Global Patent Index - EP 0673443 B2

EP 0673443 B2 20010110 - METHOD OF ANNEALING STEEL STRIP IN AN ANNEALING FURNACE WITHOUT THE FORMATION OF SOOT

Title (en)

METHOD OF ANNEALING STEEL STRIP IN AN ANNEALING FURNACE WITHOUT THE FORMATION OF SOOT

Title (de)

VERFAHREN ZUM RUSSFREIEN GLÜHEN VON STAHLBAND IN EINEM GLÜHOFEN

Title (fr)

PROCEDE DE RECUIT SANS FORMATION DE SUIE DE FEUILLARDS D'ACIER DANS UN FOUR A RECUIT

Publication

EP 0673443 B2 20010110 (DE)

Application

EP 94901900 A 19931127

Priority

  • DE 4241746 A 19921211
  • EP 9303334 W 19931127

Abstract (en)

[origin: WO9413843A1] When annealing steel strip in annealing furnaces, contamination often occurs in the form of carbon deposits on the surface of the steel. The use of hydrogen in the protective-gas atmosphere allows such deposits to be converted to methane. If, however, a thermodynamically determined methane-concentration limit is exceeded, soot deposits are formed. In order to avoid this, methane formed as a reaction product is removed at intervals from the dome of the furnace in a protective-gas purge cycle. The invention calls for the purge cycle to depend on the amount of CH4 formed and to be controlled by a system which measures the fixed thermodynamic values of the H2/CH4 system and compares them with permitted limits. If the measured values are above or below the respective limits, an additional purge is carried out during the hold time for a period of approximately 1 hour. This ensures optimum purging and improved product quality at reduced annealing cost.

IPC 1-7

C21D 9/67; C21D 1/76

IPC 8 full level

C21D 1/76 (2006.01); C21D 9/67 (2006.01); C21D 9/52 (2006.01); C21D 11/00 (2006.01)

CPC (source: EP US)

C21D 1/76 (2013.01 - EP US); C21D 9/67 (2013.01 - EP US); C21D 9/52 (2013.01 - EP US); C21D 11/00 (2013.01 - EP US)

Citation (opposition)

Opponent :

  • DE 3931195 A1 19900329 - BANDSTAHLKOMBINAT MATERN VEB [DD]
  • DE 3631551 C1 19871119 - MESSER GRIESHEIM GMBH
  • "Die Schmierung beim Kaltwalzen und das Glühen von Kaltband unter Wasserstoff - insbesondere im Hinblick auf die Bandsauberkeit", Verein Deutscher Eisenhüttenleute, Fachausschussbericht 4032, Düsseldorf, Oktober 1990, S. 185-197
  • W.A. Beugeling: "Improved Performance of Batch Annealing at Hoogovens Ijmuiden, by Applying 100% Hydrogen as Process Atmosphere", S. 1-9 vorgetragen am Internationalen Kongress HICON/H2, 20-22 Mai, 1992 in Linz (AT)
  • Lehrbuch "Grundlagen der allgemeinen und anorganischen Chemie",H.R. Christen, 3. Aufl. 1971, S. 177, 206-211
  • B.J. Hewitt: "The New Quality achieved with HICON/H2 Bell Annealer", S.1-17, vorgetragen am Internationalem Kongress HICON/H2, 20.-22. Mai 1992 in Linz (AU), S. 1-18

Designated contracting state (EPC)

AT BE DE FR GB IT LU

DOCDB simple family (publication)

WO 9413843 A1 19940623; AT E149575 T1 19970315; DE 4241746 C1 19940825; DE 59305669 D1 19970410; EP 0673443 A1 19950927; EP 0673443 B1 19970305; EP 0673443 B2 20010110; HR P931483 A2 19950228; HR P931483 B1 19980630; SI 9300652 A 19940630; SI 9300652 B 20020228; US 5645655 A 19970708; ZA 939267 B 19950213

DOCDB simple family (application)

EP 9303334 W 19931127; AT 94901900 T 19931127; DE 4241746 A 19921211; DE 59305669 T 19931127; EP 94901900 A 19931127; HR P931483 A 19931210; SI 9300652 A 19931210; US 48877695 A 19950608; ZA 939267 A 19931210