Microwave sintering response of different grade stainless steels and its influence on metallurgical properties

ABSTRACT

Ultra-rapid microwave sintering of powder metals will provide fine microstructural features that improve mechanical properties. In present study, three grades of stainless steel powder compacts (316L, 430L, 410) were produced using a uniaxial compaction unit. These compacts were sintered by microwave hybrid heating method at 1300°C (super-solidus region). The densification response, microstructural attributes, and mechanical properties were compared at 30, 45 and 60 min holding times. The compositional analysis was performed with the help of optical emission spectroscopy (OES) and scanning electron microscopy equipped with energy dispersed spectroscopy(SEM-EDS). The results obtained from both spectroscopies are compared for the sintered samples. The correlation of mechanical properties is analysed with evolved microstructural attributes (pore volume, pore shape and pore distribution). The excellent strength of 457 ± 16 MPa, 466 ± 6 MPa and 476 ± 26 MPa with 23 ± 1.3%, 14 ± 1.5% and 11 ± 1% of ductility is observed for sintered AISI 316L, 430L and 410, respectively.

KEYWORDS:

• Densification
• microwave hybrid heating
• stainless steels
• pore morphology
• pore shape factor

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Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.

Notes on contributors

K. Veera Venkata Nagaraju

K. Veera Venkata Nagaraju is currently a researcher in the Department of MME, National Institute of Technology Tiruchirappalli (NITT), India. He received his B. E degree from Andhra University (SRKREC) and M. Tech degree from the National Institute of Technology Durgapur (NITD). In 2017 he also started his dissertation, which is based on powder metallurgical iron-based components.

S. Kumaran

S. Kumaran is currently a professor in Department of MME, National Institute of Technology Tiruchirappalli (NITT), India. He is having a long association with the Institute as a regular faculty since 2000. He had been conferred Ph.D for his research on Powder processing of Titanium aluminides from the National Institute of Technology, Tiruchirappalli. He is the recipient of DST fast track research project award. He had received a DST-Boycast fellowship for his Post-Doctoral Research under the mentoring of Prof. C. Suriyanarayana at the University of Central Florida, USA. Later, he was a visiting scientist MRISUS, AIST Nagoya, Japan; Centre for Innovative Sintered Product, Pennstate University, Park, PA, USA and Surface Engineering Laboratory, Stony Brooke University, USA. He has published more than 200 articles and successfully completed 25 reputed project studies in a wide range of research and mostly on powder metallurgy topics.

T. Srinivasa Rao

T. Srinivasa Rao is currently a professor (HAG) in the Department of MME, National Institute of Technology Tiruchirappalli (NITT), India. He was worked as Director, National Institute of Technology Warangal (NITW), India. He had received DST-Boycast fellowship for his Post-Doctoral Research, University of Texas, Austin, USA in 1995-1996. He had duties as a Member in Board of Governors, NITT MHRD, 2008, AICTE Expert Member for inspecting the Engineering Colleges AICTE. He was awarded the Greaves Foseco Award for the best project work in Foundry Engineering IIT Kharagpur.