Brochure MPP
5Pages

MEASURING OF ROLLED STRIP PROFILE AUTHORS FULL NAMES: Mr. Robert Karásek, Commercial representative for Spanish Market Mr. Pavel Vitoslavský, Commeorcial Director of the company UVB TECHNIK s.r.o., Ostravska 79 A, 748 01 Hlucin, Czech Republic is impertinent to follow up all possible causes changing the transverse strip profile shape continuously to ensure the optimal roll usage. PREAMBLE Not even the best-manufactured metal strip will achieve the perfect geometry, as far as perpendicular and longitudinal profiles, straightness, and surface flatness are concerned. The strip can come close to the ideal to varying degrees, and in some cases it can even be difficult to find any deviations. But to produce an 'ideal' strip is invariably uneconomical. For this reason, in practice, the strips are manufactured within specified USED METHODS FOR MEASURING OF TRANSVERSE STRIP PROFILE Presently, the profile shape is mainly measured on cut samples by hand micrometers in few predetermined spots and results are manually recorded into tables and graphs, statistically expressed for future comparisons. This method enables only very imperfect profile presentation influenced except other by slight changes of measuring procedures, changes in recording persons etc. Disadvantage is also the cumbersome and elaborate work used to collect and convey the measured results. The basic imperfections of transverse strip profile are convex (1a) concave (1b) or wedge (1c) profile types. Using X-ray thickness scanner it is possible to provide only rough (orientation) measurement of strip profile – due to the strip movement the measurement is done not in the transverse direction but at a slant angle depending on the strip speed. Measurement is not done from the strip very edge not even when the strip is motionless furthermore is also not provided at singular points (spots) but xraying a surface of several cm square. Pic. 1 Basic types of imperfect strip profile. On-line measurement using multi-points X-ray instruments having in the measuring head more detectors to check profile in limited number of spots and again provide only partial information about the strip profile. The rolling process experiences many other profile problems caused for example by the work rolls wear off or damage and it 1

On-line measuring instrument Shapemeter is placed directly at the rolling line and measures tension of single lines across strip lines usually not providing a direct readings and furthermore measures only few strip sections. It is very useful for transverse profile comparison but cannot evaluate changes of profile done by roll wear. higher computer systems for archiving and later evaluations. Next, very often used measuring method is an off-line measurement using tables with fastened trip sample onto it. Values evaluated by either moving measuring head or sample are transferred to graphical...

− Digital presentation of measured thickness (as a single entry or continuously), − Graphical display of measured deviation from nominal thickness (strip profile graph, distance from the edge / thickness deviation), − Display of strip surface tolerance – to be explained later, − Arithmetical calculation of profile parameters („crown“; „wedge“; „feather edge“; „thickness differences“); on request - other mathematical formulae could be discussed, − Print out in tabular and graphical modes, − Archiving of all measured parameters on HDD and company’s network, − Evaluation of all archived data’s...

BASIC EQUATIONS USED FOR PROFILE CALCULATION Crown: Magnitude of crown is given by the difference of thickness in the middle of rolled strip and average values of measured thicknesses 40 mm from the strip edge: TN 40 + TS 40 Crown 40 = TC − 2 Wedge shape: Magnitude of wedge shape is given by the difference of thicknesses 40 mm from strip edge: Wedge40 = TN40 – TS40 Feather edge: Its magnitude is given by percentage difference of thickness between points measured 5 mm and 100 mm from the strip edge: TN 100 − TN 5 FeatheredgeN = * 100% TN 100 TS100 − TS 5 FeatheredgeS = * 100% TS100 High...

1. Why the instrument had been bought / how it is used: widely differ from a simple manual thickness measuring at predetermined point across the strip to partly or fully automatic measuring instruments. Measured values are statistically evaluated and stored for further reporting, quality analyses and rolling mills adjustments. Strip profile measuring instrument MPP is a complex equipment eliminating elaborate and time-consuming manual measurement with its inherited inacuracies and possible mistakes. Even in comparison to some of presently operating laboratory units it has few improvements...