Feed Rate; Electrode Size; Electrode Extension - NURIS TRACTOR User Manual

Lowering the voltage creates a harder arc. This increases penetration, penetration into a deep weld
groove and durability of arc blast. An excessively low tension creates a high, narrow seam and makes it
difficult to remove slag from the seam edge.

FEED RATE

If the feed rate is increased, the heat output per unit length of a seam decreases and less filler metal
is applied for two weld unit lengths. This results in a smaller resource boost. Thus, the welding seam is
less.
Within limits, pacing can be adjusted to control resource size and population size. In this respect, it is
dependent on the current and the type of welding powder. Excessive feed rate increases undercut, arc
blow, pore and uneven weld seam. The relatively low velocities allow time for the gases to escape
from the molten metal, thus reducing the pores.
Extremely low speed:
1. A concave seam shape for cracking,
2. Excessive rear exposure is uncomfortable for the operator,
3. A large pool of melt flowing around the arc forms a rough seam with slag inlets.

ELECTRODE SIZE

Electrode size affects weld seam shape and penetration depth at constant current and fill rate. A small
electrode diameter at any current results in greater current density and higher filling density compared
to the electrode. However, a large electrode can carry a larger current compared to a smaller
electrode and realize a higher filling rate at higher current. If a desired electrode feed rate is greater
or lower than the motor can provide, the choice of size electrode can provide the desired filling rate.

ELECTRODE EXTENSION

At current densities higher than 125 A/mm², electrode extension becomes an important variable. At
high current densities, the electrode resistance heating between the arc and the welding nozzle
increases the melting rate of the electrode. The longer the electrode extension, the greater the
amount of heating and the higher the melting rate will be. This resistance is commonly called I²R
heating. An electrode extension equal to approximately 8 times the electrode diameter is a good
starting point. As the method develops, it is changed to obtain the optimum electrode melting rate at a
certain current.
An increased electrode extension adds a resistor element to the welding circuit and dissipates the
previously supplied energy. A smaller tension on the arc reduces seam width and penetration. Because
the lower arc voltage increases the convexity of the seam. The stitch shape will differ from the shape
obtained from the normal electrode extension. Therefore, when the electrode extension is increased to
take advantage of the higher melting rate, the tension setting on the machine must be increased to
provide the correct arc length. Affects the welding nozzle effect level. Welding nozzles should be
replaced at specified intervals to ensure consistent welding conditions.
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12/2021 Rev. 1.0