The day before yesterday I visted to another plant where steam/water drums are being manufactured..
I understood the complete working of drum shop. The following are the main stages :-
1) Sheet is obtained and after getting tested by Indian Boiler Regulation (IBR) inspector layout is drawn on it. ( We don't get sheet of width more than 2.5 m in India) .
2) Now we send it for sand blast which helps in removing mill-defects.After that the sheet is sent for rolling. The roling machines can roll sheets of thickness upto 75 mm.
3) Now the rolled sheet is sent for welding. There are three types of welding involved. SMA , SAW and Flux Coated arc welding.
In the first run manual welding is done. After that it is sent to automatic Submerged arc welding machine ( L Seam welding). After that depending upon the drum length no. of drums joined and welded circularly ( C seam)
4) After this the partially made drum sent for radiography , where we check for defects in weld joint .
5) Dish ends are not made in-house and are obtained from some vendors. Dish ends have man-holes for entry of technicians into drum.
6) A lot of small auxilliaries are fitted inside the drum.
After all these there are other processes like drilling of holes of pipe fitting. Hydrotesting, painting etc .
