Metallurgical apparatus – Having means for contacting a solid metalliferous material... – With heating means – e.g. – flame contact
Patent
1994-08-11
1995-12-26
Kastler, Scott
Metallurgical apparatus
Having means for contacting a solid metalliferous material...
With heating means, e.g., flame contact
266132, C21D 908
Patent
active
054780543
DESCRIPTION:
BRIEF SUMMARY
The present invention refers to tempering steel tubes, which are cooled at a high speed by contact with a cooling fluid. More specifically, an injection nozzle is used for cooling from the inner surface of the steel tube, which is dipped into a tank containing a cooling fluid, for cooling it also from its outer surface.
In recent years a continuous search for petroleum reserves has been effected, especially in deep regions of the sea and oceans. With a view to meeting the new requirements for the quality of the steel tubes designed for prospection and production conditions in these oil fields, methods and equipment have been developed for heat treatment of the steel tubes employed therein. Most of the tubes to be tempered seek to meet the requirements of the API (American Petroleum Institute) standards. For certain degrees of quality, these standards require the use of a temper system in the process of manufacturing steel tubes, among such the following can be cited: C75, C90, C95, L80, N80, P105, P110, and Q105. Among these standards can be cited API 5 CT (SPEC 5 TC) which refers to Casing and Tubing type pipes designed for oil well linings and production, and API 5 D referring to Drill Pipe type tubes, directed for drilling oil wells.
At present there are different methods and devices for tempering steel tubes by means of internal and/or external cooling, by employing water, air and oil as a cooling fluid, among others.
Among the principal methods for cooling steel tubes the following can be cited: containing a cooling fluid and having an injection nozzle installed inside the cooling-fluid tank, by rotating the steel tube during the process; nozzle in accordance with the teachings of European patent No. EP 0086988 to Kruppeft Enterprises Inc.; means of a water curtain upon and along the tube, in accordance with the teachings of DE Pat 3216496 A1; injection nozzle matched with the size of the tube in accordance with the teachings of EP 0 172 250.
In the case of cooling steel tubes having a thick wall according to method (1) it is impossible to obtain cooling speeds that guarantees temper of the whole wall thickness. Since it is impossible to obtain a 100% even distribution of the cooling fluid on the whole surface of the steel tube, due to the position of one ring around it and to the distribution of the nozzles on the rings, which lead the cooling fluid to the outer surface of the steel tube, the cooling speeds are variable along the outer surface of the tube, thus causing the latter to bend, which in turn makes the movement/transport of the steel tube after the temper difficult and even impossible also giving rise to eventual damages in the installation. Besides these limitations this method requires a large flow of cooling fluid.
According to method (2), the cooling essentially starts from the outer surface just as in method (1), and, as a result, it has the limitation of the wall thickness of the steel tube. The amount of cooling fluid that enters the tube at the time of dipping vaporizes, thereby forming vapour pockets that cause an uneven cooling from the inner surface. Another limitation of method (2) is that the dipping of the tube into the cooling medium occurs in an uncontrolled manner.
Finally, DE Pat 3216496 describes an installation without immersion tank, in which the cooling water can be led to both the inner and the outer surfacer the steel tube being turned while tempering.
The cooling from the outer surface occurs by the action of the laminar flow of the cooling fluid led to the tube. The internal cooling is provided by an equipment bearing an injection head. The tube is secured by one of its ends to this equipment bearing an injection head, which is provided with a plurality of auxiliary elements and is coupled to a movable base, driven by chains and pulleys, its movement being possible only horizontally in a reciprocating manner. The tube is maintained against the injection nozzle by at least one pair of fixing devices, each being made up of a plurality of drives arranged integral with
REFERENCES:
patent: 3997375 (1976-12-01), Franceschina et al.
patent: 4032369 (1977-06-01), Jatczak et al.
patent: 4417928 (1983-11-01), Heine, Jr. et al.
Alencar Paulo F.
Dreistein Werner F.
Louzada Edesio E. D.
Titze Eberhard E.
Kastler Scott
Mannesmann, S.A.
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