Products and solutions, 2004-07-02, 02:00 AM
First coil after construction period of just 16 months - New cold rolling mill at ThyssenKrupp Nirosta
ThyssenKrupp Nirosta GmbH, one of the world`s biggest producers of flat-rolled stainless steel products, inaugurated a new cold rolling mill on July 2, 2004. The 30 million euro mill completes a 170 million plus euro program of investment in cold strip technology at the company`s Krefeld, Germany site.
Previously, ThyssenKrupp Nirosta had spent 86 million euros on a new finishing shop in Krefeld, which went into operation in 2002, and 56 million euros on an annealing and pickling line, which started production last year. "This investment program strengthens our competitive position and means that ThyssenKrupp Nirosta is now well equipped to meet future challenges," said Prof. h.c. (CHN) Dr. Ulrich Middelmann, Executive Board Chairman of ThyssenKrupp Steel AG, at the inauguration ceremony.
The new cold rolling mill will supply some 110,000 metric tons of cold strip a year to the new annealing and pickling line. The 20-high mill can reduce stainless steel strip in widths up to 1,350 millimeter to thicknesses of 0.2 to 2.5 millimeters. The maximum rolling speed is 800 meters per minute. Coils of up to 30 metric tons can be processed. The first coil was rolled on the mill in February 2004, just 16 months after the contract was concluded. The construction period was so short that the rolling mill has already produced 14,000 tons more cold strip than planned. ThyssenKrupp Nirosta contracted Sundwig GmbH, part of the Austrian Andritz group, to build the mill. All electrical equipment was supplied by ABB.
The mill is of four-column design and equipped with state-of-the-art instrumentation and controls, ideal for the production of high-grade stainless steel products in light gauges and excellent surface quality. Roll bending, intermediate roll shifting and automatic pass line adjustment systems ensure optimum strip flatness. With tolerances of max. 0.7 percent strip thickness is also controlled to high precision. The thickness of the strip, moving at just under 50 kilometers per hour, is measured around one meter in front of the roll gap, and the control system sets the roll gap to the required size in fractions of a second.
A further technical highlight of the new mill is its patented strip cooling system, which sprays oil onto the strip at only around half the pressure of conventional systems but with the same effect, thus protecting the surface. An automatic roll changer replaces the work rolls with such precision that scratches are virtually ruled out.
The new mill takes the total number of cold rolling mills at ThyssenKrupp Nirosta GmbH`s Krefeld plant to five. The oldest dates from 1956 and was the first Sendzimir mill in Germany. Since modernized, the mill is still in operation producing cold strip with a width of 1,000 millimeters.
SG 5 rolling mill, ThyssenKrupp Nirosta - Technical data
Max. strip width: 1,350 millimeters
Strip thickness starting material: 0.5 - 5.0 millimeters
Strip thickness finished material: 0.2 - 2.5 millimeters
Max. coil weight: 30 metric tons
Max. rolling speed: 800 meters per minute
Max. strip tension: 500 kilonewtons
Max. rolling force: 8,000 kilonewtons
Roll oil system: 10,000 liters per minute
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