Oriented Silicon Steel Normalizing with Tension Control
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Solution Overview
Problem
Existing methods for manufacturing grain-oriented silicon steel face challenges such as high heating temperatures leading to significant energy loss and production inefficiency, inhomogeneous martensite distribution affecting magnetic performance, and difficulty in accurately controlling cooling speeds for consistent martensite formation.
Innovation Solution
A method involving a two-stage normalizing process with controlled stress application during cooling to optimize martensite content and distribution, combined with conventional melting, casting, hot rolling, and subsequent annealing steps to enhance magnetic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high temperature heating (1350-1400°C) is used to achieve sufficient solid solution of impurities, then magnetic performance is improved, but energy consumption increases and production efficiency decreases
Solution Approach 1:
The patent changes the temperature parameter from traditional high temperature (1350-1400°C) to a lower temperature range (1100-1250°C) while compensating through extended holding time (30-120 minutes) and controlled cooling rates, achieving the same solid solution effect with reduced energy consumption
Solution Approach 2:
The patent applies preliminary tension stress (50-200 MPa) during the cooling process to promote martensite formation and homogeneous distribution before final annealing, preparing the microstructure in advance to achieve desired magnetic properties without requiring higher heating temperatures
2Ease of manufacture
If high temperature hot rolling is used to achieve proper microstructure, then processing is facilitated, but flange creak increases and production efficiency decreases
Solution Approach 1:
The patent lowers the hot rolling temperature from traditional high temperature to 950-1150°C, which reduces flange creak and energy consumption while maintaining adequate plasticity for rolling through extended processing time and controlled cooling
Solution Approach 2:
The patent combines hot rolling with immediate controlled cooling and tension application in a continuous process sequence, eliminating intermediate steps and maintaining productive action throughout the transformation process
3Manufacturing precision
If rapid cooling is used to form martensite, then magnetic performance is improved, but martensite distribution becomes inhomogeneous
Solution Approach 1:
The patent applies dynamic tension stress (50-200 MPa) during the cooling process that varies with temperature and time, promoting uniform martensite nucleation and growth throughout the material while maintaining the rapid cooling rate needed for high magnetic performance
Solution Approach 2:
The patent uses tension stress as an intermediary factor that mediates between the conflicting requirements of rapid cooling (for martensite formation) and uniform distribution, with the stress field promoting homogeneous phase transformation throughout the material
4Stability of the object's composition
If extended holding time is used to achieve sufficient solid solution, then impurity distribution is improved, but production efficiency decreases
Solution Approach 1:
The patent changes the temperature parameter to an optimized range (1100-1250°C) that provides adequate thermal energy for impurity diffusion while allowing shorter holding times (30-120 minutes) compared to traditional high-temperature processing, balancing composition uniformity with production efficiency
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 approach allows for stable and accurate control of martensite content, resulting in improved magnetic performance and homogeneous martensite structure, enhancing the final product's magnetic properties while reducing energy consumption and production costs.
Implementation Method 1
the temperature is maintained for more than 1h, so as to facilitate the sufficient solid solution of impurities of AlN, MnS or MnS
Implementation Method 2
the hot-rolled steel strip is coiled after being rapidly splashed and cooled with water
Implementation Method 3
the steel sheet is subjected to decarburizing and annealing process to reduce [C] content in steel sheet
Implementation Method 4
the steel sheet is subjected to decarburizing and annealing process to reduce [C] content in steel sheet
Implementation Method 5
the steel sheet is subjected to decarburizing and annealing process
Implementation Method 6
an annealing separator, whose main composition is MgO, is coated on the steel sheet to carry out high temperature annealing, and the steel sheet is subjected to a secondary recrystallization to form an under coating of Mg 2 SiO 4
Implementation Method 7
the steel sheet is subjected to a secondary recrystallization to form an under coating of Mg 2 SiO 4
Data Source
Figure 1~2
AI summary
A method for manufacturing a grain-oriented silicon steel having excellent magnetic performance, comprising steps as follows 1) conventionally melting and casting into a steel blank; 2) heating the steel blank and hot rolling the same into a strip of steel; 3)normalizing process; carrying out the normalizing process having two stages, wherein the strip is firstly heated to 1100∼1200°C, then cooled to 900∼1000 °C within 50-200s; and next, the strip is rapidly cooled in water having a temperature of 10∼100; in this period, a tension force is applied to the strip of steel, the strip of steel in the temperature range of 900°C∼500°C has a stress of 1∼200N/mm2; 4)cold rolling, i.e. carrying out a primary cold rolling, or a double cold rolling with intermediate annealing; 5)carrying out primary recrystallizing annealing, then coating an annealing separator, whose main composition is MgO, to carry out final product annealing comprising secondary recrystallizing annealing and purifying annealing. The invention optimizes the content and distribution of martensite in the steel plate after normalization by adjusting the tension force applied to the steel plate while normalization transformation, so as to make the content of martensite in the range ensuring a better magnetic performance of the final product and to optimize the magnetic performance of final products.