Transfert mode, how to identify ?

[abbver98]

How to identify the transfer mode for GMAW ? Short-arc, Globular or Spray-arc. Someone says that only by hearing the noise!!!!!!!!!!!!!!!!!!
Some speak about pulse mode. The pulse concerns tha current and can influent the three transfer mode. there is no pulse mode transfer. Right ?
No standard to identify the transfert mode ??
Thanks for your contribution,

 

[abbver98]

Can I ask the welding machine to specify under which conditions I'll have a specific mode ? Since the machine is synergic.

 

[gtaw]

Short circuiting transfer involved the electrode shorting out against the weld pool and then "breaking" to form a momentary arc, only to short out against the surface of the weld pool again. It sounds like frying bacon because the process of shorting out and breaking occurs between 80 to 120 times a second (approximately)

Globular transfer results in the end of the electrode "growing" to be about two to three times the diameter of the electrode and then the large droplet detaches and is flung across the arc to the weld pool.

Spray mode transfer has a hiss to it and the electrode almost forms a point at the end. Very small droplets flow axially off the end of the electrode through the arc to the weld pool. The sound is very distinct and the arc is almost a perfect cone when everything is running properly.


Best regards - Al

 

[abbver98]

gtaw,

the only way to identify them is the sound ? Any other method or standard that specify how can be determined the transfer mode ? Can the machine supplier provide a certificate stating a conditions to reach such mode transfert ?

thanks,

 

[gtaw]

Chyeck the web site of the electrode manufacturer. They typically list the welding parameters for spray and short circuiting. With that in mind, the type of shielding gas also influence the mode of transfer. In general, at least 80% argon is needed to spray and less than 75% argon will have a tendency to short circuit when reduced voltage and wire feed speed is dialed in.

Best regards - Al

 

[Duwe6]

I have seen and worked in the spray-arc mode using 75% Argon - 25% CO2. Its just a matter of current density. And it makes a quiet, 'forceful' hiss.

As for globular, the spatter will be the size of large BB's / small buckshot. It is significant larger than the spatter from Short-Circuiting transfer. And it sounds different.

Just take the time to gain the experience. Play with a GMAW welder. With 0.035" wire, set the amps at 200A ans volts at 20V. That should be short-circuiting. Turn the volts down, 1 V at a time. The ShortArc will get so 'cold' that you weld will turn to a steel-to-steel braze.

Now go back to 20V and work your way up. Check the spatter for a change in size. Globular was kind of subtle for me to see. You will find Spray to be unmistakable.