Self-Shielding Tubular Welding Wire for Root Pass
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Root pass welding in flux-cored arc welding systems is complex and costly due to the need for a backing material and external shielding gas, which increases system weight and complexity.
Innovation Solution
A self-shielding tubular welding wire with a granular core and metallic sheath, containing components like silicon dioxide, aluminum, and lithium, that provides a shielding atmosphere and deoxidizes the workpiece, allowing for open root pass welding without a backing or external shielding gas, using a short circuit transfer mode to control the welding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a backing material is used to support molten material during root pass welding, then weld quality is improved, but system complexity and cost increase
Solution Approach 1:
The welding wire contains glassy slag promoter (greater than 2.4% by weight) that self-generates a shielding atmosphere and slag layer during welding, eliminating the need for external backing materials and shielding gas equipment. The wire itself provides the protective environment needed for quality root pass welding.
Solution Approach 2:
The welding wire uses a composite formulation combining metallic sheath with granular core containing glassy slag promoter, aluminum, and other components. This composite structure enables the wire to simultaneously provide structural integrity, shielding atmosphere, and deoxidation functions that previously required separate backing materials and gas systems.
2Reliability
If external shielding gas is used to displace ambient environment, then weld deposit properties are improved, but system weight and complexity increase
Solution Approach 1:
The glassy slag promoter in the welding wire composition generates its own shielding atmosphere when heated during welding, eliminating the need for external shielding gas cylinders and delivery systems. This self-shielding mechanism reduces system weight while maintaining protective atmosphere for quality weld deposits.
Solution Approach 2:
The invention changes the chemical composition parameters of the welding wire by incorporating greater than 2.4% glassy slag promoter by weight. This compositional change enables the wire to generate protective slag and shielding atmosphere internally, replacing the need for external gas systems.
3Reliability
If shielding gas is used to limit porosity and embrittlement, then weld quality is improved, but cost increases
Solution Approach 1:
The welding wire's glassy slag promoter creates an internal shielding atmosphere and slag layer that protects the weld pool from atmospheric contamination, eliminating porosity and embrittlement without requiring expensive external shielding gas equipment or consumables.
Solution Approach 2:
The glassy slag promoter is a cost-effective compositional additive within the welding wire that provides temporary but sufficient shielding protection during the welding process. This disposable internal shielding mechanism replaces expensive external gas systems.
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
Enables open root pass welding with reduced system complexity, weight, and cost, while maintaining weld quality and mechanical properties, as the tubular welding wire self-shields and controls the welding arc, reducing spatter and porosity.
Implementation Method 1
the tubular welding wire... provides a shielding atmosphere and deoxidizes the workpiece
Implementation Method 2
the tubular welding wire... provides a shielding atmosphere and deoxidizes the workpiece
Implementation Method 3
Arc welding systems generally apply electrical current to an electrode to form an arc between the electrode and a workpiece, thereby forming a weld deposit on the workpiece
Implementation Method 4
as the electrode and the workpiece are heated by the arc
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The present systems and methods relate generally to the field of welding systems, and particularly to flux-cored arc welding systems with self-shielded electrodes (FCAW-S). In an embodiment, a tubular welding wire includes a core and a sheath disposed around the core. Further, the tubular welding wire includes greater than approximately 2.4% glassy slag promoter by weight.