Molybdenum Casting Core With Refractory Protuberances for Coating Protection
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Solution Overview
Problem
Current casting cores used in lost-wax processes are not sufficiently resistant to oxidation, leading to damage of anti-oxidation coatings due to friction during handling and positioning, which compromises the integrity and performance of the cast parts.
Innovation Solution
A casting core with a main portion made of molybdenum or molybdenum alloy, featuring protuberances of refractory material and an anti-oxidation coating, including an adhesion layer and a protective layer, ensures robust protection against oxidation and precise positioning in the mould.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a casting core is coated with an anti-oxidation coating, then oxidation resistance is improved, but the coating is damaged by friction during handling and positioning
Solution Approach 1:
The invention uses a composite structure combining molybdenum (or molybdenum alloy) with refractory material protuberances. The molybdenum base provides structural integrity while the refractory protuberances provide friction resistance. This composite approach allows the core to maintain coating integrity during handling while preserving oxidation resistance.
Solution Approach 2:
The invention applies local quality by adding refractory material protuberances at specific locations on the casting core surface. These localized protuberances provide enhanced friction resistance at contact points without requiring the entire core to be made of refractory material, thus maintaining overall coating integrity and oxidation resistance while improving handling characteristics.
2Reliability
If meticulous handling is used to avoid friction damage, then coating integrity is maintained, but productivity is drastically reduced
Solution Approach 1:
The refractory material protuberances are pre-formed on the casting core before the casting process. This preliminary action prepares the core to withstand normal handling and positioning friction without requiring meticulous care during operation, thus maintaining coating integrity while enabling faster, more productive handling and positioning operations.
3Manufacturing precision
If refractory material protuberances are added for positioning, then positioning precision is improved, but device complexity increases
Solution Approach 1:
The refractory material protuberances are added only at specific locations on the casting core where positioning is needed. This localized approach provides precise positioning capability without requiring complex structural modifications to the entire core, thus improving positioning precision while minimizing increases in overall device complexity.
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 core provides excellent oxidation resistance and ease of use, maintaining coating integrity and enabling precise positioning without complicating the casting process, resulting in high-quality hollow metal parts with complex geometries.
Implementation Method 1
the portions required for positioning the core in the casting mould are more subject to friction with the mould or during handling. Such friction can damage the coating
Implementation Method 2
these alloys do not have a sufficient temperature resistance to oxidation for direct application in foundry processes
Data Source
AI summary
A casting core includes a main portion made of molybdenum or a molybdenum alloy, and, at the surface of the main portion, at least two protuberances made of a refractory material, the whole of the main portion and the protuberances being covered with an anti-oxidation coating.