No abstract

Perusahaan migas merupakan pengguna terbesar pipa baja untuk menghasilkan produk minyak dan gas dari proses penambangan, pengolahan, dan distribusi minyak dan gas siap  pakai. Pipa baja yang digunakan dalam industri migas bisa mencapai puluhan sampai ribuan kilometer dengan banyaknya sambungan las tiap beberapa meter. Kemungkinan terjadinya korosi pada pipa baja sangat besar sekali sehingga diperlukan lapisan yang tahan korosi. Material Inconel sering dijadikan bahan pelapisan bagian dalam pipa baja yang dilakukan dengan cara pengelasan cladding. Dalam penelitian ini dilakukan pengujian korosi intergranular lapisan material Inconel hasil pengelasan cladding pada pipa baja dengan filler metal UNS N06625 untuk mengetahui kerentanan material terhadap korosi yang ditimbulkan oleh aliran fluid migas di dalam pipa. Filler metal yang digunakan adalah merek Ra***tna 625 dan Nov***etal 625. Pengujian korosi intergranular dilakukan dengan menggunakan standar ASTM G-28. Hasil pengujian korosi intergranular menunjukkan lapisan cladding menggunakan filler metal merek Ra***tna 625 dan Nov***etal 625 tidak terdapat korosi intergranular yang teramati namun terdapat korosi seragam pada merek Ra***tna 625 dengan laju korosi 0,46 mm/tahun dan 0,50 mm/tahun pada merek  Nov***etal 625.

Tests for determining the elemental composition of stainless steel (SS) in the weld metal and Heat Affected Zone (HAZ) were carried out using the Non-Destructive Evaluation (NDE) Positive Material Identification (PMI) method with X-ray Fluorescence (XRF) technology. This study aimed to identify the chemical composition of metals using the PMI method with XRF technology as a determinant of the feasibility of the stainless-steel materials tested, namely SS 316 and SS 2205. The results of the tests were then matched with the applicable standards, namely ASME Section II Part A for pipe materials and ASME Section II Part C for welding electrodes. The measurement results show that SS 316 with welding electrode grade ER 316 all parts of the object of inspection fall within the standard range used except for material 4, which is the connection between the flange and elbow is declared rejected because the values ​​for Cr, Ni, and Mo do not fall within the standard range. Meanwhile, SS 2205 with a welding electrode grade of ER 2594 shows that all parts of the object being measured meet the requirements of the standard range used.

Sesuai ASME BPVC Sec.IX, Welding Procedure Specification (WPS) dinyatakan layak digunakan untuk proyek pengelasan dengan diikualifikasi dahulu menggunakan Procedure Qualified Record (PQR). Pengujian mekanikal dengan menimbulkan kerusakan untuk mengetahui ketahanan suatu material dengan cara ditekan, ditarik, dan dilengkungkan. Penelitian bertujuan mengetahui kualitas pengelasan dan rentang ketebalan material yang dapat dikualifikasi menggunakan test coupon pada PQR. Pengujian mekanikal yang dibutukan pada PQR ini yaitu dua spesimen tensile test dan empat spesimen bend test dengan acceptance criteria spesifikasi ASME BPVC Sec. IX-2019. Pada spesimen tensile test 1 dan 2, diketahui nilai ultimate tensile strength yaitu sebesar 584 MPa dan 594 MPa. Salah satu spesimen root bend pada bend test memiliki diskontinuitas terbuka di area weld sebesar 0.5 mm. Berdasarkan pada ASME BPVC Sec. IX-2019, nilai minimum yang diijinkan untuk tensile test pada material SA-312 TP304L yaitu sebesar 485 MPa, serta ukuran maksimum diskontinuitas terbuka yang diperbolehkan untuk bend test pada area weld dan HAZ, yaitu sebesar 3 mm.

The Batam industry materials are steel, an alloy material between iron and carbon, and a few other elements. Low-carbon steel is one type of metal. However, this low-carbon steel has the disadvantage of corrosion resistance, mainly if applied to corrosive environments. In the utilization of Low carbon steel in the industry, corrosion can cause problems and cost a lot of money in its maintenance. Chitosan contained in invertebrate animals is predicted to be able to prevent corrosion as an inhibitor. This study aims to analyze the optimal conditions of chitosan inhibitors against the corrosion rate of low-carbon steel in environments with variations in the length of immersion of specimens in corrosive media. This study is a true-experimental study with a pre-post-test design. The determination of the optimal conditions of corrosion inhibition of low-carbon steel plate specimens by chitosan was carried out with variations in the parameters of HCl concentration, specimen immersion time, and chitosan concentration. The analysis carried out is the measurement of specimen weight loss in each parameter by determining the difference in weight before and after the experiment and determining the efficiency of the inhibitor. The experiment’s results showed that the optimal conditions of inhibition of corrosion were at 1M HCl, 400ppm chitosan, and a soaking time of 3 days with an efficiency of 48%. The efficiency value of this optimum corrosion inhibition of chitosan in low-carbon steel is 48%. To improve the efficiency of corrosion inhibition, it is necessary to further research with higher accuracyTo determine the effect of inhibition of corrosion using chitosan on the quality of steel surfaces, it is necessary to analyze the steel surface structure using ultrasonic testing or using XRD Analysis.