Abstract:
A method, apparatus and salt for descaling a strip (15) of metal includes a nozzle assembly (45) mounted within a spray box (25) for spraying descaling product on the strip. The nozzle assembly (45) includes a spray chamber (52); nozzles (60, 66) mounted directly to the spray chamber; and a heater (87) for heating the chamber, the descaling product in the chamber, and the nozzles by conduction through the chamber. The nozzles are oriented to direct the descaling product in a spray against the upper and lower surfaces of the metal strip (15) for an amount and a time sufficient to descale the metal strip (15). The nozzle assembly (45) is attached to the spray box (25) and can be easily removed therefrom for inspection.
Abstract:
Procédé de traitement thermique en continu d'une bande d'acier selon lequel: la bande traverse des chambres successives de traitement thermique; un refroidissement rapide de la bande, en particulier supérieurà 200°C/sec, est effectué dans l'une au moins des chambres par projection sur la bande de liquide, ou projection d'un fluide composé de gaz et de liquide ou projection d'une combinaison de gaz et de liquide de type brouillard; et, après le refroidissement rapide, une couche métallique protectrice est déposée sur la bande au trempé; le fluide projeté pour le refroidissement de la bande est un fluide à propriété décapante à l'égard des oxydes de fer ou d'autres éléments d'alliages contenus dans l'acier à traiter, pour limiter l'oxydation de la bande et réduire les oxydes ayant pu se former sur la bande pour réduire ou annuler les défauts de surface lors de l'opération de revêtement au trempé; le fluide est projeté sous une pression et à une distance de la bande telles que l'effet combiné de la propriété décapante et de l'action mécanique du fluide projeté réduit la couche d'oxydes à la surface de la bande; et la température de la bande en fin de refroidissement est celle nécessaire pour réaliser le cycle de traitement souhaité, en particulier comprise entre 200 et 750°C, typiquement supérieure à 200°C.
Abstract:
Methods and systems are provided for treating oxide scale on the surface of a metal object. In one embodiment, a system (100) temperature control apparatus (105) controls the temperature of metal object's (106) surface (112) to an application temperature below the Leidenfrost temperature point of an alkali metal hydroxide aqueous conditioning solution. An application apparatus (108) wets the metal object's surface at the controlled temperature with a thin layer (111) of the solution that engages the oxide scale, and a heating apparatus (113) heats the wetted surface to a final conditioning temperature above a melting point of the alkali metal hydroxide by an additional value selected to effect conditioning of the oxide scale at a reasonable but not excessive rate by the melting alkali metal hydroxide reacting with the oxide scale. The system terminates additional conditioning to prevent creation of additional oxide scale beyond the conditioned depth.
Abstract:
This process for the secondary descaling of running metal strips, especially made of steel, while being hot-rolled, by spraying water onto their surface using spray rails having nozzles supplied with pressurized water, is characterized in that the nozzles are supplied at low hydraulic pressure, not exceeding 30 bar (preferably below 10 bar, but without going below 4 bar), and in that, for the purpose of providing a thermal effect of the water sprayed onto the surface to be descaled quantitatively similar to the thermal effect obtained with the usual known method of secondary descaling at high pressure, namely a cooling of the strip which reduces its surface temperature to around 600°C, said nozzles are adjusted in order that the heat flux density extracted from the strip (HF) resulting from the cooling of its surface by the sprayed water is similar to that produced with said known high-pressure practice. The invention applies to any secondary descaling, both upstream of the finisher and upstream of the roughing device of a rolling mill train. It provides an immediate operational response to the reduction of the descaling costs, that is to say compatible with a restructuring of existing industrial equipment, therefore without necessarily involving the reinstallation of complete new equipment.
Abstract:
An automatic control system is provided for acid concentration in an aluminum strip cleaning line wherein an aluminum strip is contacted with an acid solution while passing through an acid cleaning bath and the concentration of the acid in the bath is adjusted by adding either concentrated acid or water to the bath. A conductivity probe provides a signal for the free acid concentration of the bath and an on-line process titrator periodically provides a second signal indicative of the actual free acid concentration and the total acid concentration. These first and second signals are used to obtain a corrected value for free acid concentration. The bath acid concentration is then adjusted as required based on the corrected specific conductivity value.
Abstract:
Methods and systems are provided for treating oxide scale on the surface of a metal object. In one embodiment, a system (100) temperature control apparatus (105) controls the temperature of metal object's (106) surface (112) to an application temperature below the Leidenfrost temperature point of an alkali metal hydroxide aqueous conditioning solution. An application apparatus (108) wets the metal object's surface at the controlled temperature with a thin layer (111) of the solution that engages the oxide scale, and a heating apparatus (113) heats the wetted surface to a final conditioning temperature above a melting point of the alkali metal hydroxide by an additional value selected to effect conditioning of the oxide scale at a reasonable but not excessive rate by the melting alkali metal hydroxide reacting with the oxide scale. The system terminates additional conditioning to prevent creation of additional oxide scale beyond the conditioned depth.
Abstract:
A method for the surface preparation of metallic strips, drafts and/or draw pieces comprises the treatment of the surface of the metallic strip, draft and/or draw piece by the ejection onto the strip of jets of fluid, at a high velocity, with a slope of the axis of the fluid jet with respect to the perpendicular to the surface of the strip struck, of less than 60°.
Abstract:
Methods for deoxidizing metallic surfaces are disclosed. Such a method may include contacting a surface of a metal strip (102) with one or more chemical solutions until a potential drop across a thickness of the metal strip (102) is less than a pre-selected value. To process a metal strip (102) such that it may be suitable for fabrication of a bipolar plate for use in a fuel cell, the metal strip (102) may be processed until the potential drop is less than about 15 mV. A surface of the metal strip (102) may be contacted for a first period of time with a first chemical solution having a pH of between 10 and 14. Thereafter, the surface may be contacted for a second period of time with a second chemical solution having a pH of between 1 and 3. A conductive organic coating may then be applied to the surface. Such methods are particularly suitable for use in connection with a coil coating process.
Abstract:
The invention relates to a method for scouring or cleaning rolled steel strip which, in the form of loops, is moved through several scouring or cleaning containers that are arranged in the treatment line, and at least one side of the strip is subjected to the action of the scouring medium or cleaning medium supplied by squirting or spraying units. Said units can be switched on or off and/or their spray width can be adjusted and/or they can be operated with a controllable squirting or spraying pressure and/or volume flow. The aim of the invention is to substantially reduce the space requirements and, at the same time, to be able to attain a precise adaptation to the respective scouring task or cleaning task with the objective of reducing scouring time or cleaning time and to attain an improved scouring or cleaning effect over the width of the strip. To these ends, the strip, before being inserted into the scouring or cleaning treatment part, is diverted from the horizontal strip running plane into a vertical strip running plane arranged in an edgewise manner and is diverted into its normal horizontal strip running plane after exiting the scouring or cleaning treatment part.