Pada penelitian ini dilakukan proses austenisasi terhadap besi ulet dinding tipis (TWDI) dengan ketebalan 1 mm pada temperatur 960°C selama 30 menit kemudian dilanjutkan dengan austempering pada 350°C selama 10 menit sehingga diperoleh besi ulet austemper dinding tipis (TWADI), kemudian dilakukan perbandingan morfologi dan jumlah nodul antarpelat terhadap kekuatan tarik dan kekerasannya. Hasil penelitian menunjukan bahwa peningkatan jumlah nodul hingga 59%, kenodulan 6% dan diameter nodul maksimum 33% TWADI tidak berpengaruh signifikan terhadap nilai kekerasan namun berpengaruh signifikan terhadap kekuatan tarik di mana kekuatan tarik maksimum mengalami peningkatan hingga 71%. Kekuatan tarik tertinggi (765 N/mm2) dan elongasi terbesar (1%) diperoleh pada jumlah nodul, kenodulan dan diameter nodul TWADI berturut-turut 317 nodul/mm2, 90% dan 3 µm. Sedangkan kekerasan terbaik (379 BHN) diperoleh pada jumlah nodul, kenodulan dan diameter nodul TWADI berturut-turut 285-350 nodul/mm2, 92% dan 3 µm.
This research was held by austenizing the thin wall ductile irons (TWDIs) 1 mm at temperature given 960°C for 30 minutes then austempered at 350°C for 10 minutes so that thin wall austempered ductile irons (TWADIs) were obtained, then the morphology and nodule count each samples were compared to their tensile strength and hardness. The result exhibited that the increased of maximum 59% nodule count, 6% nodularity and 33% nodule diameter were not affect to the hardness significantly (only max. 1%) but highly influenced to tensile strength where the ultimate tensile strength increased untill 71%. In particular, the best result of tensile strength (765 N/mm2) and elongation (1%) were found when the nodule count, nodularity and nodule diameter of TWADIs were 317 nodule/mm2, 90% and 3 µm respectively. Whereas the best result of hardness (379 BHN) were found when the nodule count, nodularity and nodule diameter of TWADIs were 285-350 nodule/mm2, 92% and 3 µm respectively. |
