NUROKHMAN, FIKIH (2025) ANALISIS PERLAKUAN PANAS PADA SIFAT MEKANIK BAJA KARBON RENDAH ST 37 UNTUK PISAU PENCACAH RUMPUT. Skripsi thesis, Universitas Pancasakti Tegal.
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Abstract
FIKIH NUROKHMAN. 2025. “Analisis perlakuan panas pada sifat mekanik baja karbon rendah ST 37 untuk pisau pencacah rumput”. Program Studi Teknik Mesin, Fakultas Teknik dan Ilmu Komputer, Universitas Pancasakti Tegal 2025 Heat treatment adalah perlakuan panas yang melibatkan pemanasan suatu material berdasarkan suhu yang diinginkan dan mempertahankannya pada suhu tersebut untuk jangka waktu tertentu yang telah ditetapkan. Perlakuan ini memerlukan pemanasan untuk memodifikasi sifat fisik material, terutama struktur mikronya, yang menghasilkan penguatan (pengerasan) atau pelunakan dari material tersebut. Baja ST 37 merupakan salah satu jenis material yang baik untuk dapat dijadikan pisau pencacah rumput. proses pencacahan rumput untuk pakan ternak menggunakan cara manual atau tenaga manusia yang kurang efektif. Hal tersebut diketahui dari hasil pencacahan rumput untuk pakan dalam jumlah yang relatif banyak memerlukan waktu pencacahan yang relatif lama sehingga pemenuhan kebutuhan pakan untuk hewan ternak dalam jumlah banyak kurang maksimal. Tujuan penelitian ini yaitu untuk mengetahui pengaruh heat treatment dengan variasi suhu 8000C, 8250C, 8500C kemudian di tempering suhu 250℃ terhadap uji tarik,kekerasan,dan impak pada baja ST 37 untuk pisau pencacah rumput. Proses penelitian ini menggunakan suhu 800℃, 825℃, 850℃ metode hardening kemudian ditempering 250℃. Siapkan spesimen baja ST 37, air garam dan mesin heat treatment (thermolyne). Pertama atur suhu yang di tentukan masukan spesimen baja ST 37 lalu tunggu sampai 30 menit, setelah itu spesimen dimasukan ke dalam ember yang sudah terisi air garam. Selanjutnya di tempering di suhu 250℃ selama 30 menit lalu didinginkan melalui udara. Bersihkan spesimen, lalu dilakukan pengujian tarik,kekerasan,dan impak. Hasil penelitian rata-rata uji tarik tidak diberikan heat treatment, suhu 800℃, 825℃, 850℃ yaitu 424,97 N/〖mm〗^2, 464,81 N/〖mm〗^2, 432,91 N/〖mm〗^2, 424,23 N/〖mm〗^2. Hasil rata-rata uji kekerasan tidak diberikan heat treatment, suhu 800℃, 825℃, 850℃ yaitu 120,78 HB, 132,66 HB, 126,88 HB, 130,77 HB. Hasil rata-rata uji impak tidak diberikan heat treatment, suhu 800℃, 825℃, 850℃ yaitu 179,58 Joule, 171,81 Joule, 168,32 Joule, 210,54 Joule. Nilai pengujian tarik di suhu 800℃ dan 825℃ meningkat disebabkan pada saat proses perlakuan panas martensit yang terbentuk cukup maksimal sehingga meningkatkan nilai kekuatan tarik pada baja. Penurunan di suhu 850℃ ini disebabkan pembentukan bainit dan perlit yang lebih banyak sehingga menurunkan nilai kekuatan tarik baja. Nilai pengujian kekerasan di suhu 800℃, 825℃, 850℃ meningkat disebabkan pada proses perlakuan panas struktur mikro yang terbentuk lebih banyak berupa martensit sehingga meningkatkan nilai kekerasan dibanding raw material. Nilai pengujian impak suhu 850℃ disebabkan pada proses perlakuan panas pembentukan struktur mikro yang seimbang sehingga meningkatkan nilai pengujian impak. Penurunan di suhu 800℃, 825℃ pada saat proses perlakuan panas struktur mikro yang terbentuk tidak sempurna sehingga nilai kekuatan impak menurun dibanding raw material. Katakunci : Heat treatment, ST 37, Uji Tarik, Uji Kekerasan, Uji Impak FIKIH NUROKHMAN. 2025. “Analysis of Heat Treatment on the Mechanical Properties of Low Carbon Steel ST 37 for Grass Chopper Blades”. Mechanical Engineering Study Program, Faculty of Engineering and Computer Science, Pancasakti University Tegal, 2025. Heat treatment is a thermal process involving heating a material to a desired temperature and maintaining it at that temperature for a specific period of time. This process is used to modify the material's physical properties, especially its microstructure, which results in either strengthening (hardening) or softening the material. ST 37 steel is a good material choice for making grass cutting blades. The process of chopping grass for animal feed is done manually or using human labor, which is less effective. This is evident from the fact that chopping a large quantity of grass for feed takes a relatively long time, resulting in an insufficient supply of feed for a large number of livestock. The objective of this research is to investigate the effect of heat treatment with variations in temperature (800°C, 825°C, 850°C) followed by tempering at 250°C, on tensile strength, hardness, and impact properties of ST 37 steel for grass cutting blades. The research process used temperatures of 800°C, 825°C, and 850°C with a hardening method, followed by tempering at 250°C. ST 37 steel specimens, salt water, and a heat treatment machine (Thermolyne) were prepared. First, the desired temperature was set, and the ST 37 steel specimens were placed inside. After 30 minutes, the specimens were immersed in a bucket filled with salt water. Next, they were tempered at 250°C for 30 minutes and cooled by air. After cleaning the specimens, tensile, hardness, and impact tests were conducted. The results of the study showed the following average values: for the tensile test, untreated steel, and the steel treated at 800°C, 825°C, and 850°C had tensile strengths of 424.97 N/mm², 464.81 N/mm², 432.91 N/mm², and 424.23 N/mm², respectively. For the hardness test, untreated steel, and the steel treated at 800°C, 825°C, and 850°C had hardness values of 120.78 HB, 132.66 HB, 126.88 HB, and 130.77 HB, respectively. For the impact test, untreated steel, and the steel treated at 800°C, 825°C, and 850°C had impact values of 179.58 Joules, 171.81 Joules, 168.32 Joules, and 210.54 Joules, respectively. The tensile test values at 800℃ and 825℃ increased due to the fact that during the heat treatment process, the formed martensite was maximized, thereby improving the tensile strength of the steel. The decrease at 850℃ is caused by the formation of more bainite and pearlite, which reduces the tensile strength of the steel. The hardness test values at 800℃, 825℃, and 850℃ increased because, during the heat treatment process, the microstructure formed consisted mostly of martensite, resulting in higher hardness compared to the raw material. The impact test value at 850℃ increased due to the balanced microstructure formed during the heat treatment process, which improved the impact test result. The decrease at 800℃ and 825℃ during the heat treatment process was due to an imperfect microstructure formation, which led to a lower impact strength compared to the raw material. Keywords: Heat treatment, ST 37, Tensile test, Hardness test, Impact test.
| Item Type: | Karya Ilmiah (Skripsi) |
|---|---|
| Subjects: | T Technology > TJ Mechanical engineering and machinery |
| Divisions: | Fakultas Teknik dan Ilmu Komputer > Teknik Mesin |
| Depositing User: | admin repository upstegal |
| Date Deposited: | 19 Feb 2025 07:28 |
| Last Modified: | 19 Feb 2025 07:28 |
| URI: | http://repository.upstegal.ac.id/id/eprint/10119 |
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