Ogival Submerged Entry Nozzle for Steel Casting Flow Control
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Solution Overview
Problem
Submerged entry nozzles for continuous casting of molten metal face issues such as excessive turbulence and surface defects due to high casting rates, leading to poor distribution of lubricant, uneven heat exchange, and instability in the meniscus, which result in cracks and surface flaws in the slab. Existing solutions like electromagnetic braking devices are difficult to control and costly, and current nozzle designs suffer from flow instability and clogging at high flow rates.
Innovation Solution
A submerged entry nozzle with an ogival or rocket-shaped divider geometry and a diffusion portion that reduces flow velocity progressively, eliminating the need for electromagnetic brakes and stabilizing the flow to achieve symmetrical circulation loops and reduced turbulence, while a throttle under the regulation region increases pressure for improved control and reduced erosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high casting rates are used to increase productivity, then the casting speed increases, but excessive turbulence and wave amplitude occur at the meniscus
Solution Approach 1:
The patent employs curved surfaces throughout the nozzle geometry, including a rounded inlet, curved transition sections, and a diffuser with gradual curvature. The ogival divider geometry uses smooth curved contours rather than sharp angles. These curved surfaces guide the molten metal flow more smoothly, reducing turbulence and wave formation at the meniscus while maintaining high casting speeds.
Solution Approach 2:
The patent changes geometric parameters along the flow path, including the cross-sectional area ratio (S2/S1 between 0.4-0.6), the diffuser angle (5-15 degrees), and the ogival divider vertex angle (30-60 degrees). These parameter optimizations control the flow velocity distribution and pressure gradient, reducing turbulence intensity while maintaining high productivity.
2Object-generated harmful factors
If electromagnetic braking devices are used to reduce turbulence, then wave amplitude decreases, but device complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the electromagnetic braking device from the system, replacing it with a purely geometric solution. The ogival divider and diffuser geometry alone are sufficient to control turbulence and reduce wave amplitude, simplifying the overall device while achieving the desired flow control.
Solution Approach 2:
The nozzle geometry itself performs the flow control function that would otherwise require external electromagnetic braking devices. The ogival divider and diffuser sections automatically regulate the molten metal flow, creating symmetrical circulation loops and reducing turbulence without additional active control systems.
3Ease of manufacture
If conventional nozzle geometry is used, then manufacturing is simple, but flow instability and clogging occur at high flow rates
Solution Approach 1:
The ogival divider geometry with its smooth curved contours and the rounded inlet section prevent flow separation and dead zones that cause instability and clogging. The curved surfaces guide flow more uniformly, maintaining reliable operation at high flow rates while remaining manufacturable using standard forming techniques.
Solution Approach 2:
The patent optimizes geometric parameters including the cross-sectional area ratio (S2/S1 between 0.4-0.6), diffuser angle (5-15 degrees), and ogival vertex angle (30-60 degrees). These parameter changes improve flow stability and prevent clogging while maintaining ease of manufacture through conventional fabrication methods.
4Reliability
If the nozzle inlet is positioned deeper in the tundish, then flow regulation improves, but refractory erosion increases due to higher pressure
Solution Approach 1:
The rounded inlet geometry distributes the incoming flow more uniformly across the nozzle cross-section, reducing localized high-velocity jets that cause refractory erosion. This curved inlet design maintains effective flow regulation while reducing the harmful concentration of flow energy at specific points.
Solution Approach 2:
The patent optimizes the inlet positioning and geometry parameters to balance flow regulation effectiveness with erosion control. The cross-sectional area ratio and inlet curvature radius are specifically designed to distribute flow pressure more evenly, reducing refractory wear while maintaining stable flow control.
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 reduces wave amplitude at the meniscus, minimizes turbulent fluctuations, and enhances mold level control, resulting in improved surface quality and reduced refractory wear, effectively addressing the challenges of high flow rates and instability in the casting process.
Implementation Method 1
The divider has an ogival or rocket-shaped geometry and its contour (outline) is continuous and smooth without the presence of angular points
Implementation Method 2
a diffusion portion that reduces flow velocity progressively, eliminating the need for electromagnetic brakes and stabilizing the flow
Implementation Method 3
a throttle under the regulation region increases pressure for improved control and reduced erosion
Implementation Method 4
to evenly distribute the molten metal in the mold so that heat extraction and solidified shell formation are uniform
Implementation Method 5
reduced refractory wear, effectively addressing the challenges of high flow rates and instability in the casting process
Data Source
Figure 1~2
Figure 3~6
Figure 7
AI summary
Invention relates to a submerged entry nozzle (21) for the thin slab casting comprising a divider (14) having a geometry of the ogival type, continuous contours and an angle θ at the vertex comprised between 30° and 60°. The divider in its lower portion is narrowing symmetrically with its sides (15,15') towards the median vertical axis (13).