Octaviana, Nurfitri (2019) Studi Eksperimen Pengaruh Heat Input Pengelasan GTAW dan Konsentrasi NaClO terhadap Laju Korosi Stainless Steel 304. Undergraduate thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Stainless Steel tipe 304 memiliki kemampuan las dan ketahanan korosi yang baik. Pengaplikasian material ini salah satunya pada industri pengolahan air bersih. Pada industri pengolahan air bersih, proses pemurnian air dilakukan dengan menggunakan senyawa sodium hipoklorit (NaClO). Pemanfaatan senyawa ini memiliki dampak tambahan dimana ion hipoklorit (ClO-) dapat menimbulkan reaksi antara ion dengan pipa yang akan meningkatkan kerentanan terhadap korosi. Dalam pengaplikasian stainless steel tersebut, proses pengelasan sering dipilih untuk metode penyambungan. Adanya pengaruh heat input pengelasan akan mempengaruhi ketahanan korosi pada stainless steel 304.
Penelitian dilakukan untuk mempelajari pengaruh heat input pengelasan GTAW dengan menggunakan variasi arus dan konsentrasi NaClO terhadap laju korosi pada stainless steel 304. Untuk pengujian kecenderungan korosi digunakan potensiostat dengan larutan elektrolit NaClO konsentrasi 250 ppm, 325 ppm, 425 ppm, dan 500 ppm. Hasil dari pengujian berupa kurva polarisasi, dimana untuk mendapat hasil dari kurva dilakukan ekstrapolasi tafel. Setelah melakukan ekstrapolasi tafel, didapatkan nilai Icorr, Ecorr, dan laju korosi dari hasil pengujian untuk spesimen uji (base metal, weld metal, dan HAZ). Selanjutnya, dilakukan analisa laju korosi daerah las (weld metal dan HAZ) terhadap heat input serta analisa laju korosi daerah las terhadap larutan NaClO.
Berdasarkan penelitian didapatkan hasil bahwa semakin meningkat nilai heat input, maka semakin besar butir dan luasan daerah las yang terbentuk. Laju korosi yang terjadi pada daerah las memiliki nilai lebih tinggi bila dibandingkan dengan nilai laju korosi pada base metal. Laju korosi pada base metal mengalami peningkatan seiring dengan peningkatan konsentrasi NaClO. Peningkatan konsentrasi NaClO mengakibatkan peningkatan laju korosi pada material dengan heat input 105,6 J/mm, sedangkan untuk material dengan heat input 118,8 J/mm dan 147,6 J/mm mengalami penurunan laju korosi pada peningkatan konsentrasi NaClO.
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Stainless Steel 304 has good weldability and corrosion resistance. One of many uses of this material is used in cleaning water industries. On the processing industry of clean water, process water purification is carried out using the compound sodium hypochlorite (NaClO). The use of this compound has a side effect which hypochlorite ion (ClO-) could give rise to a reaction between ion and the pipe that will increased the vulnerability of its corrosion resistance. In the application of stainless steel, welding processes are chosen for connecting each joint. The presence of heat input would affect the corrosion resistance of stainless steel 304
This research was done to study the effect of heat input in gas tungsten arc welding with various current and NaClO concentration towards corrosion rate in stainless steel 304. For testing corrosion tendency used potentiostat with an electrolyte solution, NaClO 250 ppm concentration, 325 425 ppm, ppm, and 500 ppm.
The results from this research are shown in the polarisation curve, where to get this curve to need a tafel extrapolation. After performing the extrapolation of tafel, the value of Icorr, Ecorr, along with the rate of corrosion of the test results are obtained for the test specimen (base metal, weld metal, HAZ) Then, the corrosion rate of welding areas (weld metal and HAZ) are analyzed towards heat input and the corrosion rate of the welding areas are analyzed too against NaClO solution.
Based on the research results that are obtained by increasing the value of heat input, then the greater the grain and land coverage area of las formed. Corrosion rate that happens at welding area in average has a higher value compared to corrosion rate at base metal. Corrosion rate on base metal increased due to the increasing of NaClO concentration. The increasing of NaClO concentrate causing the enhancement of corrosion rate in materials with heat input 105,6 J/mm, while for materials with heat input 118,8 J/mm and 147,6 J/mm as for the material with a heat input of 118.8 mm and J/J/147.6 mm has decreased the rate of corrosion.
| Item Type: | Thesis (Undergraduate) |
|---|---|
| Additional Information: | RSM 671.52 Oct s-1 2019 |
| Uncontrolled Keywords: | GTAW, Heat Input, Laju Korosi, NaClO, Stainless steel 304 |
| Subjects: | T Technology > TA Engineering (General). Civil engineering (General) > TA418.74 Corrosion and anti-corrosives T Technology > TJ Mechanical engineering and machinery T Technology > TN Mining engineering. Metallurgy > TN879.6 Welding |
| Divisions: | Faculty of Industrial Technology > Mechanical Engineering > 21201-(S1) Undergraduate Thesis |
| Depositing User: | Nurfitri Octaviana |
| Date Deposited: | 30 Jul 2021 06:52 |
| Last Modified: | 30 Jul 2021 06:52 |
| URI: | http://repository.its.ac.id/id/eprint/61178 |
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