Resistive Preheating of Welding Wire for Low-Hydrogen Welds
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Solution Overview
Problem
Welding processes often result in hydrogen-induced cracking and embrittlement due to the presence of hydrogen in welding wires, particularly in tubular wires, which are challenging to control and can lead to defects in welds used in industries like shipbuilding and pipelines.
Innovation Solution
A system and method for preheating welding wires using resistive heating with multiple preheating circuits and contact points to increase hydrogen diffusion, reducing hydrogen content before welding, and incorporating hydrogen sensors for closed-loop control to maintain optimal preheat parameters based on wire type and composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If welding wire is used without preheating, then the welding process is simple and fast, but hydrogen-induced cracking and embrittlement occur due to high hydrogen content in the wire
Solution Approach 1:
The patent applies preliminary action by preheating the welding wire before it reaches the welding arc. A heating element positioned within the torch assembly heats the wire as it feeds through, reducing hydrogen content and moisture on the wire surface before welding begins. This preliminary treatment prevents hydrogen-induced cracking and embrittlement without complicating the overall welding system.
Solution Approach 2:
The patent uses an intermediary heating element as a mediator between the wire feed and the welding arc. This heating element, positioned in the path of the wire, acts as an intermediate device that reduces hydrogen content through controlled heating. The intermediary component enables hydrogen reduction without requiring complex external preheating equipment or modifying the fundamental welding process.
2Reliability
If preheating is applied to reduce hydrogen content, then hydrogen-induced cracking is reduced, but energy consumption increases
Solution Approach 1:
The patent applies local quality by concentrating the heating action only on the specific section of the wire that passes through the torch assembly, rather than heating the entire wire spool or surrounding area. The heating element is positioned to contact only the wire in the immediate path, creating a localized heating zone that reduces hydrogen content while minimizing overall energy consumption. This localized approach heats only the necessary portion of the wire for a short duration.
3Productivity
If extended storage is applied to welding wire, then production costs are reduced, but hydrogen content increases leading to cracking risk
Solution Approach 1:
The patent applies self-service by enabling the welding wire to treat itself through in-line heating within the torch assembly. As the wire feeds through the torch, the heating element automatically reduces hydrogen content and moisture on the wire surface right before welding. This self-service approach eliminates the need for external controlled storage environments or humidity control systems, allowing extended storage without hydrogen accumulation while maintaining wire quality.
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 preheating system effectively reduces the risk of hydrogen-induced cracking and embrittlement by consistently lowering hydrogen levels in welds, improving weld quality and extending the shelf life of welding wires, while also reducing production and storage costs associated with hydrogen management.
Implementation Method 1
A system and method for preheating welding wires using resistive heating with multiple preheating circuits and contact points to increase hydrogen diffusion
Data Source
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AI summary
Systems and methods to heat welding wire for low hydrogen welding are disclosed. An example method includes drawing a supply material through a die to form a wire; and applying electrical current to a portion of the wire to reduce a hydrogen content of the wire.