Submerged Entry Nozzle with Alternating Compression Zones
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The continuous casting of steel faces challenges in maintaining stable flow dynamics and reducing turbulence, which can lead to surface defects and cracks in the cast steel due to varying flow velocities and turbulence in the molten steel from the submerged entry nozzle (SEN) into the mold, particularly in Compact Strip Production (CSP) where narrower dimensions increase inclusion entrapment.
Innovation Solution
A submerged entry nozzle with a housing having an inlet, a distribution zone, and a main body with sectional geometries that alternately compress and decompress the molten steel flow to control velocity, featuring a flow divider with baffles to divide the flow into four discharge flows, and a transition from circular to rectangular geometry to reduce turbulence, using zirconia graphite for wear resistance, and a ceramic fiber wrap for thermal protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the molten steel flow velocity is increased to improve productivity, then the casting speed increases, but turbulence and flow instability increase causing surface defects and cracks
Solution Approach 1:
The nozzle bore is divided into multiple flow path zones with alternating compression and decompression sections. Each zone independently controls flow velocity, allowing the first zone to operate at higher velocity for productivity while the second zone reduces velocity to prevent turbulence and surface defects, thus resolving the contradiction between casting speed and surface quality.
Solution Approach 2:
The patent changes the flow velocity parameter dynamically along the flow path by alternating between compression zones (increasing velocity) and decompression zones (decreasing velocity). This parameter variation allows optimization at different stages: high velocity for productivity in the first zone, low velocity for quality in the second zone, eliminating surface defects and cracks.
2Productivity
If the nozzle bore size is increased to improve steel flow rate, then productivity increases, but turbulence and transient phenomena increase leading to inclusion entrapment
Solution Approach 1:
The flow path is segmented into multiple zones with different velocity characteristics. The first flow path zone handles high flow rate for productivity, while the second zone reduces velocity to minimize inclusion entrapment. This segmentation allows the system to achieve both high steel flow rate and low inclusion content by distributing the flow through controlled velocity zones.
3Reliability
If the flow velocity is reduced to decrease turbulence and improve surface quality, then defects are reduced, but the casting speed decreases
Solution Approach 1:
The nozzle is divided into two functional segments: the first flow path zone optimized for high velocity and casting speed, and the second flow path zone optimized for low velocity and surface quality. This segmentation allows the system to achieve both high productivity and high reliability by performing different functions in different zones.
Solution Approach 2:
The flow velocity parameter is changed along the flow path through alternating compression and decompression zones. The first zone maintains high velocity for casting speed, while the second zone reduces velocity to minimize turbulence and surface defects, thus achieving both productivity and quality objectives.
4Reliability
If the bore geometry is changed to control flow dynamics, then turbulence is reduced, but the device complexity increases
Solution Approach 1:
The bore geometry is segmented into multiple flow path zones with distinct compression and decompression characteristics. Each zone has a specific geometric configuration optimized for its function, allowing flow stability control through modular geometric segments rather than a single complex shape.
Solution Approach 2:
The geometric parameters of the bore (cross-sectional area, length, shape) are varied along the flow path to create alternating compression and decompression zones. These parameter changes control flow velocity and turbulence, achieving flow stability through systematic geometric variation rather than complex external structures.
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 achieves stable and balanced steel flow velocities, reducing turbulence and inclusion entrapment, thereby improving the surface quality and consistency of the cast steel by maintaining a low amplitude standing wave and preventing shear-off of slag or particles, thus enhancing the production of high-quality steel slabs.
Implementation Method 1
said bore having sectional geometries capable of alternately compressing and decompressing the molten steel flow in flow path zones to alternately increase and decrease the steel flow velocity
Implementation Method 2
using zirconia graphite for wear resistance
Implementation Method 3
a ceramic fiber wrap for thermal protection
Data Source
AI summary
A submerged entry nozzle (SEN) for use in a casting machine to conduct molten steel from a tundish to a mold may include a housing having an inlet capable of receiving an incoming flow of molten steel from the tundish, a distribution zone capable of delivering the molten steel to the mold; and a main body having a bore capable of conducting molten steel therethrough from the inlet to the distribution zone, the bore having sectional geometries capable of alternately compressing and decompressing the molten steel flow in flow path zones to alternately increase and decrease the steel flow velocity with at least two flow path zones capable of compressing the molten steel flow, and to deliver the molten steel from the distribution zone into the mold with flow turbulence inhibited.