Vertical Pouring Large Plate Castings with Active Cooling
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Solution Overview
Problem
Large-sized massive plate castings prepared in a horizontal position often suffer from nonuniform crystallization and solidification, leading to defects such as surface irregularities, thermal radiation-induced defects, and internal porosities due to uneven cooling and metal shrinkage.
Innovation Solution
A method involving a vertically assembled mould with independent moulding flasks, active cooling segments, and vibratory compaction of moulding sand using near-resonance frequencies to ensure uniform cooling and minimize defects, utilizing facing sand with increased strength and a specific cement-resin mixture, and water mist cooling for precise heat management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If large-sized massive plate castings are prepared in a horizontal position, then the moulding process is simpler, but nonuniform crystallisation and solidification occur leading to surface defects and internal porosities
Solution Approach 1:
The patent inverts the conventional horizontal moulding position to a vertical position. This inversion fundamentally changes the direction of metal filling and solidification, allowing gravity to assist uniform downward flow and cooling, thereby eliminating the nonuniform crystallisation and surface defects that occur in horizontal positioning while maintaining manufacturing simplicity
Solution Approach 2:
The patent changes the spatial orientation parameter from horizontal to vertical positioning. This parameter change transforms the gravitational field's effect on metal flow and heat distribution, resulting in uniform crystallisation and solidification throughout the casting, thereby resolving the manufacturing precision issue without complicating the moulding process
2Productivity
If heavy thermal radiation affects the mould cavity during horizontal casting, then the casting process completes, but surface defects such as pits, sinters, burns, and warps occur
Solution Approach 1:
By inverting the mould from horizontal to vertical position, the patent changes which surface is exposed to thermal radiation. The previously upper surface (prone to radiation damage) becomes the lower surface in contact with the base, while the new upper surface is protected from direct radiation, thereby preventing surface defects while maintaining productivity
Solution Approach 2:
The patent applies different local conditions to different parts of the mould cavity. The vertical positioning creates a gradient where the lower portion experiences different thermal conditions compared to the upper portion, with the lower area benefiting from better heat dissipation and the upper area protected from excessive radiation, thereby improving overall surface quality
3Productivity
If metal shrinks during solidification in horizontal position, then the casting forms, but internal porosities and shrinkage cavities are created
Solution Approach 1:
Inverting the mould to vertical position changes the direction of metal flow and shrinkage. The vertical orientation allows shrinkage to occur uniformly downward toward the base, preventing the formation of internal porosities and shrinkage cavities that occur in horizontal positioning, thereby improving internal structure integrity while maintaining casting formation efficiency
Solution Approach 2:
The vertical positioning creates a more uniform gravitational potential gradient throughout the mould cavity during filling and solidification. This equipotential effect promotes uniform metal flow and shrinkage distribution, preventing localized porosity formation and ensuring homogeneous internal structure throughout the casting
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 method produces defect-free large-sized castings with improved microstructure and geometrical properties, reducing machining needs and time, and eliminating internal and surface defects like slag and non-metallic inclusions.
Implementation Method 1
active cooling segments, with a shape matching the casting and known heat capacity
Implementation Method 2
the process of cooling the casting with water mist is started
Implementation Method 3
the process of vibratory compaction of the moulding sand is initiated, causing vibrations of the entire system with a near-resonance frequency
Implementation Method 4
vibrations of the entire system with a near-resonance frequency, continuing for a further time corresponding to 10% of the total duration of filling the moulding flask
Implementation Method 5
an isopropyl alcohol-based mould coating is applied onto the inner portions of the mould parts, upon which, after its evaporation from the mould coating
Data Source
AI summary
The method involves preparing two mutually fitting parts of the mould, each of them in an independent moulding flask standing on a mould base with a pattern along with centering elements placed therein, provided with at least one active cooling segment fixed inside it, with a shape matching the casting and known heat capacity, wherein during the sprinkling of the pattern a gating system is formed and the process of vibratory compaction of the moulding sand is initiated, causing vibrations of the entire system with a near-resonance frequency. Once the moulding sand has set, both moulding flasks are clamped together, and subsequently raised to a vertical position, and a priming tank is installed on the upper wall of the flask, and hoses connecting the collector to active cooling segments are attached, upon which the mould is filled with liquid metal, and the process of cooling the casting with water mist is started.