Speaker
MAKOTO GOTO
(Nippon Steel & Sumikin Engineering CO., LTD.)
Description
Nippon Steel & Sumikin Engineering (NSENGI) has constructed 80 or more Blast Furnaces since 1974. This paper introduces technologies of new type copper stave which NSENGI performed improvement and development continuously.
From around 1990, a lot of Blast furnaces have been using copper staves for cooling. Though, quite a few of them have faced with some troubles. They can be roughly divided into two types: wear of working surface and water leakage from the welded portion on the channels.
In terms of water leakage, it can be resolved by NSENGI’s staves enabling weld-less structure. On the other hand, in these days more and more troubles of premature wear have been reported from all over the world. In the worst case, the lifetime was only 3 years after starting.
As the failure of staves results in significant damage to stably operating, the measure against wear is a very important issue. Thus, NSENGI has put effort into the development of new type copper stave with wear resistant.
Since the accretion layer which can be piled up and stuck on the surface often fall off due to operation fluctuation, copper stave should be designed to be prevented from wear even without accretion.
Generally, sliding wear speed between two objects depends on “contact force” and “scratching speed”.
Therefore, copper stave is assumed to be protected from wear by decreasing above two parameters. NSENGI achieves it by applying the special shape of stave inner surface by utilizing the unique manufacturing method of embedding steel pipes in a copper casting.
As results of applying them to actual BF, the assurance of more than 15 years lifetime has been confirmed.
The furnace profile is maintained for long time by applying above wear resistance copper stave, and the reduction of running cost with stably operating will be realized.
From around 1990, a lot of Blast furnaces have been using copper staves for cooling. Though, quite a few of them have faced with some troubles. They can be roughly divided into two types: wear of working surface and water leakage from the welded portion on the channels.
In terms of water leakage, it can be resolved by NSENGI’s staves enabling weld-less structure. On the other hand, in these days more and more troubles of premature wear have been reported from all over the world. In the worst case, the lifetime was only 3 years after starting.
As the failure of staves results in significant damage to stably operating, the measure against wear is a very important issue. Thus, NSENGI has put effort into the development of new type copper stave with wear resistant.
Since the accretion layer which can be piled up and stuck on the surface often fall off due to operation fluctuation, copper stave should be designed to be prevented from wear even without accretion.
Generally, sliding wear speed between two objects depends on “contact force” and “scratching speed”.
Therefore, copper stave is assumed to be protected from wear by decreasing above two parameters. NSENGI achieves it by applying the special shape of stave inner surface by utilizing the unique manufacturing method of embedding steel pipes in a copper casting.
As results of applying them to actual BF, the assurance of more than 15 years lifetime has been confirmed.
The furnace profile is maintained for long time by applying above wear resistance copper stave, and the reduction of running cost with stably operating will be realized.
Author
MAKOTO GOTO
(Nippon Steel & Sumikin Engineering CO., LTD.)