BigPatents India

A process for improving the strength of steel drum, provided with top dished end cover with filling openings and bottom dished end cover without opening having steps of:- a. Selecting length of the steel sheet to form drum shell less than desired diameter; b. Forming the cylindrical drum shell of the said steel sheet by resistance welding along longitudinally over the lapping joint; c. Cold expanding the said shell by means of segmented expander with steadily increasing the expansion force throughout the length beyond elastic limit; d. Forming the corrugation to the said steel shell one at a time; and e. The said top and bottom dished end covers fitted by twisting together flanges of the said shell and dished end cover together forming double or triple seam joint. Drawing: 03 Sheets. Total Pages: 15. Fig. Nil