Arc Welding Torch Position Correction in Buried Arc Welding
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Solution Overview
Problem
In buried arc welding, the position of the welding wire relative to the groove cannot be accurately reflected in the welding current, hindering precise correction of the welding torch position.
Innovation Solution
An arc welding device and method that temporarily transition to a non-buried state, allowing the arc sensor to detect the offset of the welding torch position based on welding current variations, and correct the position during this state, using techniques such as adjusting the welding power source voltage, torch movement, or wire feed speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If welding is performed in a buried arc state where the tip end portion of the welding wire progresses into the space surrounded by the molten part, then welding thick sheets of metal with one welding pass is achieved, but the position of the welding wire relative to the groove cannot be accurately reflected in the welding current, hindering precise correction of the welding torch position
Solution Approach 1:
The patent applies periodic action by alternately switching between buried arc welding state and non-buried arc welding state. During non-buried states, the system periodically detects welding torch position using arc sensor and welding current variations, then transitions back to buried arc state for continued welding. This periodic switching enables position correction without permanently abandoning the efficient buried arc welding method.
Solution Approach 2:
The patent uses welding current variations as an intermediary to indirectly detect the position of the welding wire relative to the groove. Since direct optical detection is blocked in buried arc state, the system measures electrical parameters (welding current, voltage) that change with position, using these electrical intermediaries to infer mechanical position information needed for correction.
2Reliability
If multi-layer welding is used to weld thick sheets of metal, then complete welding is achieved, but the number of process steps increases and the amount of heat input is increased to deform the base metal and make the welded section brittle
Solution Approach 1:
The patent applies parameter changes by significantly increasing welding current (equal to or larger than 300 A) and adjusting wire feed speed (5-100 m/min) to enable single-pass welding of thick sheets. These parameter modifications allow the welding process to achieve complete penetration and reliable welds in one pass, eliminating the need for multiple layers and associated process complexity.
3Productivity
If large current is supplied to the welding wire to enable high-speed feeding and single-pass welding of thick sheets, then welding efficiency is improved, but a recessed molten part is formed that causes the welding wire tip to progress into the space surrounded by the molten part
Solution Approach 1:
The patent implements feedback control by continuously monitoring welding current and voltage during the welding process. When the welding wire tip progresses into the molten part space (detected through current variations), the system provides feedback signals to adjust wire feed speed or torch position, maintaining optimal welding parameters despite the dynamic buried arc conditions created by high-current welding.
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 accurate correction of the welding torch position using an arc sensor even in buried arc welding, improving positional accuracy and reducing inaccuracies associated with the buried state.
Implementation Method 1
forms an arc between a tip end portion of the welding wire and the base metal by the supplied power
Implementation Method 2
a recessed molten part is formed on the base metal by the heat of an arc
Data Source
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AI summary
A consumable electrode type arc welding device that comprises a welding power source for supplying power between a welding wire (6) and a base metal (5) and a welding robot for moving and weaving a welding torch along a groove (5a) and that causes the tip end portion of the welding wire (6) to progress into a space surrounded by a recessed molten part (7) formed on the base metal (5) to thereby weld the base metal (5). The arc welding device temporarily makes a transition to a non-buried state where the tip end portion of the welding wire (6) does not progress into the space for a predetermined time period, acquires, from an arc sensor for detecting an amount of offset of a central position for welding from a position of the groove (5a) based on welding current flowing from the welding wire (6) to the base metal (5), a detection result of the amount of the offset at least in the non-buried state, and corrects a position of the welding torch (11) relative to the groove (5a) based on the detection result by the arc sensor in the non-buried state.