Welding Torch Nozzle Geometry for Diffusible Hydrogen Extraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The welding industry faces challenges with hydrogen embrittlement and hydrogen cracking in weld metals due to diffusible hydrogen, which is exacerbated by high-strength steel usage, and existing methods such as preheating, post-heating, and fluoride addition are energy-intensive, costly, and can compromise welding quality.
Innovation Solution
A welding torch design that includes a contact tip, a suction nozzle surrounding the welding wire to extract hydrogen, and a shielding gas supply nozzle, optimized with specific geometric relationships and materials to enhance hydrogen suction performance while protecting the torch components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If preheating and post-heating are performed to reduce diffusible hydrogen, then hydrogen embrittlement and cracking are prevented, but energy consumption increases and welding productivity decreases
Solution Approach 1:
The suction nozzle extracts hydrogen-containing gases directly from the welding zone by creating a negative pressure field, removing the harmful substance (hydrogen) before it can be absorbed by the weld metal, thereby eliminating the need for energy-intensive preheating and post-heating processes
Solution Approach 2:
The invention replaces the thermal field-based approach (preheating/post-heating) with a fluid field-based approach (suction nozzle creating negative pressure), substituting mechanical/physical removal of hydrogen with thermal processing
2Reliability
If fluorides are added to flux to reduce diffusible hydrogen, then hydrogen cracking is prevented, but welding quality may deteriorate due to arc instability and slag inclusion
Solution Approach 1:
Instead of using fluorides that create harmful side effects (arc instability, slag inclusion), the invention converts the harmful hydrogen byproducts into removable gases that can be extracted by the suction nozzle, achieving hydrogen reduction without compromising weld quality
Solution Approach 2:
The suction nozzle acts as an intermediary device that removes hydrogen-containing gases from the welding zone before they can be absorbed by the weld metal, providing a third-party solution that doesn't interfere with the welding process itself
3Productivity
If suction nozzle is positioned closer to contact tip to improve hydrogen suction, then hydrogen removal efficiency increases, but torch component protection deteriorates due to heat exposure
Solution Approach 1:
The suction nozzle is nested within the shielding gas supply nozzle, creating a multi-layer protective structure where the outer shielding gas nozzle protects the inner suction nozzle from heat and spatter, allowing close positioning without compromising torch durability
Solution Approach 2:
The invention optimizes the three-dimensional positioning of the suction nozzle relative to the contact tip and workpiece, finding the optimal balance between suction efficiency (requiring close positioning) and heat protection (requiring distance), by considering radial and axial dimensions simultaneously
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 design effectively reduces diffusible hydrogen in weld metals, improving welding quality, reducing energy costs, and minimizing the burden on operators, while maintaining torch durability and shielding properties.
Implementation Method 1
a suction nozzle that surrounds a periphery of the welding wire protruded from a tip portion of the contact tip, and sucks a gas from a space formed between the suction nozzle and the welding wire
Implementation Method 2
a shielding gas supply nozzle that is provided on an outer periphery of the suction nozzle, and supplies the shielding gas toward a welded portion at a tip of the welding wire from a space formed between the shielding gas supply nozzle and the suction nozzle
Implementation Method 3
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 4
the welding wire 201 is melted by an arc 209 at the tip of the welding wire 201 to form a weld metal 210
Data Source
AI summary
A welding torch for arc welding in a shielding gas atmosphere, includes: a contact tip for feeding a welding wire; a suction nozzle surrounding the welding wire, and sucking a gas from a space between the suction nozzle and the welding wire; and a shielding gas supply nozzle provided on the outer periphery of the suction nozzle, and supplying the shielding gas toward a welded portion from a space between the shielding gas supply nozzle and the suction nozzle. The welding torch satisfies “7≤Ltk≤17 and 0≤Lts≤18”, where Lts [mm] is a distance between the tip of the contact tip and the tip of the shielding gas supply nozzle, and Ltk [mm] is a distance between the tip of the contact tip and the tip of the suction nozzle.