Example for answering a welding question.

TIG WELDING:
-write the definition of welding.
-TIG welding or Gas Tungsten Arc Welding(GTAW) is a non-pressure arc welding.
-Write principle of arc welding.
-Draw figure.
Welding heat is produced from an electric arc established between the job and bare non-consumable tungsten electrode.A shielded gas(argon, heliumn nitrogen etc) is used as flux.Filler metal if required is fed separately.
ARGON: It requires a lower arc voltage, easier arc starting and provides a smooth arc action.It is economical and heaviest.
HELIUM: Higher arc voltage, hence is used where higher heat input is required.
Sometimes active carbon dioxide is used more economical and requires higher current.Used normally with only DC with +ve electrode.
Argon and helium are used for both AC and DC power sources.
Welding operation is done by striking an arc between the workpiece and tungsten electrode mounted on a special holder.Inert gas is used as flux.The arc is allowed to impinge on the job and a weld pool is created.The welding torch and filler metal are generally kept inclined at angles 70-80 degree and 10-20 degree respectively with the flat workpiece.
-Write advantages and disadvantages.
-Write applications
-Finally precautions.