MMK completes reconstruction of mill 2500
The general contractor for construction was joint-stock company Prokatmontazh. Novokramatorsky Machine-Building Plant (NKMZ, Ukraine) is the manufacturer of the main technological equipment for mill 2500. In February 2018, MMK also signed a contract with SMS group GmbH for the supply of equipment for the reconstruction of the finishing group of mill crates.
"In April 2019, two new universal reversible stands with vertical and horizontal rolls were commissioned at the draft group of hot-rolling mill 2500," said Alexander Polunin, Deputy Head of Technology at Sheet Rolling Shop No. 4, "Mostly they work in tandem, but each cage can also work independently, thanks to its individual rolling mode." New coiling machines No.7-8 are also being launched, which can wind coils of up to 40 tonnes from a slab up to 10 metres, as well as conveyors for moving coils to the warehouse for hot-rolled coils at Sheet Rolling Shop No.4. In September of this year, another conveyor with a cart will be built to transfer coils to Sheet Rolling Shop No.5. This is the so-called cleaning line No.3. It is worth noting that with the line's introduction, the coils are now reeled off and sent to warehouses and consumers in a horizontal position, which eliminates the risk of further damage during transportation."
The launch of the new H65 shears and the installation of the hydro scale (for hydraulic descaling) are planned for July. Also, as part of the reconstruction of the finishing group of crates, a new F0 crate (delivered under the earlier contract with NKMZ) and four new crates (under the contract with SMS group) will be installed, instead of the old 7-10 crates, as well as a new discharge roller with an upgraded laminar strip cooling system and the new coiling machine No.6.
At the moment, the old ones are being dismantled, the five new crates are being assembled and connected (four from the SMS group and one F0 from NKMZ) and the inter-crate spaces are being installed. Reconstruction is scheduled on the laminar strip cooling system on the new discharge roller. Its design will significantly improve the passage of the strip to the coiling machine, eliminating risk of jamming.
"As part of the reconstruction of the finishing group, a coil box will also be installed for the first time," said Alexander Polunin, "This is an intermediate rewinding device that will turn the roll which is returning from the black group of crates at a high speed, immediately unwinding it at a lower speed and setting the other end into the finishing group of crates. This technology will allow us to maintain the rolling temperature, eliminate the temperature spike and reduce the energy required for rolling."
In addition, commissioning works are underway on the new cross-cutting unit No. 1. The launch of this unit will eliminate claims for non-flatness and expand the range produced. To date, about 150 tonnes of metal products have been cut, and in July, the scheduled operation of the unit is due to begin.
Continuous wide-strip hot-rolling has been operating at mill 2500 since December 1960. Various sections of the mill have been reconstructed on more than one occasion. This year, large-scale reconstruction is being completed on existing production which began in the shop in 2007.