| 摘要 |
PURPOSE: To provide a continuous hot-dip galvanizing device and process that allow correct treatment of a strip containing oxidizable addition elements whose content is sufficient to improve the mechanical properties of the steel. CONSTITUTION: In a line for the continuous hot-dip galvanizing of a steel strip(1) containing oxidizable addition elements in a proportion allowing the mechanical properties of the steel to be improved, in which line the strip passes through a galvanizing furnace(3) in a reducing atmosphere before being dipped into a galvanizing bath(2), the line comprises, upstream of the galvanizing furnace, a means(8) for heating the strip to a temperature of between approximately 150 deg.C and 400 deg.C, and a zone for exposing the strip to an oxidizing gas, the oxygen content of which is such that, owing to the temperature and the duration of treatment, the oxidizable addition elements in the steel strip are oxidized within this strip before they migrate to the surface in order to form thereat an oxide layer, wherein the heating means(8) consists of an induction furnace which also constitutes the zone for exposing the strip to an oxidation gas, wherein the heating zone is sealably connected to the inlet of the furnace by a chamber in which the oxygen concentration is monitored and adjusted to the treatment to be obtained, wherein the induction furnace includes at least one induction coil that is moved closer to or further away from the galvanizing furnace in order to vary the heating rate produced, wherein the heating means consists of a gas furnace, and wherein the line includes a control means(7) suitable for acting on the heating means in order to maintain the strip at a defined temperature at the outlet of the heating means, in response to information provided by sensors(4,5,6). |
