Yusanto, Feldyan (2021) Pengaruh Variasi Diameter Bola Baja Shot Peening dan Post-Weld Heat Treatment Terhadap Laju Korosi Sambungan Las Pada Baja Karbon Rendah. Sarjana thesis, Universitas Brawijaya.
Abstract
Penelitian ini berfokus pada meningkatkan ketahanan sambungan las pada baja karbon rendah terhadap korosi dengan menghilangkan tegangan sisa menggunakan perlakuan shot peening dan post weld heat treatment pada material. Pada penelitian ini dilakukan proses shot peening pada sambungan las GMAW baja karbon rendah Structural Steel 400 dengan variasi diameter bola baja yaitu: 1 mm, 1,5 mm, 2 mm, 2,5 mm, 3 mm. Variasi diameter bola baja tersebut dilakukan pada spesimen dengan perlakuan shot peening serta spesimen dengan perlakuan post weld heat treatment dan shot peening lalu data yang didapat akan dibandingkan. Sebelum dilakukan penembakan, spesimen tanpa perlakuan dilakkan uji kekeraasan terelebih dahulu untuk menentukan daerah tembakan. Setelah diberikan perlakuan, laju korosi spesimen diukur dengan menggunakan Potentiostat/Galvanostat/Impedance Analyze (PalmSens4). Data berupa foto makroskopik, mikroskopik, dan SEM juga digunakan pada penelitian ini sebagai data pendukung. Hasil pengujian laju korosi menunjukkan pada spesimen dengan perlakuan shot peening, nilai laju korosi tertinggi hingga terendah yaitu diameter bola baja 1 mm sebesar 0,664 mmpy, diameter bola baja 3 mm sebesar 0,526 mmpy, diameter bola baja 1,5 mm sebesar 0,315 mmpy, diameter bola baja 2,5 mm sebesar 0,407 mmpy, dan diameter bola baja 2 mm sebesar 0,130 mmpy. Pada spesimen dengan perlakuan post weld heat treatment dan shot peening, nilai laju korosi tertinggi hingga terendah yaitu diameter bola baja 1 mm sebesar 0,715 mmpy, diameter bola baja 3 mm sebesar 0,189 mmpy, diameter bola baja 1,5 mm sebesar 0,187 mmpy, diameter bola baja 2,5 mm sebesar 0,169 mmpy, dan diameter bola baja 2 mm sebesar 0,128 mmpy. Serta laju korosi spesimen tanpa perlakuan sebesar 1,229 mmpy sebagai data pembanding. Hasil penelitian ini menunjukkan nilai laju korosi spesimen cenderung turun hingga titik terendahnya lalu laju korosi akan meningkat kembali seiring dengan bertambahnya diameter bola baja. Penurunan laju korosi diakibatkan oleh terbentuknya tegangan tekan sisa pada permukaan material, sehingga jarak antar atom semakin dekat yang mengakibatkan laju korosi spesimen menurun. Sedangkan kenaikan laju korosi diakibatkan oleh kekasaran permukaan tinggi yang berarti semakin besar pula luas penampang pada permukaan spesimen. Selain itu nilai laju korosi pada spesimen dengan perlakuan shot peening cenderung lebih tinggi dibandingkan spesimen dengan perlakuan shot peening dan post weld heat treatment. Dikarenakan post weld heat treatment mampu menurunkan kandungan tegangan sisa pada spesimen. Selain itu semakin sempitnya batas butir akibat post weld heat treatment juga menurunkan laju korosi.
English Abstract
Feldyan Yusanto, Department of Mechanical Engineering, Faculty of Engineering, Brawijaya University, July 2021, The Effect of Steel Ball Diameter Variation in Shot Peening and Post-Weld Heat Treatment on Corrosion Rate of Welded Joints in Low Carbon Steel, Academic Advisor: Teguh Dwi Widodo and Rudianto Raharjo. This research focuses on increasing the resistance of welded joints on low carbon steel to corrosion by eliminating residual stresses using shot peening and post-weld heat treatment on the material. In this study, the shot peening process was carried out on low carbon Structural Steel 400 GMAW welded joints with variations in the diameter of the steel ball, namely: 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm. Variations in the diameter of the steel ball were carried out on specimens with shot peening treatment and specimens with post-weld heat treatment and shot peening treatment and the data obtained will be compared. Before the shooting, the untreated specimens were subjected to a hardness test to determine the area of the shot. After being given treatment, the corrosion rate of the specimen was measured using a Potentiostat/Galvanostat/Impedance Analyzer (PalmSens4). Data in the form of macroscopic, microscopic, and SEM photos were also used in this study as supporting data. The results of the corrosion rate test show that in shot peening specimens, the highest to lowest corrosion rate values are 1 mm steel ball diameter of 0.664 mmpy, 3 mm steel ball diameter of 0.526 mmpy, 1.5 mm steel ball diameter of 0.315 mmpy, ball diameter 2.5 mm steel is 0.407 mmpy, and the diameter of the 2 mm steel ball is 0.130 mmpy. In specimens treated with post-weld heat treatment and shot peening, the highest to lowest corrosion rate values were 1 mm steel ball diameter of 0.715 mmpy, diameter of 3 mm steel ball of 0.189 mmpy, diameter of 1.5 mm steel ball of 0.187 mmpy, ball diameter of 0.187 mmpy. 2.5 mm steel is 0.169 mmpy, and the diameter of the 2 mm steel ball is 0.128 mmpy. And the corrosion rate of untreated specimens is 1.229 mmpy as comparison data. The results of this study indicate that the corrosion rate of the specimen tends to decrease to its lowest point then the corrosion rate will increase again along with the increase in the diameter of the steel ball. The decrease in corrosion rate is caused by the formation of residual compressive stress on the surface of the material so that the distance between atoms is getting closer which results in a decrease in the corrosion rate of the specimen. While the increase in corrosion rate is caused by high surface roughness which means the greater the cross-sectional area on the surface of the specimen. In addition, the value of the corrosion rate on specimens with shot peening treatment tends to be higher than specimens with shot peening and post-weld heat treatment. Because post-weld heat treatment can reduce the residual stress content in the specimen. In addition, the narrower grain boundaries due to post-weld heat treatment also reduce the corrosion rate. Keywords: weld joint, steel ball diameter, shot peening, post weld heat treatment, corrosion rate, low carbon steel
Other obstract
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| Item Type: | Thesis (Sarjana) |
|---|---|
| Identification Number: | 621.8 |
| Uncontrolled Keywords: | Kata kunci : sambungan las, diameter bola baja, shot peening, post weld heat treatment, laju korosi, baja karbon rendah-- weld joint, steel ball diameter, shot peening, post weld heat treatment, corrosion rate, low carbon steel |
| Subjects: | 600 Technology (Applied sciences) > 621 Applied physics > 621.8 Machine engineering |
| Depositing User: | Unnamed user with email gaby |
| Date Deposited: | 20 Oct 2021 07:13 |
| Last Modified: | 24 Sep 2024 03:29 |
| URI: | http://repository.ub.ac.id/id/eprint/184342 |
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