Pulse Arc can be used for any thickness of aluminum. Used properly, it also will give a lower heat input than spray arc. This is one of its main benefits on aluminum. With some aluminum grades, the weld can make the heat affected zone strength decrease by approximately 1/2. The lower your heat input, the less the strength decreases. So you can actually get a stronger weld with pulse transfer on aluminum than with spray.

G Roberts

Heat input is a measure that has general application, but is often used incorrectly when taken in isolation. Theoretically you can get exactly the same heat input using higher amperage settings as with lower settings. Let us take a look at two situations with exactly the same heat input:

1)28V with 200A and 300mm/min travel speed
2)24V with 150A and 193mm/min travel speed

Taking this in isolation, you would come to the conclusion that using both sets of variables will result in exactly the same finished product. This is not so, because set 1 will result in a narrower HAZ and associated higher thermal gradients in the base metal than set 2. What does this mean? With higher thermal gradients, typically your distortion will increase. With narrower HAZ's, the loss of strength issues become somewhat smaller.

At the end of the day, you need to decide what is important and make the machine settings accordingly. If distortion control is the big issue, then use settings that result in slower welding speeds, while maintaining the heat input at low levels. In this case, pulsed spray would probably be a good bet.

Regards
Niekie Jooste