CSN re-engineers mill to improve productivity

Originally, CSN bought this mill from a Chinese equipment supplier. Since commissioning, the mill has been unable to reach the expected production level.

Russula visited the CSN plant,assessed the main areas of improvement and proposed a plan to bring the mill up to its full production capacity. Since then, CSN has contracted Russula to undertake the upgrade project, which is divided into three main technical deliverables:

Electrical Supply

Upgrade existing control system and adjust drives

Mechanical Supply

Replace brake slide and straightening grids with a new mechanical design

Process Consultancy

Identify cooling bed mechanical issues and propose solutions

Electrical & Control Upgrade

At the beginning of the first phase of the project, Russula performed an automation system survey on site to review the mill process. Many of the fundamental functions such as bar tracking, automatic cobble detection, loop control, tension control, bar cut optimization and the phantom billet were not working or even installed. After the mill survey, Russula delivered to the CSN team a technical report with recommendations for improvement.

The existing automation hardware PLC is based on the S7-400 series and the HMI is Wonderware Intouch; Russula is very familiar with this control configuration. All rolling mill drives are ABB ACS800 and DCS800, besides the finishing mill block, which is TMEIC.

The goal of the electrical upgrade was to adapt the existing equipment already installed to the new control system with the latest generation of software control for all Rolling Mill areas.

Automation and services scope of supply

Process consulting
Diagnostic survey to assess main areas of improvement
Siemens Simotion cards for high speed positioning systems
Main operating desk
Hardware development for the new control and sensor equipment
Software development for the new control configuration
iba reconfiguration & optimization
Installation supervision
Commissioning
Training

Control Revamp First Quarter 2016

Russula together with CSN has defined a strategy to minimize the total mill downtime. First the wire rod line will undergo the upgrade while keeping the bar mill in production. After the wire rod line is commissioned, the entire mill will be stopped for one week. After which, the wire rod line will begin production, while the bar mill completes its control revamp in one week. This multi-phase revamp approach limits the total impact on production to one week.

Brake Slide

The second phase of the project consists of the mechanical supply of a new brake slide for braking and discharging the bars onto the cooling bed. The system includes the roller tables, sliding aprons, main shaft with hydraulic cylinders, all cast iron grids, roller table covers, diverter device and magnetic aprons. The motors, drives, hydraulic units will be reutilized. In order to minimize installation time the brake slide will be pre-assembled, aligned and tested in the Russula workshop.

A detailed site audit was conducted to avoid any major changes at site and hence minimize mill downtime. Accordingly the new equipment was designed such that it could be installed on the existing foundations and also interface with the existing hydraulic units.

Consulting Process

At the same time that the control system was revamped and the brake slide supplied, several technical specialists from Russula visited the plant to guide CSN on the next steps to bring the mill to its expected production, proving once again Russula's commitment to its customers.