Conduit Welding Outer Root Pass to Prevent Inner Deposition
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Solution Overview
Problem
Welding conduits is a time-consuming and costly process due to the deposition of weld material inside the conduits, which leads to corrosion and requires extensive machining to remove excess material, increasing the risk of deformation and reducing conduit life.
Innovation Solution
A method and system that involves aligning conduit ends, performing a root weld from the outer surface to prevent spattering, applying an outward thrust using a support member along the inner surface to ensure shrinkage of weld materials radially and longitudinally outward, and filling the gap with a filler weld, thereby preventing material deposition and deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If backing rings are provided along the welding zone to prevent weld material deposition, then weld material deposition is prevented, but the process becomes more complex and requires additional machining to remove the backing rings
Solution Approach 1:
The invention removes the backing ring from the system entirely by performing the root weld from the outer surface of the conduit. This extraction eliminates the harmful effect of weld material deposition on the inner surface while also removing the complexity associated with installing and removing backing rings. The root weld is completed without any internal support structure, and the gap is subsequently filled from the outer surface.
Solution Approach 2:
Instead of welding from the inner surface with backing rings to prevent deposition, the invention inverts the approach by welding from the outer surface. This reversal allows the welder to access the root gap from the outside, preventing weld material from being deposited on the inner conduit surface while eliminating the need for backing rings and subsequent machining operations.
2Object-affected harmful factors
If machining is performed to remove deposited weld material, then weld material deposition is removed, but time and cost increase significantly
Solution Approach 1:
The invention performs preliminary action by welding the root layer from the outer surface before any filler welds are applied. This preliminary root welding is done without backing rings, preventing weld material deposition on the inner surface in the first place. By addressing the deposition prevention issue during the root weld stage rather than correcting it afterward through machining, the invention eliminates the time-consuming machining step entirely.
3Manufacturing precision
If filler weld is performed to fill the root gap, then the gap is filled, but compression stress causes root layer plastic deformation and weld material pressing out
Solution Approach 1:
The invention performs preliminary strengthening of the root layer by applying a support layer or reinforcement welds before performing the filler weld. This preliminary action strengthens the root layer to resist the compression stress that will be applied during filler weld deposition, preventing plastic deformation and weld material pressing out while still allowing complete gap filling.
Solution Approach 2:
The invention provides beforehand cushioning by applying a support layer or reinforcement structure before the filler weld process. This cushioning layer absorbs or distributes the compression stress generated during filler weld deposition, preventing the stress from causing plastic deformation of the root layer or pressing out of weld material.
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 approach reduces the need for machining, enhances the durability of the weld by managing stress and preventing cracking, and results in a more efficient and cost-effective welding process by preventing weld material deposition inside the conduits.
Implementation Method 1
performances of the filler weld upon the application of the outward thrust ensures shrinkage of the filler and root weld materials longitudinally and radially outward, across the two or more conduit members
Data Source
AI summary
A method for welding two or more conduits includes aligning end portions thereof in an abutting relationship to define a gap. The method includes performing a spatter free root weld along the gap to configure a root layer while the inner circumferential surface side is unobstructed. After the root weld is complete, an outward thrust is applied along the inner circumferential surfaces of the conduits. During the application of the outward thrust, a filler weld is performed along the gap to fill the gap and to facilitate shrinkage of the filler and root weld materials longitudinally and radially outward while preventing pressing out of the filler and root weld materials radially inward of the inner circumferential surface.