Hydrogen-Induced Cracking (HIC) Test (NACE TMO284)

Hydrogen induced cracking test ( HIC test ) method evaluates the resistance of pipeline and pressure vessel plate steels to Hydrogen Induced Cracking caused by hydrogen absorption from aqueous sulfide corrosion.

An unstressed test specimen is exposed to a solution at temperature of 25 degree centigrade with continuous H2S gas flow and pressure and after a specified time.In either case, H2S is bubbled through the solution constantly throughout the test period. NACE TM0284 specifies test duration of 96 hours.The test requires evaluation of pH values of the test solution before exposure and after the exposure. Then HIC test specimens are cut into sections and examined under a microscope for hydrogen-induced corrosion cracks.The dimensions of any such cracks are recorded and used to compute the values in percentage for Crack Length Ratio (CLR), Crack Thickness Ratio (CTR) and Crack Sensitivity Ratio (CSR) as per the NACE Standard.