Arc Welding Current Control for Galvanized Steel Stability
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Solution Overview
Problem
In arc welding of galvanized steel sheets, the zinc on the surface vaporizes due to arc heat, leading to unstable welding and increased spatter generation, especially when the welding wire feed speed alternates between forward and reverse periods.
Innovation Solution
An arc welding control method that switches between three arc periods with different currents (Ia1 > Ia2 > Ia3) and controls the welding current and voltage to prevent zinc vapor from remaining in the molten pool, using constant current during the first arc period and constant voltage during the second arc period, with the first arc current set to prevent zinc vapor discharge and the third arc current minimized to avoid wire melting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If arc welding is performed on galvanized steel sheet with alternating forward and reverse feed periods, then welding quality is improved, but zinc vapor ejection increases causing unstable welding state
Solution Approach 1:
The patent applies periodic action by dividing the arc period into three distinct phases (first arc period with high current Ia1, second arc period with intermediate current Ia2, third arc period with low current Ia3) that repeat cyclically. This periodic current variation enables systematic control of zinc vapor ejection and molten pool stability while maintaining the beneficial effects of alternating feed periods for welding quality
Solution Approach 2:
The patent changes the current parameter over time within each arc period, transitioning from high current (Ia1) to intermediate current (Ia2) to low current (Ia3). This dynamic parameter adjustment allows optimization of heat input at different stages: initial rapid heating to vaporize zinc, intermediate stabilization, and final cooling to prevent vapor entrapment, thereby resolving the contradiction between welding quality and stability
2Productivity
If high arc current is applied to vaporize zinc quickly, then zinc vapor discharge is improved, but spatter generation increases
Solution Approach 1:
The patent uses periodic action by applying high current (Ia1) only during the first arc period for rapid zinc vaporization, then switching to intermediate current (Ia2) during the second arc period to stabilize the molten pool and reduce spatter. This time-separated approach allows efficient zinc removal without continuous high-current-induced spatter
Solution Approach 2:
The patent applies skipping by rapidly heating the molten pool with high current (Ia1) during the first arc period to quickly vaporize zinc, then immediately transitioning to lower currents (Ia2, Ia3) to complete the welding process without prolonged high-temperature exposure that would generate excessive spatter. This rushed-through approach minimizes the duration of harmful high-current effects
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 method stabilizes the welding process and reduces spatter generation by optimizing heat input and arc management, ensuring zinc vapor is discharged and maintaining a stable arc length.
Implementation Method 1
zinc on the surface of the base material turns into vapor due to the arc heat
Implementation Method 2
generating an arc between the welding wire and a base material
Data Source
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AI summary
To stabilize a welding state when a base material is a galvanized steel sheet in a welding method in which a feed speed of a welding wire is alternately switched between a forward feed period and a reverse feed period. In an arc welding control method for controlling welding in which a material of a base material is a galvanized steel sheet, a feed speed of a welding wire is alternately switched between a forward feed period and a reverse feed period, and a short circuit period and an arc period are repeated, during the arc period, a first arc period Ta1 during which a first arc current Ia1 is applied, a second arc period Ta2 during which a second arc current Ia2 is applied, and a third arc period Ta3 during which a third arc current Ia3 is applied are switched over time, and it is controlled so as to be Ia1 > Ia2 > Ia3. Constant voltage control is performed during the second arc period Ta2, and constant current control is performed during the first arc period Ta1. A value of the first arc period Ta1 and/or the first arc current Ia1 is changed according to a zinc deposition amount per unit area of the base material.