API 5L X65 Pipe

API 5L X65 is a standard specified for gas, oil and water pipes by the American Petroleum Institute. These are high yield pipes meant for transportation of liquids over distance pipe lines. They have the minimum yield strength of 65000PSI and the minimum tensile strength of 77000PSI. This carbon steel has two different product specifications. The PSL1 and PSL2 could be used interchangeably but the API 5L X65 PSL2 has some higher mechanical properties compared to PSL1. The API 5L X65 PSL1 is the most commonly used product specification level of API 5L Grade X65. The nominal bore size differs from 3/8 inches to 30 inches and the other dimensions vary according to the schedules. The API 5L X65 Grade B comes in beveled, coupling and in plain end forms. The HIC Tested X65 is tested for hydrogen embrittlement and could be used under cryogenic conditions and with hydrogen gas rich environments. The ISO 3183 L450 is a certification of these pipes. The API 5L X65 Sour Service pipes high corrosion resistance. The API 5L X65 Nace conforms to corrosion resistance standards. It can come in NACE specifications MR0175, TM0177 and TM0284 as well. The wall thickness of the pipes can vary up to 250mm depending on the various schedules up from 20 and up to XXS and higher.

X65 Seamless Line Pipe Standard Specification


Seamless/ SAW/ ERW / LSAW / DSAW

2" to 24" O.D.


Wall Thickness

Schedule 10 to 160, STD, XS, XXS


Pipe End

Plain, Bevelled

Standard and Dimensions
Trade Name API SPEC 5L ISO 3183 PSL1 / PSL2 X65, ASTM A106/ A53/ A333 Grade 6/ API 5L GR.B X65
Standard Specification API 5CT, ASTM A333/A333M, ASTM A139, GB/T3091, ASTM, GB9948, GB/T14975, ASTM A53/A53M, ASTM A106/A106M, EN10296, ANSI/API GB13296-91, ASME B36.10, 5L, GB/T9711 ISO3183, GB/T14976
  • Grade A25 X65 PSL1
  • Grade B X65 PSL2
Pipe End Finish
  • X65 PSL1 : Plain, threaded, special coupling pipe, bevelled
  • X65 PSL2 : Plain-end
PSL1 Grade
  • Grade A
  • Grade B
Production Process SAWL, LW, HFW, SAWH, LFW, SMLS
Length 6-12 meters
Testing H2 SERVICE, DWT, CVN impact, HIC, TM0177, NACE MR0175, TM0284, IBR, Hardness, SSC
Equivalent Standard
Material Origins Indian, Korean, US, European, Ukraine, Japanese, Russian
Mill Test Certificate (MTC) EN 10204/3.1B

Most commonly used API 5L X65 PSL1/2 Pipe Types

API 5l X65 PSL2

API 5l X65 PSL2

Sour Service Line Pipes, Hsaw / Fluid Pipe

API 5l X65 Seamless Pipe

API 5l X65 Seamless Pipe

Seamless Line Pipe, Piling, Saw / Dsaw/ Sawh Pipe

API 5l X65 PSL 1

API 5l X65 PSL 1

Welded Steel Line Pipe, High Yield Pipe, Steel Pipeline

In X65M PSL2 what is the meaning of "M"?

Grade Letter Delivery Condition
X65M "M" letter means Thermomechanical rolled or thermomechanical formed

In X65Q PSL2 why mark "Q" on Line Pipe?

Grade Letter Delivery Condition
X65Q "Q" letter means Quenched and tempered eg API 5L X65QS

"N" indicate for which condition in X65N PSL2 Pipe

Grade Letter Delivery Condition
X65N "N" letter means normalized or normalized and tempered, Normalizing rolled, normalizing formed

USC Unit applicable for X65 Pipeline?

ISO 3183 L450 Pipe / L450Q / L450M / L450N

PSL2 X65 PSL2 is Repairable?

X65 PSL2 Linepipe shall not repair by welding, but as per agreement PSL1 Pipe may be repair by welding.

X65 Sour Service Line Pipes External & Internal Coating

X65 Sour Service Line Pipes Coating Types

Grade X65 Pipe Equivalent Standard

X65 PSL1 L450
X65 PSL2 L450Q / X65Q
L450M / X65M

API 5L X65 PSL2 Pipe Chemical Properties

API X65 PSl1
C max Mn max P S max V max Nb max Ti max
min max
B 0.28 1.2 0.03 0.03 c.d c,d d
X65 0.28 1.4 0.03 0.03 f f f

C Si Mn P S V Nb Ti Other
0.18 0.45 1.7 0.025 0.015 g g g h,l

X65 Carbon Steel Pipe Mechanical Specification

API Yield Stress Mpa Tensile Stress Mpa Raito Elongation
minimum max minimum max max minimum
BN 245 450 415 655 0.93 f
X65Q 450 600 535 760 0.93 f

X65 Steel Pipe Temperature Range

with epoxy coating Temperature
X65 200°C

API 5L X65 Pipe Allowable Pressure Rating

450 Mpa 65300 Psi

API 5L X65 PSL2 Pipeline Uses and Applications

  • Oil and Gas Transmissions
  • Petrochemical industries
  • Fuel Handling and Storage Tanks
  • Marine Piping on Vessels
API 5L X65 PSL2 Pipeline Application
  • If the Seamless or welded pipe is < size 16 then Interior marking are done instead of exterior.
  • Eg: 12" x 9.5mm API 5L Gr. B / ASTM A106/ A53/ A333

In petroleum industry, pipelines play an important role to supply oil from the wells to large storage points and refineries.