Submerged Arc Welding Startup with Staged Hot and Cold Wire Feeding
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Solution Overview
Problem
Submerged arc welding processes face challenges in achieving a stable arc during the initial stages, particularly when using multiple hot wires and cold wires, leading to weld defects, reduced melting rates, and equipment instability due to the destabilizing effect of cold wires.
Innovation Solution
A method involving an arc ignition phase followed by an arc-stabilizing phase with constant hot and cold wire feed speeds, and a stable arc phase with continuous adjustments based on welding current and hot wire feed speed, ensures rapid generation of a stable arc by minimizing the negative impact of cold wires during the initial stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cold wire is fed towards the work piece during arc ignition, then deposition rate is increased, but arc stability deteriorates
Solution Approach 1:
The hot wire is fed at a constant speed during an initial sub-phase before cold wire feeding begins, establishing a stable arc in advance. This preliminary stabilization of the arc allows subsequent cold wire feeding to increase deposition rate without compromising arc stability
Solution Approach 2:
The arc-stabilizing phase is divided into multiple sub-phases: an initial sub-phase with only hot wire feeding for arc establishment, followed by main sub-phases where cold wire feeding is added. This segmentation allows sequential introduction of elements to avoid instability
2Productivity
If hot wire feed speed is increased to improve productivity, then deposition rate increases, but arc stability deteriorates
Solution Approach 1:
The hot wire is fed at a constant, optimized speed during the initial sub-phase to establish arc stability before full productivity mode begins. This preliminary constant-speed feeding ensures proper arc formation
Solution Approach 2:
The wire feed speed system transitions from constant speed during arc-stabilizing phases to dynamically adjusted speed during stable arc phase, allowing optimization of both arc stability and deposition rate at different process stages
3Productivity
If multiple hot wires and cold wires are used simultaneously, then deposition rate increases, but process complexity increases
Solution Approach 1:
The welding process is segmented into distinct phases (arc ignition, arc-stabilizing with initial and main sub-phases, stable arc phase) with different wire feeding configurations for each phase. This temporal segmentation simplifies control by activating different wire feeds at appropriate times
Solution Approach 2:
The wire feeding system dynamically adjusts which wires are active and at what speeds based on process phase. During arc-stabilizing phases, only hot wire feeds at constant speed; during stable arc phase, all wires feed at continuously adjusted speeds optimized for maximum deposition
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 from the beginning of the process by quickly establishing a stable arc, reducing defects and equipment instability, and maintaining consistent heat input and penetration.
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 weld current forms an arc between the consumable electrode and the work piece to create a weld pool
Implementation Method 3
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.