Therefore, these
parameters affecting the arc and welding bath should
be estimated and their changing conditions during process
must be known before in order to obtain optimum
results; in fact a perfect arc can be achieved when all the
parameters are in conformity [4]. These are combined in
two groups as first order adjustable and second order
adjustable parameters defined before welding process.
Former are welding current, arc voltage and welding
speed, and later are torch angle, free wire length, nozzle
distance, welding direction, position and the flow rate of
gas [3,5]. However, wire electrode diameter and its composition,
type of protective gas are the defined parameters
before starting welding and cannot be changed
during the process.