Blooming and Billet Mill of Bhilai Steel Plant is the prime mill of plant. About 2.5 MT ingots are rolled per year in to blooms in Blooming Mill and these blooms are further rolled in to billets in Billet Mill. The function of main drive spindle is to give drive to main stand roll of Blooming Mill. These spindles are used to connect main drive to rolls of 1150m.m. stand. One end of spindle is having fixed roll coupling where as other end of spindle is having detachable roll coupling. Some time ago while changing detachable side roll coupling, it was found that the end portion of spindle at coupling seating was badly cracked/damaged through and through. The extent of crack was 470m.m.axially and 220m.m.depth at the end portion on the coupling seating. The estimated cost of a new spindle assembly is approximately Rs.5crores. Weight of spindle is 32.63T. The present Russian units and also other units around the world are reluctant to supply such massive spare. Hence it was decided to reclaim the cracked / damaged end of the main spindle. For repair it was decided to remove the cracked portion and to be rebuilt by welding by fixing steel bolts on the damaged portion for reinforcements. As machining was not feasible, hence it was decided that finishing is to be done by grinding. A gauge for grinding was made. This paper deals with complete repair scheme adopted for reclamation of damaged portion of spindle and to revive this vital spare. This paper includes selection of welding consumables, preheat and post heat treatment, welding parameters, quality parameters, preparation and precautions for reclamation procedures.
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