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Cilegon, October 14, 2021

New hot strip mill for PTKS in operation

One of the world’s most modern hot strip mills started operation in May 2021. The new mill for PT. Krakatau Steel (Persero), Tbk. (PTKS) is the second we supplied to the Indonesian steel producer.

We supplied HSM No. 2 as a complete turnkey project under our the consortium leadership and the participation of PTKS subsidiary PT. Krakatau Engineering (PTKE). Beside the supply of the entire process plant equipment for HSM No. 2, further components of the turnkey scope of delivery were all utility systems and auxiliary plants, supplementary buildings and infrastructures.

With the now implemented phase 1 on the HSM 2, PTKS can produce 1.5 million tons of a wide range of high-quality hot strip products with maximum widths up to 1,650 millimeters and final thicknesses of 1.40 millimeters. Overall, we have implemented a very flexible plant concept. As soon as future market demands require an increase in production capacity, the concept allows the gradual upgrade of the capacity up to a final expansion stage with an annual production of 4 million tons of high-quality hot strip with a minimum final thickness of 1.20 millimeters.

Furnace technology

Our Italian colleagues from SMS group S.p.A supplied a walking beam furnace for slab reheating prior to the rolling process, which is designed for the use of two fuels, either natural gas or COG (Coke Oven Gas) as a by-product from the upstream steelmaking process.

Reheating furnace PTKS Reheating furnace PTKS Reheating furnace PTKS
With low-emission burners, the walking beam furnace achieves low pollutant values.
Pulpit reheating furnace PTKS. Pulpit reheating furnace PTKS. Pulpit reheating furnace PTKS.
All values and process data are being monitored continuously and can be accessed digitally.
Roughing mill

The front part of the hot strip mill consists of a high-pressure descaler each for the roughing and finishing mill, a four-high reversing roughing stand with an attached edger, highly efficient heat insulation hoods of the HIBOX® type with a long service life and a drum shear.

Reversing roughing PTKS Reversing roughing PTKS Reversing roughing PTKS
Four-high reversing roughing stand with an attached edger.
Thermal heat insulation hoods Thermal heat insulation hoods Thermal heat insulation hoods
Roller tables provided with thermal heat insulation hoods in HI-BOX® design – here in the closed position.
Finishing mill

The finishing mill is provided with six mill stands in four-high design. All stands are equipped with hydraulic roll gap adjustment for thickness control and the proven CVC® plus (Continuously Variable Crown) system for work roll shifting with integrated work roll bending. In this way, in combination with the associated process models and technological control systems, the tightest geometrical product tolerances and the best hot strip quality can be ensured.

Finishing mill stands Finishing mill stands Finishing mill stands
Finishing mill stands.
Finishing mill stands Finishing mill stands Finishing mill stands
The equipment of the finishing mill also includes roll gap lubrication, interstand cooling and interstand descaling.

The laminar strip cooling in the exit of the finishing train is equipped with 'super re-inforced' cooling zones to provide the required cooling rates. After passing the laminar cooling and setting the required metallurgical properties, a down coiler with a hydraulic step control function picks up the finished strip. Step control function and tension control ensure a tightly and stably coiled coil with straight strip edges and minimize the mechanical stress on the equipment.

AMOVA GmbH, part of the SMS group, was involved in the order with the supply of the coil conveyor system, comprising a circulating pallet transportation system providing gentle handling of the finished product, fully automatic coil circumference and eye strapping machines, coil marking robots and a coil inspection station.

Laminar cooling Laminar cooling Laminar cooling
Exit side view on the laminar cooling, finishing mill and roughing mill area.
Down coiler Down coiler Down coiler
Down coiler provided with Step Control Function and coil conveyor.
Electrics and automation

SMS group supplied the complete X-Pact® electrics and automation including the most modern process models comprising the rolling mill up to the coil transport. It was implemented by an international team led by SMS group GmbH. For the first time, SMS group has implemented a central control pulpit for a new hot rolling mill, from which the entire rolling mill, including the coil transportation pallet conveying system, is centrally operated. This is a decisive step towards the “Lights-Out Factory”, which is a top topic on the SMS group's development roadmap. Also, the complete energy distribution system, the main and auxiliary drive equipment, the switch cabinets and the advanced network structures including WiFi were part of our supply scope.