API 5CT PSL-1 and PSL-2 electric resistance welded casing and tubing for non-sour oil and gas wells. Grades H40, J55, K55, N80, L80 Type 1, and P110 — ERW manufacturing is limited to non-CRA grades. OD 2⅞"–10¾", connections STC, LTC, BTC, EUE, and NUE. Cost-effective alternative to seamless pipe for sweet-service applications.
Applications
→Surface casing and conductor pipe — shallow, low-pressure strings where seamless is not required
→Intermediate casing — sweet-service (non-H₂S) wells in grades H40 through P110
→Production tubing — EUE and NUE connections for oil production in non-sour wells
→Water injection wells — casing and tubing in non-corrosive water injection service
→Cost-effective alternative to seamless — same API 5CT grading for sweet-service applications
Standards & Certifications
API 5CT—Specification for Casing and Tubing — H40, J55, K55, N80, L80 Type 1, P110
EN 10204 3.1 / 3.2—Mill test certificate documentation
Procurement Note — ERW Grade Scope
ERW manufacturing is limited to non-CRA grades. L80 is supplied as L80 Type 1 only.
Sour-service L80 9Cr and L80 13Cr variants require seamless manufacturing — see Casing & Tubing for those grades.
API 5CT grades manufactured and supplied by ZC Steel Pipe. Grade selection is driven by well depth, H₂S environment, and pressure containment requirements.
Grade
Yield MPa / ksi
Tensile MPa / ksi
Max Hardness
H₂S Service
Typical Application
H40
276 / 40
414 / 60
—
✗ No
Shallow, low-pressure wells
J55
379 / 55
517 / 75
—
✗ No
Shallow oil and gas wells
K55
379 / 55
655 / 95
—
✗ No
Surface casing, conductor
N80-1
552 / 80
689 / 100
—
✗ No
Medium-depth sweet wells
L80-1
552 / 80
655 / 95
23 HRC
✓ Yes
Mild sour service
P110
758 / 110
862 / 125
None
✗ No
Deep HPHT sweet wells
Procurement Note — ERW Grade Limitations
ERW manufacturing is limited to non-CRA grades. L80 is supplied as L80 Type 1 only.
Sour-service L80 9Cr and L80 13Cr variants require seamless manufacturing — see Casing & Tubing for those grades.
API 5CT casing and tubing dimensions and weight chart. Common sizes from 4½″ to 20″ casing and 1.050″ to 4½″ tubing — OD, wall thickness, weight range, and applicable grades per API 5CT. Contact us to confirm availability for specific size/grade combinations.
Casing — Common Sizes
OD (in)
OD (mm)
Weight Range (lb/ft)
Wall Range (mm)
Common Grades
Typical String
4½
114.3
9.50–15.10
5.21–8.56
N80, L80, L80-3Cr, R95, C90, T95, P110
Production casing / tubing
5
127.0
11.50–18.00
6.43–9.19
N80, L80, L80-3Cr, R95, C90, T95, P110, C110
Production casing
5½
139.7
14.00–23.00
6.98–10.54
N80, L80, L80-3Cr, R95, C90, T95, P110, C110
Production casing — most common
7
177.8
17.00–38.00
6.91–14.27
N80, L80, R95, C90, T95, P110
Intermediate / production casing
7⅝
193.7
24.00–45.30
8.33–15.11
N80, L80, R95, T95, P110, C110
Intermediate casing
9⅝
244.5
32.30–58.40
8.94–15.11
N80, L80, R95, T95, P110, C110
Intermediate casing
10¾
273.1
32.75–65.70
7.09–13.84
J55, K55, N80
Surface casing
13⅜
339.7
48.00–72.00
8.38–12.19
J55, K55, N80
Surface casing
16
406.4
65.00–109.00
9.53–15.88
J55, K55
Conductor / surface
20
508.0
94.00–133.00
11.13–15.88
H40, J55
Conductor pipe
Tubing — Common Sizes
OD (in)
OD (mm)
Weight Range (lb/ft)
Wall Range (mm)
Common Grades
1.050
26.7
1.14–1.80
2.41–3.91
J55, N80
1.315
33.4
1.70–2.90
2.90–4.55
J55, N80
1.660
42.2
2.30–3.40
2.90–4.85
J55, N80
1.900
48.3
2.75–4.70
3.18–5.08
J55, N80, L80
2⅜
60.3
4.00–6.40
3.18–5.54
J55, N80, L80, L80-3Cr, T95, P110
2⅞
73.0
6.40–10.40
5.51–7.82
J55, N80, L80, L80-3Cr, C90, T95, P110, C110
3½
88.9
7.70–12.95
5.49–8.31
J55, N80, L80, L80-3Cr, T95, P110
4
101.6
9.50–14.00
5.74–8.38
N80, L80, L80-3Cr, C90, T95, P110, C110
4½
114.3
12.60–26.10
6.88–16.00
N80, L80, L80-3Cr, C90, T95, P110, C110
Procurement Note — Size Confirmation
The tables above show common API 5CT sizes. Not every size/grade combination is held in stock — ZC Steel Pipe is order-to-make. Send us your full specification (OD, weight, grade, connection, PSL, quantity) and we will confirm availability and lead time within one business day.
ZC Steel Pipe manufactures casing and tubing exclusively by the seamless process. All grades from N80Q through Q125 are produced by quench and temper heat treatment for controlled yield and hardness.
1
Billet Inspection
Continuous cast or rolled billets inspected for surface defects and internal quality before entry to the pipe mill.
2
Hot Rolling / Piercing
Billets heated to rolling temperature and pierced on a mandrel mill or push bench to form the seamless mother tube.
3
Sizing & Straightening
Hot-rolled tube sized to target OD and wall, then hot straightened for dimensional conformance.
4
Heat Treatment
Q+T grades (N80Q, L80, T95, P110, C110, Q125) quenched and tempered in continuous furnace lines to achieve the API 5CT yield band and hardness ceiling.
5
Cold Straightening
Post-heat-treatment straightening to API 5CT straightness limits.
6
End Finishing
Pipe ends machined to customer connection specification — STC, LTC, BTC, or premium thread profile. Thread protectors fitted before dispatch.
7
Inspection & Testing
Full mechanical testing, NDE, dimensional inspection and MTC documentation. Third-party inspector witness available throughout.
All ZC Steel Pipe casing and tubing is tested and documented per API 5CT. PSL-2 orders include mandatory NDE and impact testing. Third-party inspection to EN 10204 3.2 available on request.
1Magnetic Particle Test (MPT) — surface crack detection
2Hydrostatic Test — pressure integrity per API 5CT
3Ultrasonic Test (UT) — internal and external defect detection of pipe body and weld seam
4Eddy Current Test (ECT) — surface and near-surface defect detection
API 5CT casing pipe weight calculator and burst pressure calculator. Calculate pipe weight per metre (kg/m) or per foot (lb/ft) from OD and wall thickness. All formulas per API 5CT / TR 5C3.
Pipe Weight per Metre
Formula: W = 0.02466 × t × (OD − t) kg/m | API 5C3
Hydrostatic Test Pressure (API 5CT §10.12.3)
Formula: p = (2 × f × YS_min × t) / D | Rounded to 0.5 MPa. Max 69.0 MPa.
f = 0.6 for H40/J55/K55 with OD > 244.5 mm (9⅝"); f = 0.8 for all other grades and sizes.
Quick Unit Converter
Results update as you type.
These calculators are provided as engineering reference tools. Always verify critical design values against API 5CT tables before use in casing design.
