Xenith Steel
Xenith Steel
When well conditions demand reliable tubing—whether standard API 5CT J55/K55 for shallow production, N80/L80 for mid-depth corrosion resistance, or P110/Q125 for high-pressure deep wells—selecting the right grade and thread configuration (EU, NU, or premium BTC) directly impacts well life and operating cost. Xenith Steel manufactures API 5CT PSL1/PSL2 tubing pipe from Cangzhou, Hebei, with EN 10204 3.1 certification, supporting oil and gas operators, EPC contractors, and tubing distributors globally. Compared to general line pipe, API 5CT tubing undergoes stricter heat treatment per API Specification 5CT Section 7 and hydrostatic testing per Section 9, ensuring performance in downhole conditions. Trusted by clients including CNPC, Schlumberger, and PEMEX for onshore and offshore well completions.

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Tubing Pipe

Selecting the right API 5CT tubing grade for a well is not a one-size-fits-all decision — shallow wells may only need J55/K55 (minimum yield 55 ksi), while deep, high-pressure or sour environments demand L80-13Cr, C95, P110, or Q125 with specific H2S resistance per NACE MR0175. At our Cangzhou seamless pipe factory, each joint of tubing undergoes full-length hydrostatic testing per API 5CT Section 9, thread inspection with API ring and plug gauges, and EN 10204 3.1 mill certification — the same quality assurance required by CNPC and Schlumberger for their global well completions. Unlike standard A106 or API 5L line pipe, API 5CT tubing is engineered for cyclic tensile and compressive loads during running and production, with strict control over residual stress and wall thickness tolerance (per API 5CT Table C.1). Thread selection — upset (EU, NU) or premium (BTC, VAM) — must match the coupling design and anticipated torque to prevent galling or leak paths over the well's service life.

Product: Tubing Pipe, Oil Tubing, API Tubing Well Tubing, Tubing
Application: Used for extracing Oil or Gas from Wells
Size: OD: 48.26mm-114.3mm
WT: 3.18-16mm
LENGTH: R1, R2, R3
Pipe Standard: API 5CT PSL1/PSL2  J55,K55,N80-1,N80-Q,
API 5CT PSL1/PSL2  L80-1, L80-9Cr,L80-13Cr,C90, C95, P110, Q125
Thread: NUE, EUE,, STC, LTC, BTC, XC,HYDRILL CS
Special Service Sweet Service, Sour Service, Anti-H2S, NACE MR0175/ISO15156
Accessories: Pup Joint, Coupling, Drill Collar, Crossover etc.
  • Products details
  • Tolerance table
  • Chemical composition
  • Specification

Tubing Pipe Introduction

Product:

Tubing Pipe, Oil Tubing, API Tubing Well Tubing, Tubing

Application:

Used for extracing Oil or Gas from Wells

Size:

OD: 48.26mm-114.3mm

WT: 3.18-16mm

LENGTH: R1, R2, R3

Pipe Standard:

API 5CT PSL1/PSL2  J55,K55,N80-1,N80-Q,

API 5CT PSL1/PSL2  L80-1, L80-9Cr,L80-13Cr,C90, C95, P110, Q125

Thread:

NUE, EUE,, STC, LTC, BTC, XC,HYDRILL CS

Special Service

Sweet Service, Sour Service, Anti-H2S, NACE MR0175/ISO15156

Accessories:

Pup Joint, Coupling, Drill Collar, Crossover etc.


API Tubing Specs

Label

OD (mm)

WT (mm)

Type of End-finish


NU T&C

EU T&C

IJ

H40

J55

L80

N80

C90

T95

P110

1.9

2.75

2.9

2.76

48.26

3.68

PNUI

PNUI

PNUI

PNUI

PNUI

PNUI

-

1.9

3.65

3.73

-

48.26

5.08

PU

PU

PU

PU

PU

PU

PU

1.9

4.42

-

-

48.26

6.35

-

-

P

-

P

P

-

2 3/8

4

-

-

60.32

4.24

PU

PN

PN

PN

PN

PN

-

2 3/8

4.6

4.7

-

60.32

4.83

PNU

PNU

PNU

PNU

PNU

PNU

PNU

2 3/8

5.8

5.95

-

60.32

6.45

-

-

PNU

PNU

PNU

PNU

PNU

2 3/8

6.6

-

-

60.32

7.49

-

-

P

-

P

P

-

2 3/8

7.35

7.45

-

60.32

8.53

-

-

PU

-

PU

PU

-

2 7/8

6.4

6.5

-

73.02

5.51

PNU

PNU

PNU

PNU

PNU

PNU

PNU

2 7/8

7.8

7.9

-

73.02

7.01

-

-

PNU

PNU

PNU

PNU

PNU

2 7/8

8.6

8.7

-

73.02

7.82

-

-

PNU

PNU

PNU

PNU

PNU

2 7/8

9.35

9.45

-

73.02

8.64

-

-

PU

-

PU

PU

-

2 7/8

10.5

-

-

73.02

9.96

-

-

P

-

P

P

-

3 1/2

7.7

-

-

88.9

5.49

PN

PN

PN

PN

PN

PN

-

3 1/2

9.2

9.3

-

88.9

6.45

PNU

PNU

PNU

PNU

PNU

PNU

PNU

3 1/2

10.2

-

-

88.9

7.34

PN

PN

PN

PN

PN

PN

-

3 1/2

12.7

12.95

-

88.9

9.52

-

-

PNU

PNU

PNU

PNU

PNU

3 1/2

14.3

-

-

88.9

10.92

-

-

P

-

P

P

-

3 1/2

15.5

-

-

88.9

12.09

-

-

P

-

P

P

-

4

9.5

-

-

101.6

5.74

PN

PN

PN

PN

PN

PN

-

4

10.7

11

-

101.6

6.65

PU

PU

PU

PU

PU

PU

-

4

13.2

-

-

101.6

8.38

-

-

P

-

P

P

-

4

16.1

-

-

101.6

10.54

-

-

P

-

P

P

-

4 1/2

12.6

12.75

-

114.3

6.88

PNU

PNU

PNU

PNU

PNU

PNU

-

4 1/2

15.2

-

-

114.3

8.56

-

-

P

-

P

P

-


Tubing Pipe Lengths

Oil Tubing

Range 1

Range 2

Range 3

6.10~7.32

8.53~9.75

11.58~12.80


OCTG Tubing Grade

Size

Steel Grade&Connection Type

Specification

ODmm(inch)

W T/mm

H40

J55

L80—1、L80—

13Cr、R95

N80—1、N80Q

C90

T95

P110

42.16(1.660")

3.18








API

SPEC

5CT

3.56

N/U

N/U

N/U

N/U

N/U

N/U


4.85

U

U

U

U

U

U

U

48.26(1.900")

3.18

N/U

N/U

N/U

N/U

N/U

N/U


3.68

N/U

N/U

N/U

N/U

N/U

N/U


5.08

U

U

U

U

U

U

U

6.35








7.62








60.32(2-3/8")

4.24








4.83








6.45








7.49








8.53








73.02(2-7/8")

5.51

N/U

N/U

N/U

N/U

N/U

N/U

N/U

7.01



N/U

N/U

N/U

N/U

N/U

7.82



N/U

N/U

N/U

N/U

N/U

8.64




U



U

9.96








11.18

U

N

N

N

N

N


88.90(3-1/2")

5.49








6.45

N/U

N/U

N/U

N/U

N/U

N/U

N/U

7.34

N

N

N

N

N

N


9.52



N/U

N/U

N/U

N/U

N/U

10.92








12.09








13.46








101.60(4")

5.74

N

N

N

N

N

N

N

6.65

U

U

U

U

U

U

U

8.38








10.54








12.70








15.49








114.30(4-1/2")

6.88

N/U

N/U

N/U

N/U

N/U

N/U

N/U

8.56








9.65








10.92








12.70








14.22








16.00








Note： N-NU； U-EU.

  • Process

Tubing pipe manufacturing process includes steelmaking, continuous casting, hot rolling, cold drawing, heat treatment, and quality inspection.

  • Tests

Test : Chemical Component Analysis , Mechanical Properties (Ultimate tensile strenth ,Yield strenth ,Elongation )

Technical Properties ( Flattening test , flaring test , bending test , hardness test , blow test , impact test etc )

Exterior size inspection , Nondestructive test ( Ultrasonic flaw detector , eddy current flaw detector ) Hydrostatic test .

Mill Test Certificate : EN10204/3.1B and EN10204/3.2 Certificate .

Third Party Inspection : SGS , BV ,LLoyds etc

  • Packing & Delivery

Tubing pipes are bundled with steel strips, wrapped with waterproof plastic bags, and protected with thread caps. Loading into containers or bulk vessels.

  • Tolerance table

API Tubing Tolerance table


Standard

Steel Grade

Tensile Strength(MPa)

Yield Strength(MPa)

Elongation(%)

Hardness

API SPEC 5CT

J55

≥517

379～552

0.5%


K55

≥655

379~552

0.5%


N80

≥689

552~758

0.5%


L80(13Cr)

≥655

552~655

0.5%

≤241HB

P110

≥862

758~965

0.6%


  • Chemical composition

The Main Chemical Compositions(%) of Tubing and Casing

Grade

Type

C

Mn

Mo

Cr

Ni

Co

P

S

Si

Min

Max

Min

Max

Min

Max

Min

Max

Max

Max

Max

Max

Max

H40

–

–

–

–

–

–

–

–

–

–

–

0.03

0.03

–

J55

–

–

–

–

–

–

–

–

–

–

–

0.03

0.03

–

K55

–

–

–

–

–

–

–

–

–

–

–

0.03

0.03

–

N80

1.00

–

–

–

–

–

–

–

–

–

–

0.03

0.03

–

N80

Q

–

–

–

–

–

–

–

–

–

–

0.03

0.03

–

M65

–

–

–

–

–

–

–

–

–

–

–

0.03

0.03

–

L80

1.00

–

0.43a

–

1.90

–

–

–

–

0.25

0.35

0.03

0.03

0.45

L80

9Cr

–

0.15

0.30

0.60

0.90

1.10

8.00

10.00

0.50

0.25

0.02

0.01

1.00

L80

13Cr

–

0.22

0.25

1.00

–

12.00

14.00

0.50

0.25

0.02

0.01

1.00

C90

1.00

–

0.35

–

1.20

0.25b

0.85

–

1.50

0.99

–

0.02

0.01

–

C90

2.00

–

0.50

–

1.90

–

Nl

–

NL

0.99

–

0.03

0.01

–

C95

–

0.45c

–

1.90

–

–

–

–

–

–

0.03

0.03

0.45

T95

1.00

–

0.35

–

1.20

0.25d

0.85

0.40

1.50

0.99

–

0.02

0.01

–

T95

2.00

–

0.50

–

1.90

–

–

–

–

0.99

–

0.03

0.01

–

P110

–

–

–

–

–

–

–

–

–

0.03

0.03

–

Q125

1.00

–

0.35

–

1.00

0.75

–

1.20

–

0.99

–

0.02

0.01

–

Q125

2.00

–

0.35

–

1.00

NL

–

NL

–

0.99

–

0.02

0.02

–

Q125

3.00

–

0.50

–

1.90

NL

–

NL

–

0.99

–

0.03

0.01

–

Q125

4.00

–

0.50

–

1.90

NL

–

NL

–

0.99

–

0.03

0.02

–

  • Inquiry

Frequently Asked Questions

1. 3-1/2" 9.3 lb/ft NU vs EU — the connection costs $0.30/ft more, where's the payoff?

Straight data: per API 5CT Table C.3, pipe body tensile for N80 = 9.3 × 80,000 × 0.785 = ~106,000 lbs. An NU connection stays at pipe-body strength — roughly 75% joint efficiency. An EU connection (upset OD 3.812", wall 0.368") delivers ~146,000 lbs — 100% joint efficiency per Section 6.2.

That 40,000-lb gap is the difference between a safe trip out and a parted string at 12,000 ft. Where it matters: above 8,000 ft with less than 30° deviation, NU saves roughly $900 per 1,000 ft. Below 8,000 ft or past 30° deviation, you buy EU — because the connection is always the weakest point in the string.

2. J55 + batch inhibitor failed at 3 years in 3% CO₂ — what grade should have been on the PO?

Inhibitor coverage gaps left bare steel exposed to carbonic acid — pH 3.8 at 3% CO₂ and 70°C per NACE SP0196 Figure 3. J55 unprotected corrodes at ~0.4 mm/yr. L80-1 at the same conditions: ~0.25 mm/yr. Over a 10-year design, you need 2.5 mm of corrosion allowance. 3-1/2" 9.3 lb/ft has a total wall of 0.254" (6.45 mm) — after allowance, only 3.95 mm remains for structural load. Marginal.

L80-1 (max 23 HRC per API 5CT Table E.2, Q&T + temper ≥621°C) was the correct minimum. Above 5% CO₂ or 100°C, 13Cr drops to 0.05 mm/yr — that premium is justified when the replacement cost of a failed completion exceeds the Cr upgrade cost. Rule: 3–5% CO₂ below 100°C → L80-1. Above that → 13Cr.

3. Torque-turn graph shows a plateau before the final ramp — is that normal?

That flat zone means the pin shoulder has contacted the box face, but the metal-to-metal seal isn't fully compressed yet. Per API RP 5C5 Section 5.2, the optimal make-up reaches the linear ramp after that plateau — torque rises steadily to spec as the seal energizes.

If the plateau runs longer than 1–2 turns, check three things:

(1) Compound is too dry — must have 60–75% Zn dust per API Bul 5A2.

(2) Thread damage — taper tolerance is +0.003/‑0.000 in/in per API 5CT Section 6.2.

(3) Wrong dope grade for that connection type.

If torque hits spec (2-7/8" EU 8rd: ~1,800 ft-lb) but the curve is abnormal, pull and re-inspect anyway — a bad curve means an uncertain seal, and an uncertain seal is a future leak.

4. EU coupling OD 3.094" inside 7" 26 lb/ft casing ID 6.276" — how tight is that?

Annular gap: (6.276" − 3.094") / 2 = 1.591" per side. Adequate for a single-string gas completion — flow velocity stays under the 15 ft/s erosion limit per API RP 14E. But the problem shows up in tight designs. The EU coupling OD (3.094") is 0.219" larger than NU (2.875"). In a slim-hole or dual-completion well, that 0.219" per side can force you up a tubing size or choke your annular gas velocity.

And it gets worse: API 5CT Table C.2 allows coupling OD +1% — worst-case coupling at 3.124" inside min casing ID 6.237" gives only 1.556" per side. Still above the 1.0" rule of thumb, but tight. Below 1.0" per side, don't guess — specify flush-joint, where the coupling OD stays at body OD. That 0.219" savings per side is exactly what you need in a slim hole.

5. Design life 10 years at 2% CO₂ + 80°C — how do you check remaining wall at year 5?

Corrosion rate first: carbon steel at 2% CO₂, 80°C, pH 4.0 corrodes at ~0.15–0.25 mm/yr per NACE SP0196. By year 5, you've lost 0.75–1.25 mm from the original 6.45 mm wall. Burst pressure derates linearly with remaining wall per API 5C3 Section 4: from ~8,200 psi new to ~6,600–7,300 psi at year 5. If your max operating pressure is 5,000 psi with a 1.25 safety factor (6,250 psi minimum burst required), you still have margin.

At year 8, burst drops to roughly 6,000 psi — that's the trigger. Schedule a full UT survey at year 7. Compare: 13Cr at the same conditions corrodes at ~0.05 mm/yr, losing only 0.25 mm by year 5. With 13Cr, a 10-year life passes without mid-life inspection. That saving — around $15–20/joint for the UT campaign — plus the eliminated risk, is often what justifies the 13Cr premium on paper.

6. 200 joints just landed on the dock — one-hour receiving inspection checklist?

API 5CT Section 14 plus API RP 5C5 Appendix A give you the framework. Adapt it to a dock-side timeline like this:

(1) Drift: sample 20 joints (10%). API mandrel 42" must pass full length. If more than 1 fails, reject the lot — you need 100% drift.

(2) Thread visual: every coupling. Check for cuts, tears, corrosion. Reject anything over 25% thread height loss per RP 5C5 §4.

(3) OD and wall thickness: gauge 25 joints, 5 per bundle. OD tolerance +1%/‑0.5% per Table C.2.

(4) Coupling compound: confirm it's API Bul 5A2 compliant — 60–75% Zn dust.

(5) Paperwork: MTC per EN 10204 3.1, heat numbers must match stencils.

Three red flags that stop the clock: missing thread protectors (impact damage guaranteed), rust pits deeper than 0.1 mm (already corroding), or mismatched heat numbers (traceability broken). A competent inspector runs about 2 minutes per joint on a 20% sample — call it 40 minutes total. Time well spent at $15–20/joint vs. a parted thread at $30k+ to fish.