Abstract: Ferritic stainless steel which resists oxidation at high temperature, of use in particular for a catalyst support structure, such as for example structures contained in the exhaust pipes of motor vehicles. This stainless steel comprises by weight:12 to 25% chromium, 4 to 7% aluminium, less than 0.03% carbon, less than 0.02% nitrogen, less than 0.22% nickel, less than 0.002% sulphur,less than 0.6% silicon, less than 0.4% manganese,the active elements selected from the group comprising cerium, lanthanum, neodymium, praseodymium, yttrium taken alone or in combination, at a content of lower than 0.08%, at least one stabilizing element selected from the group comprising zirconium and niobium,the zirconium and/or niobium contents satisfying the following conditions:for the zirconium,(C%/12+N%/14)-0.1.ltoreq.Zr.ltoreq.91 (C%/12+N%/14)+0.1for the niobium,93.times.0.8(C%/12)-0.1.ltoreq.Nb .ltoreq.93.times.0.8(C%/12)+0.15 and Nb<0.3%,for the zirconium and the niobium,91(N%/14)-0.05.ltoreq.Zr .ltoreq.91(N%/14)+0.

Abstract: The process comprises applying an aqueous pickling solution containing hydrochloric acid and ferric and ferrous pickling irons in solution, and, for the purpose of maintaining a constant pickling power of the aqueous solution of hydrochloric acid having a pH lower than 1, maintaining the concentration of Fe.sup.3+ ions at a value between 1 g/litre and 300 g/litre, by reoxidation by means of an oxygenation of the Fe.sup.2+ ions produced during the pickling, the REDOX potential being maintained at a value between 0 and 800 mV, the potential being measured between a platinum electrode and a reference AG/AGCl electrode which are placed in the solution.

Abstract: A process for smelting steel is implemented in an electric arc furnace of the type including a vessel containing a bath of molten steel, a roof resting on top of the said vessel and a single roof electrode or a plurality of roof electrodes lying within a circle. In the process an oxygenic gas in the form of gas jets is blasted into the vessel toward the surface of the bath, so that the areas of impact of the jets on the surface do not cover the electrode or the circle. The jets are blasted in from the upper part of the furnace and have a shallow depth of penetration into the bath.

Abstract: The casting roll includes a hub (2) and a shell (3) which are arranged coaxially, and two flanges (5, 6) for supporting and radially centering the shell on the hub. Each flange includes a frustoconical part (51, 61) which cooperates with a corresponding frustoconical surface (34, 35) of the bore in the shell, the frustoconical surface being located in a region (A) where the internal diameter variations of the shell due to the expansion deformations are substantially zero.

Abstract: The subject of the invention is a nozzle for introducing liquid metal into a mold for the continuous casting of flat metal products, having two large walls and two side walls, of the type having at its lower end two outlet ports which are made in its lateral wall opposite each other and intended to send the liquid metal each toward a side wall of said mold, and at least two holes made in the bottom of said lower end, wherein a first group of said holes is arranged on one side of a longitudinal plane of symmetry of the nozzle, which plane includes the axes of the outlet ports, and a second group of said holes is arranged on the other side of said plane of symmetry.

Abstract: Process for continuously producing on a production line a rolled stainless steel sheet product having an improved surface state, characterized in that the hot produced sheet is subjected to a treatment comprising at least:a primary pickling for removing scale,cold rolling in at the most three rolling passes,a final annealing,a final pickling, anda cold rolling of the "skin pass" type.There is optionally effected, before the primary pickling, a stretcher levelling which produces a residual elongation of 1 to 5% for cracking the layer of oxide and rendering the sheet planar. Apparatus for carrying out the invention process is also described.

Abstract: The subject of the invention is a process for the continuous casting of an austenitic stainless steel strip directly from liquid metal of composition, expressed in percentages by weight: C.ltoreq.0.08%, Si.ltoreq.1%; Mn.ltoreq.2%; P.ltoreq.0.045%; S.ltoreq.0.030%; Cr between 17.0 and 20.0%; Ni between 8.0 and 10.5% on a machine for casting onto one or between two moving walls whose external surface is provided with dimples and in which the region surrounding the meniscus is inerted with an inerting gas of controlled composition, wherein:a Cr.sub.equ /Ni.sub.equ ratio greater than 1.55 is conferred on said liquid metal, with:Cr.sub.equ =% Cr+1.37.times.% Mo+1.5.times.% Si+2.times.% Nb+3.times.% Ti andNi.sub.equ =% Ni+0.31.times.% Mn+22.times.% C+14.2.times.% N+% Cu;one or more moving walls are used whose entire surface includes touching dimples having a diameter of between 100 and 1500 .mu.m and a depth of between 20 and 150 .mu.

Abstract: The nozzle includes a chimney whose upper end is connected to the output nozzle of a vessel containing liquid metal and whose lower end is connected to a terminal part of the nozzle provided with outlets for distributing liquid metal into the casting space defined by the mold. The terminal part includes, in its upper region, at least one opening for allowing the reheating of the inside of the terminal part by a burner. The nozzle is particularly adapted for use with a bottomless mold having intensively internally cooled walls, and is preferably made of a refractory material.

Abstract: The solidification of the strip (9) is performed by introducing liquid metal between two horizontal rolls rotating in opposition directions (1, 1') which are cooled by an internal circulation of a coolant fluid. A casting space is defined between the rolls and their outer surfaces (3, 3') have a roughness. The casting space is blanketed by a cooling gas or a mixture of gases through a lid (10) covering the casting space. An adjustment of the crown or profile of the rolls (1, 1') is performed by modulating the quantity of cooling gas blown onto the rolls and/or the nature and composition of the gas at least in the vicinity of the surface of each roll (1, 1') upstream of its region of contact with the liquid metal (2).

Abstract: The subject of the invention is a process for conditioning the copper or copper-alloy external surface of an element of a mold for the continuous casting of metals, of the type including a step of nickel plating of said surface and a step of nickel removal therefrom, wherein:a preparation of said surface, comprising in succession an operation of cleaning said bare surface, an operation of pickling said bare surface in an oxidizing acid medium and an operation of brightening said bare surface, is carried out;then, an operation of nickel plating of said bare surface is carried out by electroplating, by placing said element as the cathode in an electrolyte consisting of an aqueous nickel sulfamate solution containing from 60 to 100 g/l of nickel;then, after said element has been used, an operation of partially or completely removing the nickel from said surface electrolytically is carried out, by placing said element as the anode in an electrolyte consisting of an aqueous nickel sulfamate solution containing fro

Abstract: The present invention relates to a process for producing a ferritic stainless steel having an improved corrosion resistance, and especially resistance to intergranular corrosion and to pitting corrosion. The steel is subjected, in a first phase, to cooling at a rate of between 400.degree. C. and 600.degree. C./hour down to a temperature of 900.degree. C. and then, in a second phase, to rapid cooling at a rate of between 1200.degree. C. and 1400.degree. C./h.

Abstract: The invention relates to a nozzle for introducing a liquid metal into a mold for continuous casting of metals, of the type comprising a tubular first part, one end of which is intended to be connected to a receptacle enclosing said liquid metal, and the other end of which opens into a hollow second part in which at least one portion of the internal space is oriented substantially perpendicularly to said tubular first part, said portion comprising at each of its ends at least one orifice intended to emerge into the casting space of said mold, which comprises an obstacle placed in the path of the liquid metal inside said tubular first part or in its extension, said obstacle consisting of at least one perforated component intended to divert the metal from its preferential trajectory inside the nozzle.

Abstract: Control process for twin-roll continuous casting, in which, during casting, the roll separation force (RSF) is measured and the position of the bearings of at least one of the rolls is varied in order to increase or decrease the center-to-center spacing of the rolls, with a view to keeping the force substantially constant, a band (.DELTA.RSF) of force values bracketing a desired nominal force (RSF.sub.0) is predetermined and the position of the bearings is varied more sharply when the value of the measured force lies outside the band than when it lies within the band. Application especially to the twin-roll continuous casting of thin steel strip.

Abstract: The invention relates to a device for supporting a side wall (2) of an installation for the twin-roll continuous casting of thin metal products of the type including two cooled rolls (1) with horizontal axes, two side walls (2) applied against the sides (3) of the rolls (1), said support device including a carriage (5) which can be displaced on command in a direction parallel to the axes of the rolls (1), a thrust device (6) carried by said carriage (5) and a panel (4), integral with the side wall (2), connected to said thrust device (6) by means of a thrust plate (8) and thrust members (9, 9', 9", 9'") bearing on said thrust plate (8) and said panel (4), wherein said panel (4) includes at least one tie (11, 11') passing through the thrust plate (8) and the free end of which is equipped with a stop (13, 13') which can be applied against the rear face (14) of said thrust plate (8).

Abstract: The device includes two rolls (10, 11) held by bearings (13, 14) on a frame (16) and, for each roll, devices (22) for measuring the position of the generatrix diametrically opposite the neck between the rolls, at three or more points lying respectively in a mid-plane (P.sub.3) perpendicular to the axes and in secondary planes such as (P1, P5) parallel to the mid-plane, and means (23) for measuring, in the said mid-plane, the position of a generatrix lying at 90.degree. to the neck. The method according to the invention uses these measurements to determine continuously the gap between the rolls, taking into account the in-service deformations of the rolls.

Abstract: The twin-roll continuous casting device comprises two counterrotating rolls (1, 2), having parallel axes, defining between them a casting space (5), and a shroud (4) placed above the casting space and including two longitudinal walls (41) which extend respectively along the surface of each roll. Each wall (41) includes two gas inlet pipes (45, 46) which include openings emerging towards the said surfaces, these pipes being mutually parallel and adjacent to the surface of the roll, and are separated by pressure-drop seals (50, 64) so that the flow of gas supplied by the pipe (45) lying upstream, in relation to the direction of rotation of the roll, is exclusively directed towards the outside of the shroud, the flow supplied by the pipe (46), located further downstream, being directed towards the casting space. Application especially to the twin-roll continuous casting of thin steel strip.

Abstract: A strip is continuously cast between rolls that includes a pair of rolls driven in rotation, two side dams urged against the ends of the rolls, and a jack for pressing the side dams against the rolls. The thrust force on the side dams is measured and the friction force exerted on the side dams by the rolls as a result of the rolls rotating is measured. From these measurements of thrust and friction forces, a coefficient representative of friction conditions between each of the surfaces of contact between the side dams and rolls is deduced and casting parameters are adjusted in response to the contact state between the surfaces.

Abstract: The invention relates to a device for supporting a sidewall of a plant for the continuous twin-roll casting of thin metal products, of the type including two cooled rolls having horizontal axes, and a sidewall applied against the ends of the rolls. The support device further includes a carriage which can be controllably moved in a direction parallel to the axes of the rolls, a thrust device carried by said carriage, and a mounting plate connected to the thrust device and solidly attached to the sidewall. The mounting plate includes at least two pads which can be controllably moved in a direction parallel to the axes of the rolls by devices which can apply each of the pads against an end of one of the rolls.

Abstract: A casting roll for continuous casting of metals. The roll comprising a core (2) and a sleeve (3), coaxially arranged one with respect to the other. The sleeve is axially coupled to the core by a inward projection (33) on the sleeve which abuts a shoulder (24) on the projection. The projection and the shoulder are located in a plane (P) substantially median with respect to the roll. The sleeve is radially centered on the core by flanges (5) and (6) which are elastically coupled together. The flanges and sleeve have relieved surfaces (37) which allow the sleeve to expand axially without bowing. The invention is particularly well suited for continuous casting thin metallic strips, especially steel strips, between two of these casting rolls.

Abstract: A metallurgical container of the type having a vessel having a bottom wall and an inner refractory lining includes a hearth bottom electrode extending through the bottom wall and the lining and including, in a superposed condition, a bar and a connector. The bar is flush with the surface of the refractory lining. The connector is fastened to a lower surface of the bar, is internally cooled, has a diameter smaller than the diameter of the bar, and is attached to the bar at its upper front face at a level within the thickness of the refractory lining. A ring is interlocked to the vessel wall, surrounds the connector, and has an upper face located below the bar so as to be capable of carrying the bar. In order to prevent liquid materials from penetrating by infiltration between the bar and the ring, the bar is prolonged or elongated toward the bottom wall by a skirt which surround the connector laterally. The invention is particularly applicable to direct current operated steel plant arc furnaces.