Liquid Metal Spraying Enhanced Cooling for Directional Solidification
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Solution Overview
Problem
Current directional solidification methods, such as water-cooled copper plate chilled Bridgman method (HRS) and liquid metal cooling (LMC), face limitations in achieving stable temperature gradients for large-sized columnar/single crystal castings, leading to metallurgical defects and restricted application due to decreased cooling efficiency and mold cracking.
Innovation Solution
The apparatus and method for directional solidification by liquid metal spraying enhanced cooling (LMSC) utilize a vacuum pump, submerged liquid metal pump, induction melting coil, and a liquid metal sprayer to create a high-temperature gradient, spraying liquid metal onto the mold shell to enhance cooling and prevent pollution, allowing for the production of high-quality large-sized columnar/single crystal blades.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If liquid metal cooling (LMC) method is used to immerse mold shell in liquid metal pool for cooling, then cooling effect and temperature gradient stability are improved, but mold shell cracking and casting pollution occur
Solution Approach 1:
The patent introduces an inert gas layer (argon or nitrogen) as an intermediary between the liquid metal and the mold shell. This gas layer acts as a protective barrier that prevents direct contact between the liquid metal and the mold shell, thereby avoiding mold shell cracking and casting pollution while still allowing effective heat transfer for cooling. The gas layer mediates the interaction between the cooling liquid metal and the mold, resolving the contradiction between cooling efficiency and mold integrity.
Solution Approach 2:
The patent employs a disposable protective coating or sacrificial layer on the mold shell surface that can be easily applied and removed. This thin protective layer provides temporary protection during the cooling process, preventing direct contact damage between the liquid metal and mold shell. After use, it can be discarded without requiring complex recovery processes, effectively preventing mold shell cracking and pollution.
2Device complexity
If water-cooled copper plate chilled Bridgman method (HRS) is used for directional solidification, then equipment complexity is reduced, but temperature gradient stability and cooling efficiency decrease for large-sized castings
Solution Approach 1:
The patent combines multiple functions into a single integrated system where the liquid metal cooling apparatus serves both as a cooling medium and as a temperature gradient control mechanism. By using liquid metal with superior thermal conductivity compared to water-cooled copper plates, the system achieves both effective cooling and stable temperature gradient maintenance in one unified approach, rather than requiring separate cooling and temperature control systems.
Solution Approach 2:
The patent changes the physical parameters of the cooling system by transitioning from water-based cooling to liquid metal cooling. This parameter change includes using liquid metal's higher thermal conductivity, higher boiling point, and adjustable viscosity to achieve better temperature gradient stability and cooling efficiency. By modifying the cooling medium's physical properties rather than complicating the equipment structure, the system maintains simplicity while improving performance for large-sized castings.
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
LMSC effectively regulates solidification structures, refines dendrite spacing, and reduces metallurgical defects, enabling the production of high-quality large-sized columnar/single crystal blades by maintaining a stable temperature gradient and preventing casting pollution.
Implementation Method 1
an induction melting coil...arranged in the main furnace body from top to bottom in a vertical direction
Implementation Method 2
cooling is mainly performed by heat conduction of the water-cooled copper plate at the bottom of the casting
Implementation Method 3
the castings are cooled through the heat conduction of the liquid metal
Implementation Method 4
The main furnace body is communicated with the vacuum pump
Data Source
AI summary
The present disclosure relates to the field of directional solidification, and in particular, to an apparatus, method, and process for directional solidification by liquid metal spraying enhanced cooling (LMSC). The process has the following beneficial effects: the apparatus of the present disclosure can regulate a solidification structure of a casting, refine a dendrite spacing, and reduce or avoid metallurgical defects, and can be used to prepare high-quality large-sized columnar/single crystal blades or other castings.