Chromium Alloy Assembly Component for Gas-Tight Seals
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Solution Overview
Problem
Existing stainless steel components face a trade-off between strength and corrosion resistance, with high-temperature nitrogen treatment methods often compromising core strength while maintaining corrosion resistance, and there is a need for a gas-tight seal in high-pressure gas pipes that is both strong and resistant to corrosion.
Innovation Solution
An assembly component made from an alloy with at least 10% chromium, subjected to cold deformation below the recrystallization temperature, featuring a nitrogen-rich hardened layer with microhardness between 250 HV 0.05 to 370 HV 0.05 at a depth of 0 µm to 100 µm, which provides enhanced tensile strength and corrosion resistance without nitride formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature nitrogen treatment is applied to stainless steel, then corrosion resistance is improved, but core strength is compromised
Solution Approach 1:
The patent applies local quality by creating a nitrogen-enriched surface layer with microhardness of 250-370 HV at depth 0-100 µm, while maintaining the base material's strength properties. This localized treatment provides enhanced corrosion resistance and surface hardness at the interface where it is most needed, without compromising the core structural integrity of the component.
Solution Approach 2:
The patent utilizes parameter changes by controlling nitrogen content and microhardness within specific ranges (250-370 HV at 0-100 µm depth) through cold deformation below recrystallization temperature. By precisely adjusting these parameters, the invention achieves optimal balance between surface corrosion resistance and core strength retention.
2Strength
If cold deformation is applied to increase strength, then tensile strength is improved, but corrosion resistance deteriorates
Solution Approach 1:
The patent applies preliminary action by performing cold deformation below the recrystallization temperature to increase tensile strength first, then subsequently applying nitrogen treatment to restore and enhance corrosion resistance. This sequence of operations ensures that the strength gains from cold deformation are preserved while correcting the corrosion resistance deterioration that would otherwise occur.
3Strength
If nitrogen content is increased to enhance hardness, then surface hardness is improved, but nitride formation occurs reducing corrosion resistance
Solution Approach 1:
The patent applies partial action by limiting nitrogen enrichment to specific depth ranges (0-100 µm) and controlling microhardness to 250-370 HV, avoiding excessive nitrogen penetration that would cause nitride formation. This controlled partial treatment achieves the desired surface hardness improvement while maintaining corrosion resistance in the bulk material.
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 assembly component achieves up to three times higher tensile strength compared to conventional cold-deformed components, maintaining corrosion resistance and ensuring a gas-tight seal in high-pressure applications.
Implementation Method 1
subjected to cold deformation below the recrystallization temperature
Implementation Method 2
cold deformation of a steel component will increase its strength
Implementation Method 3
the high, e.g. 10%(w/w) or more, content of chromium that forms a protective oxide layer on the surface, which provides corrosion resistance
Implementation Method 4
the alloy having a content of nitrogen in solid solution providing a microhardness in the range of 250 HV 0.05 to 370 HV 0.05 at a depth from the surface in the range of 0 µm to 100 µm
Data Source
Figure 1~2A
Figure 2B~3A
Figure 3B
AI summary
The present invention relates to an assembly component of an alloy based on iron, nickel and/or cobalt containing at least 10% (w/w) chromium, the assembly component having an annular shape with an inner surface and an outer surface and a thickness between the inner surface and the outer surface in the range of 0.1 mm to 5 mm, the alloy having a content of nitrogen in solid solution providing a microhardness in the range of 250 HV0.05 to 370HV0.05 at a depth from the surface in the range of 0 µm to 100 µm. The invention also relates to an assembly with the assembly component.