Analisa Pengaruh Temperatur Tempering Terhadap Struktur Mikro Dan Sifat Mekanik Pada Baja AAR-M201 Grade E

Baja paduan banyak digunakan pada konstruksi komponen-komponen kereta api. Baja yang umum digunakan adalah baja paduan mangan (manganese steel) dengan seri penamaan baja AAR-M201. Struktur mikro pada suatu baja paduan tergantung pada beberapa variabel seperti unsur paduan, konsentrasi unsur paduan, dan proses perlakuan panas. Pada penelitian ini menggunakan baja AAR-M201 Grade E as cast, perlakuan hardening, dan perlakuan hardening-tempering. Hardening dilakukan pada temperatur austenitisasi 925C, selama 45 menit, dan media pendingin air. Hardening-tempering dilakukan pada temperatur tempering 625,650, dan 675C, selama 45 menit. Temperatur tempering mempengaruhi struktur mikro baja AAR-M201 Grade E, dengan terbentuknya struktur mikro yaitu bainit temper, berupa bilah-bilah ferit dan partikel-partikel karbida sementit (Fe3C). Peningkatan temperatur tempering menghasilkan struktur bainit temper yang semakin kasar dan karbida sementit semakin banyak. Temperatur tempering mempengaruhi sifat mekanik baja AAR-201 Grade E. Peningkatan temperatur tempering, menurunkan kekuatan luluh,kekuatan maksimum, kekerasan dan meningkatkan keuletan dan energi impak. ==================================================================================================== Alloy steels are commonly used in railway components contruction. Steel that commonly used is manganese steel, AAR-M201 standard. Microstructures of an alloy steel depends on the alloying elements, concentration, and heat treatment. This research used AAR-M201 Grade E steel, as cast, hardened, and hardened-tempered. Hardening was done at austenitization temperature, 925C, for 45 minutes, and cooled in water. Hardening-tempering process was done at varying tempering temperature of 625,650, and 675C, for 45 minutes each. Tempering temperature influences microstructure of AAR-M201 Grade E, the microstructure formed is tempered bainite which consists of ferrite lath and particles of cementite carbide (Fe3C). With increasing tempering temperature, the microstructure consists of more coarse tempered bainite and more cementite cabide. Tempering temperature influences mechanical properties of AAR-M201 Grade E. With increasing tempering temperature, the yield strength, ultimate tensile strength, and hardness decreases, while the ductility and impact energy increases