Application of Improved Quality Tap Hole Sleeve to Increase Shop Productivity at Rourkela Steel Plant

Abstract

Rourkela Steel Plant (RSP) has undergone massive modernization to increase production from the existing level of 2.18 Mt to 4.2 Mt crude steel after commissioning of one additional 4060 m3 blast furnace and a third converter of 150 t capacity in Steel Melting Shop-II (SMS-II). The increased volume of quality steel production will largely depend on shop productivity with higher converter availability along with a lower down time for maintenance. The design and refractory quality of the tap hole sleeve for the converter plays an important role in the production of liquid steel and availability of the converter. At RSP, MgO-C quality zonal lining material is manufactured at the in-house brick plant (LDBP) while the tap hole sleeve for the converter is procured from various reputed refractory manufacturers. The life of the sleeve varies between 58 heats and 100 heats with an average of around 70 heats. The frequent change of tap hole sleeves not only affects converter lining life due to thermal spalling but also decreases availability of the converter. Improved dense quality tap hole sleeves with less material segregation leading to uniform density, chemical composition and strength across the entire tap hole length were procured and tried in converter A of SMS-II. These tap hole sleeves were manufactured in small pieces, pre-assembled to the required size and delivered as single entities of varying denominations. The service life of these tap hole sleeves reached an average level of 93 heats with a peak of 130 heats and the major portion of heats fell within 5–7 min tap duration which helped in less slag carryover and suggestive of reduced consumption of deoxidants.