The industrious employees of Mechanical Shop of SAIL, Rourkela Steel Plant have shown a remarkable display of innovativeness and cost effectiveness by successfully developing critical pinch rolls for Hot Strip Mill 2 (HSM-2) in-house using available resources. This has brought about substantial saving for the company and improved equipment availability ensuring smooth production.
These rolls, essential for the mill’s operation, perform the crucial function of pinching hot-rolled plates and feeding them into the coiler mandrel, which turns the plates into finished coils.
The top pinch roll, were originally supplied during the mill’s commissioning. Subsequently spare rolls were procured from Original Equipment Manufacturer (OEM) with complete assembly costing more than 9 crores per set.
The huge cost of procurement and the absence of required drawing of pinch rolls posed a significant challenge for the company. The Mechanical Shop took up the challenge. Design Department was delegated the responsibility of developing drawings from the existing samples. The top roll barrel was cast at the Foundry using 9 tonnes of cast steel and then sent to the Mechanical Shop for machining. Utilizing the Homma Vertical Borer, the barrel was machined according to specifications. The ends of the top pinch roll, fabricated from scrapped universal spindles of the Plate Mill, were machined and shrink-fitted into the barrel.
Final machining of the top pinch roll is currently in progress and will be sent to Structural and Fabrication S&F Shop for cladding to achieve the required hardness.
Similarly, the bottom pinch roll has been developed using a scrap universal spindle from the Plate Mill. The cladding process for the bottom roll is underway at the S&F Shop. Following the final machining of both rolls, the surfaces will be ground to the required specifications before delivery. Developing the pinch roll set internally has cost only Rs. 10 lakh leading to huge cost savings.
