Boiler waterwall panel

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.

1 . A boiler waterwall panel comprising a metal panel member with water passages as a panel body equipped with a plurality of rows of tubular portions to be served as cooling water passages, web portions connecting the rows of tubular portions, and a pair of fin portions located at outsides of outermost tubular portions and extending in a tubular axial direction, at least one surface of the panel body being covered with a fusion-bonded coating of a corrosion resistant alloy,
 wherein the panel member with water passages as the panel body comprises a plurality of metal seamless finned single tubes as constituent units, each provided with a single tubular portion and a pair of fin portions provided at peripheral opposite sides of the single tubular portion, the single tubular portion and the fin portions exist sharing a common metal phase continuously extended, and   wherein the plurality of metal seamless finned single tubular portions are joined by welding with each other at tip ends of the fin portions of the constituent units so that a welded portion is located at a median line position of the web portion.   
     
     
         2 . A boiler waterwall panel comprising a metal panel member with water passages as a panel body equipped with a plurality of rows of tubular portions to be served as cooling water passages, web portions connecting the rows of tubular portions, and a pair of fin portions located at outsides of outermost tubular portions and extending in a tubular axial direction, at least one surface of the panel body being covered with a fusion-bonded coating of a corrosion resistant alloy,
 wherein the panel member with water passages as the panel body comprises a plurality of metal seamless finned tube-web assembles as constituent units, each having a few rows of tubular portions corresponding to a part of the plural rows of the tubular portions, the web portions connecting said few rows of the tubular portions, and a pair of fin portions provided at outer sides of outermost tubular portions, the tubular portions, the web portions and the fin portions exist sharing a common metal phase continuously extended, and   wherein the plurality of metal seamless finned tube-web assemblies are joined by welding with each other at tip ends of the fin portions of the constituent units so that a welded portion is located at a median line position of the limited web portions.   
     
     
         3 . A boiler waterwall panel comprising a metal panel member with water passages as a panel body equipped with a plurality of rows of tubular portions to be served as cooling water passages, web portions connecting the rows of tubular portions, and a pair of fin portions located at outsides of outermost tubular portions and extending in a tubular axial direction, at least one surface of the panel body being covered with a fusion-bonded coating of a corrosion resistant alloy,
 wherein the panel member with water passages as the panel body has a seamless integrated structure in which an entirety of the panel member is constituted by a single metal seamless finned tube-web assembly, comprising the plurality of rows of the tubular portions, the web portions connecting the rows of tubular portions, and the pair of fin portions located at the outsides of the outermost tubular portions, exist sharing a common metal phase continuously extended.   
     
     
         4 . The boiler waterwall panel as recited in  claim 3 , wherein an external surface of a transition portion ranging from the tubular portion to the fin portion or the web portion of the panel member as the panel body is formed into a concave surface. 
     
     
         5 . The boiler waterwall panel as recited in  claim 3 , wherein the seamless finned tubular member or the seamless finned tube-web assembly, each being formed with the single common metal phase, constituting the panel body is produced by a seamless forming method such as a hot extrusion method. 
     
     
         6 . The boiler waterwall panel as recited in  claim 3 , wherein the corrosion resistant alloy constituting the fusion-bonded coating is made of a Ni-rich Ni—Cr based alloy in which an amount of boron is restricted to 0.1 mass % or below and an amount of silicon is restricted to 0.5 mass % or less at a frame-like region including frame-like edge portions of the panel. 
     
     
         7 . The boiler waterwall panel as recited in  claim 1 , wherein an external surface of a transition portion ranging from the tubular portion to the fin portion or the web portion of the panel member as the panel body is formed into a concave surface. 
     
     
         8 . The boiler waterwall panel as recited in  claim 2 , wherein an external surface of a transition portion ranging from the tubular portion to the fin portion or the web portion of the panel member as the panel body is formed into a concave surface. 
     
     
         9 . The boiler waterwall panel as recited  claim 1 , wherein the seamless finned tubular member or the seamless finned tube-web assembly, each being formed with the single common metal phase, constituting the panel body is produced by a seamless forming method such as a hot extrusion method. 
     
     
         10 . The boiler waterwall panel as recited  claim 2 , wherein the seamless finned tubular member or the seamless finned tube-web assembly, each being formed with the single common metal phase, constituting the panel body is produced by a seamless forming method such as a hot extrusion method. 
     
     
         11 . The boiler waterwall panel as recited in  claim 1 , wherein the corrosion resistant alloy constituting the fusion-bonded coating is made of a Ni-rich Ni—Cr based alloy in which an amount of boron is restricted to 0.1 mass % or below and an amount of silicon is restricted to 0.5 mass % or less at a frame-like region including frame-like edge portions of the panel. 
     
     
         12 . The boiler waterwall panel as recited in  claim 2 , wherein the corrosion resistant alloy constituting the fusion-bonded coating is made of a Ni-rich Ni—Cr based alloy in which an amount of boron is restricted to 0.1 mass % or below and an amount of silicon is restricted to 0.5 mass % or less at a frame-like region including frame-like edge portions of the panel.