The Differences between Sour Service Pipes and None Sour Service Pipes for PSL2
Standard: API Spec 5L 46th
Note: The below mentioned shall not be applied to PSL1 pipe, as PSL1 pipe is not considered suitable for sour service.
1. Steel making
None Sour Service Pipes: the steel shall be killed and made according to fine grain practice.
Sour Service Pipes: the steel shall be made to a clean steel practice using either the basic oxygen steel making process or the electric furnace process and shall be killed.
2. Chemical Composition for Pipe with t≤25.0mm
The major steel grade of none-sour service pipe
|
Steel Grade |
Mass Fraction Based on Heat and Product Analyses % max |
Carbon Equivalent % max |
||||||||
|
C |
Si |
Mn |
P |
S |
V |
Nb |
Ti |
CEIIW |
CEPcm |
|
|
X42N |
0.24 |
0.40 |
1.20 |
0.025 |
0.015 |
0.06 |
0.05 |
0.04 |
0.43 |
0.25 |
|
X42Q |
0.18 |
0.45 |
1.40 |
0.025 |
0.015 |
0.05 |
0.05 |
0.04 |
0.43 |
0.25 |
|
X52N |
0.24 |
0.45 |
1.40 |
0.025 |
0.015 |
0.10 |
0.05 |
0.04 |
0.43 |
0.25 |
|
X52Q |
0.18 |
0.45 |
1.50 |
0.025 |
0.015 |
0.05 |
0.05 |
0.04 |
0.43 |
0.25 |
|
X60N |
0.24 |
0.45 |
1.40 |
0.025 |
0.015 |
0.10 |
0.05 |
0.04 |
As agreed |
|
|
X60Q |
0.18 |
0.45 |
1.70 |
0.025 |
0.015 |
V+Nb+Ti≤0.15 |
0.43 |
0.25 |
||
The major steel grade of sour service pipe
|
Steel Grade |
Mass Fraction Based on Heat and Product Analyses % max |
Carbon Equivalent % max |
||||||||
|
C |
Si |
Mn |
P |
S |
V |
Nb |
Ti |
CEIIW |
CEPcm |
|
|
X42NS |
0.14 |
0.40 |
1.35 |
0.020 |
0.003 |
0.05 |
0.05 |
0.04 |
0.36 |
0.19 |
|
X42QS |
0.14 |
0.40 |
1.35 |
0.020 |
0.003 |
0.04 |
0.04 |
0.04 |
0.34 |
0.19 |
|
X52NS |
0.16 |
0.45 |
1.65 |
0.020 |
0.003 |
0.10 |
0.05 |
0.04 |
0.43 |
0.22 |
|
X52QS |
0.16 |
0.45 |
1.65 |
0.020 |
0.003 |
0.07 |
0.05 |
0.04 |
0.39 |
0.20 |
|
X60QS |
0.16 |
0.45 |
1.65 |
0.020 |
0.003 |
0.08 |
0.05 |
0.04 |
0.41 |
0.22 |
3. For the sour service pipe, add to the following inspection
A. HIC Test
Meet the following requirements according to ISO 15156-2
a. Crack sensitivity ratio ≤ 2%
b. Crack length ratio ≤ 15%
c. Crack thickness ratio ≤ 5%
B. Hardness Test
The hardness in pipe body, the weld, and HAZ shall be ≤ 250 HV10 or 22HRC.
C. SSC Test
After removal of the SSC test specimens from the test medium, the specimen surface previously under tension shall be examined under a low-power microscope at X10 magnification. The occurrence of any surface breaking fissures or cracks on the tension surface of the test specimen shall constitute failure of the specimen unless it can be demonstrated that these are not the result of SSC.
