MICROSTRUCTURE AND HARDNESS EVALUATION OF STRAIN INDUCED MARTENSITE ON COLD ROLLED AUSTENITIC STAINLESS STEEL CRMN

• Main Author: Cahaya Erlangga, Recsa
• Format: Final Project
• Language: Indonesia
• Subjects: Teknik (Rekayasa, enjinering dan kegiatan berkaitan)
• Online Access: https://digilib.itb.ac.id/gdl/view/47539
• Institution: Institut Teknologi Bandung

In industries such as petrochemical, automotive and kitchenware there are challenges in obtain components such as pipes and tanks that made from high strength austenitics stainless steel. Solution of this problem is to do strengthening mechanism by cold deformation. Austenitic stainless steel with metastable austenite transformed into martensite when plastic deformation applied. This research was focused on effect strain induced martensite on microstructure and hardness using cold rolling method in austenitic stainless steel CrMn. The plastic deformation process is carried out by reducing the specimen thickness by 5%, 10%, 20%, 30%, 40% and 50%. Microstructure investigations was conducted by means optical metallography. Hardness testing was performed by means Rockwell A test. X-ray diffraction and magnetic measurements were used for phase identification. The results showed that cold rolling in metastable stainless steel will produce slip bands and indication of the presence of blocky ? ’martensite.Phases ? ’and ? martensite that were difficult to be observed by optical microscopes have been identified through XRD analysis. In addition, the transformation of martensite was supported by the increased magnetism of the austenitic stainless steel. Cold rolling up to 50% reduction in austenitic stainless steel CrMn resulted martensitic volume fraction 30% and increases hardness from 52.4 HRA to 76.7 HRA. Increment hardness accompanied by martensitic transformation that occurred showed the success of strengthening austenitic stainless steel CrMn through strain induced martensite.