| 摘要 |
PURPOSE:To easily and effectively improve the sulfide-stress corrosion cracking resistance of a welded steel part, by forming the first layer of Ni-Cr and the second layer of Al, each layer having a thickness exceeding a specified value, on the welded part of a steel article in a plasma spray-coating method. CONSTITUTION:The first layer composed of Ni-Cr is formed on the welded part of a steel article by plasma spray, and the second layer composed of Al is further formed on the first layer by the same plasma spray. In this case, the adhesiveness of the layers to the substrate is enhanced by the first layer, and the substrate is protected from corrosive environment by the second layer. In this regard, the thickness of the first layer is maintained at 0.10mm. or more, the thickness of the second layer is maintained at 0.15mm. or more, and the total thickness of the first and second layers is maintained at 0.5mm. or less. |
