Api 5l x52 specification of seamless and welded pipe

API 5L Spec x52 Line Pipe

Scope of API 5L X52

API 5L X52 is a steel grade of API 5L which specifies the manufacture of two product levels (PSL1 and PSL2) line pipe, X52 Line Pipe can be made seamless or welded, which are widely used as pipeline in the transportation of petroleum and natural gas. AGICO supplies other grades: X42, X46, X52, X56, X60, X65, X70 pipeline pipe for oil and gas trasportations allover the world.

Manufacture Process

Ingots, blooms, billets, coils or plates used for the manufacture of pipe shall be made via basic oxygen, electric furnace or open hearth in combination with a ladle refining process. For PSL2, the steel shall be killed and melted according to a fine grain practice. Coil or plate used for PSL2 pipe shall not contain any repair welds.

For welded API 5L x52 Line Pipe,There are 3 welding types: ERW (Electric Resistance Welding), LSAW (Longitudinally Submerged Arc Welding), and SSAW (Spirally Submerged Arc Welding) welding types.

Delivery condition

PSL Delivery Condition Pipe grade
PSL1 As-rolled, normalized, normalizing formed A
  As-rolled, normalizing rolled, thermomechanical rolled, thermo-mechanical formed, normalizing formed, normalized, normalized and tempered or if agreed Q&T SMLS only B
  As-rolled, normalizing rolled, thermomechanical rolled, thermo-mechanical formed, normalizing formed, normalized, normalized and tempered X42, X46, X52, X56, X60, X65, X70
PSL 2 As-rolled BR, X42R
  Normalizing rolled, normalizing formed, normalized or normalized and tempered BN, X42N, X46N, X52N, X56N, X60N
  Quenched and tempered BQ, X42Q, X46Q, X56Q, X60Q, X65Q, X70Q, X80Q, X90Q, X100Q
  Thermomechanical rolled or thermomechanical formed BM, X42M, X46M, X56M, X60M, X65M, X70M, X80M
  Thermomechanical rolled X90M, X100M, X120M
  The suffice (R, N, Q or M) for PSL2 grades, belongs to the steel grade  

Chemical Composition for PSL 1 pipe with t ≤ 0.984”

Steel Grade Mass fraction, % based on heat and product analyses a,g
C Mn P S V Nb Ti
max b max b max max max max max
Seamless Pipe
X52 0.28 1.4 0.3 0.3 d d d
Welded Pipe
X52 0.26 1.4 0.3 0.3 d d d

Chemical Composition for PSL 2 pipe with t ≤ 0.984”

Steel Grade Mass fraction, % based on heat and product analyses Carbon Equiv a
C Si Mn P S V Nb Ti Other CE IIW CE Pcm
max b max max b max max max max max max max
Seamless and Welded Pipe
X52N 0.24 0.45 1.4 0.025 0.015 0.1 0.05 0.04 d,e,l 0.043 0.25
X52Q 0.18 0.45 1.5 0.025 0.015 0.05 0.05 0.04 e,l 0.043 0.25
Welded Pipe
X52M 0.22 0.45 1.4 0.025 0.015 d d d e,l 0.043 0.25
a. SMLS t>0.787”, CE limits shall be as agreed. The CEIIW limits applied fi C > 0.12% and the CEPcm limits apply if C ≤ 0.12%,
b. For each reduction of 0.01% below the specified max. concentration for carbon, and increase of 0.05% above the specified max. concentration for Mn is permissible, up to a max. of 1.65% for grades ≥ B, but ≤ = X52; up to a max. of 1.75% for grades > X52, but < X70; and up to a maximum of 2.00% for X70.,
c. Unless otherwise agreed Nb = V ≤ 0.06%,
d. Nb = V = Ti ≤ 0.15%,
e. Unless otherwise agreed, Cu ≤ 0.50%; Ni ≤ 0.30% Cr ≤ 0.30% and Mo ≤ 0.15%,
f. Unless otherwise agreed,
g. Unless otherwise agreed, Nb + V + Ti ≤ 0.15%,
h. Unless otherwise agreed, Cu ≤ 0.50% Ni ≤ 0.50% Cr ≤ 0.50% and MO ≤ 0.50%,
i. Unless otherwise agreed, Cu ≤ 0.50% Ni ≤ 1.00% Cr ≤ 0.50% and MO ≤ 0.50%,
j. B ≤ 0.004%,
k. Unless otherwise agreed, Cu ≤ 0.50% Ni ≤ 1.00% Cr ≤ 0.55% and MO ≤ 0.80%,
l. For all PSL 2 pipe grades except those grades with footnotes j noted, the following applies. Unless otherwise agreed no intentional addition of B is permitted and residual B ≤ 0.001% .

Mechanical properties

Pipe Grade Tensile Properties – Pipe Body of SMLS and Welded Pipes PSL 1 Seam of Welded Pipe
Yield Strength a Tensile Strength a Elongation Tensile Strength b
Rt0,5 PSI Min Rm PSI Min (in 2in Af % min) Rm PSI Min
X52 52,200 66,700 c 66,700

Hydrostatic test

Pipe to withstand a hydrostatic test without leakage through the weld seam or the pipe body. Jointers need not be hydrostatic tested provide the pipe sections used were successfully tested.

Bend test

No cracks shall occur in any portion of the test piece and no opening of the weld shall occur.

Flattening test

Acceptance criteria for flattening test shall be:

  • EW pipes D<12.750 in:
  • X60 with T 500in. There shall be no opening of the weld before the distance between the plates is less than 66% of the original outside diameter. For all grades and wall, 50%.
  • For pipe with a D/t > 10, there shall be no opening of the weld before the distance between the plates is less than 30% of the original outside diameter.
  • For other sizes refer to the full API 5L specification.
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