Abstract: The invention concerns a flexible tubular pipe comprising, from inside outwards, a web (1) made of interlocked steel strips, an inner impervious sheath (2) in polymer material, a short-stepped helical winding of interlocked forming wire (3) arranged above the internal sheath (2), at least a hoop (4) consisting of a short-stepped metal wire winding without interlock, at least a long-stepped tractive armouring layer (5) wound around the pressure vault and an outer polymer protective and sealing sheath (8); the sickness (Ef) of the hoop (4) is greater than the thickness (Ez) of the metal forming wire (3), preferably by one to three times.

Abstract: A tubular flexible pipe which from the inside outward includes an inner sealing sheath of polymer, a cylindrical pressure vault comprised of a helical wire winding with gaps between the windings, perhaps a wound tensile armoring layer and a scaling outer sheath. The vault includes an elongated masking element, at least partially masking the gaps between the windings of the wire and being at the inner sheath, The masking element is a wire helically coiled in a recess at the inner face of the vault or is an axial extension of the vault wire.

Abstract: Method of manufacturing a metal carcass for flexible pipe or umbilical comprising shaping a band of metal strip and then helically winding it to form the metal carcass which, in cardioid mode, has a given collapse strength, wherein the metal strip is work-hardened prior to shaping to give it at least a 15% higher elongation at rupture, and in that the said metal carcass which is made from the said work-hardened metal strip has, in cardioid mode, a collapse strength which is at least 15% higher than the given collapse strength.

Abstract: A flexible tubular pipe having an internal sheath and a pressure vault around the sheath with a helically would short pitch metal wire. The metal wire has an I-shaped cross-section with a narrowed central web and greater thickness internal and external flanges. Recesses in at least one set of the flanges enable fastening elements to be installed for holding to adjacent wire windings. The ratios of widths of the flanges, height and width of the wire, moments of inertia in the width wise and radial direction are disclosed.

Abstract: The invention provides a steel containing by weight 23% .ltoreq.Cr.ltoreq.28%; 15%.ltoreq.Ni.ltoreq.28%; 0.5%.ltoreq.Mn.ltoreq.6%; 3%.ltoreq.Mo.ltoreq.8%; 0.35%.ltoreq.N.ltoreq.0.8%; and 1%.ltoreq.W.ltoreq.5%. The steel has a high resistance to corrosion and may be used for manufacturing massive parts for any application, in particular for manufacturing equipment for oil platforms and chemical works, containers for transporting corrosive products, ship hulls and ply sheets.

Abstract: The steel contains, in proportions by weight, from 20 to 30% of chromium, from 25 to 32% of nickel, from 3 to 7% of molybdenum, from 0.35 to 0.8% of nitrogen, from 0.5 to 5.4% of manganese, up to 0.06% of carbon and up to 1% of silicon. Because of its multifariousness of corrosion resistance the steel can be employed in particular for the manufacture of equipment for removing pollutants from fumes, of equipment for the paper pulp industry, for the chemical industry or for petroleum exploitation, for seawater plants and for the manufacture of tankers for transporting corrosive products. The steel has a very high structural stability.

Abstract: The clad sheet comprises a first layer or cladding of an iron-base or nickel-base alloy including at least 11% chromium and at least 17% nickel and resisting corrosion by very corrosive mediums such as acids, and a second layer or base of austenitic stainless steel including at least 11% chromium and at the most 17% nickel resisting atmospheric corrosion. The clad sheets may be cold re-rolled down to a thickness of 2 mm.