Studi Eksperimen Pengaruh Temperatur Austenisasi dan Media Pendingin Terhadap Nilai Kekerasan dan Kedalaman Pengerasan Baja AISI 1045

Auliyah, Nur Hanifah Auliyah (2026) Studi Eksperimen Pengaruh Temperatur Austenisasi dan Media Pendingin Terhadap Nilai Kekerasan dan Kedalaman Pengerasan Baja AISI 1045. Other thesis, Institut Teknologi Sepuluh Nopember.

Text 5007211047-Undergraduate_Thesis.pdf - Accepted Version Restricted to Repository staff only Download (5MB) | Request a copy

Abstract

Peningkatan kebutuhan batubara di industri, khususnya pembangkit listrik, mendorong penggunaan sistem shuttle trolley dengan grab bucket dalam proses distribusi. Roda shuttle trolley merupakan komponen vital yang sering mengalami kegagalan dini, dengan umur pakai sekitar 12 bulan dari target 3 tahun. Hasil analisis menunjukkan bahwa kegagalan tersebut disebabkan oleh kedalaman kekerasan yang kurang memadai. Roda shuttle trolley memerlukan kekerasan minimum 446 HVN, sehingga diperlukan proses hardening yang dipengaruhi oleh komposisi kimia baja, temperatur austenisasi, waktu penahanan, dan jenis media pendingin. Penelitian ini menerapkan metode through hardening pada baja AISI 1045 dengan spesimen berdiameter 24 mm dan panjang 120 mm. Perlakuan panas dilakukan pada temperatur austenisasi 830°C dan 900°C selama 1 jam, diikuti quenching menggunakan media air dan larutan PEG 400 5%, serta tempering pada 300°C selama 1 jam. Tahapan pengujian diawali dengan uji komposisi kimia, dilanjutkan pengukuran dimensi spesimen meliputi panjang, kebulatan, dan kelurusan. Pengujian makroetsa dilakukan untuk mengamati karakteristik makroskopik hasil perlakuan panas. Distribusi kekerasan dan kedalaman pengerasan hingga batas minimum 446 HVN ditentukan melalui uji kekerasan Vickers dan diverifikasi melalui pengamatan struktur mikro menggunakan uji metalografi.Hasil penelitian menunjukkan bahwa spesimen memiliki kadar karbon sebesar 0,45% dengan tambahan unsur paduan nikel, kromium, dan molibdenum. Spesimen yang di-quench di temperatur austenisasi 830°C cenderung menghasilkan kekerasan di permukaan lebih tinggi dibanding temperatur 900°. Quenching menggunakan media air menghasilkan kekerasan maksimum sebesar 807,403 HVN pada spesimen WQ830 yang ditandai dengan terbentuknya martensit berbutir halus, tetapi gradien penurunan kekerasannya lebih tajam. Quenching dengan larutan PEG 400 5 wt.% menghasilkan kekerasan 806,403 HVN pada spesimen PQ900 dengan struktur martensit yang lebih kasar. Namun, gradien penurunan kekerasannya lebih landai sehingga kekerasan bagian inti (590,013 HVN) lebih tinggi dibandingkan spesimen water quench (563,711 HVN). Proses tempering menurunkan kekerasan secara signifikan pada spesimen yang diaustenisasi di temperatur 900° dengan penurunan sebesar 200-350 HVN dibandingkan spesimen yang diaustenisasi di temperatur 830°C. Penurunan kekerasan tersebut menyebabkan kekerasan 446 HVN dicapai pada kedalaman sekitar 9-10 mm dari permukaan, kecuali pada spesimen PQT900 yang hanya mampu mempertahankan kekerasan minimum hingga kedalaman sekitar 2 mm.
=================================================================================================================================
The increasing demand for coal in industry, particularly in power plants, has driven the use of shuttle trolley systems with grab buckets for material distribution. The shuttle trolley wheel is a critical component that frequently experiences premature failure, with a service life of approximately 12 months compared to the target of 3 years. Analysis indicates that this failure is primarily caused by insufficient hardness depth. The shuttle trolley wheel requires a minimum hardness of 446 HVN; therefore, an appropriate hardening process influenced by steel chemical composition, austenitizing temperature, holding time, and quenching medium is essential. This study applied a through-hardening method to AISI 1045 steel specimens with a diameter of 24 mm and a length of 120 mm. Heat treatment was conducted at austenitizing temperatures of 830°C and 900°C for 1 hour, followed by quenching in water and a 5 wt.% PEG 400 polymer solution, and tempering at 300°C for 1 hour. Testing procedures included chemical composition analysis, dimensional measurements (length, roundness, and straightness), macro-etch testing to observe macroscopic characteristics, hardness distribution evaluation using Vickers hardness testing, and microstructural verification through metallographic examination.
The results indicate that the specimens contained 0.45% carbon with additional alloying elements of nickel, chromium, and molybdenum. Specimens austenitized at 830°C generally exhibited higher surface hardness than those treated at 900°C. Water quenching produced a maximum hardness of 807.403 HVN in specimen WQ830, characterized by fine martensitic structure, although the hardness gradient toward the core was relatively steep. Quenching in a 5 wt.% PEG 400 solution yielded a hardness of 806.403 HVN in specimen PQ900 with coarser martensite morphology. However, the hardness gradient was more gradual, resulting in higher core hardness (590.013 HVN) compared with the water-quenched specimen (563.711 HVN). Tempering significantly reduced hardness, particularly in specimens austenitized at 900°C, with a decrease of 200–350 HVN compared with those austenitized at 830°C. Consequently, the minimum required hardness of 446 HVN was maintained only up to a depth of approximately 9–10 mm from the surface, except for specimen PQT900, which sustained this minimum hardness only to a depth of about 2 mm.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Temperatur Austenisasi, Media Pendingin, Kekerasan, Kedalaman Pengerasan, Austenization Temperature, Cooling Medium, Hardness, Hardening Depth.
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) > TA418.42 Hardness properties and tests. Hardness--Testing. T Technology > TN Mining engineering. Metallurgy > TN690 Metallography. Physical metallurgy T Technology > TN Mining engineering. Metallurgy > TN752.I5 Steel--Heat treatment
Divisions:	Faculty of Industrial Technology > Mechanical Engineering > 21201-(S1) Undergraduate Thesis
Depositing User:	Nur Hanifah Auliyah
Date Deposited:	04 Feb 2026 04:08
Last Modified:	04 Feb 2026 04:08
URI:	http://repository.its.ac.id/id/eprint/132031

Actions (login required)

View Item