Grain-Oriented Electrical Steel Sheet Processing to Prevent Cold-Roll Cracking
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Solution Overview
Problem
Grain-oriented electrical steel sheets often experience cracking during final cold rolling, especially with high carbon content, leading to defects and magnetic aging issues, which complicates production and increases iron loss.
Innovation Solution
A method involving hot rolling, intermediate annealing, decarburization, and final annealing, with specific conditions for carbon content and pickling treatments to prevent cracking and reduce carbon levels, including the use of hydrochloric acid with controlled Fe ion concentrations, to ensure stable production of low-iron-loss steel sheets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-temperature slab heating (1300°C or higher) is performed to dissolve inhibitor components into solid solution for fine particle distribution, then the inhibitor distribution is improved, but the energy consumption and manufacturing complexity increase
Solution Approach 1:
The patent changes the temperature parameter of slab heating from conventional high temperatures (1300°C or higher) to a lower range (1150°C to 1250°C), achieving effective inhibitor dissolution and distribution without the excessive energy consumption associated with traditional high-temperature processing
Solution Approach 2:
The patent employs readily available common inhibitors (AlN, MnS, MnSe) that can be effectively dissolved at lower temperatures, replacing the need for specialized high-temperature processing equipment and procedures
2Reliability
If inhibitor components (AlN, MnS, MnSe) are used to stabilize secondary recrystallization, then the grain orientation stability is improved, but the manufacturing process complexity increases due to required high-temperature heating
Solution Approach 1:
The patent modifies the heating temperature parameter to the range of 1150°C to 1250°C, which is sufficient to dissolve inhibitor components and achieve stable secondary recrystallization without requiring the complex high-temperature (1300°C or higher) heating systems
Solution Approach 2:
The inhibitor components (AlN, MnS, MnSe) naturally dissolve and distribute in the steel slab during the controlled heating process, eliminating the need for additional complex processing steps or specialized equipment beyond standard heating capabilities
3Strength
If high carbon content steel material is used, then the material strength is improved, but cracking occurs during final cold rolling
Solution Approach 1:
The patent performs preliminary decarburization treatment before final cold rolling to reduce carbon content to 0.005% or less, preventing the formation of coarse carbides that would cause cracking during subsequent cold rolling operations
Solution Approach 2:
The patent changes the carbon content parameter from high levels to 0.005% or less through controlled decarburization, maintaining material strength while eliminating the cracking susceptibility associated with high carbon content during cold rolling
4Productivity
If carbon content is not reduced to 50 ppm or lower, then the production efficiency is maintained, but magnetic aging occurs in the final product
Solution Approach 1:
The patent performs preliminary decarburization treatment before final annealing to reduce carbon content to 50 ppm or lower, preventing magnetic aging in the final product without requiring additional post-processing steps that would reduce production efficiency
Solution Approach 2:
The patent integrates decarburization treatment into the continuous production flow before final annealing, maintaining uninterrupted production while achieving the low carbon content necessary to prevent magnetic aging
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 effectively prevents defects during cold rolling, reduces carbon content, and suppresses magnetic aging, enabling the stable production of grain-oriented electrical steel sheets with low iron loss.
Implementation Method 1
pickling treatment is performed with a treatment solution having an acid concentration of 1 mass % or more and 20 mass % or less and an Fe ion content of 2 mass % or more and 15 mass % or less
Implementation Method 2
subjecting the steel sheet to final annealing
Implementation Method 3
then subjecting the cold-rolled steel sheet to decarburization annealing
Data Source
AI summary
To provide a method for producing a grain-oriented electrical steel sheet that can solve the problem of cracking in steel sheets during final cold rolling and that can stably produce a grain-oriented electrical steel sheet with low iron loss. A production method includes predetermined steps, wherein the conditions: T≤−4000×A+440, and T≤360 are satisfied, where A denotes an average C content in mass % in a predetermined region of the steel sheet after subjection to annealing preceding final cold rolling and before subjection to the final cold rolling, and T denotes a time in hours from just after the completion of the annealing preceding the final cold rolling to just before the start of the final cold rolling, and after the final cold rolling and before the decarburization annealing, pickling treatment is performed with a predetermined treatment solution.