- Welded billets permit endless rolling with high product quality
- Considerable boost in plant output and utilization levels
- First use of ERT-EBROS in the Middle East
- System will pay for itself within less than two years
Emirati steel producer Union Iron & Steel Company LLC (Union Iron & Steel) has placed an order with Primetals Technologies to supply ERT-EBROS endless rolling technology for the company's existing bar rolling mill in Mussafah Industrial Area, Abu Dhabi, United Arab Emirates. The aim is to boost plant output and utilization levels. The system welds together billets intended for rolling, thus enabling a continuous rolling process with a consistently high product quality. The new ERT-EBROS plant is scheduled to commence operation in the late 2017 and will pay for itself within less than two years. It is the first system of its kind in the Middle East.
Union Iron & Steel is one of the most important steel producers in the United Arab Emirates. Its principal products are ribbed steel. Their bar rolling mill has an annual production capacity of 320,000 metric tons of steel rods, and was supplied by Primetals Technologies in 2004 (formerly VAI Pomini). It processes billets with a square cross-section of 130x130 and 150x150 millimeters and produces reinforcement steel with diameters between 8 and 40 millimeters from low carbon and low alloy steel grades.
Primetals Technologies is responsible for project engineering and also assembly and commissioning supervision of the new equipment, and will be supplying the ERT-EBROS billet welding system, including a deburring station, extraction system and complementary equipment such as pinch roll and roller table. The ERT-EBROS system will be designed for an annual production capacity of 420,000 metric tons, and will accommodate billets with a square cross-section of both 130x130 and 150x150 millimeters. The scope of supply also includes the fluid systems, the electrical equipment and automation system and also technology packages for control of welding.
The ERT-EBROS system welds consecutive billets together so that, once joined in this way, they can be processed in an endless rolling process. This increases output, cutting the time otherwise taken by two billets between rolling. Utilization of cooling bed capacity can be enhanced and production of customized coil weights is also possible. ERT-EBROS is installed between the reheating furnace and the first roll stand and uses a flash welding process with fast and intensive heating. This results in solid-state joining of the billets without the need for additional filler metal. A dynamic flash control system helps to control all the process parameters in real time and thus ensures high joint quality as well as reduced energy consumption and material loss.
After welding and head upsetting, joints are deburred on a self-cleaning deburring station. The deburring machine operates independently of the welding unit and so the cycle time is not increased. Active spatter protection protects the mechanical and electrical equipment from steel spatters. This is crucial for process quality, extends components' useful lives and facilitates maintenance. The core of the electrical system is the integrated high-frequency transformers. These compact components are extremely reliable and can perform an indefinite number of welding operations without maintenance. Each transformer is equipped with diodes that convert the high-frequency square-wave voltage into a stable, extremely flat DC voltage. The square-wave voltage is generated by converters with which the current can be controlled ten times faster than with thyristor circuits. A stable voltage and short control times are essential for a stable and repeatable process flow.