Analisis Pengaruh Variasi Temperatur Flame Straightening Terhadap Struktur Mikro, Sifat Mekanik, Dan Ketahanan Korosi Pada Lembaran Baja Tahan Karat Aisi 304

Ainun, Viski Rizh (2026) Analisis Pengaruh Variasi Temperatur Flame Straightening Terhadap Struktur Mikro, Sifat Mekanik, Dan Ketahanan Korosi Pada Lembaran Baja Tahan Karat Aisi 304. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Baja tahan karat austenitik AISI 304 banyak digunakan sebagai material sheeting roof pada carbody kereta api karena memiliki ketahanan korosi yang baik, keuletan tinggi, dan kemampuan fabrikasi yang unggul. Namun, proses pengelasan dalam fabrikasi carbody sering menimbulkan distorsi akibat gradien suhu yang ekstrem. Salah satu metode yang umum digunakan untuk memperbaiki distorsi tersebut adalah flame straightening. Meskipun efektif secara mekanis, proses ini berpotensi menurunkan kualitas material apabila parameter suhu pemanasan tidak dikontrol dengan baik, terutama terhadap struktur mikro, sifat mekanik, dan ketahanan korosi. Penelitian ini bertujuan untuk menganalisis pengaruh variasi suhu flame straightening terhadap struktur mikro, kekerasan, dan ketahanan korosi baja tahan karat AISI 304, serta menentukan batas aman suhu pemanasan yang optimal. Variasi suhu flame straightening yang diteliti adalah 350, 400, dan 450 °C. Pengujian yang dilakukan meliputi analisis komposisi kimia menggunakan Optical Emission Spectroscopy (OES), pengamatan mikrostruktur melalui metalografi, pengujian kekerasan mikro Vickers, serta uji ketahanan korosi menggunakan metode salt spray sesuai ASTM B117. Hasil penelitian menunjukkan bahwa peningkatan suhu flame straightening meningkatkan efektivitas flame straightening distorsi, dengan nilai recovery tertinggi sebesar 68.74% pada suhu 450 °C. Namun, pengamatan mikrostruktur mengindikasikan bahwa suhu 450 °C memicu terjadinya sensitisasi yang ditandai dengan terbentuknya dual structure pada pengujian oxalic acid etch. Selain itu, uji salt spray menunjukkan penurunan ketahanan korosi yang signifikan pada suhu tersebut. Sebaliknya, suhu 400 °C mampu memberikan keseimbangan terbaik antara efektivitas flame straightening, pelunakan material akibat reversi martensit, serta ketahanan korosi yang paling stabil tanpa indikasi sensitisasi. Berdasarkan hasil tersebut, suhu flame straightening sebesar 400 °C direkomendasikan sebagai batas aman dan optimal untuk perbaikan distorsi baja tahan karat AISI 304 pada aplikasi sheeting roof carbody kereta api, karena mampu mempertahankan integritas struktur mikro, sifat mekanik, dan ketahanan korosi material.
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Austenitic stainless steel AISI 304 is widely used as a sheeting roof material for railway car bodies due to its good corrosion resistance, high ductility, and excellent fabricability. However, welding processes during car body fabrication often cause distortion as a result of extreme thermal gradients. One commonly applied method to correct such distortion is flame straightening. Although mechanically effective, this process may degrade material quality if the heating temperature parameters are not properly controlled, particularly with respect to microstructure, mechanical properties, and corrosion resistance. This study aims to analyze the effect of flame straightening temperature variations on the microstructure, hardness, and corrosion resistance of AISI 304 stainless steel, as well as to determine the optimal and safe heating temperature range. The flame straightening temperatures investigated were 350 , 400, and 450 °C. The experimental procedures included chemical composition analysis using Optical Emission Spectroscopy (OES), microstructural observation through metallographic examination, Vickers microhardness testing, and corrosion resistance evaluation using the salt spray test in accordance with ASTM B117. The results indicate that increasing the flame straightening temperature enhances the effectiveness of distortion correction, with the highest recovery value of 68.74% achieved at 450 °C. However, microstructural observations reveal that heating at 450 °C induces sensitization, as evidenced by the formation of ditch structures in oxalic acid etching tests. In addition, salt spray testing shows a significant decrease in corrosion resistance at this temperature. In contrast, the temperature of 400 °C provides the best balance between distortion correction effectiveness, material softening due to martensite reversion, and stable corrosion resistance without any indication of sensitization. Based on these findings, a flame straightening temperature of 400 °C is recommended as the optimal and safe limit for correcting distortion in AISI 304 stainless steel used for railway car body sheeting roof applications, as it maintains the integrity of the microstructure, mechanical properties, and corrosion resistance of the material.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Kekerasan, Ketahanan Korosi, Struktur mikro AISI 304, Corrosion Resistance, Flame Straightening, Hardness, Microstructure
Subjects:	Q Science > QD Chemistry > QD1 Oxidation-reduction reaction. T Technology > TS Manufactures T Technology > TS Manufactures > TS205 Metals--Heat treatment. T Technology > TS Manufactures > TS227 Welding.
Divisions:	Faculty of Industrial Technology > Material & Metallurgical Engineering > 28201-(S1) Undergraduate Thesis Faculty of Industrial Technology and Systems Engineering (INDSYS) > Material & Metallurgical Engineering > 28201-(S1) Undergraduate Thesis
Depositing User:	Viski Rizh Ainun
Date Deposited:	26 Jan 2026 13:31
Last Modified:	26 Jan 2026 13:31
URI:	http://repository.its.ac.id/id/eprint/130455

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