EVALUATION OF HYDROGEN EMBRITTLEMENT INDUCED DAMAGES IN STEELS USING ACOUSTIC EMISSION

摘要

In the oil and gas industry, it is known that equipments which operate in hydrogen sulfide (H_2S) media can be subjected to damages like Hydrogen Induced Cracking (HIC) and Sulfide Stress Cracking (SSC). At the present time, material selection for sour environments is generally obtained using standard tests (NACE TM0177 and NACE TM0284) which give information about the resistance of steels in sour service. These tests are suitable for a quick assessment of candidate steels by operators or steel suppliers. However they cannot provide detailed information to better understand and quantify the damage occurring during the service life of steel components.Acoustic emission (AE) is an efficient technique to monitor degradation of materials. In the present work it is used for the early detection, characterization and time progress description of cracking phenomena caused by hydrogen embrittlement of steel in sour media.The methodology used for the identification of AE sources related to HIC (H_2 bubbles, FeS corrosion layer, cracking) is described. AE results are discussed and correlated with crack length ratio and AE performance for quantifying HIC damage is evaluated.