Silicon Steel Hot-Rolled Strip Casting-Rolling Process
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Solution Overview
Problem
The existing methods for producing hot-rolled strip for grain-oriented electrical steel are either energy-intensive or result in quality loss, and the annealing furnaces used are not compact, leading to high investment costs.
Innovation Solution
A method involving a casting-rolling composite system where a specific steel alloy is melted, cast into a strand, rolled with high deformation, heated to a final temperature of 1050-1250°C, and then finish-rolled, with controlled cooling to achieve finely dispersed and homogeneously distributed growth inhibitors, allowing for efficient production of high-quality hot strips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional annealing furnaces are used to heat slabs, then the steel can be processed into grain-oriented electrical steel, but the process becomes very energy-intensive and the furnaces are not compact, increasing investment costs
Solution Approach 1:
The patent changes the temperature parameters and heating method by using a heating device that heats the strip to 1050-1250°C in a controlled manner after rolling, replacing conventional annealing furnaces. This parameter change enables the same metallurgical transformation with reduced energy consumption and more compact equipment.
Solution Approach 2:
The patent performs high-degree deformation rolling (10-50% per pass, total >50%) before the final heating step, preliminarily creating the structural conditions needed for grain-oriented electrical steel. This preliminary action reduces the burden on the subsequent heating step, allowing lower energy input while achieving the desired microstructure.
2Manufacturing precision
If conventional annealing furnaces are used to heat slabs, then the steel can be processed into grain-oriented electrical steel, but the furnaces are not compact, increasing investment costs
Solution Approach 1:
The patent changes the heating method and temperature parameters, using a compact heating device that brings the strip to 1050-1250°C after rolling. This replaces bulky annealing furnaces with more compact equipment while maintaining the necessary thermal treatment for grain-oriented electrical steel production.
Solution Approach 2:
The patent performs high-degree deformation rolling before the final heating step, preliminarily creating the structural conditions needed for grain-oriented electrical steel. This preliminary action reduces the burden on the subsequent heating step, allowing the use of more compact heating equipment while achieving the desired microstructure.
3Manufacturing precision
If high degrees of deformation (10-50%) are applied during pre-rolling, then growth inhibitors can be finely dispersed, but the process requires intermediate heating to 1260-1400°C followed by hot rolling, increasing energy consumption
Solution Approach 1:
The patent changes the temperature parameter from the conventional 1260-1400°C intermediate heating to a lower 1050-1250°C final heating after high-degree deformation rolling. This parameter change reduces energy consumption while still achieving fine dispersion of growth inhibitors through the prior high-degree deformation (total >50%).
Solution Approach 2:
The patent performs high-degree deformation rolling (10-50% per pass, total >50%) as a preliminary action to finely disperse growth inhibitors before the final heating step. This preliminary dispersion action allows the subsequent lower-temperature heating to be effective, reducing overall energy consumption compared to conventional high-temperature intermediate heating.
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 method enables the cost-effective production of high-quality hot strips with excellent magnetic, electrical, and geometric properties by ensuring uniform distribution of growth inhibitors, reducing energy consumption and investment costs while maintaining compactness.
Implementation Method 1
heating the intermediate belt in an oven; heating the strip to a final temperature of 1050 to 1250 °C
Implementation Method 2
cooling and winding up the strip; cooling and coiling of the strip
Implementation Method 3
Pre-rolling the descaled slab into an intermediate strip with high degrees of deformation of 10 - 50%; the total degree of deformation of all passes being > 50%
Data Source
Figure 1~2
AI summary
The invention relates to a method and to a device for producing hot-rolled strip from silicon-alloyed steels for further processing into grain-oriented electrical steel strip. The aim of the invention is to create a method and a combined casting/rolling installation (1) with which high-quality hot-rolled strip for further processing into grain-oriented electrical steel strip can be produced at low cost. Said aim is achieved by a method wherein the following method steps are performed on a combined casting/rolling installation in the sequence specified: a) melting a steel having a chemical composition in wt % of Si 2 to 7%, C 0.01 to 0.1%, Mn < 0.3%, Cu 0.1 to 0.7%, Sn < 0.2%, S < 0.05%, Al < 0.09%, Cr < 0.3%, N < 0.02%, P < 0.1%, remainder Fe and impurities; b) casting a strand (3) having a thickness of 25 to 150 mm on a continuous casting installation (2); c) rolling into a strip (4) in up to 4 rolling passes directly after casting the strand, wherein at least in one rolling pass a true strain is > 30% or the total true strain of all passes is > 50%; d) heating the strip to a final temperature of 1050 to 1250 °C, preferably 1100 to 1180 °C; e) finish rolling the strip in a second rolling train (8), then f) cooling and winding the strip.