1:
The patent changes the chemical composition parameters of the insulating coating by incorporating specific ratios of phosphates (Al, Mg, Mn, Zn, Ca, Ba, Sr) and colloidal silica, with SiO2 content controlled at 50-150 parts by mass relative to phosphate solids. This compositional parameter change enables the coating to maintain structural stability at high temperatures during stress relief annealing, preventing sticking while retaining insulation properties.
Solution Approach 2:
The patent creates a composite insulating coating material combining multiple phosphate compounds with colloidal silica. This composite structure leverages the high-temperature stability of phosphates and the glass-forming properties of silica to achieve superior heat resistance and sticking prevention during stress relief annealing at temperatures exceeding 800°C.
2Reliability
If the insulating coating is made thicker to improve insulation, then insulation properties improve, but the coating may stick together during high-temperature annealing
Solution Approach 1:
Rather than increasing thickness, the patent changes the chemical composition parameters of the coating to achieve better heat resistance. The specific formulation with colloidal silica content at 50-150 parts by mass relative to phosphate solids creates a coating that maintains its protective function at high temperatures without sticking, resolving the contradiction between insulation quality and thermal stability.
3Reliability
If chromic anhydride is used in the coating to improve tension and reduce iron loss, then magnetic properties improve, but environmental concerns arise
Solution Approach 1:
The patent extracts and removes chromic anhydride from the coating formulation, replacing it with environmentally friendly phosphate-based materials (Al, Mg, Mn, Zn, Ca, Ba, Sr phosphates) combined with colloidal silica. This extraction eliminates the harmful chromium component while maintaining the coating's ability to impart tension and reduce iron loss through alternative chemical mechanisms.
Solution Approach 2:
The patent changes the chemical composition parameters by substituting chromic anhydride with phosphate-colloidal silica systems. This parameter change achieves the same functional outcomes (tension impartment, iron loss reduction) through environmentally benign materials, resolving the conflict between magnetic property enhancement and environmental protection.
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 results in a grain oriented electrical steel sheet with a highly heat-resistant insulating coating, reducing sticking and improving the magnetic properties and workability of the steel sheets.
Implementation Method 1
the plasma treatment is a treatment which includes irradiating the surface of the grain oriented electrical steel sheet after the baking with plasma generated from plasma gas containing at least 0.3 vol% of hydrogen for 0.10 seconds or more
Implementation Method 2
conditions of the baking in which a baking temperature T (unit: °C) ranges 800 ≤ T ≤ 1000
Data Source
Figure 1
AI summary
Provided are an insulating-coated oriented magnetic steel sheet having an insulating coating of excellent heat resistance, and a method for manufacturing the same. This insulating-coated oriented magnetic steel sheet has an oriented magnetic steel sheet, and an insulating coating arranged on the surface of the oriented magnetic steel sheet. The insulating coating contains Si, P, and O, and at least one element selected from the group consisting of Mg, Ca, Ba, Sr, Zn, Al, and Mn, the K-absorption edge of the P in the insulating coating having an XAFS spectrum that exhibits three absorption peaks from 2156 eV to 2180 eV.