Thermit Welding

Hot Action 1: Preparation are underway for welding one of the track joints. Surareddipalem, 21-8-2004. By Pavan Kumar.

Hot Action 2: Holder containing mixture of Magnesium and Iron being positioned over the track joint. Surareddipalem, 21-8-2004. By Pavan Kumar.

Hot Action 3: Here goes the flame, mixture getting fired. Surareddipalem, 21-8-2004. By Pavan Kumar.

Hot Action 4: Molten iron flowing into the casing below. Surareddipalem, 21-8-2004. By Pavan Kumar.

Hot Action 5: Molten iron lighthing up with its heat, temperature may be around 3000c. Surareddipalem, 21-8-2004. By Pavan Kumar.

Hot Action 6: This is what it becomes after some thing and extra iron is removed. Surareddipalem, 21-8-2004. By Pavan Kumar.

portion of the rails to be welded.

the portion to be welded being cleaned with kerosene & wire brush.

pre fabricated mould fitted onto the rails in a mould shoe.

the assembly being prepared.

special type of powder prepared under the supervision of RDSO called "Luting sand"

Using the gases either LPG & Oxygen or Petrol-Air mix at specified pressure.

closing pin is placed at the bottom of crucible for plugging the pouring gate.

Asbestos powder is placed to avoid direct contact between superheated thermit steel & closing pin.

Asbestos powder is further covered with slag powder to avoid displacement due to turbulence during thermit reaction.

The excess Thermit steel above the head of the rail is removed soon after solidification.

finally the portion is welded & later the grinding of the railhead is done by using a suitable rail grinding m/c. to achieve the specified grinding tolerance.