Abstract: A continuous process of producing carbonaceous pitch, including heat-treating an aromatic heavy oil for obtaining a first cracked product, and thermally cracking the first product in a cracking zone by direct contact with a gaseous heat transfer medium to obtain distillable cracked components and a mesophase-containing pitch. A first portion of the liquid phase in the cracking zone, including the mesophase-containing pitch, is separated into a mesophase-rich pitch and a matrix pitch having a low concentration of mesophase. The mesophase-rich pitch is recovered while at least a portion of the matrix pitch is recycled to the cracking zone. The distillable cracked components are withdrawn from the cracking zone and separated into light, middle and heavy fractions. At least a portion of the heavy fraction is heat treated and is recycled to the cracking zone.

Abstract: A corrosion resistant duplex plated sheet steel is disclosed, which comprises a sheet steel having on at least one surface thereof a lower layer of Zn base alloy plating and an upper layer thereon selected from a zinc plating having a coating weight of 0.1-5 g/m.sup.2 and a zinc alloy or zinc composite plating having a coating weight of 0.1-10 g/m.sup.2. The ratio of the coating weight of the lower layer to that of the upper layer is at least 1:1 and in the case of upper layer of zinc alloy or zinc composite plating, it comprises, on a weight basis as metal, at least 80% Zn, and one or more additives as Zn corrosion inhibitors selected from Ni, Co, Mn, Sn, Ti, Al, Mg and Si. The duplex plated sheet steel is suitable for coating thereon with an electrophoretic coating composition and exhibits excellent cratering resistance in cathodic electrophoretic coating and excellent cosmetic resistance after painting.

Abstract: In a leveling line, the shape of a rolled material is corrected by applying a longitudinal tensile force to the material on the entrance or the exit side or both the sides of a roller leveler or within it, a warp of the material is corrected by applying a bending tension to the material within the roller leveler, and a camber of the material is corrected by applying a larger plastic elongation to either one of the widthwise edges of the material than to the other, on the entrance or the exit side or both the sides of the roller leveler or within it.

Abstract: A precipitation-hardening Ni-base alloy exhibiting improved resistance to corrosion under a corrosive environment containing at least one of hydrogen sulfide, carbon dioxide and chloride ions and method of producing the same are disclosed. The alloy is of the .gamma."-phase, or (.gamma.'+.gamma.")-phase precipitation hardening type in which Ti is restricted to less than 0.40% and is comprised of:C: not greater than 0.050%,Si: not greater than 0.50%,Mn: not greater than 2.0%,Ni: 40-60%,Cr: 18-27%,Ti: less than 0.40%,Mo: 2.5-5.5% and/or W: not greater than 11%, t 2.5%.ltoreq.Mo+1/2W.ltoreq.5.5%,Al: not greater than than 2.0%,Nb: 2.5-6.0% and/or Ta: not greater than 2.0%, 2.5%.ltoreq.Nb+1/2Ta.ltoreq.6.0%.

Abstract: This invention relates to a repairing apparatus for an industrial furnace wall using a plasma spray gun. The plasma flame of the gun traces the damaged part to be repaired by moving the gun in three-dimensional directions (up-and downwardly, right-and leftwardly, and forwardly and backwardly) relative to the furnace wall to be repaired. Furthermore, the optimum spray distance of the plasma flame follows the unevenness of the furnace wall and the depression extent of a damaged part to be repaired from the sound surface of a furnace wall by changing the mixture ratio of the operation gas for the gun to control the length of the plasma flame.

Abstract: A method and an apparatus for cooling blast furnace gas for use in a blast furnace gas treating system having incorporated therein a coarse particle removing unit having a dust collecting box. Nozzles extend through the box as arranged circumferentially thereof at a plurality of locations for injecting a cooling fluid into the unit without wetting the inner wall thereof. Since the unit which has a large capacity is used also as a cooling container, a large quantity of cooling fluid can be injected to effectively cool the blast furnace gas even when the gas has a considerably high temperature. The system can be constructed at a low cost without necessitating any additional cooling container.

Abstract: A silicon aluminum oxynitride containing refractory for use in continuous casting is placed between a mold and a tundish and is formed by sintering an admixture of silicon nitride (Si.sub.3 N.sub.4), aluminum nitride (AlN), boron nitride(BN), and a mineral clay. The refractory further includes aluminum oxide(Al.sub.2 O.sub.3).

Abstract: A dual-phase stainless steel exhibiting improved resistance to corrosion caused by nitric acid is disclosed, which consists essentially of:C: not more than 0.02% by weight, Si: 2-6% by weight,Mn: 0.1-2% by weight, Cr: 20-35% by weight,Ni: 3-27% by weight, P: not more than 0.02% by weight,N: not more than 0.30% by weight,Fe and incidental impurities: balance the amount of ferrite to be 30-70% by volume.

Abstract: A flaw detection apparatus for detecting flaws at the outer surface of a product, such as a steel bar, wire or steel pipe, which is round in section and produced by the hot rolling, by use of a probe of non-contact type and rotating around the product to be inspected, the apparatus providing a means for suppressing vibrations of an object to be inspected, a means for measuring a distance (lift-off) between the object to be inspected and the probe, and a means for carrying out positional control on the basis of the detection result of the lift-off measurement so that the axis of rotation of probe is allowed to be coincident with the axis of object to be inspected.

Abstract: A superplastic deforming process of a duplex stainless steel is disclosed. The process comprises the steps of:heating a ferrite + austenite duplex stainless steel to a temperature between the alpha-temperature and a temperature 200.degree. C. lower than the alpha-temperature, the heating temperature being 1000.degree. C. or higher;water quenching or force-cooling the duplex stainless steel to a temperature of 500.degree. C. or lower, alternatively working the duplex stainless steel at a temperature of 700.degree. C. or higher with a working ratio of 30% or more, or at a temperature lower than 700.degree. C. with a working ratio of 20% or more;reheating it to a temperature of between 700.degree. C. and a temperature 200.degree. C. lower than the alpha-temperature; andplastic deforming the thus-pretreated duplex stainless steel at a strain rate of 1.times.10.sup.-4 -5.times.10 S.sup.-1.

Abstract: Controlling for obtaining the aimed strip shape using a rolling mill provided with rolls, which are variable in amount of crown by feeding a pressurized oil in the inside. In addition, the rolling mill is provided with right and left pressing-down balancers and roll benders. The strip shape in the width direction of the strip is detected, the detected shape being approximated by a function including terms of the first, second, fourth, sixth or eighth power of a variable, which is a position or a distance in the width direction of the strip, the amount of pressing-down of the right and left pressing-down balancers being adjusted to coincide the term of the first power with the aimed value thereof, the amount of crown of the roll being adjusted to coincide the term of the second power with the aimed value thereof, and a roll bending force being adjusted to coincide the term of the fourth, sixth or eighth power with the aimed value thereof.

Abstract: A molten metal discharging device comprising:a stationary plate adapted to be mounted at a bottom portion of a container accomodating molten metal, the stationary plate having a molten metal passage bore for permitting the molten metal from the container to be discharged therethrough, anda slide plate slidable along a lower face of the stationary plate and adapted to open or close the passage bore by being slidably displaced relative to the stationary plate, in whicha circumferential wall of the passage bore in the stationary plate is made of dense refractory material and the circumferential wall made of the dense refractory material has a plurality of gas supply holes therein for permitting a gas to be supplied into the passage borehas less fear that the passage bore thereof may be blocked by the solidification of the molten metal and/or deposition of metal oxides and has an improved resistance against corrosion by the molten metal.

Abstract: An oil well pipe joint comprising a metal-to-metal sealing portion without thread is disclosed. A metal-plated or resin-coated layer exhibiting improved resistance to galling is provided on the outer peripheral surface of a thread-free lip portion which constitutes part of the metal-to-metal sealing portion on an externally-threaded member. At the metal sealing portion, satisfactory sealing properties are maintained under severe corrosive conditions, enabling the joint to be connected and disconnected over 10 times, and usually over 25 times.

Abstract: Herein disclosed is a loop type continuous metal casting machine in which two side dams are revolved in a loop passing along a casting zone from the entrance end thereof between upper and lower endless revolving casting belts to define a downhill moving mold and in which each of the side dams is formed of a multiplicity of metal dam blocks so strung onto a flexible metal strap loop that the metal dam blocks abut in end-to-end relationship against one another but are allowed to slide on and relative to the metal strap loop.

Abstract: A plurality of sets of three rolls are disposed around the periphery of the round continuously drawn from a mold and movable to the direction for or counter to the rounds, the sets being disposed along the drawing direction of the rounds. It is not necessary to replace the apparatus even when the size of the round is changed due to the replacement of molds, as the roll position are adjustable to the rounds.

Abstract: A process for manufacturing a high tensile steel wire, characterized by comprising the steps of pre-cooling a hot-rolled steel rod to a temperature between 750.degree.-900.degree. C. by means of a cooling apparatus provided between a group of intermediate rolling mills and a group of finishing rolling mills in a hot rolling line for steel rod, finishing rolling the thus pre-cooled steel rod, quenching the hot rolled steel rod to a temperature of 700.degree. C. or lower to provide a supercooled austenite phase, then finishing-cooling the thus quenched rod to provide martensite, and drawing the resulting steel rod with roller dies without descaling is disclosed.

Abstract: Herein disclosed is a process for producing a steel bar or steel wire having an improved structure of spheroidal cementite. The process is characterized in that a finish rolling is conducted within a temperature range between Ar.sub.1 and Ar.sub.3 or Arcm with a reduction ratio of at least 20%.The cooling rate of the steel before the finish rolling should be controlled in the following manner:When the hardenability of the steel is not higher than that of 0.15% C plain carbon steel, it is preferable to cool the steel at a cooling rate higher than 250.degree. C./sec.When the hardenability of the steel is between those of 0.15% to 0.4% C plain carbon steel, it is preferable to cool the steel at a cooling rate higher than 10.degree. C./sec.When the hardenability of the steel is not lower than that of 0.4% C plain carbon steel, it is preferable to cool the steel at a cooling rate higher than 2.degree. C./sec.

Abstract: A technique for detecting flaws in a metal product which uses a combined eddy current and magnetic flaw detection technique. A first magnetic field having flux lines parallel to the surface of the test object and a second field having flux lines perpendicular to the surface of the test object are generated. The resultant magnetic field is affected by faults in the metal test object. A magnetic field detector adjacent the test object detects the resultant magnetic field and produces an output signal which is processed by a circuit to provide a pair of component signals representing the portion of the output signal corresponding to the individual components of the resultant magnetic field, thus providing an indication of the type of faults that are present in the test object.

Abstract: A method and apparatus of continuous electroplating of a strip with an alloy by passing the strip through a plating bath of the immersion type in both down-pass and up-pass with an anode being positioned in each pass so as to face at least one side of the strip are disclosed. Said anode is an insoluble anode which is spaced from the strip by a distance of about 10-50 mm, and the plating solution is blown into the gap between said anode and said strip countercurrently with respect to the movement of said strip.

Abstract: A process for controlling the molten metal level in continuous thin slab casting in which molten metal poured from a large-sized tundish into a small-sized tundish through a sliding nozzle is caused to overflow from the small-sized tundish for casting through a tiltable casting spout into a twin-belt-type continuous casting machine is disclosed. The process comprises measuring the level of molten metal on the casting machine to provide a deviation signal representative of a deviation of the level of the molten metal from a target value; and adjusting a directly influencing factor on the molten metal level, such as a pouring rate of the molten metal into the mold and a pulling speed of the molten metal according to the deviation signal.