Thread and coupling

CHEMICAL REQUIREMENTS(in %)

NL : no limit

C : casing

T: tubing

The carbon content for L 80 may be increased to 0.50 % maxi if the product is oil quenched.

No minimum tolerance if the wall thickness is less than 0.700 inches for C 90 grade.

The carbon content for C 95 may be increased to 0.55 % maxi if the product is oil quenched.

The molybdenum content for grade T 95–Type 1 may be decreased to 0.15 % minimum if the wall thickness is less than 0.700 inches.

The phosphorous is 0.020 % maximum and the sulfur is 0.010 % maximum for EW (electric weld, resistance or induction, without the addition of filler metal) grade P 110.

TENSILE REQUIREMENTS

S = seamless

EW = electric weld (resistance or induction) without the addition of filler metal.

QT = quenched and tempered

• The minimum elongation in 2 in. (50.8 mm) shall be that determined by the following formula (inch-pound units) :

\(e = 625,000 * { A^{0.2}\over U^{0.9}}\)

where
e = minimum elongation in 2 in. (50.8 mm) in percent to nearest 1/2 percent.
A = cross-sectional area of the tensile test specimen in sq. in.
U = specified minimum ultimate tensile strength in ksi.

• Full length normalized (N), normalized and tempered (NT), or quenched and tempered (QT), at manufacturer’s option or if so specified on the purchase order.

N : normalized
T : tempered
Q : quenched

• Types 9 Cr and 13 Cr may be air quenched

TOLERANCES

CONNECTIONS

Casing pipe

API ROUND THREAD

The pipe is threaded at both ends to have a thread pin the pipes are joined together by means of a coupling. To API specifications, short or long threads with corresponding couplings are available. Long thread casing can transmit higher axial loads than short thread casing.

API EXTREME-LINE

Pipes completely differ from the 2 previous types. Endsof pipe are slightly upset where box and pin threads are. In addition, the bottom of the box thread is provi- ded with a machined area where the threaded pin will be pressed during make-up. The thread profile is trapezoidal.

API BUTTRESS

Theconnectingsystemisidenticaltoroundthread.Ins- tead of the «round thread», there is a «buttress» type threadwhichallowsthe transmission of veryhigh axialloads.

Tubing pipe

COUPLING JOINT

Threaded and coupled API tubing is externally threa- dedonbothendsofanonupset orupset pipe. Single lengthsarejoinedbyaninternallythreadedcoupling. CouplingO.D. canbe«regular» or «special» clea- rance (reduced O.D.). Tubingthread is API round

Nota :special bevel couplings can be furnished for non-upset and upset tubing, as specified on purchase

INTEGRAL JOINT

IntegraljointAPItubingisexternallythreadedoninter- nal upset pipeendandinternally threadedonexternal upset pipe end.

marking casing – tubing

Note1

GRADEMARKING

Note2

PROCESS O MANUFACTURE

seamless:S

electric welded :E

Note3

TESTPRESSURE

StandardtestpressureST

Alternate testpressureAT

Agreedonpressuregreater thanstandard testpressureHP

Test pressureis3000psiandthestandardtestpressureisgreaterthan3000psi.3K

Note4 TYPEOF THREAD

Note 5
COLOR IDENTIFICATION

marking : casing – tubing