GMAW Weaving Width Control for Ni-Rich Groove Welding
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Solution Overview
Problem
The challenge in welding large-capacity LNG tanks is the difficulty in achieving excellent welding quality due to the difference in composition between the steel sheet and the welding wire, particularly when the welding wire contains 5% or more of Ni, leading to issues like sagging of the fusion zone and poor bead appearance.
Innovation Solution
A control method and device for GMAW that involves setting work information including plate thickness, groove depth, and estimated welding metal height, and calculating a weaving width based on this information to correct welding conditions, ensuring optimal welding quality even when the workpiece and welding wire have different compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If automatic welding by GMAW is used to improve welding work efficiency, then productivity increases, but welding quality deteriorates due to inability to adjust welding conditions based on welding situation
Solution Approach 1:
The patent applies dynamics by enabling the welding robot to automatically adjust welding conditions (welding speed, weaving width, arc voltage, welding current) in real-time based on detected welding situation. The control device dynamically modifies parameters during the welding process, transforming a static automatic welding system into an adaptive one that responds to actual welding conditions, thereby maintaining high quality while preserving productivity benefits.
Solution Approach 2:
The patent implements feedback through a detection device that monitors welding situation and feeds this information back to the control device. The control device uses this feedback to automatically adjust welding conditions, creating a closed-loop control system. This feedback mechanism enables the automatic welding system to respond to actual welding conditions, ensuring high welding quality while maintaining the productivity advantages of automation.
2Manufacturing precision
If welding speed is reduced to ensure high quality welding, then manufacturing precision improves, but productivity decreases
Solution Approach 1:
The system dynamically adjusts welding speed based on real-time detection of welding situation. When welding conditions are favorable, the system maintains higher speeds; when challenges are detected, it automatically reduces speed to ensure quality. This dynamic speed adjustment eliminates the need for uniformly reduced welding speeds, allowing high quality welding without sacrificing overall productivity.
Solution Approach 2:
The patent changes multiple welding parameters (welding speed, weaving width, arc voltage, welding current) in coordination based on welding situation. By adjusting these parameters dynamically rather than fixing them, the system can maintain high welding quality while preserving higher average welding speeds, thus resolving the contradiction between quality and productivity.
3Productivity
If GMAW is used to maintain deposition efficiency, then productivity is improved, but welding quality deteriorates due to difficulty in ensuring excellent welding quality with high deposition efficiency
Solution Approach 1:
The detection device monitors welding situation and provides feedback to the control device, which automatically adjusts welding conditions including weaving width and welding speed. This feedback control enables GMAW to maintain both high deposition efficiency and excellent welding quality by adapting to actual welding conditions, resolving the contradiction between productivity and quality that plagues conventional GMAW applications.
Solution Approach 2:
The system dynamically changes welding parameters (particularly weaving width and welding speed) based on detected welding situation. These parameter changes allow GMAW to maintain high deposition efficiency while ensuring excellent welding quality, overcoming the limitation that previously prevented high-quality automatic GMAW welding of dissimilar materials.
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
This approach enables automatic welding with GMAW to achieve excellent welding quality and efficiency, overcoming the challenges posed by the composition differences between the steel sheet and the welding wire.
Implementation Method 1
automatic welding by GMAW (Gas metal arc welding)
Implementation Method 2
the melting point of Ni-based alloy serving as a welding material is lower than the melting point of 9% Ni steel by 100°C or more
Data Source
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AI summary
Provided is a control method with which it is possible to achieve exceptional welding quality even using a GMAW method having high welding efficiency in welding when a groove is provided in a material being welded, the compositions of the material being welded and a welding wire are different from one another, and the welding wire used contains 5% or more of Ni. A method for controlling a welding robot or a control device relating to GMAW when a groove is provided in a material being welded, the compositions of the material being welded and a welding wire are different from one another, and the welding wire contains 5% or more of Ni, the method having: an execution information setting step for setting execution information that includes at least one from among the plate thickness, the groove depth, and the estimated welding metal height, as well as at least one from among the gap size and the groove width in a central position at a layer height calculated in advance; and a welding condition setting/correction step for calculating a weaving width before or during welding on the basis of the execution information and setting or correcting welding conditions including at least the weaving width.