GB/T 8650-2015Evaluation of pipeline and pressure vessel steels for resistance to hydrogen-induced cracking (English PDF)

Foreword

This standard is drafted in accordance with the rules given in GB/T 1.1-2009.

This standard replaces GB/T 8650-2006 "Pipeline steel and pressure vessel steel anti-hydrogen cracking assessment method". With GB/T 8650-2006 compared to the main technical changes are as follows.

- increase the sampling position and orientation of spiral welded pipe specimens (see 6.2);

- Increased conditions for post-storage samples for test (see 6.4);

- increase the size of the pipe, the size of the flange, the direction of the sample and the number of samples, sample preparation, sample cleaning and storage (see Chapter 8 and Chapter 9);

- Increased pipe and flange sampling position (see Appendix C);

- modified the amount of starch indicator in the iodometric method (see Appendix F);

- The formula for calculating the concentration of hydrogen sulfide (H2S) has been modified (see Appendix D).

1 Scope

1.1 This standard specifies the pipeline steel and pressure vessel steel plate and flanges and fittings in the corrosive environment containing sulfide aqueous solution, Hydrogen - induced Hydrogen - induced Cracking (HIC) Evaluation Method.

1.2 This standard provides the size, quantity, position and orientation of each steel product type, the type of steel product including steel pipe, steel plate, Fittings and flanges.

1.3 This standard includes small diameter (nominal diameter [DN] 50 ~ 150, nominal pipeline size [NPS] 2 ~ 6), thin wall (wall thickness is not greater than 6mm) resistance welding (ERW) and seamless steel pipe special steps required. Unless otherwise specified in this standard, these small diameters, thin-walled materials, And other steel pipe with the same method of testing.

1.4 This standard does not contain guidelines for acceptance or rejection, but Chapter 8 of GB/T 20972.2-2008 provides guidance.

2 Normative reference documents

The following documents are indispensable for the application of this document. For dated references, only the dated edition applies to this document. For undated references, the latest edition (including all modifications) applies to this document.

GB/T 8923.1-2011 Visual evaluation of surface cleanings of steel surface before coating of coatings - Part 1: Uncoated Of the steel surface and the full removal of the original coating after the steel surface corrosion grade and treatment level

GB/T 20972.2.2-2008 Petroleum and natural gas industries - Materials for use in hydrogen sulfide-containing environments for oil and gas extraction - Part 2: Anti- Cracking carbon steel, low alloy steel and cast iron

GB Z2.1 Workplace Hazardous Factors Occupational Exposure Limits Chemical Hazardous Factors

3 Test principle

3.1 The test method of this standard is to immerse the stress-free sample in any of the following two standard solutions. Solution A, normal temperature and pressure (H2S), sodium chloride (NaCl) and acetic acid (acetic acid, CH3COOH) in distilled water or deionized water; solution B, under normal temperature and pressure, with saturated H2S artificial seawater. After soaking for a predetermined period of time, the sample is taken out and evaluated.

3.2 The test method of this standard is not simulated service conditions. This method provides only a reproducible test environment so that it can be in phase The sensitivity of different steel samples to hydrogen induced cracking (HIC) is different for short periods of time.

Note: The test time may not be able to extend the crack to the maximum in any test steel, but it is sufficient to meet the purpose of this test.

4 Reagent

4.1 Solution A The reagents should be nitrogen (N2) for deaeration, H2S gas (safety considerations for controlling H2S toxicity, see Appendix A), NaCl, CH3COOH and distilled water or deionized water. Solution B should be used for the removal of N2, H2S and artificial seawater.

4.2 Analytical pure chemicals for NaCl and CH3COOH applications.

4.3 H2S gas purity of not less than 99.5%, N2 for high purity nitrogen, water application of distilled water or deionized water (see Appendix B).

4.4 artificial seawater reagents should be formulated in accordance with Appendix C.