CN-122016788-A - In-situ analysis method for silicon steel normalizing process

CN122016788ACN 122016788 ACN122016788 ACN 122016788ACN-122016788-A

Abstract

The invention relates to the technical field of silicon steel normalizing process, in particular to an in-situ analysis method for the silicon steel normalizing process. The method comprises the steps of processing a silicon steel sample into a sheet and polishing, placing the sample in a high-temperature laser confocal microscope, setting temperature, atmosphere and scanning parameters, utilizing the microscope to observe microscopic tissues of the sample in real time and in situ in the whole stage of temperature rise, temperature preservation and temperature reduction in the normalizing process, collecting image data at high frequency, and finally quantitatively analyzing the image data. The invention realizes the dynamic and continuous in-situ observation of grain evolution and second phase particle behavior in the silicon steel normalizing process for the first time, overcomes the limitation of information deficiency of the traditional post analysis method, can precisely reveal the instantaneous influence of process parameters on microstructure, and provides direct and accurate data support for optimizing normalizing process to improve the magnetic performance of silicon steel.

Inventors

JIN XING
WANG XIAOFENG
YANG JING
XU RONGJIE
YU JIAYAO
HUANG LEI

Assignees

鞍钢股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260209

Claims (8)

1. The in-situ analysis method for the silicon steel normalizing process is characterized by comprising the following steps of: s1, sample preparation, namely selecting a silicon steel sample, processing the silicon steel sample into a sheet sample suitable for observation by a high-temperature laser confocal microscope, and polishing the observation surface of the sample; S2, equipment debugging and parameter setting, namely placing a sample on a high-temperature laser confocal microscope sample stage, setting microscope parameters, and controlling the temperature and atmosphere of a heating furnace; S3, starting a heating program, performing real-time in-situ observation on a microstructure of a sample by using the microscope in the heating, heat preservation and cooling stages in the normalizing process, and collecting image data; S4, analyzing and processing the acquired image data to acquire microstructure evolution information of the silicon steel in the normalizing process.
2. The in-situ analysis method of a silicon steel normalizing process according to claim 1, wherein in the step S1, the sheet sample is a wafer with a diameter of 4-7 mm and a thickness of 1-3 mm, and the polishing treatment comprises surface oxide layer removal and machining damage.
3. The method for in-situ analysis of a silicon steel normalizing process according to claim 1, wherein in step S2, the temperature control includes heating to a normalizing target temperature of 800-940 ℃ at a rate of 200-600 ℃ per minute by a heating system with an accuracy of not lower than ±0.1 ℃ and maintaining the temperature for 0-6 min.
4. The in-situ analysis method of a silicon steel normalizing process according to claim 1, wherein in the step S2, the atmosphere is controlled by introducing argon with purity not lower than 99.99% into the heating furnace as a protective gas, and the gas flow is controlled to be 100-300 mL/min.
5. The method for in-situ analysis of a silicon steel normalizing process according to claim 1, wherein in step S2, the setting of the microscope parameters includes setting the laser scanning frequency to 30-120 frames/sec.
6. The method according to claim 1, wherein in step S3, the observation during the incubation period comprises an observation of precipitation or dissolution behavior of the second phase particles.
7. The method of claim 1, wherein the observation of the behavior of the second phase particles comprises an observation of at least one of a number, a size, a shape, and a distribution of the particles.
8. The method of in-situ analysis of a silicon steel normalizing process according to claim 1, wherein in step S4, the analysis includes measuring grain size, counting grain size distribution, identifying second phase particles and calculating at least one parameter of their number density, average size and form factor.

Description

In-situ analysis method for silicon steel normalizing process Technical Field The invention relates to the technical field of silicon steel normalizing process, in particular to an in-situ analysis method for the silicon steel normalizing process. Background Silicon steel is used as a key soft magnetic alloy and widely applied to iron cores of power transformers, motors and generators, and the magnetic properties (such as iron loss and magnetic permeability) of the silicon steel directly determine the electric energy conversion efficiency. The normalizing treatment is an important intermediate heat treatment procedure in the silicon steel production, and aims to eliminate work hardening after cold rolling, promote recrystallization, optimize grain size and texture and provide a proper structure state for the subsequent process. The process parameters of the process (e.g., heating rate, target temperature, holding time, cooling rate) directly affect the final microstructure and magnetic properties of the material. At present, the research and process optimization of the silicon steel normalizing process mainly depends on the traditional post analysis method. Specifically, after the sample is subjected to a normalization process in a laboratory or a production line, the sample after the treatment is subjected to off-line observation and analysis by means of a metallographic microscope, a scanning electron microscope, a transmission electron microscope, or the like. Although such methods can achieve static structure results (e.g., average grain size, second phase particle distribution, etc.) after normalization, there are the following inherent, long-term unresolved technical limitations: 1. The traditional method can only provide a 'static snapshot' of the process starting point and the process end point, and can not catch the continuous and dynamic processes of key phenomena such as grain nucleation, growth, grain boundary migration, second phase particle precipitation/dissolution and the like in the normalizing process (especially in the initial stage of heating and heat preservation). This results in an understanding of process dynamics that is heavily dependent on inference rather than direct observation. 2. The continuity of the tissue evolution behavior cannot be accurately reflected, namely, due to the lack of continuous monitoring, the traditional method is difficult to accurately reveal the continuity behavior such as the change rule of recrystallization fraction along with time, the triggering time of abnormal growth of crystal grains, the precipitation sequence of second phase particles and the like, so that fault and uncertainty exist in the knowledge of the process-tissue relationship. 3. It is difficult to accurately evaluate the transient effects of critical process parameters, i.e., the transient factors such as uniformity of the temperature field, and variation of the temperature rise/fall rate have subtle and important effects on microstructure evolution during normalization. Conventional off-line analysis methods cannot closely correlate and correlate the microscopic state at a certain time with the precise process parameters (particularly temperature and time) at that time, and thus it is difficult to quantify the precise impact of these dynamic parameters on tissue formation. In recent years, although the high-temperature metallographic technology can realize tissue observation at a certain temperature, the high-temperature metallographic technology often depends on surface relief effect, has limited resolution, is difficult to realize high-quality and stable in-situ observation in a high-temperature range (such as more than 800 ℃) applicable to silicon steel, and cannot provide a high-frequency dynamic image sequence for quantitative analysis. The high-temperature laser confocal microscope is advanced material in-situ analysis equipment, integrates a high-precision heating table, a laser scanning imaging system and a controllable atmosphere system, and theoretically has the capability of carrying out high-speed and high-resolution surface imaging at high temperature. However, in the prior art, the device is mainly used in the basic research fields of metal melting, solidification or high-temperature oxidation, and no published report or mature scheme for systematically and creatively integrating and applying the device to solve the specific technical problem of dynamic monitoring and quantitative analysis of the specific industrial heat treatment process of silicon steel normalization is yet to be seen. Disclosure of Invention In order to overcome the defects of the prior art, the invention provides an in-situ analysis method for a silicon steel normalizing process. The analysis method for real-time, in-situ, dynamic and quantitative observation of the whole silicon steel normalizing process is realized, so that the essential association of technological parameters and tissue evolution i