Steam Generator Cladding via Protruding Temporary Welding Surface
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Solution Overview
Problem
The existing welding methods for cladding or buttering on the inner surface of steam generator channel heads with opening portions face challenges in applying uniform coverage due to the arc-shaped edges, leading to difficulties in proximity to the opening edges and increased manual labor for border areas.
Innovation Solution
A welding method involving the formation of a protruding portion with a temporary welding surface extending toward the center of the opening portion, allowing for initial belt-like cladding or buttering, followed by cutting to match the contour shape and subsequent continuous second cladding or buttering, eliminating the need for manual intervention at borders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If electroslag welding or submerged-arc welding is used to make belt-like cladding or buttering with predetermined width, then large area cladding can be efficiently made, but the edge portion is formed in a linear manner making it difficult to apply along the circular opening edge
Solution Approach 1:
A protruding portion is formed on the base material in advance, with a temporary welding surface extending toward the center of the opening portion. This preliminary structure allows the automatic welding to reach closer to the opening edge, and the protruding portion is later cut off after serving its temporary purpose.
Solution Approach 2:
The welding process is divided into two stages: first making belt-like parallel cladding with automatic welding to cover the large area efficiently, then manually making cladding only in the border area near the opening edge after the protruding portion is removed. This segmentation reduces the manual work area.
2Reliability
If the opening edge is processed into an arc shape to alleviate stress concentration, then stress distribution is improved, but flux drops along the arc making it difficult to make cladding to the immediate proximity of the opening edge
Solution Approach 1:
The protruding portion with temporary welding surface is formed in advance to extend the welding area toward the center of the opening. This allows automatic welding to deposit material closer to the arc-shaped edge than would otherwise be possible, reducing the flux drop issue.
Solution Approach 2:
The protruding portion acts as an intermediary structure that bridges the gap between the automatic welding capability (belt-like parallel lines) and the arc-shaped opening edge. It provides a temporary platform for welding material deposition that would otherwise be inaccessible.
3Extent of automation
If cladding is made from the exterior side to follow the circular opening portion, then automatic welding can be performed, but manual cladding is still required at the border with inner surface cladding increasing work complexity
Solution Approach 1:
The protruding portion is formed in advance to extend the temporary welding surface toward the opening center. This allows the automatic welding to make belt-like cladding that reaches closer to the opening edge, reducing the border area that requires manual intervention.
Solution Approach 2:
Instead of making cladding from the exterior side first and then manually joining to inner surface cladding, the method inverts the approach by using the protruding portion to enable automatic welding to reach the border area, making the manual work minimal and simplifying the joining process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables efficient and continuous cladding or buttering along the contour shape of the opening portion, reducing manual labor and ensuring reliable coverage without flux drop issues, thus improving the efficiency of the welding process.
Implementation Method 1
welding method for sequentially making cladding or buttering on a surface of a base material, an inner surface of an opening portion formed in the base material, and a cut surface formed continuously from the surface of the base material to the inner surface of the opening portion
Implementation Method 2
making a first cladding or buttering in which belt-like welding having a predetermined width is formed in parallel with respect to the surface of the base material and the temporary welding surface
Data Source
AI summary
A welding method for making cladding or buttering on an inner surface of a base material, an inner surface of an opening portion formed in the base material, and the cut surface formed in such a manner that the cut surface is continuous from the inner surface of the base material to the inner surface of the opening portion, wherein the welding method includes a step of forming a protruding portion on the base material in advance, the protruding portion including a temporary welding surface extending toward the center of the opening portion in such a manner that the temporary welding surface is uniformly continuous to the inner surface of the base material and including the cut surface buried therein.