Abstract: A cast-iron pipework element adapted to be buried has an external coating made up of an inner layer of zinc, a porous intermediate layer of zinc/aluminium alloy containing from 5 to 55% of aluminium, and a porous outer layer, or pore-blocking layer, comprising an organic binder, especially a water-based paint, a bitumen varnish or an epoxy resin.

Abstract: The invention concerns a method and apparatus for thermally treating cast-iron pipes formed in a continuous casting die. The pipe or tube undergoes tempering by passing through a vat which is located downstream from the continuous casting die. The vat contains a continuously cooled bath of fluidized sand or the like which lowers the temperature of the tube in a uniform manner and makes it possible to obtain a very precise and homogeneous tube structure.

Abstract: The vertically ascending casting of a thin-walled metal pipe and integral end fitting from a bath of molten metal is implemented using a housing 12 and a core 14 to mold the end fitting or bell housing and a tubular draw tube 6 to mold the pipe shank. The end fitting E is first formed by forcing the metal to rise in the annular space 16 between the housing and the core, simultaneously forming the initial section of the pipe shank. Once the end fitting has solidified it is extracted upwardly, step by step, while shank sections are simultaneously withdrawn from the metal bath. These sections are also solidified step by step along a tapering front S in the bath until the desired length of pipe T has been obtained.

Abstract: Liquid metal M in a casting ladle 1 located under a mold A is cast uphill under low pressure into the mold cavity 10 through a vertical shaft 3. The metal is treated by a soluble inoculation wire 13 suspended down through the cavity over a length L greater than the height h of the mold with its lower part H submerged in the liquid metal filling the shaft. The ladle pressure is maintained until the wire is fully dissolved, and then raised to fill the mold cavity with the inoculated liquid metal.

Abstract: The die (6) comprises a thick cylindrical body (7) which is surrounded by a cooling jacket (15) clamped against the pouring basin (2) and in contact with the latter in a plane (P). The body (7) is extended in the casting orifice (4) by a composite head (17) comprising a thin inner annular lip (22), whereof the inner surface extends that of the body (7) and a ring (24) of refractory material fitted between the lip, the body and the casting orifice. The (hot) lip (22) is connected to the body (7) in the plane (P), so that the ring (24) rejoins it also in this plane and that the flow of heat (f.sub.1) passing from the casting orifice to the cooling jacket must skirt around this ring.

Abstract: To fast load a metal alloy casting furnace 1 at a high casting temperature to supply foundry molds at an industrial pace, a liquid portion of the overall load is first introduced deep inside the furnace with a device L comprising a telescopic channel 30-31. A solid portion of the remaining overall load is then introduced with a device S comprising a tilting pusher-equipped channel 20 disposed below a static hopper 15. The liquid part of the load includes alloy compounds which are the least sensitive to oxidation; the solid part includes compounds which are highly sensitive to oxidation.

Abstract: The cast tube (T) is subjected internally in a chill-mould (1) to the uniform spraying of water from 1000.degree. C. approximately to 350.degree. C. approximately. Then it is extracted from the chill-mould and in a furnace is subjected to isothermal bainitization maintenance, after which it is cooled in the atmosphere to ambient temperature. Without it being necessary to add expensive chilling elements, one thus obtains lightened tubes having very good mechanical properties and the ovalization of which remains acceptable.

Abstract: The process is particularly intended for the casting of thin tubes of iron in a vertical annular die defined by a mould and a core. It comprises maintaining in the liquid state metal under pressure poured into the die and in contact with the core so as to create a substantially frustoconical solidification front which extends from a point of the wall of the mould in the vicinity of the input end of the die and reaches practically the lower end edge of the core. The installation for carrying out this process comprises a heating device inside the core and a liquid metal jacket under pressure which surrounds the mould and is surrounded by a water cooling jacket.

Abstract: A low-pressure metal repetitive casting apparatus comprising a large capacity fluidtight vessel containing liquid metal to cast, in particular a high melting point metal; an upwardly open supply pipe partly extending into the vessel through a wall of the vessel and having a lower end immersed in the metal; a source of gas under pressure; a device for selectively putting the source in communication with the interior of the vessel and closing off said communication; and a series of blind sand moulds each defining at least one mould cavity, a main runner whose sectional size is in the neighborhood of the sectional size of the supply pipe and communicates with the mould cavity and has a lower open end portion capable of being adapted for connection to an upper end portion of the supply pipe, and at least one secondary runner which puts the main runner in communication with the mould cavity and has a cross-sectional area so calibrated that, during the casting, the solidification time of the secondary runner is sli

Abstract: A mould cavity for casting the part is supplied with liquid metal by a main runner formed in the mould and connected to the upper end of a supply pipe whose sectional size is in the neighborhood of the sectional size of the main runner and which extends into a fluidtight vessel containing the liquid metal. The metal is supplied to the mould cavity by the action of a gas pressure on the free surface of the metal in the vessel.According to the invention, the mould cavity is supplied with the metal from the main runner through a secondary runner whose sectional size is much less than the sectional size of the main runner, and the gas pressure is maintained until the secondary runner has solidified whereafter the gas pressure is returned to atmospheric pressure, whereby the liquid metal in the main runner and supply pipe returns to the vessel.