Thread and coupling
Buttress
| Outside dia. Regular | – inches (–mm) | 
| Outside dia. Special Clearance | 7.0 inches (177,8mm) | 
Extreme-lines
| Drift diameter | 5.73 inches (145,54mm) | 
| Outside diameter | 7.0 inches (177,8mm) | 
| Size Designation | 2 7/8 : Inches | 
| Outside diameter | 2.875 Inches (73,0 mm) | 
| Grade | L80 | 
| Wall thickness | 0.44 inches (11,18mm) | 
| Pipe Carateristics | |
| Weight | 24.0 lb/ft (35,7kg/m) | 
| Inside diameter | 1.995 inches (50,67mm) | 
| Drift diameter | 5.796 inches (147,22mm) | 
| Outside dia. Regular | – inches (–mm) | 
| Outside dia. Special Clearance | 7.0 inches (177,8mm) | 
| Drift diameter | 5.73 inches (145,54mm) | 
| Outside diameter | 7.0 inches (177,8mm) | 
| STD | 3,0 ksi | 
| Alt | – ksi | 
| STD | 6,8 ksi | 
| Alt | – ksi | 
| Court | |
| STD | – ksi | 
| Alt | – ksi | 
| long | |
| STD | 6,8 ksi | 
| Alt | – ksi | 
| Regular | |
| STD | 6,8 ksi | 
| Alt | – ksi | 
| Special Clearance | |
| STD | 4,7 ksi | 
| Alt | – ksi | 


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.

S = seamless
EW = electric weld (resistance or induction) without the addition of filler metal.
QT = quenched and tempered
\(e = 625,000 * { A^{0.2}\over U^{0.9}}\)
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.
N : normalized
 T : tempered
 Q : quenched


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.

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.

Note1
GRADEMARKING
| H40 | H | 
| J55 | J | 
| K55 | K | 
| M 65 | M | 
| N80 | N | 
| P110 | P | 
| L80type1 | L | 
| L80type9 Cr | L9 | 
| L80type13Cr | L13 | 
| C90type1 | C90– 1 | 
| C90type2 | C90– 2 | 
| C95 | C95 | 
| T95type1 | T1 | 
| T95type2 | T2 | 
| Q125type1 | Q1 | 
| Q125type2 | Q2 | 
| Q125type3 | Q3 | 
| Q125type4 | Q4 | 
Note2
PROCESS O MANUFACTURE
seamless:S
electric welded :E
Note3
TESTPRESSURE
StandardtestpressureST
Alternate testpressureAT
Agreedonpressuregreater thanstandard testpressureHP
Test pressureis3000psiandthestandardtestpressureisgreaterthan3000psi.3K
Note4 TYPEOF THREAD
| casing Short round threadLong round thread Buttressthread Extremeline | STCLCBC XC | 
| tubing Nonupset ExternalupsetIntegraljoint | NU EUIJ | 
Note 5
 COLOR IDENTIFICATION

