Droplet Transition in Gas Metal Arc Welding can be divided into four categories: short circuit, particle (coarse droplet), spray, and pulse. The following are its core contents:
Classification and Characteristics
-Short circuit transition: Low current and low voltage, periodic short circuit between droplets and molten pool, suitable for thin plate and all position welding, low heat input but more spatters.
-Particle (Coarse droplet) transition: medium current, droplet diameter bigger than welding wire, unstable transition, generally an abnormal state of mismatched process parameters, many spatters, and poor forming.
-Spray transition: High current voltage, fine droplets are sprayed along the arc axis, suitable for flat welding of medium and thick plates, with deep penetration and high efficiency, but high heat input and easy deformation.
-Pulse transition: bottom and peak current modes, controllable droplet transition, suitable for all position welding, precise and controllable heat input, less spatter but high equipment cost.
Analysis of Similarities and Differences
Difference
-Transition form: big particles for particles transition; short-circuit arc-burning cycle for short circuit transition; fine spray for spray transition; Pulse transition combined with pulse current to achieve periodic spray.
-Current and voltage range: Short circuit transition requires low voltage and small current; Spray transition needs big current ( higher than the critical current); Pulse transition is regulated by pulse current, with a flexible range.
-Protection gas : The spray transition has higher requirements on argon’s purity (over than 80%), to avoid arc divergence or unstable droplet transition; Among other transition methods, short-circuit transition and particle transition can use mixed gases (such as CO ₂ or argon+CO ₂), while the protection gas of pulse transition will differ according to the difference of material.
-Application scenario: Short circuit transition is suitable for thin plates and all position welding; Spray transition is suitable for high-speed welding of medium and thick plates (requiring rich argon protection); Particle transition is used for medium current scenarios; Pulse transition can accurately control heat input and is suitable for materials such as aluminum alloys that are prone to thermal cracking.
-Arc stability: Spray transition and pulse transition arcs are more stable, while short-circuit transition may produce splashing due to frequent short circuits. Particle transition stability is between the two.
Key points for category selection
-According to material thickness: choose short circuit or pulse for thin plates, and spray for thick plates.
-According to welding position: Short circuit or pulse welding is used for all position welding, and flat welding is prioritized for spraying.
-According to splash control: less pulse and spray splash, and avoid coarse droplet transition.
-Press heat input: Select short circuit or pulse for low heat input, and spray transition for high heat input.
Different transition methods have their own advantages and disadvantages, and precise matching of process requirements can improve welding quality and efficiency.