Abstract:
The present invention is directed to a method and apparatus of producing a dual-phase galvanized steel strip with improved formability while maintaining a high tensile strength. The present invention comprises a step of cooling and a step of reheating. In the cooling step, the galvanized steel strip has a temperature reduction of from about 3000C to about 1500C-2500C. This step of cooling should cool to a maximum extent of about 1500C different between the initial temperature and the final temperature. This cooling may be accomplished by a hot water quench, or the use of a cooling tower, or other means. The step of reheating should follow the step of cooling. The step of reheating should heat the galvanized steel strip to a temperature of about 340°-390°C. This reheating causes the martensite in the galvanized steel strip to be tempered at a relatively low temperature, which reduces the Fe-Zn phase formation in the GI-coating.
Abstract:
A heat treatment or heat soak furnace for use in both galvannealing and galvanizing processes including a heating apparatus configured to supply heat and remove heat. The heating apparatus may draw hot air from the exhaust of a direct fire strip annealing furnace, gas burners or electric heat exchangers as necessary. The furnace also may include a plurality of cooling mechanisms in order to ensure heat is removed and the temperature within the furnace regulated. In addition, the furnace may include baffles configured to allow portions of the interior of the furnace to be separated into different temperature zones. The furnace under this invention is capable of providing a suitable thermal environment for a desired time, duration, for steel sheet substrates with different chemistries, different coating thicknesses and different process speeds to achieve an optimum phase microstructure of the galvannealed, zinc-iron alloy coating; or to promptly solidify the galvanizing unalloyed zinc coating so that it has a high quality surface morphology.
Abstract:
Dispositif permettant de limiter le risque de formation d'une atmosphère explosive dans le four d'une ligne continue de traitement thermique de bandes métalliques dont les sections sont sous une atmosphère constituée d'un mélange de gaz inerte et d'hydrogène dont la teneur volumique en hydrogène est comprise entre 5 et 100%, équipé d'une section de chauffage rapide ô induction et d'une section de refroidissement rapide, comprenant : une chambre (9) maintenue sous gaz inerte ô l'entrée de la section de chauffage rapide du four et ô la sortie de la section de refroidissement rapide, la pression dans la chambre (9) étant égale ou supérieure ô la pression atmosphérique lorsque le chauffage du four fonctionne normalement; un dispositif (10) d'entrée de la bande dans la chambre (9), ô partir de l'air atmosphérique; un dispositif (11) de séparation d'atmosphère et d'entrée de la bande dans la section de chauffage du four depuis la chambre (9) sous gaz inerte, ce dispositif (11) étant équipé d'un soutirage (14) de gaz; un dispositif (13) de séparation d'atmosphère et de sortie de la bande de la section de refroidissement rapide du four, équipé d'un soutirage (14) de gaz, et un dispositif (12) de sortie de la bande de la chambre (9) vers l'air atmosphérique.
Abstract:
La présente invention se rapporte ô un dispositif de refroidissement, pour réaliser une opération de trempe d'une bande d'acier, comprenant un déversoir (4) dans lequel est complètement immergée une pluralité de tubes (1) empilés essentiellement verticalement et symétriquement de part et d'autre de la bande (2) le long de celle-ci et qui éjectent chacun, sous forme de jets turbulents essentiellement horizontaux, un fluide de refroidissement au travers d'une fente ou d'une pluralité de trous. Deux tubes (1) successifs quelconques, disposés d'un même côté de la bande (2), sont séparés par un intervalle (B) identique pour tous les tubes (1) en vue de l'évacuation du fluide de refroidissement. L'intervalle (B) est choisi, ô une valeur donnée de débit spécifique dudit fluide, pour minimiser la perte de charge dans les canaux d'évacuation correspondants audits intervalles (B).
Abstract:
The present invention relates to a method of cooling strip or wire products in which, subsequent to being annealed, the product (3) is cooled to a temperature of about 20-50°C beneath its oxidation temperature. The invention is characterised by winding the product (3) around a drum (1) immediately downstream of an annealing path so that the product (3) is brought to lie in mutually juxtaposed turns and thereafter to be unwound from the drum (1) after a number of turns, wherein the product is wound onto the drum (1) through a number of turns such that said product (3) will be cooled to a desired temperature, and wherein the drum (1) is given a diameter that exceeds the diameter at which the product (3) will be influenced mechanically by plastic deformation.
Abstract:
Cooling jets for moving webs such as continuously annealing steel strip can be deflected to aim at the edge of the web, and thereby stabilise it as it passes between. Flutter of the web is thereby reduced. The offset is between 2 DEG and 15 DEG , alternatively 25-75% of the divergence angle of gas leaving the jet.
Abstract:
The present invention is directed to a process comprised of a controllably variable liquid quenching means for metal alloys at or above the Leidenfrost temperature without metal alloy distortion.
Abstract:
A heat-treating apparatus for heating, cooling or drying a steel band by blowing a jet streams of a gas to the steel band, including a resistance body provided at the distal end of a nozzle for jetting a gas jet stream in such a manner that the projection area of the resistance body is not more than 3 to 12 % of the sectional area of the nozzle, or a resistance plate provided at the distal end of a nozzle for jetting a gas jet stream in such a manner that the projection sectional area of the resistance plate is less than 3 % of the sectional area of the nozzle and the plate length in a nozzle axial direction inside the nozzle is at least 50 % of the nozzle diameter.