Lincoln Electric IM845-A manual Benefits of Pulse on Pulse from Lincoln Electric, TIG Gtaw, Smaw

BENEFITS OF PULSE ON PULSE FROM LINCOLN ELECTRIC

•Excellent appearance of the weld bead

•Improved cleaning action

•Reduced porosity

Table B.2 shows WFS and Trim settings for common aluminum types and wire sizes when welding with Pulse-on-Pulse. The welds made to obtain the values in the table were fillet welds in the flat position. The values in the table can be helpful as a starting point to establish a welding procedure. From there, adjust- ments need to be made to set the proper procedure for each specific application (out-of-position, other types of joints, etc.).

The comments on Table B.3 show values of WFS below which it is not recommended to weld. The rea- son is, that below these values the weld transfer will change from a spray arc to a short-arc, which is not advisable when welding aluminum.

TIG GTAW

The TIG mode features continuous control from 5 to 425 amps. The TIG mode can be run in either the Touch Start TIG or Scratch start mode.

The Arc Control level selects the starting mode.

Between –10 and 0, the Touch Start TIG mode is selected. The OCV is controlled below 10V and the short circuit "TIG touch" current is maintained at approximately 25 amps, independent of the preset current. When the tungsten is lifted, an arc is initiated and the output is regulated at the preset value. A set- ting of 0, results in the most positive arc initiation. A setting of -10 reduces hot start. Procedure to start the weld, and from there, to ramp to the welding procedure over a specified amount of time. Typically starting procedure on a higher “+” setting is known as a “Hot Start”. Setting a start- ing procedure on a lower setting is known as a “Cold Start”.

Between 0 and 10, the Scratch starting TIG mode is selected. In this range, the OCV of the machine is controlled between 50 and 70 volts

(See Figure B.3)

SMAW

In SMAW (STICK mode), arc control adjusts the arc force. It can be set to the lower range for a soft and less penetrating arc characteristic (negative numeric values) or to the higher range (positive numeric val- ues) for a crisp and more penetrating arc. Normally, when welding with cellulosic types of electrodes (E6010, E7010, E6011), a higher energy arc is required to maintain arc stability. This is usually indi- cated when the electrode sticks to the work-piece or when the arc pops-out during manipulative technique. For low hydrogen types of electrodes (E7018, E8018, E9018, etc.) a softer arc is usually desirable and the lower end of the Arc Control suits these types of elec- trodes. In either case the arc control is available to increase or decrease the energy level delivered to the arc.

ARC GOUGING

Gouging is basically removing metal to form a bevel or groove in a piece of steel with controlled forced air and a carbon rod.

The common procedures for Arc Gouging metal are:

•Removing poor welds from a weldment so that new welds can be made.

•Creating a welding groove or grooves in two pieces of steel butted together. (See Example below)

WELD GROOVES CREATED BY ARC GOUGING

STEEL BUTTED TOGTHER

Mode 9 in the POWER WAVE 355M is specifically for gouging. Gouging can also be done in the stick soft and crisp modes. Setting the output of the Stick Soft mode to 425 amps will enable the arc-gouging mode. The actual output current will depend on the size of carbon used. The recommended maximum size car-