Casting Nozzle Bridging Segment for Stress Dispersion

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Solution Overview

Problem

Long nozzles used in continuous steel casting are prone to breaking at the air gap region, leading to uneven gas blowout and the risk of air infiltration and molten steel leakage, due to stress concentration and deformation.

Innovation Solution

A bridging segment is provided in the gas pool between the nozzle body and the metal casing to restrain the nozzle body radially, and heat-resistant particles are filled to disperse stress, preventing cracking and oxidation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a gas pool is formed between the nozzle body and metal casing to prevent oxidation and leakage, then sealing performance is improved, but the nozzle body becomes prone to breaking due to stress concentration

Engineering Contradiction:
Improvesealing performanceVSAvoidnozzle body strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies local quality by providing reinforcement structures (such as strengthening ribs or thicker wall sections) specifically in the gas pool region where stress concentration occurs, while maintaining the original thin-walled structure in other regions to minimize overall weight and material usage. This localized reinforcement prevents breaking in the critical area without compromising the overall design benefits.

Inventive Principle:
Principle #3Local quality

2Weight of moving object

If the nozzle body is made thinner to reduce weight and material usage, then manufacturing cost and weight are reduced, but the nozzle becomes more susceptible to breaking in the gas pool region

Engineering Contradiction:
Improvenozzle weightVSAvoidnozzle body strength
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The patent implements local quality by concentrating structural reinforcement only in the gas pool region where stress concentration occurs during gas blowing operations. The rest of the nozzle body maintains a thin-walled design to minimize weight and material consumption, achieving an optimal balance between weight reduction and breaking prevention.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If detaching and re-attaching operations are performed frequently during ladle replacement, then adaptability to different ladles is improved, but the joint portion becomes damaged and gaps form

Engineering Contradiction:
Improvecompatibility with different ladlesVSAvoidjoint portion sealing
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies preliminary action by performing protective measures before the damaging effects occur. Specifically, the reinforcement structures are pre-installed in the joint portion and gas pool area to prevent damage during subsequent detaching and re-attaching operations. This proactive approach maintains sealing reliability despite frequent assembly/disassembly cycles required for ladle replacement.

Inventive Principle:
Principle #10Preliminary action

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 suppresses breaking of the nozzle body, reduces oxidation, and prevents molten steel leakage, thereby improving the sealing performance and steel quality.

Implementation Method 1

a technique of blowing inert gas from the vicinity of an upper end of the long nozzle is employed

Methodology Applied
Scientific EffectGas displacement:

Implementation Method 2

heat-resistant particles are filled to disperse stress, preventing cracking and oxidation

Methodology Applied
Scientific EffectStress dispersion:

Implementation Method 3

a long nozzle as a casting nozzle is commonly used... a nozzle body made of a refractory material

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP3643427B1Casting nozzle
Publication Date: 2022.12.07 KROSAKI HARIMA CORP
  • EP3643427B1 patent drawingFigure 1~2
  • EP3643427B1 patent drawingFigure 3~6
  • EP3643427B1 patent drawingFigure 7~10

AI summary

Disclosed is a casting nozzle intended to suppress or prevent breaking of a nozzle body thereof. The casting nozzle comprises: a nozzle body 3; a metal casing 4 disposed to surround an upper end of the nozzle body 3 to form a gas pool 2 between an outer peripheral surface of the upper end of the nozzle body 3 and an inner peripheral surface of the metal casing 4; and a bridging segment 1 provided in at least a part of the gas pool 2 to bridge between the outer peripheral surface of the upper end of the nozzle body 3 and the inner peripheral surface of the metal casing 4.