Tilt Pouring Molten Metal Casting Oxide Skin Control

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Solution Overview

Problem

The existing tilt pouring method for casting introduces turbulence when pouring molten metal from a ladle into a casting vessel, leading to mixing with the metal oxide skin and detrimental effects on the microstructure of the cast part.

Innovation Solution

The method involves ladling molten metal directly from a bale-out furnace into a tiltable casting vessel, allowing the metal oxide skin to form and float on top, and then rotating the vessel and mold together to pour the metal, ensuring the skin remains on the surface and minimizing turbulence, with controlled speed and positioning to maintain uniform pouring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If molten metal is poured from a ladle into a casting vessel, then the casting vessel can be filled with molten metal, but turbulence occurs and metal oxide skin mixes with molten metal causing detrimental effects on microstructure

Engineering Contradiction:

Improvefilling of casting vesselVSAvoidturbulence and oxide skin mixing

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The harmful intermediate step of pouring from ladle to casting vessel is eliminated. The ladle is removed from the process, and the casting vessel is filled directly from the bale-out furnace, extracting the source of turbulence and oxide skin formation from the critical pouring path.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The casting vessel is pre-positioned and pre-aligned with the bale-out furnace before filling. The vessel is prepared in advance to receive molten metal directly, preventing turbulence before it can occur during the filling operation.

Inventive Principle:

Principle #10Preliminary action

2Speed

If casting vessel is tilted to pour molten metal into casting mold, then pouring can be initiated, but metal oxide skin may contaminate the cast part

Engineering Contradiction:

Improvepouring initiationVSAvoidoxide skin contamination

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The metal oxide skin, which would normally be a harmful contaminant, is converted into a beneficial protective layer. By maintaining the oxide skin on the surface during pouring, it acts as a shield that prevents atmospheric contamination of the molten metal and ensures clean pouring into the mold.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

Instead of trying to remove or prevent oxide skin formation, the invention inverts the approach by allowing and even utilizing oxide skin formation. The oxide skin is maintained on the surface throughout the pouring process, reversing the conventional wisdom of keeping molten metal surfaces oxide-free.

Inventive Principle:

Principle #13The other way round (Inversion)

3Speed

If molten metal is poured with high kinetic energy, then pouring speed increases, but turbulence and mixing with oxide skin increase

Engineering Contradiction:

Improvepouring speedVSAvoidturbulence

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The pouring parameters are optimized by controlling the tilt angle and pouring speed to maintain laminar flow conditions. The kinetic energy of the molten metal is carefully regulated to ensure sufficient filling speed while preventing turbulence that would cause oxide skin mixing.

Inventive Principle:

Principle #35Parameter changes

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 results in a homogeneous pouring operation with reduced turbulence, preventing irregularities in the cast part's material structure and achieving high-quality casting by ensuring the metal oxide skin remains intact and floats on the molten metal until the end of the pouring process.

Implementation Method 1

a metal oxide skin (6) forms in the casting vessel (2) on the surface of the molten metal (1)... the metal oxide skin (6) floating predominantly on top of the molten metal (1) during the pouring process

Methodology Applied

Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 2

the molten metal (1) is poured from the casting vessel (2) into the casting mold (3) by a common rotation of the casting vessel (2) and the casting mold (3) about an axis of rotation

Methodology Applied

Scientific EffectGravitational flow: Gravitation

Data Source

PatentUS9925586B2Method for casting a cast part

Publication Date: 2018.03.27 NEMAK SAB DE CV

AI summary

A method for casting a cast part according to the tilt pouring principle includes pouring a molten metal from at least one tiltable casting vessel into a casting mold including a mold cavity which forms the cast part. The molten metal is ladled directly out of a bale-out furnace using the casting vessel, and a metal oxide skin forms in the casting vessel on the surface of the molten metal. The casting vessel containing the molten metal and the metal oxide skin floating thereon is brought to the casting mold. The molten metal is poured from the casting vessel into the casting mold by a common rotation of the casting vessel and casting mold about an axis of rotation. The metal oxide skin rises to the top of the molten metal during the pouring process, floating predominantly on top and on the surface of the molten metal.