ArcSave® maintains steel quality while reducing cost, increasing yields and improving safety

ABB, the leading power and automation group, launches a product whose stronger stirring ability enables liquid steel producers to save time, money and materials. ArcSave, ABB’s next generation electric arc furnace electromagnetic stirrer (EAF-EMS), reduces carry over slag and shortens tap-to-tap time while strengthening slag-melt homogenization and increasing yield. It also contributes to safer operations. The product is the result of over five years of research and development.

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The ArcSave’s powerful electromagnetic stirring enhances the melting of large scrap items and makes stratification less significant due to forced convection. The forced convection in the whole melt is instrumental in generating a homogenous temperature distribution and high scrap melting rate. The melt velocity achieved is roughly ten times faster, as compared to just having natural convection in the bath, and results in less power on time.

The temperature homogenization further helps manufacturers, not only to obtain an exact tapping temperature for different grades of steel, but also allows smooth tapping without delays. The uniform melt gives producers a safer, more reliable EAF operation with a reduction in the number of scrap cave-ins, fewer instances of over tap temperature and carbon boiling out, as well as less un-molten big scrap.

Increased steel yields, as well as savings in scrap cost and conversion are achieved, given that manufacturers can more readily attain a low carbon and oxygen mix, with a reduction in the slag’s iron oxide (FeO) content.

Damage at the slag-line level is reduced due the stirrer’s ability to lessen superheat during power on, lower tapping temperatures, the decreased FeO content in the slag and the diminished oxygen in the steel. As most critical damage tends to occur at the slag-line, by optimizing performance here, ArcSavehelps producers enjoy refractory repair savings.

“This improved stirrer brings together much of what ABB stands for - productivity, safety, energy efficiency and quality”, says Anders Lehman, Vice President, Metallurgy Products. “ArcSave reduces operational costs without compromising on end product quality.”

ABB (www.abb.com) is a leader in power and automation technologies that enable utility, industry, and transport and infrastructure customers to improve their performance while lowering environmental impact. The ABB Group of companies operates in roughly 100 countries and employs about 140,000 people.

For help with any technical terms in this release, please go to: www.abb.com/glossary

Published inProduction

Some 28 percent has been cut from the running costs of a metal bending machine, operated by component manufacturer, voestalpine Metsec plc of Oldbury, West Midlands, following the retrofitting of a variable-speed drive (VSD).

The VSD controls the speed of the motor used by the hydraulic pump on the machine, saving energy during non-active times in the cycle.

voestalpine Metsec is keen to improve its energy efficiency and was attracted to the proposal of AAR Powerdrives to conduct an energy appraisal of its plant to identify applications that could benefit from using VSDs.

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voestalpine Metsec is saving 28 percent on its energy bill after retrofitting an ABB variable-speed drive on a metal bending machine

“As we spend around £40,000 a month on electricity costs, we are keen to be more energy efficient but want proof that any proposed system or solution will work,” says voestalpine Metsec’s Maintenance Manager, Eddie Raymond.

AAR Powerdrives conducted an appraisal, looking at machine running hours, energy costs, VSD costs and the energy and CO2 it could save over one, five and 10 years together with the payback time. With the help of voestalpine Metsec, AAR Powerdrives identified an Addison metal bending machine that would be suitable for a drive application.

“The machine makes frame components for the cabs of JCBs,” says Raymond. “This was suitable because of the high idle times the machine has in its cycle. Depending on the parts being manufactured, the component can take anything from 20-40 seconds to make. As an example, for a component that takes 20 seconds to form, there can be 30-40 seconds of idle time, accounting for some 60 percent of the total cycle time.”

The machine’s energy appraisal showed that the average current drawn was between 14 A and 18 A, reaching a peak of 46 A at the start-up of the pump. Following installation of the drive, the average current reduced to between 10 and 13 A, with a start-up peak of 34 A. This was a saving of 28 percent of the energy used by the machine.

AAR Powerdrives supplied, installed and commissioned a 22 kW ABB ACS550 drive for the permanent installation. The full load speed was slowed by 17 percent to 1,185 rpm and the no load speed was slowed by 42 percent to 830 rpm.

A challenge of the application was to receive the signal from the bending machine to initiate the motor to start the hydraulic compressor.

“Initially, we used a pressure switch but we could not find the correct place on the hydraulic pack to get the right signal,” says Raymond. “We found that the drive was ramping up and down continuously, causing the part that is being bent to distort and go out of tolerance.

“To cure this, we moved to a timer on the drive. The machine controller sends an “in cycle” signal to the drive. When this signal is not present, the drive is in idle mode, which is the case for 60 percent of the time. After receiving this signal from the machine, the drive waits for two seconds then ramps up the speed for the motor.

“Sometimes the operator would press the cycle start and then finds that he wants to pause the cycle due to the part slipping between the jaws. The two seconds is the check time to allow the cycle to get in full motion and ensures the part is at the correct angle for bending.”

“As well as the energy saving, the lower pressure on the hydraulic system meant less heat build-up, giving a better lifetime, and less noise. The oil is also now lasting longer,” says Raymond. “We also predict a longer life for the motors as they are not running at full speed constantly as previously.”

Voestalpine Metsec is converting four more of its machines to VSD operation over the next few months, with a total of 50 machines being candidates for drive installation.

ABB (www.abb.com) is a leader in power and automation technologies that enable utility, industry, and transport and infrastructure customers to improve their performance while lowering environmental impact. The ABB Group of companies operates in roughly 100 countries and employs about 140,000 people.

Published inMachinery

An ABB project that delivered over 7,000 MWh of savings has been recognised with an EEF Future Manufacturing Award for environmental efficiency.

The project at TATA Steel Port Talbot focused on the optimisation of motor driven applications to improve the energy efficiency and productivity levels of the company’s facility.

EEF’s environmental efficiency category celebrates the achievements of manufacturing businesses who have improved operational efficiency while reducing their environmental impact or developed business opportunities associated with the green agenda.

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Nick Linklater from category partner, ENER-G; Steve Hughes, UK sales manager from ABB Ltd & Stephen Fitzsimons, EEF Membership & External Affairs Manager

ABB was selected for the award by a panel of judges drawn from business leaders, industry experts and academics and was up against competing entries from a range of businesses, small and large, from across the North West.

TATA Steel’s engineering teams at Port Talbot have, over several years, collaborated successfully with ABB to install variable-speed drives (VSDs) on many large motor driven applications to save energy.

However, TATA Steel recognised that a large number of relatively smaller motors with a power rating of less than 250 kW operated with considerable running time across all plant. These motors made a significant contribution to the base load energy consumption of the site and required optimisation.

ABB recommended DriveSave to TATA Steel, a risk and rewards programme, aimed at large energy consumers that identifies and guarantees energy savings from multiple motor-driven applications across a site.

DriveSave is specifically aimed at industries like metal processing which are willing to make significant investment to achieve energy savings, totalling several thousand MW hours per year with a return on investment of under three years.

Steve Hughes, ABB’s UK sales manager for variable-speed drives said: “DriveSave was created by ABB to change the mind-set of large energy users by persuading them to buy guaranteed energy savings as opposed to specific pieces of hardware alone. It was therefore an ideal solution for TATA Steel Port Talbot.”

By the end of the DriveSave project, 7,430 MW hours per year was saved by Port Talbot by installing variable-speed drives on 24 motor-driven applications ranging between 15 to 200 kW. The reduced site base load achieved is equivalent to the entire energy consumption of Port Talbot’s sister plant at Trostre, representing significant cost and CO2 savings for TATA Steel.

“It is great to see the ABB DriveSave project with Tata Steel recognised with an EEF Award, as it reinforces the message that manufacturing companies can still achieve significant savings to contribute to energy and CO2 reductions with the right approach and expertise” added Hughes.

ABB (www.abb.com)is a leader in power and automation technologies that enable utility, industry, and transport and infrastructure customers to improve their performance while lowering environmental impact. The ABB Group of companies operates in roughly 100 countries and employs about 140,000 people.

 

Published inProduction
Nanshan Aluminum is the only listed company focusing on aluminum products in China

According to relevant industry analysis, in China, production lines for aluminum plate processing has been developing toward wide plates, and as the most typical representative, the 2800mm single stand 6 rolling mill project of Nanshan Aluminum is being currently implemented as scheduled (Nanshan Aluminum is the only listed company focusing on aluminum products in China, and the Company has been topping other large aluminum enterprises in terms of corporate size and production output) and is expected to put into operation by the end of 2014. This project was undertaken by ABB China and SMS, which may mill aluminum products with a maximum width of 2650 mm, reaching a record in width of cold rolling mills for aluminum plates in China.

ABB has cooperated with Nanshan Aluminum for a long time. Early in 2003, ABB built two 2300mm wide single stand production lines for Nanshan Aluminum, which set a benchmark for the construction of the same type roller mills, and construction of the same type of roller mills had become all the rage across China and ABB had also undertaken more than 10 high-end aluminum rolling mill projects in China afterwards. In 2012, ABB built a three stands continuous cold rolling mill production lines for Nanshan Aluminum, which was the first in Asia and the second in the world. This time, Nanshan Aluminum builds this 2800 mm single stand rolling mill project, aiming at the global high-end market, and the fact that it cooperates with ABB again demonstrates its recognition of ABB’s comprehensive strengths.

ABB is responsible for the design, debugging of the electrical and automation systems for the project as well as the follow-up services. ABB mainly supplies equipment and systems, including distribution systems, MCC, primary and secondary automatic control systems, motors and transmission systems, special instruments, operating floors and cases, and fields sensors.

This project has many features in electrical systems and automation systems and we would like to introduce as below:

Feature 1: All final transmission systems for the rolling line utilize imported ABB motors

Rolling mill stands imported from ABB Finland are equipped with main motors with a power up to 6,500 kW and a voltage grade of 3,150 V, and are also equipped with ABB ACS6000 medium voltage drive transmission systems. Most motors equipped for other parts are also imported ABB products.

Feature 2: DTC core technology provides the transmission systems unbeatable excellent dynamic properties

Medium- and low-voltage motor driving systems utilize ABB’s traditional DTC technology. Compared with PWM and other control modes, DTC has a significant advantage in response time: at a frequency of less than 40 Hz, the typical torque response time may reach a super level of 1-2 ms, 10 times faster than that of traditional control modes. DTC technology may easily achieve high precision control on motor speed and torque without speed encoders.

The nature of DTC technology determines its high energy conservation. When the system works, the adaptive motor model-based high-speed digital microprocessors might capture actual flux and torque from motors at a speed of 40,000 computations per second and compare the captured values with settings, and the system may only make adjustments when there is any difference between the settings and readings. As a result, in terms of the principle of operation, DTC technology provides theoretical basis for energy saving.

Feature 3: This is the first time for EDT milling mode to be used in aluminum mills in China, which ensures features of ordinary rolling and roughen rolling

In order to better meet the market demands, Nanshan Aluminum demanded that this rolling mill shall provide roughen rolling features, and some final products require surface texturing by EDT rolling. . In consideration of this, ABB designed EDT rolling mode for this rolling mill, in other words, use the upper intermediate roll extended bending system instead of the hydraulic screw down cylinder for rolling, so as to achieve roughen rolling with low rolling force. In addition to special electric spark roughen rollers for working rolls and special roller types for intermediate rollers, for EDT rolling, it is even more important to achieve stable rolling with small rolling reductions (rolling force ≤200t, far below the normal rolling force level). However, when the rolling reduction is less than 10%, if we continue to use normal hydraulic pressure cylinders (which provide a maximum rolling force of 30MN), we cannot meet requirements on rolling stability and control precision for roughen finishing.

As a result, for ABB, the key point is how to integrate the existing general rolling strategies and roughen finishing, and based on the mathematical model rolling mill and secondary process control, the system may switch rolling modes safely and reliably optimize rolling process control.

Feature 4: Achieve highest standard in the industry for all indicators

Nanshan Aluminum has always been strict with precisions of systems and equipment. The reason why it has long been cooperating with ABB is that, ABB may provide a wide range of mature technologies and products across electrical and automation entire industry chains, covering motors, transmission systems, instruments and meters as well as control systems, so that Nanshan Aluminum may achieve the highest indicators in the industry and lead the development of the industry. For example, for this Project, thin aluminum plate may achieve 8I-Units, and the thickness control may achieve a precision of 2 um, static tension may achieve a control precision of 1.5%, and the speed control precision may achieve 0.01%.

Mr. Sun Yongming, Head of Paper, Metals & Cement in China said, “ABB will continue to serve global high-end metallurgy projects, and provide total solutions for upgrade and renovation of electrical and automation systems to both new and existing customers.

With advantages in excellent technology, product, service and project management in electrical and automatic systems and its great success in localization and a strong service capability, and based on win-win cooperation with international mechanical equipment suppliers, ABB has dominated most of high-end aluminum rolling mill projects market in China.

In face of the current downturn in Chinese metallurgy, Sun from ABB said honestly that, “ABB will strongly support steel, nonferrous metal enterprises to upgrade and renovate their plants, including both process upgrading or periodic equipment replacement, ABB will provide personalized and marketed-oriented total solutions in solution design, equipment selection and control strategy as well as other steps in consideration of corporate situation and latest technology development trend. ABB has also obtained good practical experiences in Panzhihua Steel, Ningbo Baoxin Steel and many other enterprises.”

 

Published inMachinery