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Mönchengladbach, May 06, 2020

The potential of process optimization in stretch-reducing mills

Automation in seamless tube production with CARTA®neo

When it comes to planning and optimization in the production of seamless tubes, the CARTA® system has made a name for itself on the market in over 30 years. The further development, CARTA®neo, combines experience and state-of-the-art automation technology: irregularities in the shells are compensated, end losses are reduced and productivity is increased.

Improve quality and increase productivity

Seamless tube production generally involves three main process steps: piercing, elongating and finish rolling. In the last production step, in the stretch-reducing mill (SRM), the geometry of the incoming shell may vary depending on the process. In addition, the tension built up in the stretch-reducing mill leads to thickened ends that have to be cut off and thus ultimately reduce output. CARTA®neo (Computer Aided Rolling Technology Application) therefore addresses precisely these points: Specific adjustments of the motor speeds are used to intervene in the process, precisely adjusting the tension and thus optimizing the tube.    

An example of the performance and continuous improvement of CARTA® is illustrated by the revamping of a 2nd generation CARTA® to a 3rd generation CARTA® in 2016, where end losses were reduced by up to 30% and the wall quality of the seamless tubes was significantly improved. With a shutdown period of less than 3 days, which took place at the same time as the regular maintenance work – this is an outstanding outcome in terms of both output and quality.

CARTA® supports process engineers and operators in seamless tube production

The CARTA® system's primary task is to support the process engineer with the planning and optimization of the rolling process, and give the operator comprehensive control over the process. To achieve this, the engineer is provided with tools for configuring the reduction series, preparing the groove design, and determining the static and dynamic rotational speeds for rolling. The operator, on the other hand, is shown all process-related data and is able to control the ongoing rolling directly. The data recorded by CARTA® is then prepared for the engineer so that he can optimize the process set points. This ensures that the quality and output of the SRM can be continuously improved.

New hardware concept of CARTA®neo
During the training at the test center of SMS group, the customer receives all necessary information for operation.

The experience of the last 3 decades converged in the development of the new CARTA®neo as a robust and reliable system, designed for a long support period and an easy update and upgrade capability.

The hardware concept has been completely redesigned. The application servers benefit from the significant improvement in performance of modern hardware over recent years, through a more compact and efficient configurations. As far as real time is concerned, the expertise accumulated by SMS group's Electrics and Automation department over the last 30 years has been utilized in the form of the X-Pact® embedded system. This is not only well established, it also allows the use of advanced field buses (Profinet, Profibus, or Ethercat) and the integration of PDA solutions (like ibaPDA for example). What's more, the scope of the hardware is reduced considerably.  

CARTA®neo: Works on Windows and Linux and comes with a hot standby feature

The software has also been completely revised: The new, modular architecture allows for easy and incremental updates. Dependencies on third-party suppliers, which jeopardize long-term availability, have been removed and replaced with open, state-of-the-art solutions. As a result among others, either Windows or Linux operating systems can be used.

Furthermore, an API and a generative communication adapter, for example, provides for a simpler and more flexible connection to the automation environment of the mill. For better reliability, a self-replicating database is used, which supports a variety of different backup strategies; in addition the working memory is synchronized. This enables the implementation of a hot standby feature, which in critical situations, switches the productive server in less than 10 seconds without any loss of data.

In addition, a hardware monitoring function ensures that defects in the server hardware are detected early on. By using web technologies for user interfaces, any number or configuration of clients, PCs, or tablets can be incorporated with no extra effort. Access control is tailored to the distribution of roles at the customer's works and provides users with only the data and options that are relevant for them. As such, it creates the perquisites for role-based working practices of the future.

Problems and deviations during stretch reducing are detected immediately
Clearly structured screens and optimized user support also reduce training and personnel costs for our customers.

Not only the technology was upgraded, but also the entire workflow was updated. For a start, all screens were tidied up – only the information required to make a decision is displayed. Not only that, CARTA®neo provides users with more consistent support. The rolling process is monitored continuously, and any deviations or problems are detected, reported, and in increasingly more cases eliminated automatically.

The process engineer receives summaries of the production process and indications of problems and possibilities for optimization. The planning and process optimization were combined, and new functions, such the rolling program groups, were introduced. With these, rolling operations no longer need to be planned individually, but rather framework specifications can be created for defined groups.

This not only reduces the number of rolling operations that need to be planned, and thus the time and effort involved, it also enables rolling to be optimized group by group, so that the stretch reducing mill can be better utilized and adapted more quickly.