Deformable Sealing Washer Mask for Thermochemical Treatment
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Solution Overview
Problem
Existing masking methods for plasma carbonitriding and oxidation treatments of neutron absorbing rod claddings are inefficient, as solid masks either fail to prevent treatment of masked portions or risk damaging the parts due to thermal expansion mismatches and manufacturing tolerances, leading to inconsistent protection and potential damage.
Innovation Solution
A thermochemical treatment method using a mask with a deformable sealing washer and a tightening bushing that allows for efficient shielding of specific parts during treatment, reducing the risk of damage and ensuring consistent protection by compensating for manufacturing variability and thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid mask is used to shield portions of the part during thermochemical treatment, then the masked portions are protected from treatment, but the mask may fail to prevent treatment due to clearance gaps or may damage the part due to thermal expansion mismatches
Solution Approach 1:
The patent employs a deformable sealing washer (flexible element) that conforms to the contours of the part being masked. This flexible washer eliminates clearance gaps between the mask and part surface, ensuring complete shielding while adapting to manufacturing tolerances and thermal expansion without causing damage.
Solution Approach 2:
The deformable sealing washer acts as a cushioning element that compensates for thermal expansion mismatches between the mask and the part during heating. The flexibility of the washer allows it to absorb expansion forces before they can transmit to the part, preventing damage while maintaining sealing effectiveness.
2Device complexity
If a solid mask with clearance is used to shield portions of the part, then the mask structure is simple, but treatment atmosphere penetrates through clearances and treats the masked portions
Solution Approach 1:
The deformable sealing washer provides a flexible seal that eliminates clearance gaps without requiring complex adjustment mechanisms. The washer's ability to deform and conform to the part surface ensures precise masking while maintaining a relatively simple overall mask structure.
3Manufacturing precision
If the mask tightly contacts the part to prevent treatment penetration, then masking precision is improved, but the part may be damaged due to thermal stress and friction
Solution Approach 1:
The deformable sealing washer provides tight contact for precise masking while its flexibility allows it to accommodate thermal expansion and contraction. This flexibility reduces thermal stress transmission to the part and minimizes friction damage during heating and cooling cycles.
Solution Approach 2:
The deformable nature of the sealing washer provides cushioning that absorbs thermal stress forces before they can damage the part. The washer acts as a buffer between the rigid mask structure and the part, maintaining sealing pressure while protecting against thermal shock and stress concentration.
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 provides effective masking and protection of parts during plasma carbonitriding and oxidation treatments, reducing the risk of damage and ensuring consistent results, even with varying manufacturing tolerances, while allowing for subsequent welding operations without compromising the treated surfaces.
Implementation Method 1
A mask (45) comprising a body (47) with a seat (57), at least a deformable sealing washer (49) located in the seat (57), and a tightening bushing (51)
Implementation Method 2
a tightening bushing (51) moveable with respect to the body between a tightened position where the tightening bushing presses the sealing washer
Implementation Method 3
The method provides effective masking and protection of parts during plasma carbonitriding and oxidation treatments
Implementation Method 4
plasma carbonitriding and oxidation treatments
Implementation Method 5
hardening or a protection treatment through the diffusion of atom specie(s)
Implementation Method 6
plasma carbonitriding and oxidation treatments
Data Source
AI summary
A method for thermochemically treating a part while masking a portion and corresponding mask are provided. The method includes the steps of providing a mask comprising a body with a seat, at least a deformable sealing washer located in the seat, and a tightening bushing, the body having a cavity, placing a first portion of the part in the cavity, a second portion of the part being located in a passage in the sealing washer, and a third portion of the part being located outside the mask, moving the tightening bushing to its tightened position so that the sealing washer is deformed and applied against the second portion of the part, and applying a thermochemical treatment to the third portion of the part.