Acid Corrosion Resistant PSL-2 Line Pipe

PSL-2 acid resistance line pipe is a pipe that is resistant to acid corrosion. With the property of resistance to H2S corrosion, it is widely applicable for transporting oil and gas in oil and gas wells containing H2S corrosion gas. This anti-H2S CO2 line pipe adopts pure steel for production with low sulfur and phosphorus content. This effectively controls the residual elements and easy oxidation elements and reasonably controls the content and role of Cr, Mo, Ni and other alloying elements in the acid resistance line pipe. Based on improving the steel hardenability and performance, we also ensure that the anti-H2S CO2 line pipe has good strength and toughness.

• 1. This acid resistance line pipe strengthens the control for crack sensitivity coefficient (pcm) and carbon equivalent (CE) to avoid weld cold crack, so it has excellent welding performance. JST also focuses on development of technical superiority for high quality anti-H2S CO2 line pipe (HSL245S, HSL290S, HSL360S, HSL415S, HSL450S) containing H2S, CO2, chloride ions and other corrosive media.
• 2. In order to ensure the quality of acid resistance line pipe, we implement strict testing procedures. Products must pass the eddy current testing, magnetic particle testing, ultrasonic flaw detection and other artificial surface inspection processes. There is a third party to supervise to detect anti-H2S CO2 line pipes, and then to issue quality guarantees. Thus our acid resistance line pipes have no serious quality problems.
• 3. JST not only has advanced inspection equipment, but also owns a high-quality and high-efficient inspection team. JST inspectors must pass the rigorous examination and then acquire the work license to inspect anti-H2S CO2 line pipes. To enhance the overall quality of staff, we have relevant trainings each month. Every year, we also invite professionals to train our employees. There are mainly PDCA (Plan, Do, Check, Action) and QA (Quality Assurance) trainings and other trainings for acid resistance line pipes to continuously improve inspectors’ inspection technique.

• Grade	Performance Requirement
  	Yield Strength (Rt0.5/Mpa)	Tensile Strength (Rm/Mpa min)	Yield Ratio (Rt0.5/Rm Max.)	Elongation (%)	Impact Energy/J
  					Average	Min.
  JST245NS	245~440	415	0.9	22	27	22
  JST 290NS/JST 290QS	290~440	415	0.9	21	30	24
  JST 360NS/JST 360QS	360~510	460	0.9	20	36	30
  JST 415QS	415~565	520	0.92	18	42	35
  JST450QS	450~570	535	0.92	18	45	38

• 2. Corrosion Resistance Property
  1) Resistance to Hydrogen Induced Cracking Test (HIC Resistant Test)
  For the test of this anti-H2S CO2 line pipe, we use NACE TM0284-2003 standard and ‘A’ test solution. The test time is 96 hours. The maximum is that the average value of the three sections of each test piece does not exceed the following index: crack length ratio (CLR) equal or less than 15%, crack thickness ratio (CTR) equal or less than 5%, crack sensitivity ratio (CSR) equal or less than 2% and hydrogen blister area of broad section equal or less than 1% of the surface area of each broadwise (broad section).
  2) Resistance to Sulfide Stress Cracking Test (SSC Resistant Test)
  This test is a mandatory inspection for acid resistance line pipes. We adopt NACE TM0177-2005 standard method and ‘A’ test solution. The test time is 720 hours and the test loading stress is 72% SMYS (nominal minimum yield strength). An acceptance criterion is that the test sample should have cracks with the depth of less than 0.1mm.

Technical ParametersParameter details about this anti-H2S CO2 line pipe refer to the excel table.

H2S acidic corrosive environment can easily cause the following three corrosion damage questions.
1. Sulfide Stress Corrosion Cracking (SSCC)
Under the acidic environment, the anti-H2S CO2 line pipe is prone to produce low stress and suddenly breaks without any warning.
2. Hydrogen Induced Cracking (HIC)
When acid resistance line pipes are in a hydrogen-containing medium (such as hydrogen sulfide water solution), stepwise cracking is easily formed. Crack growth finally makes the metal material crack. Hydrogen blister is a form of HIC corrosion.
3. Electrochemical Corrosion Cracking (ECC)
When anti-H2S CO2 line pipe is in wet weather containing sulfur, electrochemical reaction occurs and forms pinholes, corrosion pits and spots on the metal surface. This will reduce the wall thickness of acid resistance line pipes and punch holes, further cause accidents.

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