Conduit Welding with Outward Thrust to Prevent Root Weld Press-Out
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Welding conduits is a costly and time-consuming process due to the deposition of weld material inside the conduits, which leads to corrosion and requires extensive machining to remove excess material, and existing static jigs fail to maintain outward thrust during thermal expansion and filler welding.
Innovation Solution
A method and system that aligns conduit ends to form a gap, performs a root weld from the outer surface to prevent spatter, applies an outward thrust using a support member along the inner surface to prevent material pressing out during filler welding, and releases the thrust upon solidification, using hydraulic, pneumatic, or mechanical actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If backing rings are provided on inner surfaces to prevent weld material deposition, then weld material deposition is prevented, but machining is required to remove the backing rings which is time-consuming and increases cost
Solution Approach 1:
The invention extracts the harmful backing ring from the welding system by performing root welding without any backing ring. The method achieves this by controlling the root weld parameters and using a V-groove joint configuration that prevents weld material from traveling across and depositing on the inner surfaces, thereby eliminating the need for subsequent machining operations to remove backing rings.
Solution Approach 2:
The invention replaces the permanent backing ring with a temporary protective measure during root welding. The method uses controlled welding parameters and groove geometry that serve as a disposable solution - the weld material is directed away from inner surfaces during the root weld phase, and no removal operation is needed afterward since no backing ring was installed.
2Manufacturing precision
If filler weld is performed to fill the root gap, then the gap is filled, but compression stress causes root layer to plastically deform and weld material to press out
Solution Approach 1:
The invention applies preliminary outward thrust to the conduit ends before and during the filler weld operation. This pre-applied force counteracts the compression stress that will be generated during filler welding, preventing the root layer from plastically deforming and weld material from pressing out. The outward thrust is maintained throughout the filler weld process to ensure dimensional stability.
Solution Approach 2:
The invention applies an opposing force (outward thrust) in advance to counteract the harmful compression stress that will occur during filler welding. By applying this anti-action force before and during the filler weld, the method prevents the root layer deformation and weld material extrusion that would otherwise occur due to the compression stress.
3Ease of operation
If static jigs are used to support conduits during welding, then alignment is facilitated, but outward thrust is not maintained during thermal expansion and filler welding
Solution Approach 1:
The invention replaces static jigs with a dynamic support system that actively maintains outward thrust throughout the welding process. The method uses a mechanical arrangement with adjustable elements that can apply and maintain the necessary outward force on the conduit ends, adapting to thermal expansion and the changing conditions during root and filler welding operations.
Solution Approach 2:
The invention employs pneumatic or hydraulic actuation mechanisms to generate and maintain the outward thrust force. These systems can dynamically adjust and maintain the required force level throughout the welding process, overcoming the limitations of static mechanical jigs that cannot compensate for thermal expansion or maintain consistent force during the welding operations.
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 prevents weld material deposition inside conduits, reduces the need for machining, ensures durable welds by managing stress and preventing cracking, and enhances the efficiency and economy of the welding process.
Implementation Method 1
applying an outward thrust, along the inner circumferential surfaces side
Implementation Method 2
performing a filler weld along the gap from the outer circumferential surfaces side
Implementation Method 3
releasing the thrust upon solidification
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.