API 5L seamless line pipe X52–X80, PSL1 and PSL2. No weld seam. Sour service grades with HIC testing per NACE TM0284. FBE, 3LPE, and 3LPP coating available.
Applications
→Onshore oil and gas gathering — X52/X60 PSL2 for moderate-pressure field gathering systems
→Gas transmission — X65/X70 PSL2 for high-pressure onshore and offshore trunk lines
→Sour service pipelines — X52/X60/X65 PSL2 + SR15C HIC tested for H2S environments
→Offshore and subsea — X65 seamless for risers, spool pieces, jumpers, and subsea tie-ins
→Compressor and pump station piping — seamless for high-pressure, cyclic-load piping
→Water and slurry transmission — X52/X60 for produced water and injection pipelines
Standards & Certifications
API 5L / ISO 3183—Specification for Line Pipe — all grades and PSL levels
NACE MR0175 / ISO 15156—Sour service material requirements — H2S environments
NACE TM0284—HIC testing — pipe body sour service qualification
ISO 21809-1 / -2—External pipeline coatings (3LPE/3LPP and FBE)
DNV-ST-F101—Submarine pipeline systems — offshore applications
EN 10204 3.1 / 3.2—Mill test certificate documentation
PSL Level Guide
Requirement
PSL1
PSL2
Max yield strength
Not controlled
Controlled per grade
Yield-to-tensile ratio
Not specified
0.93 maximum
Carbon equivalent (CE)
Not specified
≤ 0.43% IIW, ≤ 0.25% Pcm
Sulphur limit
0.030% max
0.015% max
Charpy impact test
Not mandatory
Mandatory
NDE — pipe body
Not mandatory
Mandatory full-length UT
NDE — weld seam
Not mandatory
Mandatory full-length UT
Use for gas service
Not appropriate
Required
Use for sour service
Not appropriate
Required + SR15C
Use for offshore
Not appropriate
Required + add-ons
API 5L grade selection is driven by operating pressure, wall thickness economics, sour service requirements, and welding conditions. Higher grades allow thinner walls for the same design pressure.
Grade
Min Yield MPa / ksi
Min Tensile MPa
PSL1
PSL2
Sour Service
Typical Application
X52
358 / 52
455
✓
✓
✓ PSL2 + SR15C
Gathering, moderate-pressure onshore
X60
414 / 60
517
✓
✓
✓ PSL2 + SR15C
Onshore gas and oil transmission
X65
448 / 65
531
✓
✓
✓ PSL2 + SR15C
Offshore, high-pressure onshore gas
X70
483 / 70
565
—
✓
✗ Not suitable
High-pressure gas transmission, LSAW dominant
X80
552 / 80
621
—
✓
✗ Not suitable
Ultra-high-pressure large-diameter trunklines
Procurement Note — PSL2 Suffix Letters
PSL2 line pipe carries a delivery condition suffix: N (normalised), Q (quench and tempered), M (thermomechanical), R (as-rolled). For sour service add S: X52NS, X65QS, X70MS. Always specify the full grade designation including suffix on the purchase order.
Available OD, wall thickness, and manufacturing type combinations. Contact ZC to confirm specific size/grade/PSL combinations — not all combinations are available from every manufacturing process.
Type
OD Range (inches)
OD Range (mm)
Wall / Thickness Range
Grade Range
Seamless (hot rolled)
½″ – 16″
21.3 – 406.4
2.1 – 25.4 mm
X52 – X80
Seamless (hot expanded)
16″ – 24″
406.4 – 609.6
6.4 – 40.0 mm
X52 – X70
Procurement Note — Size Confirmation
ZC Steel Pipe is order-to-make — we do not hold standard stock. Send us your full specification (grade, PSL, OD, wall thickness, end finish, length, coating, quantity) and we will confirm availability, lead time, and pricing within one business day.
ZC Steel Pipe produces seamless line pipe by hot rolling and hot expanding — no weld seam at any stage of production. All PSL2 grades undergo full-body heat treatment to the delivery condition specified on the purchase order.
1
Billet / Round Bar
Continuous cast billets or hot-rolled rounds inspected for surface and internal quality before entering the pipe mill.
2
Heating
Billets heated to rolling temperature (1150–1250°C) in a rotary hearth or walking beam furnace for uniform temperature distribution.
3
Piercing
Heated billet pierced on a rotary piercing mill (Mannesmann process) to form a seamless hollow shell — no weld seam at any stage.
4
Rolling & Sizing
Shell rolled on mandrel mill or push bench to target OD and wall thickness, then sized on a stretch-reducing mill for dimensional accuracy.
5
Heat Treatment
PSL2 grades undergo normalising, quench-and-temper, or thermomechanical treatment per the delivery condition suffix (N, Q, M) to achieve yield and toughness requirements.
6
Straightening
Hot or cold straightening to API 5L straightness limits (≤ 0.2% of pipe length). Critical for automated field welding alignment.
7
End Finishing
Pipe ends bevelled to 30° ±5° standard angle per API 5L, or plain-end as specified. End protectors fitted before dispatch.
8
Inspection & Testing
Full mechanical testing, NDE, dimensional inspection, hydrostatic test, and MTC documentation. Third-party inspection available throughout.
Hot rolling process — seamless pipe millHot expanding process for larger diametersCold rolling / cold drawing for small-bore pipeFull manufacturing process flow — seamless line pipe
All ZC Steel Pipe line pipe is tested per API 5L / ISO 3183. PSL2 adds mandatory Charpy impact testing, full-length NDE, and weld seam testing for welded pipe. Third-party inspection to EN 10204 3.2 available on request.
1Tensile test — yield strength, tensile strength, elongation per API 5L (pipe body)
2Charpy V-notch impact test — PSL2 mandatory; body specimens; SR4A/4B at project-specified low temperature
3Hydrostatic pressure test — 100% per API 5L, no leakage through body or ends
4Non-destructive examination — full-length UT or EMI pipe body (PSL2); end-area UT
Pipeline engineering reference calculators for API 5L line pipe. Hoop stress and design pressure calculated per ASME B31.8 / B31.4 formula. All results are reference only — verify against project design calculations.
Design Pressure Calculator
P = (2 × t × SMYS × F × E × T) / OD | ASME B31.8 / B31.4
Joint efficiency E = 1.0 (seamless/LSAW). Temperature derating T = 1.0 (below 120°C). Adjust for other conditions.
Minimum Wall Thickness
t = (P × OD) / (2 × SMYS × F × E × T) | Rearranged ASME B31.8
Quick Unit Converter
Results update as you type.
These calculators are reference tools only. Always verify results against full pipeline design calculations per applicable code before use in engineering design.
Supply Enquiry — Seamless Line Pipe
Tell us your grade, PSL level, OD, wall thickness, coating requirement, quantity and delivery port. We will respond within one business day.
