Double-Tube Slit Nozzle for Uniform High-Silicon Steel Strip
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Solution Overview
Problem
Existing slit nozzles used in high-silicon steel strip manufacturing exhibit variations in gas flow rates along the axis direction, leading to inconsistencies in Si concentration and defects in the steel strip.
Innovation Solution
A slit nozzle with a double-tube structure and a flow-control plate having specific angular openings between the inner and outer tubes to regulate gas flow, combined with opposing gas feed directions for adjacent nozzles, stabilizes the gas flow and Si concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional slit nozzle with a simple double-tube structure is used, then the device complexity is low, but the gas flow rate varies significantly along the axis direction causing Si concentration inconsistency
Solution Approach 1:
The flow control plate is segmented with multiple openings at different angular positions (27.5° to 332.5° range) to divide and regulate gas flow into different directional components. This segmentation allows precise control of gas flow distribution along the axis direction, reducing flow rate variations and achieving uniform Si concentration without requiring complex nozzle structures
Solution Approach 2:
The flow control plate acts as an intermediary component between the inner tube and outer tube. It receives gas from the inner tube and redistributes it through controlled openings before the gas exits through the outer tube's delivery port. This intermediary structure mediates the gas flow to eliminate variations along the axis direction while maintaining the simplicity of the double-tube nozzle configuration
2Reliability
If the treatment gas is blown onto the steel strip using a simple slit nozzle, then the ease of operation is high, but the flow rate variation causes shape defects and magnetic property variations
Solution Approach 1:
The flow control plate introduces local quality variations through its asymmetric opening distribution in the 27.5° to 332.5° angular range. Different regions of the plate have different opening configurations that locally adjust gas flow characteristics. This local quality control ensures uniform gas flow and Si concentration distribution across the steel strip surface, improving product reliability while maintaining operational simplicity
3Manufacturing precision
If adjacent slit nozzles feed gas in opposite directions alternately, then some variation in Si concentration is reduced, but the variation is not sufficiently decreased
Solution Approach 1:
Instead of alternating the feeding directions of adjacent nozzles (conventional approach), this invention inverts the approach by maintaining the same feeding direction for all nozzles but using the flow control plate's asymmetric opening configuration (27.5° to 332.5°) to create the necessary flow distribution. This inverted strategy achieves better Si concentration uniformity while simplifying the nozzle arrangement and reducing operational complexity
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 solution effectively reduces gas flow variations and Si concentration inconsistencies, enabling stable production of high-silicon steel strips with minimal defects.
Implementation Method 1
a flow-control plate which is disposed between the open end of the inner tube and an end, near the open end, of the delivery port and which closes a gap between the inner tube and the outer tube, wherein an opening is formed in a plane in which the flow-control plate is disposed only in a range of the flow-control plate of 27.5° or more and 332.5° or less in terms of a central angle
Implementation Method 2
blowing a treatment gas containing silicon tetrachloride (SiCl4) onto a thin steel strip having a Si concentration of less than 4 mass % at a high temperature to make Si permeate into the steel strip
Implementation Method 3
performing a heat treatment on the steel strip so that the Si which has permeated into the surface of the steel strip is diffused in the thickness direction
Data Source
AI summary
A slit nozzle having a double-tube structure and a method for manufacturing a high-silicon steel strip having a small variation in Si concentration depending on the position in the width direction of the steel strip. The slit nozzle has a double-tube structure, in which a flow-control plate which closes a gap between an inner tube and an outer tube is disposed between an open end of the inner tube and an end of a delivery port, and in which an opening is formed in a plane in which the flow-control plate is disposed only in a range of the flow-control plate of 27.5° or more and 332.5° or less in terms of a central angle with respect to a reference line L1 passing through the axis of the outer tube and the central position in the width direction of the delivery port.