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US 2026/0226933 A1Published application
Coated fastener and manufacturing method for same
AssigneePosco
InventorsKyung-Hwang Lee, Ji-Hoon Yang, Ki-Ho Rhee, Sung-Soo Park
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Abstract
One aspect of the present invention is to provide a fastener in which the surface hardness and corrosion resistance of a material have been improved through a thermal surface treatment layer, and a manufacturing method for same. Another aspect of the present invention is to provide a coated fastener having improved mechanical properties, such as excellent impact resistance and fatigue resistance, and high corrosion resistance due to the presence of a zinc-aluminum inorganic coating layer, and a manufacturing method for same.
Claims18
1-17. (canceled)
A fastener comprising:
- a thermal surface treatment layer formed on a surface portion,
- wherein the thermal surface treatment layer includes a nitride layer,
- wherein the nitride layer has an A value of 60% or more derived by the following Relational Expression 1:
- A
- =
- ε
- ε
- +
- γ
- ′
- ×
- 100.
- [
- Relational
-
- Expression
-
- 1
- ]
- In Relational Expression 1, ε is an area fraction (%) of an epsilon phase (ε-FexN (2≤x≤3)) of the nitride layer, and γ′ is an area fraction (%) of a gamma prime phase (γ′-Fe4N) of the nitride layer.
17 more elements
Dependencies are inferred from the claim text.