Welding Phase Transition with Controlled Arc Extinguishing
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Solution Overview
Problem
Existing gas-shielded arc welding methods face challenges in achieving a trouble-free transition between pulsed arc and short arc operating phases, leading to reduced flexibility and weld quality due to abrupt changes in heat input and process stability.
Innovation Solution
Incorporating a transitional phase with increased energy input followed by an extinguishing phase before switching from pulsed arc to short arc, and a second transitional phase with maintained arc energy input when switching back to pulsed arc, allowing for smoother transitions and adjustable heat input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the welding process switches directly from pulsed arc phase to short arc phase, then the transition is simple and quick, but the transition is unstable and causes process disturbances
Solution Approach 1:
The patent applies preliminary action by introducing a preparatory phase before the actual phase transition. When switching from pulsed arc to short arc, a preparatory short arc phase is initiated first, during which the wire is fed toward the pool and the arc is extinguished in a controlled manner. This preliminary action stabilizes the transition by preparing the welding conditions in advance, preventing direct abrupt switching that would cause instability.
Solution Approach 2:
The transition between welding phases is segmented into multiple sub-phases rather than being a single abrupt change. The transition from pulsed arc to short arc is divided into: (1) initiation of short arc with increased energy input, (2) controlled arc extinguishing while wire moves toward pool, (3) wire feeding with arc extinguished. This segmentation allows each transition step to be controlled independently, improving overall transition stability.
2Speed
If the arc is extinguished immediately when switching to short arc phase, then the transition to short circuit is faster, but the wire may not be properly positioned and short circuit duration increases
Solution Approach 1:
The patent applies preliminary action by feeding the wire toward the molten pool during the preparatory phase before arc extinguishing. This ensures the wire is properly positioned and moving at the correct speed before the arc is extinguished and short circuit occurs. The wire feed is controlled to achieve optimal approach speed, preventing both premature contact and excessive delay.
Solution Approach 2:
The wire feeding action continues continuously through the transition phases without interruption. The wire is fed toward the pool during the preparatory short arc phase, maintains contact as the arc extinguishes, and continues feeding during the short circuit phase. This continuous useful action ensures smooth transition and proper positioning throughout the entire phase change.
3Temperature
If energy input is maintained at pulsed arc levels during transition, then the wire melts adequately, but the heat input is excessive for heat-sensitive materials
Solution Approach 1:
The patent uses periodic action by alternating between high energy input during pulsed arc phases (for adequate wire melting) and low or zero energy input during short arc phases with arc extinguishing (for heat-sensitive material protection). The transitional phases use controlled energy input that is lower than full pulsed arc levels but sufficient for the specific transition requirements. This periodic variation in energy input allows the process to accommodate both melting requirements and heat sensitivity constraints.
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 continuous and reliable transitions between welding phases, enhancing the stability and flexibility of the welding process, reducing the duration of short circuits, and improving weld quality by allowing for precise control of heat input.
Implementation Method 1
material is melted at the tip of the wire and detached from the wire as drops
Implementation Method 2
the Lorenz force causes a constriction of the wire material in the melted area and thus a droplet detachment
Implementation Method 3
in the short-arc operating phase the wire is conveyed alternately towards and away from the weld pool
Data Source
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AI summary
The invention relates to a method for gas metal arc welding with a consumable electrode, in which electrode material is transferred to a weld pool, and in a pulsed arc operating phase, comprising a base current phase (5) and a pulsed current phase (4), droplet detachment occurs when the electrode is spaced away from the weld pool, and in a short-circuited arc operating phase, a short-circuited droplet detachment occurs, wherein the pulsed arc operating phase and the short-circuited arc operating phase are alternately switched, and in both the base current phase (5) and the pulsed current phase (4) of the pulsed arc operating phase, the electrode is conveyed towards the weld pool, and in the short-circuited arc operating phase, the wire (111) is alternately conveyed towards and away from the weld pool, characterized in thatthat, to switch from the pulsed arc operating phase to the short-arc operating phase, after the pulsed current phase has elapsed, a first transition phase (6) with an energy input into the wire electrode preferably increased compared to the base current phase (5) occurs for a first predetermined period, followed by an extinguishing phase (t0) in which the arc is first extinguished while the wire electrode (111) is moved towards the melt pool, and the wire electrode is advanced with the arc extinguished until it makes contact with the melt pool. The invention further relates to a device for carrying out such a method.