Withdrawing Speed Oscillation Mechanism for Billet Casting

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Solution Overview

Problem

Existing methods for reducing friction force between the mold and billet in continuous steel casting are limited in effectiveness, particularly for small cross-section billets, leading to instability in the casting process.

Innovation Solution

A method involving a mechanism for withdrawing speed oscillation using elastic parts or dampers between pinch roll motors, with structural play to adjust billet withdrawing speed during mold oscillation, reducing friction force by slowing the billet speed during upward mold movement and increasing it during downward movement, optimized for curved or vertical type continuous casting machines with specific operational parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If conventional mold oscillation methods are used to increase lubrication, then some reduction in friction force is achieved, but the effect is insufficient and unstable for small cross-section billets

Engineering Contradiction:

Improvefriction force between mold and billetVSAvoidstability of casting operation

Core Design Contradiction:

ForceVSReliability

Solution Approach 1:

The patent applies dynamics by making the withdrawing speed variable rather than constant. The withdrawing speed is dynamically adjusted to be slower during the upward movement of the mold and faster during the downward movement, creating a speed profile that adapts to the oscillation cycle. This dynamic speed adjustment optimizes the friction force reduction effect and ensures stable operation for small cross-section billets.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of withdrawing speed from a constant value to a variable value that changes with the mold oscillation phase. Specifically, the speed is reduced during upward movement and increased during downward movement, creating a non-uniform speed profile that effectively reduces maximum friction force while maintaining casting stability.

Inventive Principle:

Principle #35Parameter changes

2Force

If the billet withdrawing speed is reduced during upward mold movement to reduce friction, then friction force decreases, but the overall casting productivity may be affected

Engineering Contradiction:

Improvefriction force between mold and billetVSAvoidcasting speed

Core Design Contradiction:

ForceVSProductivity

Solution Approach 1:

The patent applies periodic action by synchronizing the withdrawing speed variations with the periodic mold oscillation. The speed is periodically reduced during upward movement and increased during downward movement, creating a rhythmic speed profile that reduces friction during critical phases while maintaining overall productivity through the faster withdrawal during downward movement.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent uses dynamic speed adjustment where the withdrawing speed is not constant but varies continuously with the mold oscillation phase. The speed profile is dynamically optimized to be slower when friction is highest (during upward movement) and faster when friction is lower (during downward movement), achieving both friction reduction and productivity maintenance.

Inventive Principle:

Principle #15Dynamics

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

This approach stably reduces the maximum friction force between the mold and billet, preventing sticking and ensuring stable continuous casting operations by promoting lubricant consumption and adjusting to changing friction forces.

Implementation Method 1

the mechanism comprises elastic parts either alone or in combination with dampers between the motors for driving pinch rolls

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

the mechanism comprises elastic parts either alone or in combination with dampers between the motors for driving pinch rolls

Methodology Applied

Scientific EffectDamping: Damping

Implementation Method 3

a mechanism having structural play, or an allowance of free motion, incorporated in the driving mechanism for pinch rolls is used to decrease the withdrawing speed during the upward movement of the mold and increase the withdrawing speed during the downward movement of the mold and thereby reduce the friction force between the mold and the billet in the mold

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS7913745B2Method of continuous casting of small cross section billet

Publication Date: 2011.03.29 NIPPON STEEL CORPORATION

AI summary

A method for continuously casting a billet with a small cross section in which a curved type or vertical type continuous casting machine is used while oscillating the mold upward and downward is characterized in that the casting machine is provided with a mechanism for withdrawing speed oscillation. The mechanism has structural play in the directions of driving and reverse driving in such a manner that the amount of a play-incurred displacement from the neutral position of the structural play in the direction of billet driving or reverse driving is ±2 to ±30 mm in the direction of driving on the pinch roll circumferential length equivalent basis. The mechanism produces a returning force toward the neutral position and operational parameters such as the billet length, the specific amount of secondary cooling water, the casting speed as well as the oscillation amplitude and frequency are optimized.