Welding Torch Nozzle Layout for Diffusible Hydrogen Removal
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Solution Overview
Problem
The welding industry faces challenges with hydrogen embrittlement and hydrogen cracking in weld metals due to diffusible hydrogen, particularly in high-tensile-strength steel, where existing methods like preheating and adding fluorides are energy-intensive and pose safety risks, and current torch designs fail to provide optimal hydrogen suction performance and shielding properties.
Innovation Solution
A welding torch with a suction nozzle configuration that surrounds the welding wire, using a shielding gas supply nozzle and a suction nozzle with specific positional and dimensional relationships, and incorporating a heat-resistant insulating member to enhance hydrogen suction performance and protect the torch components, while maintaining effective shielding properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If preheating and post-heating are performed to promote discharge of diffusible hydrogen, then hydrogen embrittlement and hydrogen cracking are reduced, but energy consumption increases and operation complexity increases
Solution Approach 1:
The suction nozzle is positioned to surround the wire protrusion portion before welding begins, creating a hydrogen suction path in advance. The shielding gas flow is pre-configured to carry vaporized hydrogen sources toward the suction nozzle, eliminating the need for post-welding heat treatment to remove hydrogen
Solution Approach 2:
The invention extracts and removes diffusible hydrogen from the welding system by using the suction nozzle to actively suck away hydrogen sources before they can be absorbed into the weld metal. This extraction approach replaces the traditional method of promoting hydrogen discharge through post-heating
2Reliability
If fluorides are added to flux to reduce diffusible hydrogen, then hydrogen cracking susceptibility is reduced, but safety risks increase and manufacturing complexity increases
Solution Approach 1:
The invention converts the harmful effect of hydrogen sources in flux and metal powder into a beneficial process by allowing them to vaporize and be carried away by the shielding gas flow toward the suction nozzle. Instead of trying to eliminate hydrogen sources through fluoride additives, the system utilizes and removes the vaporized hydrogen before it causes damage
Solution Approach 2:
The suction nozzle acts as an intermediary device between the hydrogen sources and the weld metal. It intercepts the vaporized hydrogen sources carried by the shielding gas and removes them from the system, preventing direct absorption into the weld metal without requiring chemical modifiers like fluorides
3Reliability
If a suction nozzle is added to the welding torch to suck hydrogen, then diffusible hydrogen is reduced, but device complexity increases and shielding gas flow may be disrupted
Solution Approach 1:
The suction nozzle is merged with the existing shielding gas supply system. The suction nozzle is positioned within or near the shielding gas supply nozzle, and both work together using the same shielding gas flow to carry hydrogen sources to the suction nozzle. This integration avoids adding a completely separate system and reduces overall complexity
Solution Approach 2:
The shielding gas serves multiple functions: it continues to protect the weld area from oxidation and simultaneously carries the vaporized hydrogen sources toward the suction nozzle. The suction nozzle also serves dual purposes by both sucking hydrogen and potentially influencing the shielding gas flow pattern to improve overall welding performance
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
The solution improves welding quality by effectively reducing diffusible hydrogen in weld metals, preventing pore defects, and protecting the welding torch from damage, thereby reducing energy costs and operator burdens associated with preheating and enhancing the durability of the torch.
Implementation Method 1
a gas which contains a hydrogen source discharged from a welding wire by a flow of shielding gas is sucked
Implementation Method 2
a welding current passes through a wire protrusion portion 211 of the welding wire 201, which is protruded from the contact tip 208, and therefore resistance heat generation occurs, so that the temperature is elevated
Implementation Method 3
Since the arc 209 has a high temperature of several thousand degrees, the hydrogen source 205, e.g. H 2 O, is dissociated into diffusible hydrogen 212, and absorbed by solution droplets in an arc column and the weld metal 210
Data Source
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AI summary
A welding torch (100) for arc welding in a shielding gas atmosphere, includes: a contact tip (25) for feeding a welding wire (13); a suction nozzle (23) surrounding the welding wire, and sucking a gas from a space between the suction nozzle (23) and the welding wire; and a shielding gas supply nozzle (21) provided on the outer periphery of the suction nozzle (23), and supplying the shielding gas toward a welded portion from a space between the shielding gas supply nozzle (21) and the suction nozzle (23). The welding torch (100) satisfies "7 ≤ Ltk ≤ 17 and 0 ≤ Lts ≤ 18", where Lts [mm] is a distance between the tip of the contact tip (25) and the tip of the shielding gas supply nozzle (21), and Ltk [mm] is a distance between the tip of the contact tip (25) and the tip of the suction nozzle (23).