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US 10,480,054 B2Granted
Coiled tube with varying mechanical properties for superior performance and methods to produce the same by a continuous heat treatment
AssigneeTenaris Coiled Tubes, LLC
InventorsMartin Valdez, Bruce A. Reichert, Jorge Mitre
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Abstract
Described herein are coiled tubes with improved and varying properties along the length that are produced by using a continuous and dynamic heat treatment process (CDHT). Coiled tubes can be uncoiled from a spool, subjected to a CDHT process, and coiled onto a spool. A CDHT process can produce a “composite” tube such that properties of the tube along the length of the tube are selectively varied. For example, the properties of the tube can be selectively tailored along the length of the tube for particular application for which the tube will be used.
Claims28
A method of heat treating a coiled tube, the method comprising:
- welding a plurality of steel strips together end to end to form a plurality of welded strips and longitudinally welding the plurality of strips to form a tube with a substantially constant inner diameter, outer diameter, and wall thickness along at least a first portion, a second portion and a third portion, the third portion being disposed between the first portion and the second portion:
- coiling the tube on a spool to form the coiled tube;
- uncoiling the coiled tube from the spool to obtain an uncoiled tube with the at least a first portion, the second portion and the third portion
- selecting at least one predetermined parameter to be varied during a continuous quench and temper heat treatment process;
- after uncoiling the coiled tube, performing the continuous quench and temper heat treatment process along the first portion, the second portion and the third portion, wherein the at least one predetermined parameter of the continuous heat treatment process applied to the first portion varies from the at least one predetermined parameter applied during the continuous heat treatment process to the third portion and the at least one predetermined parameter of the continuous heat treatment process applied to the third portion varies from the at least one predetermined parameter of the continuous heat treatment process applied to the second portion to thereby modify a microstructure of the uncoiled tube and thereby resulting in a composite uncoiled tube with the first portion having a greater post-heat-treatment yield strength value than a post-heat-treatment yield strength value of the third portion and the third portion having a greater post-heat-treatment yield strength value than a yield strength value of the second portion, and wherein the composite uncoiled tube after the continuous heat treatment process has a tempered martensite microstructure in the first, second and third portions of the uncoiled tube;
- and
- re-coiling the composite uncoiled tube after performing the continuous quench and temper heat treatment process;
- wherein the post-heat-treatment yield strength values are between 80 and 140 ksi.
5 more elements
A method of heat treating a tube, the method comprising:
- welding a plurality of steel strips together end to end to form a plurality of welded strips and longitudinally welding the plurality of strips to form a tube with a substantially constant inner diameter, outer diameter, and wall thickness along at least a first portion, a second portion and a third portion, the third portion being disposed between the first portion and the second portion;
- and
- selecting at least one predetermined parameter to be varied during a continuous quench and temper heat treatment process;
- after forming the tube, performing the continuous quench and temper heat treatment process along the first portion, the second portion and the third portion, wherein the at least one predetermined parameter of the continuous heat treatment process applied to the first portion varies from the at least one predetermined parameter applied during the continuous heat treatment process to the second portion and the at least one predetermined parameter of the continuous heat treatment process applied to the third portion varies from the at least one predetermined parameter of the continuous heat treatment process applied to the second portion to thereby modify a microstructure of the tube and thereby resulting in a composite tube with the first portion having a greater post-heat-treatment yield strength value than a post-heat-treatment yield strength value of the third portion and the third portion having a greater post-heat-treatment yield strength value than a yield strength value of the second portion, and wherein the composite tube after the continuous heat treatment process has a tempered martensite microstructure in the first, second and third portions of the uncoiled tube;
- wherein the post-heat-treatment yield strength values are between 80 and 140 ksi.
2 more elements
Dependencies are inferred from the claim text.