VIZ-STEEL – flatness measuring systems installation

In March 2019, installation works at VIZ-STEEL facility in Yekaterinburg, part of NLMK Group, had been completed for a project of 1200-1 and 1200-2 cold rolling mills, using there 4pcs of strip flatness measuring systems (Shapemeters) with optional automated flatness control and data recording at cold rolling of strips from transformer steel.

The project was delivered by UVB TECHNIK s.r.o. (Czech Republic) with JSC “JE Mashprom” as subcontractor.

Both the modernized 1200-1 and 1200-2 rolling mills are single-purpose 20-High of ŠKODA Plzeň brand designated for cold rolling of metal strips with front and rear stretching in reverse mode.

Dimensions of the rolled strip

• maximum input thickness – 0,85 mm
• minimum output thickness – 0,10 mm
• width – 600 – 1 050 mm
• maximum external diameter of the coil – 1,800 mm
• maximum weight of the coil – 16 500 kg

Rolling mills specification

• total strip tension on coiler – 20 – 180 kN,
• maximum rolling speed – 10,0 m / s,
• roller length – 1,200 mm

Flatness, i.e. straightness of the strip’s surface, is an important characteristic of transformer steel that determines the quality of electrical insulation layer coating on the follow-up redistribution. In the past, rolling mills could not control this parameter, which resulted in a risk of geometric faults affecting the appearance of the finished products.

An essential step in resolving this issue was the use of a new generation system for measuring flatness during rolling. STM-1200 shapemeters record differences in tension across the width of the strip during the rolling process. The processed information is conveyed to the control panel of the rolling mill. Using this data, the operator adjusts the pressure of the rolling mill segments.

Measuring of rolled strip flatness allows

1. Monitoring the flatness of cold-rolled strips by mill operators in real time;
2. Increasing the speed and simplifying the rolling mill setting in the initial phase of the rolling process;
3. Improving the accuracy of controlling strip flatness parameters when rolling in a stable mode;
4. Saving data on flatness of cold-rolled strips will allow further analysis and optimisation of cold rolling conditions.

Flatness measuring systems are based on measuring the distribution of tension across the width of strip – Shapemeters STM-1200 by UVB TECHNIK s.r.o. ensure continuous measuring of the strip flatness and total strip tension done by the winding rollers in a range of 20 – 180 kN. The accuracy of flatness measuring corresponds to the standard deviation magnitude 2σ (95,4 %): ± 2 I-Unit (± 20 μm / m).

The introduction of automated flatness measuring system will allow VIZ-Steel to significantly increase the percentage of class 1 quality and class 1 flatness of their produced strips.

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