Submerged Arc Welding Current Cycling for Stable Deep Penetration
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Solution Overview
Problem
Existing submerged arc welding methods often result in incomplete penetration, especially in single pass welding or the first layer of multi-layer welding, due to limitations in adjusting output current and voltage, which can lead to issues like lack of penetration bead and fusion width, and these methods are not effective for DC welding.
Innovation Solution
A submerged arc welding method that periodically switches between low and high current periods to achieve deeper penetration, using a control device to manage the switching of welding conditions and maintain constant arc length, effectively applying high heat input during high current periods to push molten metal deeper.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional submerged arc welding methods are used with fixed current and voltage settings, then the welding process is simple and stable, but penetration depth is insufficient and incomplete penetration occurs
Solution Approach 1:
The patent applies periodic switching between high current and low current periods during the welding process. The high current period (e.g., 300-500 A) provides deep penetration, while the low current period (e.g., 100-300 A) allows molten metal to cool and solidify slightly. This periodic variation in current intensity enables deeper penetration than conventional fixed-current methods while maintaining process stability through automated control.
Solution Approach 2:
The welding current is dynamically adjusted between high and low states during the welding process, transitioning from static fixed-current settings to dynamic variable-current operation. This dynamic control allows the system to optimize penetration depth by varying current intensity in real-time based on the welding cycle, achieving deeper penetration while preventing excessive heat buildup.
2Manufacturing precision
If high current is continuously applied to achieve deep penetration, then penetration depth increases, but heat input becomes excessive and weld quality deteriorates
Solution Approach 1:
The patent implements periodic switching between high current periods (providing deep penetration) and low current periods (reducing heat input). During high current periods, the intense heat drives molten metal deep into the base material. During low current periods, heat input is reduced, allowing the molten metal to cool and solidify, preventing excessive heat accumulation and maintaining weld quality.
Solution Approach 2:
The continuous welding process is segmented into discrete high current periods and low current periods. Each segment serves a specific function: high current segments provide penetration, while low current segments control heat input and allow solidification. This segmentation of the welding process enables precise control over both penetration depth and heat input.
3Adaptability or versatility
If alternating current with adjusted positive and negative periods is used, then penetration can be controlled, but the method is not effective for DC welding and has limited applicability
Solution Approach 1:
The patent develops a welding control method that works with both AC and DC power sources, making the penetration control technique universally applicable. The control system monitors the power source type and adjusts the switching parameters accordingly, enabling the same periodic switching mechanism to achieve effective penetration control in both AC and DC submerged arc welding applications.
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 achieves deeper penetration and stable formation of penetration beads, even when conventional methods fail, by maintaining a fluctuation range of current between 100 A and 500 A and switching frequencies between 1 Hz and 10 Hz, enhancing the quality of welds without altering the output current and voltage ranges.
Implementation Method 1
a welding power source that supplies welding current
Implementation Method 2
the arc generated between the welding wire and the base material
Data Source
AI summary
A submerged arc welding method comprises setting a first welding condition under which first average welding current is supplied to a welding wire; and setting a second welding condition under which second average welding current is supplied to a welding wire, and the first welding condition and the second welding condition are periodically switched.