Welding Prameters and Their Effects

Weld quality, and weld deposition rate both are influenced by various welding parameters and joint geometry. These parameters are the process variables as given below :
1. Welding current
2. Arc Voltage
3. Welding speed.
4. Electrode Feed rate
5. Electrode extension (stick-out)
6. Electrode diameter
7.Joint geometry.
Each of the above parameters affects, to varying extent, the following:
1. Deposition rate
2. Weld-bead shape
3. Depth of penetration
4. Cooling rate
5. Weld induced distortion.
Hence, a proper understanding of the effects of welding parameters (or process variables is important to obtain a sound welded joint with adequate metal deposition rate and minimum distortion. General effect of these variables will be discussed in the following paragraphs.1. Welding Current
Melting rate is directly proportional to the energy (current and voltage) used for a given electrode and polarity used in DC welding. Part of this energy ? is used to melt the base metal (qb), part goes to melt electrode and flux (qf) rest is dissipated as conduction (qep + qce), convection (qv) and radiation (qv)
? = qb + qf + (qcp + qce) + qv + qv)
Also, ? = IV. J/S
= I2 Ra J/S
where ? = electrical energy consumed
I = welding current
V = arc voltage
Ra = arc resistance