Sunny Steel offer an extensive range of Line pipes used in sour
service environment. The line pipes can be used for a wide range of
petrol and gas transportation under sour service environment.
For petrol and gas transportation under sour service environment.
1/4” Nominal to 24”O.D.
Wall Thickness – Schedule 10 through XXH
Line Pipe Steels Used in Sour Service
Line pipe steels used in sour service are prone to hydrogen-induced
cracking (HIC) depending on metallurgical and environmental
The metallurgical factors consist of alloying elements,
microstructure, strength, segregation, and shape of non-metallic
inclusions. Some environmental factors which influence HIC, also
known as stepwise cracking (SWC), are the partial pressures of
hydrogen sulfide (H2S) and carbon dioxide, temperature, pH of the
medium, and aggressive ions, such as chloride. Many failures of
sour gas line pipes have occurred around the world as a result of
Considerable effort has been expended by steel line pipe producers,
users, and research organizations to understand the HIC mechanism,
to develop a laboratory test method to identify and quantify
material susceptibility to HIC, and to produce steels with greater
HIC resistance. NACE International has developed a standard test,
TM-02-84, for line pipe steels.
The method describes procedures for evaluating the resistance of
pipeline steels to SWC induced by H absorption from aqueous sulfide
corrosion. The test is applicable to line pipe with wall
thicknesses of 5 mm to 30 mm. The procedure consists of exposing
unstressed coupons to synthetic seawater saturated with H2S at
ambient temperature and pressure at a pH in the range 4.8 to 5.4
for 96 h. The samples are sectioned, polished metallographically,
and etched, if necessary, so that cracks can be distinguished from
small inclusions, laminations, scratches, or discontinuities. Crack
sensitivity ratio (CSR), crack length ratio (CLR), and crack
thickness ratio (CTR) are calculated for each section. The average
is determined for each coupon. In recent work by Canada’s Centre
for Mineral and Energy
Technology in collaboration with the Canadian Standards Association
(CSA) Sour Service Task Force, two parameters were determined
experimentally for each of 19 line pipe steels:
(1) threshold H concentration (CthH) or the concentration of
diffusible H in the steel above which cracking occurs and
(2) threshold pH (pHth) or the pH below which cracking occurs.
Pipes are supplied with marking according to standard and customer
Marking is paint on the ends of pipes.
The same data, as well as additional information per customer’s
request, is indicated on the bundle’s tags.
Pipes are supplied in hexagonal bundles or round bundles tied with
Weight of bundle – up to 5000 kg upon request of customer.
Each bundle is furnished with three tags.