Studi Pengaruh Tegangan Terhadap Kerentanan Hydrogen-Induced Cracking Pada Baja Karbon Dengan Menggunakan Spesimen C-Ring

Setiabudi, Muhammad Ichlasulrafif (2024) Studi Pengaruh Tegangan Terhadap Kerentanan Hydrogen-Induced Cracking Pada Baja Karbon Dengan Menggunakan Spesimen C-Ring. Masters thesis, Institut Teknologi Sepuluh.

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Abstract

Peningkatan kebutuhan minyak bumi sebagai sumber bahan bakar utama hingga sekarang menuntut eksplorasi ladang minyak baru termasuk pada lingkungan kerja ekstrim, salah satunya adalah lingkungan mengandung H2S. Penggunaan material khususnya pipa pada lingkungan tersebut meningkatkan kerentanan akan kegagalan seperti hydrogen induced cracking (HIC). Proses manufaktur, hingga kondisi operasi dari pipa dapat mengakibatkan pemberian tegangan yang tidak dapat dihindari. Maka dari itu, pada penelitian ini bertujuan untuk mengetahui pengaruh tegangan pada fase elastis dan plastis terhadap kerentanan akan HIC pada baja karbon. Pada penelitian ini menggunakan material ASTM SA178 Gr. C sebagai material uji untuk mewakilkan baja karbon dan dibentuk c-ring sesuai dengan standar ASTM G-38. Setiap sampel c-ring akan diberikan tegangan pada fase elastis dan plastis dengan variasi pada fase elastis 0 %, 20%, 30%, dan 90% dari nilai yield strength (YS) sedangkan untuk fase plastis diberikan sebesar 120% dari nilai YS. Setelah itu, spesimen diberikan perlakuan electrochemical hydrogen charging untuk merekayasakan atom hidrogen memasuki spesimen. Dilanjutkan pengamatan morfologi untuk mengetahui bagaimana pengaruh tegangan terhadap kerentanan akan HIC. Berdasarkan hasil yang didapat, semakin besar nilai tegangan material semakin rentan terhadap HIC baik dari jumlah atau ukuran blister. Pada pemberian tegangan 20-90%, peningkatan kerentanan akan HIC terlihat dalam pembentukan jumlah blister secara masif akibat initiation site blister bertambah akibat tegangan walaupun ukurannya kecil akibat desakan antar nukleasi blister yang mencegah pertumbuhan ukuran blister. Pada tegangan fase plastis, peningkatan kerentanan ditunjukkan melalui peningkatan jumlah dan ukuran blister akibat densitas hydrogen traps dan konsentrasi tegangan secara lokal meningkat.
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The increasing demand for crude oil as the primary fuel source has led to the exploration of new oil fields, including those in extreme working environments, such as environments containing H2S. The utilization of specific materials, particularly pipes, in that environment increases the susceptibility to failures such as hydrogen induced cracking (HIC). The manufacturing process, installation, and operational conditions of pipes can result in the application of unavoidable stress. Therefore, the purpose of this study is to determine the influence of stress in the elastic and plastic phases on the susceptibility to HIC in carbon steel. This study utilizes carbon steel ASTM SA178 Gr. C as the test material. The material formed into a c-ring conforms to the ASTM G-38 standard. Each c-ring sample will be subjected to stress in both the elastic and plastic phases, with variations in the elastic phase at 20, 30, and 90% of the yield strength (YS) value, while in the plastic phase it will be subjected to 120% of the YS value. Afterwards, the c-ring specimen undergoes electrochemical hydrogen charging treatment to facilitate the infiltration of hydrogen atoms into the specimen. The morphology of the material will be observed before and after to determine the influence of stress on the susceptibility of the material to HIC. According to the results, the material is more susceptible to HIC in terms of blister number or blister size and number the higher the stress value. The development of a large number of blisters at 20–90% stress is indicative of a heightened sensitivity to HIC, even while the size of the blisters is limited because of the pressure that exists between blister nucleations, which stops the blisters from growing larger. The number and size of blisters increase in response to a local increase in stress concentration and hydrogen trap density in the plastic phase stress, indicating an increase in susceptibility.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	Baja Karbon, Hidrogen Sulfida, Hydrogen Induced Cracking, Tegangan Elastis, Plastis, Carbon Steel, Hydrogen Sulphide, Elastic Stress, Plastic Stress
Subjects:	T Technology > TJ Mechanical engineering and machinery > TJ930 Pipelines (General). Underwater pipelines.
Divisions:	Faculty of Industrial Technology and Systems Engineering (INDSYS) > Mechanical Engineering > 21101-(S2) Master Thesis
Depositing User:	Muhammad Ichlasulrafif Setiabudi
Date Deposited:	14 Feb 2024 20:27
Last Modified:	14 Feb 2024 20:27
URI:	http://repository.its.ac.id/id/eprint/106878

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