In arc stud welding, "short-circuit transition" and "spray transition" are two typical droplet control methods, with their differences mainly lying in arc behavior, weld bead formation, and spatter control. Selection should be made by considering the material properties comprehensively.
Short Circuit Transfer
Working Principle
Short-circuit contact occurs periodically between the molten droplet and the molten pool, forming a liquid metal bridge. The short-circuit current generates an electromagnetic contraction force, causing the neck of the molten droplet to shrink and detach from the wire, transitioning to the molten pool under the action of surface tension.
2. Weld Seam Formation Characteristics
Shallow melting depthWelding suitable for thin plates (<6mm), with a smaller molten pool volume.
Smooth SurfaceThe weld seam features fine ripples and low excess height.
Narrow heat-affected zoneHigh-strength steel suitable for applications sensitive to deformation.
Splash Control
Low splash volumeThe short-circuit process concentrates energy, with a smooth transition of molten droplets.
Applicable scenariosHigh-purity environments requiring溅射污染 avoidance (such as electronic component welding).
Material Adaptability
Preferred MaterialsCarbon steel, low-alloy steel (excellent conductivity, rapid short-circuit response).
Use materials with caution.Aluminum alloy (oxide film hinders short-circuiting, prone to cold cracking).
Section Two: Spray Transfer
Working Principle
The arc voltage is high, causing the wire tip to form a pencil-point-shaped droplet, which is then ejected as fine particles into the molten pool under the influence of electromagnetic force.
2. Weld Seam Forming Characteristics
Deep melting depthWell-suited for welding medium to thick plates (>8mm) with strong molten pool fluidity.
Rough surfaceWide weld seam waviness and high excess height.
Hot input concentratedControl cooling rate to avoid cold cracking.
Splash Control
Spray excessivelyThe droplet particles are small and move at a high speed, which is prone to forming fine particle splashes.
Control MeasuresUtilize pulse-jet mode or add an active gas (such as CO₂).
4. Material Adaptability
Preferred MaterialsAustenitic stainless steel (e.g., 316L), aluminum alloys (require pulse mode).
Use materials sparingly.Galvanized Plate (Zinc Vapor Interference with Arc Stability)
Section 3: Selection Strategy
| Select Dimensions | Short-circuit Transition | Jet Transition |
|---|---|---|
| Material Thickness | Sheet metal (<6mm) | Medium-thickness plate (>8mm) |
| Material Type | Carbon steel, low-alloy steel | Stainless Steel, Aluminum Alloy (Pulse Optimization Required) |
| Splash Sensitivity | High-demand scenarios | Comply with splash control measures |
| Welding Position | Full-position welding | Flat welding/Horizontal welding is superior. |
| Equipment Costs | Lower (conventional power) | Higher (requires pulsing power) |
Section 4: Suggested Process Parameter Matching
Short-circuit Transition：
Voltage: 18-22V
Current: 150-250A
Welding Wire Diameter: 1.0-1.2mm
Jet Transition：
Voltage: 28-35V
Current: 300-450A
Welding Wire Diameter: 1.2-1.6mm
In practical applications, the transition form of molten droplets can be observed through high-speed photography, and parameter optimization can be achieved by combining weld metallographic analysis (such as fusion zone width, heat-affected zone grain size). For dissimilar metal welding (such as steel-aluminum), it is recommended to use a dual-pulse jet mode, achieving a "soft landing" of the molten droplets through waveform control.
