Abstract: An optical method and device for detecting surface and structural defects of a traveling hot product, such as flat metal products during hot rolling, is disclosed. The optical method includes using images of the product from a camera and formed for one part by light for which the wavelength is in the infrared region and for another part by light for which the wavelength is in the visible spectrum. Detection of the images is provided by several linear sensors, each of them being associated with the detection of one image, each located in a different focal plane associated with each wavelength range so as to obtain superposable images. The light forming a portion of the images is sent onto the surface of the traveling product.

Abstract: The object of the present invention is an optical method and device for detecting surface and structural defects of a travelling hot product. It is particularly applied to flat metal products during hot rolling. According to the method of the invention, images of the product stemming from a camera (4) and formed for one part by light for which the wavelength is in the infrared region and for another part by light for which the wavelength is in the visible spectrum are used. Detection of the images is provided by several linear sensors (C1, C2, C3), each of them being associated with the detection of one image, each located in a different focal plane (PB, PG, PR) associated with each wavelength range so as to obtain superposable images. The light forming the portion of the images for which the wavelength is in the visible region is a light of yellow, green or blue colour, produced by additional illumination means (2), sent onto the surface of the travelling product.

Abstract: A plant which produces a metal band having a protective coating includes a series of treatment sections positioned one after another in a continuous line. The plant includes two coating sections, respectively, a galvanization section and a painting section, in which the metal band follows a running path having at least a vertical portion with a cooling or drying mechanism. The plant is positionable within a single building having a central tower with two abutting sections in which the coating section is provided and two halls in which are installed, respectively, a supply section and an exit section, each with horizontal accumulators.

Abstract: The invention relates to an installation for welding metal bands comprising two retaining members (2, 2′) for the ends of both bands, mounted respectively on a fixed frame (1) and a mobile frame (1′), means for shearing both facing parallel edges (m1, m2) on the ends of both bands (M1, M2) and electric power supply means (3) for flash butt welding of the said bands. According to the invention, the electric power supply means of both bands comprise a direct current generator (3) connected to continuous modulation means (34) of the voltage applied between the retaining members (2, 2′) in relation to the sizes of the bands (M1, M2) in transversal section and according to the nature of the metals to be welded.

Abstract: The invention relates to a plant for producing a metal band with protection coating comprising a series of treatment sections, placed one after the other in a continuous line.

Abstract: The invention relates to an installation for coating a metallic band by guiding the latter through an electrolytic bath (12), while passing in front of at least one anode plate (13) constituted of a set of bars arranged beside one another along a direction transversal to the forward direction (A) of the band (23) and carried by an anode bridge (14), whereas each bar forms an anode section (18). According to the invention, each anode bridge (14) comprises a carrier beam (31) along which have been arragned, one after the other, a number of live pins (32) isolated electrically from one another and linked separately to the source of current by an individual switching device (35), in order to enable fractional electric power supply of each of the anode sections (18).

Abstract: An installation for pickling rolled metal strip in order to remove oxides formed thereon. The strip is fed horizontally through an acid solution bath over a series of deflecting rollers rotating about axes perpendicular to the feed direction of the strip and defining, within a single vessel, outward and return paths comprising at least three superposed sections, and walls dividing the vessel into at least two superposed treatment cells of a height which is low enough for the treatment liquid to be driven along by the feeding of the strip by pumping action.

Abstract: Process and apparatus for degreasing and cleaning metal strips (3) traveling at high speed in a liquid (2) by bringing them into contact with a diverting roll (4). The roll (4) has a surface of contact with the strip (3) which comprises circumferential grooves (18). A gas is introduced into the liquid (2) in the vicinity of the surface of the roll (5) so that the fluid entrained between the strip (3) and the roll (4) is a compressible mixture of liquid and gas. In particular, when the liquid (2) is an electrolyte, the gas release can be produced by means of electrodes (10, 11). A hood (12) enables the gas released to be retained in the vicinity of the contact surface of the roll.

Abstract: The invention relates to an acid pickling tank for metal strips with a width equal to or greater than 0.50 meter.The tank incorporates an external supporting structure (1) and a metal casing (3) coating internally with rubber (6). The rubber layer (6) is lined internally with large slabs (10a, 10b) of a natural rock of volcanic origin, which has a total SiO.sub.2 and Al.sub.2 O.sub.3 content greater than 60%, a porosity of between 6 and 30% and a relative density of less than 3. At most three slabs (10b) are placed side by side along the width of the tank and at most one slab (10a) is placed along its height. The minimum dimensions of a slab (10a or 10b) are 0.50.times.0.50 meter.The invention is applicable in particular to the pickling of strips of hot-rolled metal sheets.