Abstract: A process for surface treatment of a rolling mill roll coated with a coating of metal wherein the coated roll is surface heated, e.g. by a continuous laser beam in a helical path to melt the coating and a thin superficial layer of the roll thereby forming an uninterrupted molten alloy layer comprising at least a part of the coating and of the superficial layer of the roll, cooling the alloy layer, and marking the roller by an intermittent laser beam, e.g. following the same helical path with a given delay to produce local fusion of the alloy layer and of the roll surface beneath the alloy layer and form micro-craters having bases and rims integrated, after solidification, with the alloy layer.

Abstract: Starting from a temperature at or above the A.sub.3 transformation point of the steel of the rail, the head of the rail is cooled to a temperature not lower than the Ms point at a rate lower than the critical quenching rate so that the head acquires a fine perlitic structure. Simultaneously the web is superficially cooled to the Ms point or below, at a rate greater than the head, so as to obtain a surface layer of martensite and/or bainite, and the surface cooling is controlled so that, at the end of controlled cooling, internal portions of the web not transformed to martensite and/or bainite retain sufficient heat to temper the surface layer during subsequent cooling to ambient temperature. At the same time the flange of the rail is cooled at a rate ensuring straightness of the rail.

Abstract: A light beam, e.g. from a laser, is transmitted onto the surface of a cold-rolled product such as steel strip. The light beam has a wavelength at least equal to the maximum roughness of the product surface. The reflected light energy is measured, preferably in the specular direction with respect to the incident beam; the surface roughness is deduced from that measurement. The light beam may be interrupted to provide two beams alternately incident on the same spot at different angles.

Abstract: In a secondary cooling zone below a continuous casting mold there is provided one or more chambers having an anterior wall with apertures facing the continuously cast metal product at a given distance from the surface of the product. Pressurized cooling liquid is supplied to the apertures to form a continuous layer of pressurized cooling liquid flowing in the direction of travel of the product.

Abstract: A method wherein the levels of a plurality of points on the surface of a moving rolled strip are determined in relation to a horizontal reference plane by optical triangulation and planarity, or flatness, indices of the strip are deduced therefrom. The position of at least one of the side edges of the strip is detected with respect to a predetermined fixed reference in a cross-section of the strip containing at least plurality of points. The real, or true, position of the point with respect to the fixed reference is deduced and the orientation of the emitted beam and of the re-transmitted, or reflected, beam used in the triangulation is modified to compensate for the real, or true, position of the point.

Abstract: An upper transverse chamber and a lower transverse chamber have apertures for the passage of cooling agent to a product passing between them. At least the upper chamber is divided into a central compartment corresponding to the central zone of the product, and two lateral compartments, corresponding respectively to the two edge zones of the product. The division into compartments is achieved by partitions which are perpendicular to the bottom of the upper chamber. The partitions form, inside of the upper chamber, a channel converging in the direction of motion of the product.

Abstract: A metal product having at least one plane surface, e.g. steel strip, is cooled by means of an aqueous fluid as it moves along a predetermined path by apparatus comprising a wall disposed opposite the plane surface of the product and substantially parallel thereto so as to form a chamber of substantially constant thickness between the plane surface and the wall, at least one aperture in the wall communicating with the chamber for the passage of the aqueous fluid connected to the aperture through the wall. The aperture is connected to a source of the aqueous fluid. The rate of flow of the aqueous fluid and the spacing between the wall and the plane surface are both adjustable.

Abstract: In the production of medium carbon steel wire rod, upon leaving the hot rolling mill, the rod is cooled in two phases. The first phase is operative as the rod moves at end-of-rolling speed along a cooling line disposed between the finishing block and feed rollers disposed at the entry of a head for placing the rod in overlapping turns on a conveyor, the cooling line being continuous--i.e. being devoid of air cooling breaks between consecutive intensive cooling sections, the length and capacity of the cooling line being such that the surface temperature of the rod at the end of the first phase is between, on the one hand, the start-of-martensitic-transformation temperature for the particular steel concerned and, on the other hand, the latter temperature plus 200.degree. C.

Abstract: At the exit from the hot rolling mill the rail temperature is reduced to a value not less than that at which the pearlite transformation begins in the rail head. From this temperature the continuously advancing rail is subjected to rapid cooling in a rapid cooling line. Subsequently the rail is cooled to ambient temperature. For a given rail head temperature at the extreme to the rapid cooling line, the length of the line, the speed of advance of the rail, and the average thermal flux density applied to the head, flange, and web of the rail are controlled so that the final mechanical properties of the rail head are obtained, although less then 60% of the cross-section of the head has undergone the austenite-pearlite transformation upon leaving the rapid cooling line, and differences in elongation between the head and the web and between the head and the flange are minimized.

Abstract: The ductility and/or tensile strength of certain zinc-based alloys (25 to 40 wt. % aluminum, 0.5 to 5 wt. % copper, and up to 0.1 wt. % magnesium) are improved when various elements are added. A first series of improved alloys is comprised of boron (between 5 ppm and 0.1 wt. %), possibly along with titanium (25 ppm to 0.5 wt. %), or possibly along with zirconium and/or strontium (up to 0.1 wt. %), and titanium (up to 0.1 wt. %). A second series of improved alloys is comprised of rare earths, principally lanthanum and/or cerium, in a total amount between 5 ppm and 0.1 wt. %.

Abstract: A method of measuring the water content of charge materials in a shaft furnace, such as a blast furnace, wherein a known quantity of material is introduced into the shaft furnace, the gases emerging from the throat of the shaft furnace are analyzed; and the results of this analysis are used to calculate the value of the water content of the charged material.

Abstract: The surface and/or subsurface defects of the surface to be treated are detected, preferably over the entire said surface. The defects are eliminated by scarfing with a torch and/or by milling, following which the treated surface is inspected and cleaned. The detection, elimination, inspection, and cleaning devices are maneuvered by means of programmable robots or automatons controlled by a computer. The process may be applied on-line to hot, moving products (e.g., rolled or continuous cast products).

Abstract: The plasma torch has a hot cathode (3) connectable to the negative poles of a main current course and of an arcing current source, an anode (2) connectable to the positive pole of the main current source, and an intermediate arcing electrode (6) connectable to the positive poles of both sources. An inert gas is introduced (at 8) between the cathode (3) and the arcing electrode (6). A plasma-producing gas is introduced (at 4) between the arcing electrode (6) and the anode (2). A fuel supply line (17) may open into the space between the arcing electrode (6) and the anode.

Abstract: Optical beams from lasers are directed towards the middle and edges of a hot rolled steel sheet by fixed mirrors and rotatable mirrors which allow for different sheet widths. The points of incidence of the beams are observed by photodiode cameras whose receiving axes are orientated by fixed mirrors and rotatable mirrors so that the points remain in the respective fields of observation of the cameras. The levels of the points are obtained by triangulation and are used in the calculation of the planarity of the sheet.

Abstract: A laser beam is focused as a cone whose apex is to be located on the surface of a part to be treated. A reference distance between the surface and a given point of the focusing element is determined, at which the apex is located on the surface. The actual distance between the surface and the given point is measured and the difference between the actual distance and the reference distance is determined. The focusing element is displaced so that the difference determined is cancelled.

Abstract: Hot reducing gases, mainly containing CO, H.sub.2, and optionally N.sub.2, as well as smaller quantities of H.sub.2 O and CO.sub.2, are injected through some of the tuyeres. Hot air, hot superoxygenated air, recycled gas, or combustion vapor containing sufficient CO.sub.2 is injected through the other tuyeres.

Abstract: The gas-sampling apparatus comprises at least two sampling probes at each sampling location and at least one sub-assembly for filtering the gas samples at each sampling location. A unit for processing and analyzing the gas samples is connected to all the sampling probes and is located as close as practicable to all the sampling locations.

Abstract: At the outlet of a hot rolling mill the temperature of a hot rolled rail is reduced to a value not lower than that at which the pearlitic transformation begins in the rail head. The continuously moving rail is then rapidly cooled to below 650.degree. C. so that at least 80% of the austenite-pearlite transformation has occurred at the end of rapid cooling. The rail is then cooled to ambient temperature.

Abstract: An apertured rotary member intermittently intercepts a laser beam directed at a given zone of a target. The apertures have inclined lateral walls which, during interception of the beam, deflect at least part of it to a further zone of the target.

Abstract: A continuously-taken sample of a dust-laden gaseous fluid is continuously passed through a filter for a given sampling period, this step being repeated at intervals. During each interval, while no fluid is passing through the filter, the filter is weighed after a hot dust-free gas has been passed through in order to dry the deposited dust. From the successive weights obtained, the weight of dust deposited during each sampling period is calculated.