Different Concentration Of Sulphuric Acid Affected Hydrogen Induced Cracking In A304 Pipeline Stainless Steel

Hydrogen played a vital role in the United State by industry for treating metal, producing fertilizer and processing food. U.S. petroleum refineries used hydrogen to lower the sulphur content of fuels but diffusion of atomic hydrogen through metal lattice caused hydrogen effect taking place during corrosion of metals in acidic solution. Hydrogen sulphide (112S) primarily responsible for hydrogen effects in ambient temperature corrosion processes. Hydrogen-induced cracking (HIC) noticed as a problem to the damage or failure of oil and gas stainless steel pipeline. Stainless steel pipe ASTM A304 used to convey oil and natural gas from processing field to export loading facility that usually used in the field of high operating temperature and pressures. Finding has contradicted the role of hydrogen atom as a corrosion inhibitor or corrosion enhancer on stainless steel with other aspect likes high temperature and pressure. Stainless steel plate was undergoing electrochemical charging in sulphuric acid with different concentration and duration to evaluate HIC. Tensile test performed to measure mechanical properties that provide information of tensile strength, yield strength and ductility of the material. Scanning Electron Microscopy (SEM) was performed to evaluate the stainless steel of morphology properties with 3 dimensional images (3D) and Energy dispersive X-ray spectroscopy (EDX) was utilized to measure the hydrogen composition that diffused into sample. Fourier-transform infrared spectroscopy (FTIR) was used to detect phase identification for functional group and chemical composition diffused into metal lattice for steel. Overall result showed the reduction mechanical properties of A304 after undergo hydrogen charging for sample S I (0.3) and S2 (0.6) but increased for S3 (0.9) since not undergo complete 24 hours charging. The observed result of SEM shows that microstructure of stainless steel present more porous after charging compared with uncharged sample. However, percentage of hydrogen diffused into sample cannot be observed since limitation of EDX that only plotted single spot and not cover the whole surface of sample. But FTIR analyzed that S2 (0.6) present of hydrogen bond at the broad peaks at 1250-1115cin'.
Keywords: Hydrogen-induced cracking (HIC), hydrogen effect, reduction, hydrogen diffused.