Abstract: It is an object to reduce the burden of a welding operation in producing a boiler waterwall panel and to reduce the burden of maintaining a furnace housing using the boiler waterwall panels thereby to improve the operating rate of the boiler. In a boiler waterwall panel 80, a panel body 70 with water passages is constituted by a plurality of metal seamless finned single tubes 60 as constituent units integrally produced by a hot extrusion method, etc., and joined by welding tip ends of fin portions 62. On at least one surface side of the panel body 70, fusion-bonded coating 81 for frame-like edge portions and fusion-bonded coating 82 for inner region, of a corrosion resistant alloy are formed. The finned single tube 60 has a single tubular portion 61 for a cooling water passage and a pair of fin portions 62 extending in the tube axial direction at peripheral opposite sides of the tube, and the external surface of the transition portion 63 is formed into a concave surface having a curvature radius of 3 to 6 mm.

Abstract: An alloy-coated boiler part is furnished with a melted coating of alloy material excellent in erosion/corrosion resistance when joined by welding, and free from thermal shock cracking. Super alloy coating (15) is applied over rapid temperature rise region width (C), where thermal shock cracking may occur at a welding operation, at end portions subjected to weld joint including the vicinity. Self-fluxing alloy coating (16) is applied on remaining regions other than the rapid temperature rise region width (C). While over a half proportion of each of the alloy coatings (15, 16) occupied by an Ni-enriched Ni—Cr component, the super alloy coating (15) has the contents of B and Si suppressed to equal or less than 0.1% and equal or less than 0.5%, respectively, and in the self-fluxing alloy coating (16), the content of each of B and Si is in the range of 1 to 5%.

Abstract: [Problems] To provide an alloy-coated boiler part that at all regions to be protected, is furnished with a weld deposition coating of alloy material excelling in erosion/corrosion resistance and that even when joined by welding, is free from thermal shock cracking. [Means for Solving Problems] Super alloy coating (15) is applied over rapid temperature rise region width (C), where thermal shock cracking may occur at a welding operation, at end portions subjected to weld joint including the vicinity thereof. On the other hand, self-fluxing alloy coating (16) is applied on any remaining regions other than the rapid temperature rise region width (C). While over a half proportion of each of the alloy coatings (15, 16) occupied by an Ni-enriched Ni—Cr component, the super alloy coating (15) has the contents of B and Si suppressed to equal or less than 0.1% and equal or less than 0.5%, respectively, and in the self-fluxing alloy coating (16), the content of each of B and Si is in the range of 1 to 5%.