Method and device for avoiding surface defects caused by zinc dust in a continuous strip galvanising process

US9695496B2 · kind B2 · utility

Assignee

• ThyssenKrupp Steel Europe AG · DE

Inventors

• Norbert Schaffrath · Hamm, DE
• Sabine Zeizinger · Mülheim, DE
• Michael Peters · Kleve, DE
• Gernot Nothacker · Dortmund, DE
• Klaus Josef Peters · Krefeld, DE

Key dates

• Filing date: Jul 5, 2013
• Grant date: Jul 4, 2017
• Expiry date: Jul 5, 2033

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B05D3/0236
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

The invention relates to a method and to an apparatus for avoiding surface defects, which are caused by zinc dust, on galvanized metal strip in continuous strip galvanization, in which metal strip which is to be galvanized and is heated in a continuous annealing furnace is moved through a furnace pipe in protective furnace gas and is immersed into a zinc bath, wherein the furnace pipe is provided with injection openings via which the front side and the rear side of the metal strip can be acted upon with protective furnace gas, and wherein extraction openings for extracting protective furnace gas loaded with zinc vapor are arranged adjacent to the injection openings. The apparatus according to the invention is characterized in that a multiplicity of the injection openings are configured and arranged in the furnace pipe in such a manner that the protective furnace gas streaming out of said injection openings is directed onto that surface of the metal strip which faces the respective injection opening with an angle of impact within the range of 70° to 110°, wherein the distance between the respective injection opening and at least one extraction opening assigned thereto is selected in…