Electromagnetic Strip Stabilizer
Japan's First Electromagnetic strip stabilizer for Steel Sheet for Class C Operations
Award-Winner
Electromagnetic strip stabilizer was awarded the 2009 excellent invention prize by the Chief Secretary of patent office in Japanese government.
On September 25, 2009, our electromagnetic strip stabilizer won the award of excellent invention prize by Japanese patent office. The award admires the high superiority of this device in realizing high efficient operation at CGL by continuous and stable vibration reduction control for the strip, applying electromagnetic technology. This is the first time to win the same award since our company establishment in 1917.
Reduces Steel Sheet C-wrapping and Vibration in Galvanizing and Painting Lines
Auto makers and home appliance manufacturers use pressing processes to shape steel sheet into cabinets and other components for their products. After being hot rolled and cold rolled, the steel sheet passes through other processing lines for galvanizing, painting, and washing. Our electromagnetic strip stabilizer controls C-wrapping and vibration that would otherwise occur as the steel sheet moves at high speed between the rollers of these processing lines. As a result, galvanized or paint layers can be applied with a more uniform thickness, making it possible to press the sheet more precisely, beautifully, and efficiently, while conserving galvanizing materials and paint. The electromagnetic strip stabilizer features our exclusive mineral insulation material that can withstand temperatures up to 300_C, making it suitable for Class C applications. Operation is therefore possible at high temperatures using air cooling.
Features of our electromagnetic strip stabilizer for Steel Sheet
Non-Contact Pass-Line Straightening
The electromagnetic strip stabilizer places an electromagnet strategically near the surface of the steel sheet that is passing through the rollers. C-wrapping and vibration are detected by a sensor, which activates the magnet to keep the sheet flat and vibration-free. The electromagnetic strip stabilizer consists of an electromagnet, an eddy-current type displacement sensor, a control unit, and a power unit. This simple design realizes reliable operation of our electromagnetic strip stabilizer and makes our electromagnetic strip stabilizer very easy to be maintained.
Figure 1.
Mechanism of electromagnetic strip stabilizer
Figure 2.
Configuration Example of electromagnetic strip stabilizer
In a molten zinc galvanizing line, steel sheet is passed through a high-temperature (420_C or higher) solution of molten zinc alloy at a fast speed of 200m/min. Although rollers above and below apply tension as the sheet passes, C-wrapping does occur as the central part of the sheet expands outward (C war page). Also, pressurized air from the wiping nozzle imparts a small amount of vibration. This C-wrapping and vibration cause the zinc layer to be applied unevenly, making it harder to control the thickness of the galvanized layer as compared with electroplating. Actual variations in thickness will differ depending on the type of steel sheet and the processing conditions. In the case of C-wrapping, for example, wrapping of ±4mm can be expected in 0.5mm-thick steel sheet passing through the line at a speed of 200m/min. SINFONIA TECHNOLOGY CO., LTD.’S electromagnetic strip stabilizer installed, however, C-wrapping in this case is reduced to within x1mm. In addition, the electromagnetic strip stabilizer has a stabilizing effect that reduces vibration.
Frequency Characteristics with Continuous Excitation (T=0.5mm, W=900mm)
Figure 3. Performance Examples of electromagnetic strip stabilizer
Figure 4. Examples of C-wrapping Correction Capabilities for electromagnetic strip
High-Response Circuit Ensures Excellent Control Stability
The eddy-current type displacement sensor of our electromagnetic strip stabilizer is installed in the center of the electromagnet units to ensure accurate detection of the steel sheet's condition and provide highly stable performance. Capable of analyzing variations as small as 1/100mm, the sensor provides excellent responsiveness and precision.
Heat-Resistant Electromagnet
The molten zinc alloy used in molten galvanizing lines is nearly 420_C. For electromagnetic strip stabilizer to function under such hot conditions, its heat-resistant electromagnet units must be cooled. our electromagnetic strip stabilizer is the first of its kind to be capable of Class C operation. Compared with conventional Class H magnets, Class C magnets have a wider range of rated current, which makes it possible for them withstand higher temperatures. They can also be air-cooled, making simpler, safer construction possible.
Features of our Class C Electromagnet units
Resource Conservation, Easy Maintenance
A more uniform galvanized layer saves resources, and thus reduces costs, by preventing the application of excessively thick coatings. Air cooling system is applied for our electromagnetic strip stabilizer, which is safer than water cooling and contributes to a simpler, more compact design that makes our electromagnetic strip stabilizer easier to be maintained.
