Analisis Kekerasan, Keausan, dan Struktur Mikro Track Roller Genuine dan Non-Genuine Pada Unit Excavator Kapasitas 20 Ton

Rifqi Arief Firmansyah, Dr. Lilik Dwi Setyana, S.T., M.T.

2025 | Tugas Akhir | D4 TEKNIK PENGELOLAAN DAN PERAWATAN ALAT BERAT

Penelitian ini menilai kualitas track roller pada undercarriage excavator dengan membandingkan sifat mekanik dari genuine, non-genuine, dan non-genuine setelah perlakuan panas. Pengujian yang dilakukan meliputi uji komposisi kimia (Thermo ARL 3560 OES), uji kekerasan Vickers (ASTM E92), uji keausan dengan mesin Ogoshi (Type OAT-U), serta pengamatan struktur mikro menggunakan mikroskop metalografi dengan etsa nital 2,5%. Perlakuan panas pada spesimen non-genuine dilakukan dengan austenisasi 900°C selama 30 menit, quenching air, dan tempering 200/300/400°C selama 2 jam. Hasil menunjukkan adanya sedikit perbedaan komposisi kimia antara kedua jenis track roller. Kekerasan non-genuine meningkat signifikan setelah perlakuan panas, dengan nilai tertinggi 518,17 HVN pada tempering 200°C. Laju keausan terendah juga pada perlakuan tempering 200°C 2,17 x ?10?^(-5) mm^3/kg.m. Struktur mikro mengindikasikan transformasi martensite hasil quenching menjadi tempered martensite, selaras dengan peningkatan kekerasan dan ketahanan aus. Estimasi umur pakai memperlihatkan lifetime non-genuine berperlakuan panas lebih panjang yaitu meningkat 137% dibanding kondisi awal.

This study assesses the quality of excavator track rollers in the undercarriage by comparing the mechanical properties of genuine, non-genuine, and heat-treated non-genuine parts. The tests include chemical composition (Thermo ARL 3560 OES), Vickers hardness (ASTM E92), wear testing using the Ogoshi machine (Type OAT-U), and microstructural observation with a metallographic microscope using 2.5% nital etching.). Heat treatment of the non-genuine specimens involved austenitizing at 900°C for 30 min, water quenching, and tempering at 200/300/400 °C for 2 hours. Results indicate minor differences in chemical composition between the two roller types. The non-genuine material exhibited a significant hardness increase after heat treatment, achieving a maximum of 518.17 HVN at 200°C tempering. The lowest wear rate was also obtained at 200°C, namely 2,17 x ?10?^(-5) ?mm?^3/kg.m. Microstructural observations indicate transformation of as-quenched martensite into tempered martensite, consistent with the observed increases in hardness and wear resistance. Service-life estimation shows that heat-treated non-genuine rollers have a longer lifetime an increase of approximately 137% compared with the as-received condition.

Kata Kunci : Track Roller, Excavator, Perlakuan Panas, Kekerasan Vickers, Keausan Ogoshi, Struktur Mikro.