Consumable Electrode Arc Welding for Stable Single-Pass Thick Plates
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Solution Overview
Problem
Conventional gas shielded arc welding methods fail to weld thick plates in a single pass, leading to increased heat input, deformation, and embrittlement, and struggle to maintain a stable buried arc due to unstable liquid column behavior and sputter occurrence.
Innovation Solution
An arc welding method employing a consumable electrode with a welding current of 300 A or more, where the welding wire is fed at high speed and current is periodically varied between small and large current periods to control droplet transfer and maintain a stable buried space, suppressing sputter and ensuring deep penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multi-layer welding is used to weld thick plates, then welding capability for thick plates is improved, but the number of welding steps increases and heat input increases causing deformation and embrittlement
Solution Approach 1:
The patent applies periodic action by alternating between small current periods and large current periods during welding. The small current periods allow droplet transfer to the bottom of the melted portion, while large current periods enable droplet transfer to the side part, periodically varying the arc behavior to maintain stable buried arc welding and achieve deep penetration in thick plates in a single pass
2Productivity
If welding wire is fed at high speed with large current to achieve single pass welding, then productivity is improved, but the liquid column becomes unstable and sputter occurs
Solution Approach 1:
The patent uses periodic action to alternate between small current periods (where droplet transfer occurs to the bottom) and large current periods (where droplet transfer occurs to the side part multiple times). This periodic variation stabilizes the liquid column by preventing it from becoming too long and unstable, thereby reducing sputter occurrence while maintaining high-speed wire feeding and large current conditions for single pass welding
Solution Approach 2:
The patent ensures continuity of useful action by maintaining continuous wire feeding at high speed and continuous arc generation, with the periodic current variation serving to stabilize rather than interrupt the welding process. This allows the welding to proceed continuously in a single pass without stopping or restarting
3Manufacturing precision
If large current is supplied to maintain buried arc, then deep penetration is improved, but sputter increases due to unstable liquid column
Solution Approach 1:
The patent applies periodic action by alternating between small current periods and large current periods. During large current periods, droplet transfer occurs to the side part multiple times, which prevents the liquid column from becoming too long and unstable. This periodic control allows large current to be supplied for deep penetration while minimizing sputter occurrence by stabilizing the liquid column through repeated droplet transfer cycles
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 allows for stable single pass welding of thick plates by maintaining a buried space and reducing sputter occurrence, enhancing the welding process's stability and efficiency.
Implementation Method 1
generating arc between a base material and a welding wire fed to a to-be-welded portion of the base material, to weld the base material by heat of arc
Implementation Method 2
droplet transfer occurs from the tip end to the bottom of the melted portion
Data Source
AI summary
An arc welding method of a consumable electrode type generating arc between a tip end of welding wire and a to-be-welded portion by feeding welding wire to the to-be-welded portion of a base material while supplying welding current having average current of 300 A or larger to the welding wire, to weld the base material, includes: feeding the welding wire at a speed of the tip end being inserted into a space surrounded by a concave melted portion formed in the base material by the arc generated between the tip end and the to-be-welded portion; periodically alternating between a small current period where the welding current has a small average value and droplet is transferred from the tip end to a bottom part of the melted portion and a large current period where the welding current has a large average value and droplet is transferred from the tip end to a side part of the melted portion; and controlling the welding current in the large current period so that droplet transfer from the tip end to the side part is performed a plurality of times in each large current period.