API Spec 5ST:2010 pdf download

API Spec 5ST:2010 pdf download.Specification for Coiled Tubing.
3.35
spool
The total length of “as-manufactured” coiled tubing that is placed either on the service reel or shipping reel for storage and/or transport.
NOTE The tubing in a spool of tubing can contain one or more tube-to-tube elds. Can be used interchangeably with string or the capstan reel.
3.36
spooling radius ratio
The ratio of the diameter of the shipping reel core to the diameter of the coiled tube.
NOTE This ratio is used in determining the minimum recommended bending radius for spooling coiled tubular products onto the reel.
3.37
standardization
The adjustment of nondestructive test instruments to a known reference value.
3.38
stress relief
Heat treatment to a suitable temperature to reduce residual stresses, followed by cooling sufficiently slowly to minimize the development of new residual stresses.
3.39
string
The finished product manufactured at a coiled tubing facility.
NOTE Used interchangeably with spool.
3.40
strip
A single length of skelp, cut from a master coil.
3.41
tapered string
A complex stnng of coiled tubing manufactured with a constant outside diameter and variable wall thickness within the
length of the spooled tube.
EXAMPLE A tapered string can be constructed as follows:
a) a continuously milled string incorporating single or multiple wall thickness segments joined using skelp-end lds, and
b) continuously milled coiled tubing segments of single wall thickness joined to other finished tube segments of increasing/decreasing wall thickness using the tube-to-tube vlding process.
NOTE The tapering may occur within the original strip segments that are used to fabricate the string.
3.42
undercut
Undercuts in tube-to-tube welds are defined as the reduction of thickness of the tubing wall adjacent to the weld where it is fused to the surface of the tubing.
NOTE Undercutting on the outside surface can best be identified and measured visually. Undercutting on the inside surface can be identified using radiographic or ultrasonic means.
5.3.2.2 Plasma Arc Welding
A welding process that produces coalescence of metals by heating them with a constricted arc between an electrode and the work, or the electrode and a nozzle. Shielding is obtained from the hot ionized gas issuing from the torch, which may be supplemented by an auxiliary source of shielding gas. Shielding gas may be an inert gas or a mixture of gases. Pressure may or may not be used.
5.3.2.3 Gas Tungsten Arc Welding
A welding process that produces coalescence of the metals by heating them with an arc between a single tungsten electrode and the work. Shielding is obtained from a gas. Pressure is not used, and a filler metal may or may not be used.
5.4 Heat Treatment
The product shall be heat treated in accordance with a documented procedure. For all grades, the weld seam and the entire heat-affected zone shall be heat treated so as to simulate a normalizing heat treatment (see Note) followed by full body stress relief and/or temper, except that by agreement between the purchaser and the manufacturer, alternative heat treatments or combinations of heat treatment and chemical composition may be substituted. Where such substitutions are made, the manufacturer shall demonstrate the effectiveness of the method selected using a procedure that is agreed between the purchaser and the manufacturer. This procedure may include, but is not necessarily limited to, hardness testing, microstructural evaluation, and mechanical testing.
NOTE During the manufacture of electric-welded tubing, the product is in motion through the surrounding air. Normalizing is usually defined as “cooling in still air”, hence the phrase “to simulate a normalizing heat treatment” is used here.
5.5 Traceability
The manufacturer shall establish and follow procedures for maintaining heat and master-coil identity until all required heat and master-coil tests are performed and conformance with specification requirements has been shown.
6 Material Requirements
6.1 Chemical Requirements
For coiled tubing manufactured to this specification, all skelp segments manufactured within a continuously-milled string shall be of the same grade with the same nominal specified chemistry and mechanical properties.
The composition of tubing furnished to this specification shall conform to the chemical requirements given in Table A. 1, except that other chemical compositions may be furnished by agreement between the purchaser and the manufacturer.
Niobium (columbium), vanadium, titanium, or combinations thereof may be used at the discretion of the manufacturer. For all grades, by agreement between the purchaser and the manufacturer, elements other than niobium (columbium) vanadium, and titanium may be used; however, caution should be exercised in determining the quantity that may be present for any particular size and thickness of tubing, because the addition of such otherwise desirable elements may alter the weld ability of the tubing.