Constricting Nozzle for High-Speed TIG Welding
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Solution Overview
Problem
TIG welding methods face challenges such as inferior welding ability and strength, high costs due to expensive tungsten electrode rods and argon gas, low shielding effectiveness, arc instability, and undercut formation, particularly when increasing welding speed.
Innovation Solution
A constricting nozzle design that accelerates plasma airflow by converting laminarized shielding gas into high-speed or swirling gas, enhancing arc energy density, directivity, and rigidity, while improving shielding and allowing easy tungsten electrode rod positioning for improved reproducibility and workability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If welding speed is increased to improve productivity, then productivity increases, but undercut (groove) is produced in the second weld part and welding quality deteriorates
Solution Approach 1:
The invention changes the physical parameters of the shielding gas by accelerating it to high speed (supersonic or hypersonic) through a nozzle, transforming it from ordinary laminar flow to high-speed regulated gas. This parameter change allows the shielding gas to effectively protect the weld zone even at high welding speeds, preventing undercut formation and maintaining weld quality while achieving high productivity
Solution Approach 2:
The invention uses pneumatic principles by employing a nozzle to accelerate shielding gas to high speeds, creating a high-speed gas flow that follows the arc and provides effective shielding. The gas-flow regulating grooves and positioning projections control the gas flow pattern, enabling the shielding gas to reach high velocities without turbulence, thus maintaining protective coverage during high-speed welding
2Device complexity
If conventional shielding gas flow is used to simplify the system, then device complexity is low, but shielding effect is insufficient and weld quality deteriorates
Solution Approach 1:
The invention introduces a nozzle as an intermediary device between the shielding gas source and the weld zone. This nozzle acts as a mediator that transforms the shielding gas from ordinary flow to high-speed regulated gas, improving the shielding effect without requiring complete system redesign. The gas-flow regulating grooves and positioning projections serve as additional intermediary elements that control and optimize the gas flow pattern
3Ease of operation
If tungsten electrode rod replacement is performed without positioning features to simplify operation, then ease of operation is high, but reproducibility and workability deteriorate due to inability to attach to original position
Solution Approach 1:
The positioning projections on the nozzle automatically guide and position the tungsten electrode rod during replacement, enabling the electrode to self-align with the correct position. This self-positioning mechanism eliminates the need for complex alignment procedures or specialized tools, allowing operators to quickly replace electrodes while ensuring consistent positioning and maintaining high reproducibility
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 high-speed welding with uniform bead width and equal waveform intervals, prevents re-adhesion of metallic vapors, reduces shielding gas consumption, and extends tungsten electrode rod life, while maintaining high-quality welds with enhanced shielding and reduced oxide film formation.
Implementation Method 1
a part of the shielding gas discharged from the torch body is allowed to flow through the high-speed gas passage, and is changed into high-speed regulated gas that is faster than the laminarized shielding gas discharged from the shielding nozzle
Implementation Method 2
the energy density of the arc, the directivity of the arc, and the rigidity (also termed 'retentivity') of the arc are heightened while strengthening an electromagnetic force and a magnetic field that act on the arc
Implementation Method 3
a plurality of positioning projections that are protrudently formed on an inner peripheral surface of the nozzle body at predetermined intervals in a circumferential direction and that hold the tungsten electrode rod in a center position of the nozzle body
Implementation Method 4
a plurality of gas-flow regulating grooves that are formed between the positioning projections and that regulate the shielding gas flowing through the high-speed gas passage
Data Source
AI summary
The constricting nozzle of the present invention includes (i) a cylindrical nozzle body disposed around the forward end of the tungsten electrode rod concentrically with the tungsten electrode rod and defines an annular high-speed gas passage between the nozzle body and the outer peripheral surface of the forward end of the tungsten electrode rod, (ii) a plurality of positioning projections that are protrudently formed on the inner peripheral surface of the nozzle body with predetermined intervals in the circumferential direction and that are arranged along the longitudinal direction of the nozzle body to hold the tungsten electrode rod in the center position of the nozzle body, and (iii) a plurality of gas-flow regulating grooves formed between the positioning projections and that extend in parallel in the longitudinal direction of the nozzle body and regulate the shielding gas (G) flowing through the high-speed gas passage.