Grain-Oriented Magnetic Sheets Thermo-Mechanical Processing
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Solution Overview
Problem
Conventional methods for producing oriented grain magnetic sheets require high energetic consumption, special heating furnaces, and are prone to superficial defects due to the need for high-temperature thermal treatments to control grain growth inhibitors, which complicates the production of sheets with excellent magnetic characteristics.
Innovation Solution
A thermo-mechanical process involving hot rolling in two phases using different mills, with controlled temperature and time conditions to manage the precipitation of secondary phases, reducing the need for high-temperature heating and minimizing energetic consumption, while maintaining the quality of magnetic characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature thermal treatments are used to control grain growth inhibitors, then magnetic characteristics are improved, but energetic consumption increases and superficial defects occur
Solution Approach 1:
The patent changes the temperature parameter from conventional high temperatures (above 1300°C) to a lower range (1100-1300°C), and modifies the temporal parameter by extending the holding time (10-900 seconds). This parameter transformation allows achieving the same grain growth control and magnetic property improvement with reduced energy consumption and fewer defects.
2Reliability
If high-temperature thermal treatments are used to control grain growth inhibitors, then magnetic characteristics are improved, but superficial defects increase
Solution Approach 1:
By transforming the thermal treatment parameters from high temperature/short time to lower temperature/extended time, the patent reduces the formation of superficial defects while maintaining effective control over grain growth inhibitors and achieving excellent magnetic characteristics.
3Reliability
If conventional single-phase hot rolling is used, then production process is simple, but magnetic homogeneity is insufficient
Solution Approach 1:
The patent divides the hot rolling process into two distinct phases: first hot rolling to achieve partial deformation and initial grain structure, then second hot rolling to complete the deformation and achieve final magnetic homogeneity. This segmentation of the rolling process into multiple stages with intermediate thermal treatment enables superior magnetic property uniformity.
Solution Approach 2:
The first hot rolling phase performs a preliminary deformation that prepares the material structure for the second phase. By pre-establishing certain grain characteristics and distributing phases before the final rolling, the process achieves better overall homogeneity than a single-phase approach.
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 process effectively controls grain growth and maintains excellent magnetic properties with reduced energetic costs and fewer defects, achieving homogeneous secondary recrystallization and improved magnetic permeability along the rolling direction.
Implementation Method 1
a thermo-mechanical cycle comprising the following operations: a) annealing at a temperature value in the range of 1100-1300° C.; d) hot finishing rolling... with the first rolling step with a thickness reduction higher than 40% and temperatures in the range of 900° C. to 1100° C.
Implementation Method 2
achieving homogeneous secondary recrystallization and improved magnetic permeability along the rolling direction
Implementation Method 3
hot roughcast rolling... with a reduction rate of the total thickness higher than 75%... hot finishing rolling... with a thickness reduction higher than 40%
Data Source
AI summary
The present invention has as objective a procedure for the oriented-grain magnetic sheet that provides particular operative hot rolling mill conditions of silicon steel slabs, by means which it is possible to highly contain the heterogeneities of hot rolled sheet re-crystallization. The use of these operative conditions permits to reduce the growing tendency of the crystallized grain during the annealing of the sheets at a final thickness that precedes the secondary oriented re-crystallization. Contemporarily, the particular operational conditions of hot rolling mill according to the invention permit a fine precipitation of secondary phases useful to the control of the grain growing, starting from a quantity of sulphur (S) and nitrogen (N) in matrix lower than corresponding provided by the conventional technologies and consequently disposable in metallic solid solution before the rolling after the heating of the slabs at temperature values lower than 1300° C.