Method of and apparatus for contactless planarity measurements on ferromagnetic metal strip

US6448764B2 · kind B2 · utility

Assignee

• BWG BERGWERK—UND WALZWERK—MASCHINENBAU GMBH

Inventors

• Rolf Noe · Mülheim, DE
• Andreas Noe · Kerken, DE
• Dieter Baukloh · Duisburg, DE
• Stefan Sonntag · Blöden, DE

Key dates

• Filing date: Jan 11, 2001
• Grant date: Sep 10, 2002
• Expiry date: Jan 11, 2021

Classification

• Technology area (CPC G): Physics
• CPC primary: G01B7/345
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method and apparatus for the contactless determination of planarity and a ferromagnetic metal strip during transit of the strip through a strip-processing line or cold-rolling line. Hysteresis loops repetitively impressed in the metal strip and the tangential magnetic field strength is measured at a surface thereof and electromagnetic parameters are determined from the time course of the tangential field strength signal. The parameters are functions of the mechanical stress which is evaluated to determine residual intrinsic stress distribution and then the planarity or nonplanarity of the strip.