The MMK Metalurji Dortyol project in 2008 involved the supply of a complete Danieli hot and cold mill complex.
At that time the X-Jet technology was not yet available for
industrial production (the first X-Jet installation occurred in
mid-2009, in Italy), and so the MMK hot-dip galvanizing line was
equipped with the Danieli Kohler S-Jet air knives.
Since 2008 the
HDGL production mix has progressively moved to include a higher
percentage of thin strips with very thin coatings (including Z70), and
so the initial air knives had become a limit to higher processing speed,
in effect a bottleneck to higher throughput.
The decision to install
X-Jets followed technical discussions and a thorough analysis of the
expected production benefits. Thanks to the modular design of Danieli
Kohler’s air knives, the revamping included the re-use of many parts of
the existing equipment, minimizing the capital investment. Danieli
supplied new X-Jet air knives with lip cleaners, new blowers with
special piping, modifications to the existing roll rigs and to the
associated maintenance, and electrical and automation equipment.
The new X-Jets were installed during a scheduled, one-week maintenance shutdown.
The
performance of the X-Jets in terms of coating weight versus line speed
was immediately seen as a step change compared to the previous
production parameters.
After the revamping the HDGL is able to daily
produce Z100 at 180 meters per minute, and tests have shown the X-Jets
to be capable of running Z80 with 40 g/m2/side at 180 mpm.
As a
result of the X-Jet’s performance, HDGL productivity has increased by
approximately 10%, with a payback time of less than six months for MMK.
