The gas welding, wherein coalescence is produced of metals by heating with gas flame. The major difference between electric arc welding and gas welding is only source of heat. Gaseous flame is source of heat in this welding process. There are different types of gas welding in welding science i.e oxy-acetylene, oxy-hydrogen, air-acetylene and pressure gas. The oxy-acetylene flame welding is more used in industry relatively other.