Pulsed Arc Welding of Al-Zn Coated Steel to Suppress Spatter
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Solution Overview
Problem
Hot dip Zn-based alloy coated steel sheets with high Al concentration (>1% by mass) face excessive spatter and blowhole generation during arc welding, leading to poor appearance and strength of the welded part, which existing pulsed arc welding methods fail to address effectively, especially for heavy-weight sheets and those with Al concentrations above 0.3% by mass.
Innovation Solution
A pulsed arc welding method is employed with controlled average welding current (100 A to 350 A), average welding voltage (20 V to 35 V), and pulse period (1 ms to 50 ms), along with managing the Al concentration (1.0% to 22.0% by mass) and coating weight (15 g/m2 to 250 g/m2) to suppress spatter and blowhole formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hot dip Zn-based alloy coated steel sheets with high Al concentration are arc-welded, then corrosion resistance is improved, but spatter and blowhole generation increases excessively
Solution Approach 1:
The patent applies pulsed arc welding where the welding current is applied periodically in pulses rather than continuously. This periodic action allows the molten pool to cool and solidify partially between pulses, preventing excessive Zn vapor generation and spatter, while still achieving proper welding penetration and maintaining corrosion resistance of the high Al concentration coating
Solution Approach 2:
The patent dynamically adjusts welding parameters including pulse width, peak current, and base current to control the thermal input to the coating. By making the welding process dynamic rather than static, the system can manage the volatile Zn coating material effectively, reducing spatter and blowholes while preserving the protective corrosion-resistant coating structure
2Reliability
If heavy-weight hot dip Zn-based alloy coated steel sheets are used for long-term durability, then corrosion resistance is improved, but Zn vapor generation increases excessively during arc welding
Solution Approach 1:
Pulsed arc welding with periodic current application allows vapor to escape during off-periods while maintaining coating integrity during on-periods, reducing overall vapor generation from heavy coatings
Solution Approach 2:
The patent changes the temporal distribution of welding energy through pulsed parameters, transforming the continuous thermal input into discrete pulses that manage vapor pressure and Zn vapor generation from heavy coatings more effectively
3Device complexity
If conventional arc welding is used on hot dip Zn-based alloy coated steel sheets, then welding process simplicity is maintained, but welded part appearance and strength deteriorate
Solution Approach 1:
The pulsed arc welding process introduces periodic current variation to control spatter and blowholes, significantly improving welded part appearance and strength while maintaining reasonable process complexity through standard welding power supply modifications
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 effectively reduces spatter and blowhole generation, resulting in a welded part that is excellent in appearance, strength, and corrosion resistance for hot dip Zn-based alloy coated steel sheets with high Al concentrations.
Implementation Method 1
a method of arc-welding hot dip Zn-based alloy coated steel sheets
Implementation Method 2
a current waveform formed by a welding current is a pulsed current waveform in which a peak current and a base current alternate with each other
Implementation Method 3
due to a pulsed arc, a molten pool is stirred, and is pushed down so that the molten pool becomes thin
Data Source
AI summary
Hot dip Zn-based alloy coated steel sheets (1, 1′) are arc-weld in such a way that (a) a current waveform is a pulsed current waveform in which (i) a peak current and a base current alternate with each other at a pulse period of 1 ms to 50 ms and (ii) an average welding current is 100 A to 350 A and (b) an average welding voltage is 20 V to 35 V. Each of the hot dip Zn-based alloy coated steel sheets (1, 1′) includes a coating layer that contains Zn as a main component and that contains Al at a concentration of 1.0% by mass to 22.0% by mass, and has a coating weight W of 15 g/m2 to 250 g/m2.