JSOL’s new high-capacity hot strip mill successfully commissioned by SMS group in record time

• SMS group supplied a high-capacity hot strip mill to Jindal Steel Odisha, India
• The HSM is designed for an annual capacity of five million tons
• Latest generation of rolling technologies ensures efficient and sustainable production of especially thin final gauges

By rolling the first hot strip, SMS put the new high-capacity hot strip mill (HSM) at Jindal Steel Odisha Ltd. (JSOL) successfully into operation. To JSOL’s great satisfaction, the erection and commissioning of the plant took place in record time, despite temporary restrictions caused by COVID-pandemic.

SMS implemented the new HSM in the Angul works of JSOL in the Indian federal state of Odisha. This is the first hot strip mill at this location. JSOL is a subsidiary of the O.P. Jindal Group. 

The company has a long and intensive cooperation with SMS, because SMS has already supplied several metallurgical plants to the Indian steel producer. Based on this confidence, JSOL placed an order with SMS in 2021 for the erection of a 1,780-Millimeter HSM, to be equipped with the world’s most advanced technologies in the field of hot strip production, especially when it comes to rolling of hot strip to thin final gauges.

Major equipment of the HSM
SMS’s main scope of equipment included the primary descaler, roughing stand No. 1 in 2-hi design with attached edger, roughing stand No. 2 in 4-hi design also with attached edger, transfer bar cooling system, HI_BOX^® heat preservation hoods, mandrel-less coilbox, edge heating equipment, drum shear, secondary descaler, a seven stand finishing mill, laminar cooling and three downcoilers. SMS’s integrated business unit AMOVA supplied a coil conveying system, coil strapping machines, marking machine and an inspection line. 

Challenging products 
In the roughing mill section, slabs with twelve-meter length maximum, a thickness range from 180 to 260 millimeter and a width range from 800 to 1,680 millimeter are rolled down to transfer bar thickness. The range of hot strip thicknesses is 1.20 to 20.00 millimeter. In total, JSOL’s HSM is designed for an annual capacity of five million tons.

The range of steel grades that to be processed is very wide. These include, e.g. sophisticated grades such as HSLA, pipe grades and silicon steels. The share of harder material grades is more than 20 percent. Furthermore, very thin strips can be rolled reliably and stably. This is possible by implementation of various innovative rolling technologies.

Groundbreaking technology
Transfer bar cooling. For optimal temperature regulation in the roughing mill, SMS installed the newly developed transfer bar cooling system. The transfer bar cooling prevents uncontrolled air-cooling during oscillation and comes with favorable effects on temperature profiles. The effects on the rolling process in the finishing mill are positive. By equalizing the temperature, product homogeneity is improved. 

HI_BOX^®heat preservation hoods. JSOL’s HSM is equipped with the latest generation heat panels of the HI_BOX^® type. This simplifies the inspection and maintenance of the elements and increases the service life by factor four compared to conventional preservation hoods. Using the HI_BOX^® heat panels makes the finishing train’s rolling behavior more stable and JSOL is able to shift the product mix toward smaller final thicknesses and/or higher strength steel grades. The HI_BOX^® system comes with resilient savings in terms of energy, CO₂ footprint and OPEX. 

Mandrel-less coilbox. Arranged between the second roughing stand and the finishing mill, the coilbox forms transfer bar into coils and thereby equalizes the temperature over the transfer bar length. Coiling the transfer bar prevents the inner windings from cooling. Material and heat are accumulated, providing a positive effect on the material to be rolled and the production process. The improved transfer bar temperature allows expansion of the product range to thinner gauges.

Edge heater. The edge heater, located upstream of the finishing mill descaler, utilizes inductive heating. The primary role is to enhance strip edge quality by maintaining optimal pre-rolling temperatures. This ensures flawless production, even for advanced grades. 

Finishing Mill. The seven-stand finishing mill in 4-hi design is equipped with hydraulic adjustment systems, hydraulic loopers and latest generation CVC^® plus (Continuously Variable Crown) combined work roll shifting and bending systems. Also part of the supply was the X-Pact^® Profile, Contour and Flatness process model (PCFC^®) being able to cope all requirements in terms of producing high sophisticated products with an exceptional wide range of properties and dimensions. PCFC^® calculates the optimal set points for the actuators of the CVC^® plus and bending system. This is why PCFC^® ensures the stability of the rolling process, highest product quality regarding strip geometry and a flexible rolling schedule.

The high-capacity HSM is completed by the laminar cooling system and three downcoilers. AMOVA as an integrated business unit of SMS supplied the coil conveying system strapping machines, marking machine and inspection line.