Metal treatment – Process of modifying or maintaining internal physical... – Heating or cooling of solid metal
Patent
1997-11-04
1999-07-13
Yee, Deborah
Metal treatment
Process of modifying or maintaining internal physical...
Heating or cooling of solid metal
148599, 148602, 148603, 148320, 148333, C21D 806, C21D 952, C22C 3804, C22C 3818
Patent
active
059221496
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to elongated elements of great length, such as steel wires to reinforce hoses intended for transporting pressurized effluent. The invention relates to a process for the production of these reinforcement wires, the wires that are obtained by the process, and the hoses which contain such reinforcing wires in their structure.
BACKGROUND OF THE INVENTION
Applications are known in which hoses that are reinforced with armor layers that consist of steel wires are used to transport fluids, particularly hydrocarbons. In certain cases, these hoses are placed under conditions where they are subjected to a corrosive environment, for example, in the presence of acidic fluids that contain sulfurated products. Also, in case where such hoses are placed in very deep water, more and more they need to have very high mechanical performance levels in terms of resistance to internal pressure, to axial load, and to external pressure resulting from the great depth of immersion.
In the hoses, whereby sealing is ensured by one or more polymer sheaths, mechanical resistance to internal and external pressure and to external mechanical stresses is provided by one or more armor layers that consist of wires or steel sections that have a specific profile.
Generally, the hose comprises at least one of the following armor layers: a casing for resistance to external pressure that is made of wires or sections that are arranged at an angle of close to 90.degree. relative to the axis, a layer for resistance to internal pressure (called an arch) that is arranged at an angle of greater than 55.degree., with the elongated elements of the casing and the arch preferably being wires that can be laced, and at least one tensile-strength armor layer that is wound at an angle of less than 55.degree.. According to another method, the arch and the traction armor are replaced by two symmetrical armor layers that are wound at an angle of about 55.degree., or by two pairs of layers that are wound at 55.degree., or else by a set of at least two layers, with the winding angle of at least one layer being less than 55.degree. and the winding angle of at least one another layer being greater than 55.degree.. The steel of the wires that comprise the reinforcements is to be selected in such a way that these wires, taking into account their section, provide the mechanical strength that is necessary in service at the same time that they withstand corrosion, in particular in some cases in the presence of H.sub.2 S.
These steel wires, which are generally shaped by rolling or hot or cold drawing, can have different profiles, i.e., straight sections: approximately flat or a flat surface, shaped in a U, T, or Z, with or without means for hooking to an adjacent wire, or circular.
In the case where these products are used in the presence of acid gas, basically H.sub.2 S and CO.sub.2, in addition to generalized corrosion, problems can arise that are connected with the penetration of hydrogen into the steel. Actually, H.sub.2 S (or rather the HS.sup.- ion) is a substance that inhibits the recombination of hydrogen atoms that are produced by reduction of protons at the surface of the steel. These hydrogen atoms are introduced inside the metal and recombine there, thus giving rise to two types of deteriorations: speak of "blisters"), or internal cracking (called stepwise cracking) can appear in the absence of stress and can be aggravated in the presence of residual stress, steel is put under stress (hydrogen stress corrosion).
NACE standards have been provided for evaluating the suitability of a steel structural element for use in the presence of H.sub.2 S. The steels should undergo a test on a representative specimen, under stress in an H.sub.2 S environment with a pH of 2.8 to 3.4 (NACE Test Method TM 0177 pertaining to the results of stress cracking, commonly referred to as "Sulfide Stress Corrosion Cracking" or SSCC), in order for them to be considered usable in the production of metal structures that have to withstand the e
REFERENCES:
patent: 5141570 (1992-08-01), Yutori et al.
Patent Abstracts of Japan, 16(106), C-919, Mar. 16, 1992.
Patent Abstracts of Japan, 16(086), C-916, Mar. 3, 1992.
Patent Abstracts of Japan, 14(047), C-682, Jan. 29, 1990.
Herrero Jose Mallen
Ropital Fran.cedilla.ois
Sugier Andre
Coflexip
Institut Francais du Pe'trole
Yee Deborah
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