Submerged Arc Welding Startup with Phased Hot and Cold Wire Feed
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Submerged arc welding processes involving multiple hot wires and cold wires face challenges in achieving a stable arc at the beginning, leading to weld defects, mechanical property issues, and increased heat input, which complicates the generation of a stable arc, especially when cold wires are introduced.
Innovation Solution
A method comprising an arc ignition phase, an arc-stabilizing phase with constant hot and cold wire feed speeds, and a stable arc phase where feed speeds are adjusted based on welding current and hot wire feed speed, ensuring a quick and stable arc generation by maintaining constant wire speeds during initial sub-phases and adjusting during the stable arc phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cold wires are introduced to increase deposition rate, then productivity is improved, but arc stability deteriorates
Solution Approach 1:
The method applies preliminary action by establishing a stable arc using only hot wires before introducing cold wires. The welding process is divided into phases: first hot wires create a stable arc, then cold wires are gradually fed into the weld pool once stability is achieved. This preliminary stabilization prevents the cold wires from disrupting arc formation while still achieving high deposition rates.
Solution Approach 2:
The system dynamically adjusts wire feed speeds based on arc stability. During the initial phase, only hot wires are fed at controlled speeds to establish stability. Once the arc is stable, cold wire feed speed is increased to maximize deposition. The control system continuously monitors and adjusts feed rates to maintain arc stability while optimizing productivity.
2Productivity
If multiple hot wires are used to increase deposition rate, then productivity is improved, but arc stability during ignition becomes more difficult to achieve
Solution Approach 1:
The welding process is segmented into distinct phases: arc ignition phase using only hot wires, arc stabilization phase, and then introduction of cold wires. This segmentation isolates the arc ignition process from the potentially destabilizing influence of multiple wires, ensuring reliable ignition before complexity is added.
Solution Approach 2:
The method performs preliminary arc establishment using a simplified configuration (hot wires only) before introducing the full multi-wire system. This preliminary action ensures that the arc is stable and established before the additional complexity of multiple hot wires and cold wires is introduced, preventing ignition failures.
3Productivity
If wire feed speed is increased to improve productivity, then deposition rate increases, but arc stability decreases leading to weld defects
Solution Approach 1:
The wire feed system operates dynamically with different speed profiles for different phases. During arc ignition and stabilization, wire feed speeds are controlled at lower, stable rates. Once arc stability is confirmed, feed speeds are increased to maximize deposition. This dynamic adjustment ensures high weld quality during critical phases while achieving high productivity during stable welding.
Solution Approach 2:
The method applies preliminary controlled feeding at lower speeds to establish arc stability before increasing feed rates. This preliminary action at conservative speeds ensures that the arc can stabilize properly, preventing defects, after which higher speeds are safely employed to maximize productivity.
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 ensures high weld quality and rapid generation of a stable arc, minimizing the negative impact of cold wires on arc stabilization, allowing for consistent heat input and mechanical properties, thus improving the initial stages of the welding process.
Implementation Method 1
The weld current forms an arc between the consumable electrode and the work piece to create a weld pool on the work piece
Implementation Method 2
The cold wire is melted by resistance heating as well as by the heat generated by the hot wires
Data Source
AI summary
A method comprising an arc ignition phase (IP), an arc-stabilizing phase (AP) and a stable arc phase (SP). The arc stabilizing phase comprises an initial sub-phase (IS) comprising the step of feeding at least one hot wire (4, 12) at constant feed speed and a main sub-phase (MS) comprising the steps of feeding said hot wire at constant feed speed and feeding at least one cold wire (22) at constant feed speed. The stable arc phase comprises the steps of continuously adjusting the feed speed of the hot wire and continuously adjusting the feed speed of the cold wire. The invention also relates to a welding apparatus (1) for carrying out the method. The welding apparatus comprises a hot wire feeding means (150), a contact means (2), a cold wire feeding means (35) and a control unit (31). The control unit is adapted to control said hot wire feeding means to feed the hot wire at a constant feed speed during the initial sub-phase, feed the hot wire at a constant feed speed during the main sub-phase and to continuously during the stable arc phase adjust the feed speed of the hot wire. The control unit is adapted to control said cold wire feeding means to feed the cold wire at a constant feed speed during the main sub-phase and continuously during the stable arc phase adjust the cold wire feed speed.