Immersion Nozzle Ridges for Molten Steel Flow Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The continuous casting process faces issues with imbalanced flow velocity distribution and unstable molten steel flow due to increased nozzle passage and outlet dimensions, leading to surface level fluctuations and reduced steel quality.
Innovation Solution
An immersion nozzle design featuring a pair of opposing ridges extending horizontally on the inner wall between outlets, which regulates the flow and ensures symmetric distribution, reducing the velocities of reverse flows and stabilizing the molten steel surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the diameter of the nozzle passage and outlet dimensions are increased to increase productivity, then the amount of molten steel passing through the immersion nozzle increases, but imbalances in flow velocity distribution occur between exit-streams from lower and upper portions of outlets and between right and left outlets, causing unstable molten steel flow patterns in the mold
Solution Approach 1:
The outlet is divided into multiple smaller outlets arranged in a specific pattern (e.g., 2x2 grid), which segments the flow into multiple controlled streams. This segmentation prevents excessive velocity in individual streams while maintaining total throughput, thereby resolving the contradiction between productivity and flow stability.
Solution Approach 2:
The inner wall of the nozzle passage is provided with protrusions that create locally different flow conditions. These protrusions generate rotation in the molten steel flow, which balances the velocity distribution among different outlets and stabilizes the flow pattern in the mold, allowing high productivity without flow instability.
2Productivity
If outlet dimensions are increased to increase throughput, then more molten steel can pass through the immersion nozzle, but excessive reverse flows cause level fluctuation at the molten steel surface and inclusion of mold powder, lowering steel quality
Solution Approach 1:
By dividing the outlet into multiple smaller outlets, the reverse flow from each individual outlet is reduced compared to a single large outlet. The segmented configuration distributes the flow more evenly, preventing excessive reverse flows that cause surface level fluctuation and mold powder inclusion, thus maintaining steel quality while achieving high throughput.
Solution Approach 2:
Protrusions on the inner wall create localized flow control that generates rotation and balances velocity distribution. This local modification prevents excessive reverse flows at specific outlets, reducing level fluctuation and preventing mold powder inclusion, thereby eliminating harmful factors while maintaining high productivity.
3Productivity
If the nozzle passage and outlet dimensions are increased within limited mold space to increase productivity, then the pouring rate increases, but the velocities of reverse flows increase causing unstable flow patterns and surface level fluctuation
Solution Approach 1:
The outlet is segmented into multiple smaller outlets, which reduces the velocity of individual exit-streams compared to a single large outlet. This segmentation allows higher total throughput while maintaining lower reverse flow velocities, preventing unstable flow patterns and surface level fluctuation.
Solution Approach 2:
Protrusions on the inner wall create rotation in the molten steel flow, which balances velocity distribution and reduces the velocities of reverse flows. This local flow control mechanism enables high pouring rates while keeping reverse flow velocities at acceptable levels, preventing flow instability.
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 design improves the quality and productivity of steel by reducing level fluctuations and symmetricizing the flow patterns, making it easier to manufacture and maintain.
Implementation Method 1
a pair of opposing ridges extending horizontally on an inner wall and projecting into the passage from the inner wall between the pair of outlets
Data Source
Figure 1(A)~1(B)
Figure 2
Figure 3(A)~3(B)
AI summary
An immersion nozzle 10 for continuous casting which reduces the drift of molten steel flowing from the outlets 14 of the nozzle 10 and reduces the level fluctuation at the molten steel surface and which is easy to manufacture. The immersion nozzle 10 includes: a tubular body 11 with a bottom 15, the tubular body 11 having an inlet 13 for entry of molten steel disposed at an upper end and a passage 12 extending inside the tubular body 11 downward from the inlet 13; and a pair of opposing outlets 14 disposed in a sidewall at a lower section of the tubular body 11 so as to communicate with the passage 12, the nozzle 10 characterized by a pair of opposing ridges 16 extending horizontally on an inner wall and projecting into the passage 12 from the inner wall 18 between the pair of outlets 14, the inner wall 18 defining the passage 12.