Short Note On Thermit Welding quality control

Thermit Welding & its quality control: -

A fish plated joint has been a necessary evil in the railway track right from beginning of railway. To overcome the various problems posed by the fish plated joints and reduced the maintenance cost the need for welding of rail ends was felt. Joining of two rails end by the application of heat is called welding. Among the various tetchiness of welding the AT welding is used now days for scattered and spot welding.

Quality control:- The quality of an AT welding could be ensure by adopting the following simple precautions.

i. The rail ends must be cleaned and straight.

ii. The gap should be uniformed and within limit.

iii. All the equipment used for AT welding should be complete and in order.

iv. Only prefabricated moulds of sound condition should be used welding portion and looting sent should not be of expiry date material. Pressure of oxygen and LPG should be as per specification adequate heating time should be given to heat up the rail ends.

v. Ensure uniform heating of rail ends.

vi. Welding Portion should be dry and free from any moisture content.

vii. Corrected size of thimble should be used.

viii. Specified mould waiting time should be achieved before trimming the weld joints.

ix. Small track machine should be used for trimming and grinding.

x. Chisel cutting should be avoided.

xi. After finishing tolerances must be ensured of welding joints.

xii. No traffic should be allowed over newly welded joint within 30 minutes of the welding.