The No. 2 blast furnace at Erdemir was initially blown-in in 1978. The construction type is column-supported at the mantle, with a spray water-cooled cylindrical bosh shell. Heat loads on the bosh shell increased to extremely high values after PCI installation during the partial repair in 1995. After two years of operation following the partial repair, some hot spots and shell cracks were observed on the bosh shell. To overcome this problem, a reline team was established in 1998. The main targets of this study were: to design a new, stronger bosh without changing the existing stack and hearth shell; and to achieve 2.5 tonnes per cubic meter average productivity in 24 hours with a minimum campaign life of 15 years. The new bosh shell was built conically with an angle of 81 deg and lined with graphite refractory. For this reason, half of the existing lintel plate was cut out and 12 mantle brackets were revised. 372 copper plates were used for cooling the graphite blocks. To protect graphite refractory against increased heat load attacks, no castable material was used between the copper plates and graphite blocks to improve overall heat transfer between them. To achieve better surface contact between copper plates and graphite blocks, both were designed conically with an angle of 1.5 deg and were precisely machined. All engineering was carried out by Erdemir. Replacement of the existing bosh shell with the new one was completed successfully during the year 2000 reline. Initial productivity values after reline are as expected.
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