Alloy-coated boiler component

Abstract

Provided is an alloy-coated boiler component which is to be welded at an end thereof, wherein a melted coating (15) with a first alloy material comprising not less than 1.5 % and not more than 2.5 % of B, not less than 3.5 % and not more than 4.0 % of Si, not more than 0.4 % of C, and not less than 12.0 % and not more than 17.0 % of Cr, and the balance being Ni and incidental impurities, is applied to the metallic base material on an end region including the end and its proximity and, a melted coating (16) of a second alloy material comprising more than 2.5 % and not more than 4.0 % of B, more than 4.0 % and not more than 5.0 % of Si, not less than 0.5 % and not more than 0.9 % of C, and not less than 12.0 % and not more than 17.0 % of Cr, and the balance being Ni and incidental impurities, is applied to the metallic base material on a non-end region other than the end region (percentages are expressed in terms of mass percentages). This alloy-coated boiler component has melted coatings which can be formed by thermal spraying-fusing treatment on the whole area of the metallic base material and the melted coating formed on the end region is superior in thermal shock resistance and resistance to shock.

Description

technical field [0001] The present invention relates to pipe members (hereinafter referred to as "boiler tubes") constituting heat transfer piping in various boilers, and plate-pipe composite panels (hereinafter referred to as "boiler furnace panels") constituting furnace shells with cooling channels, etc. Boiler components, and more particularly boiler components having an alloy coating for increased durability and suitable for welded construction. Background technique [0002] First of all, if the boiler tube is taken as an example, the working temperature of the boiler is lower than in the past and the erosion and corrosion environment in the furnace are not so serious. Characteristics of boiler steel pipes (low alloy steel pipes). In addition, for applications requiring corrosion resistance, stainless steel tubes are used, and titanium tubes are also used, but they are not widely used because they are expensive. [0003] In recent years, there has been an increase in t...

AI Technical Summary

Problems solved by technology

The above treatment requires special ordering of protective materials with excellent corrosion resistance (such as aluminum oxide) or needs to be embedded in a narrow boiler, so material and labor costs are high and materials need to be purchased in advance

[0008] Next, for the case of the boiler furnace panel, it is a composite structure formed by alternately matching pipes and plates as mentioned above. Due to its large size (for example, 0.5m×6m), it is equivalent to the practical auxiliary components of the above-mentioned protective materials. It is more difficult to use, and there is a problem of complicated deformation accompanying the melting treatment after thermal spraying (for example, refer to Patent Document 2 and Patent Document 3)

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