Austenitising temperature and quenchant viscosity influence on mechanical properties of normalised green oil quenched 42CrMo4 steel

Abstract

Green oils are plant extract oils such as Karanja, Pinnay, Coconut oil, which are non-corrosive, non-toxic and environmentally friendly, and are capable of replacing petrol oil quenchants. In this study, Pinnay oil, Karanja seed oil and their blends (equal volume in proportion) were used as quenchants. Before quenching for hardening, austenitising was performed at three different temperatures ranging from 890 °C to 950 °C. The effects of austenitising temperature and vegetable oil quenchants on the hardness, room-temperature impact toughness and microstructure of normalised 42CrMo4 steel were determined. Prior to the hardening treatment, the as-received 42CrMo4 steel was subjected to normalising treatment, which enhanced the hardness and toughness properties due to grain refinement of the as-received steel. As the oil viscosity decreases, the hardness increases with marginal alteration in the impact resistance. In all the quenching condition, with an increase in austenitising temperature up to 920 °C, there was an increase in hardness around 7% and decrease in toughness around 37%, whereas at 950 °C there was a decrease in hardness around 24% and an increase in the toughness of the steel around 47% as compared to that of 920 °C. Also, blend oil quenched specimens showed balanced hardness and impact toughness compared to Pinnay oil and Karanja oil quenched specimens.

Keywords:

• 42CrMo4 steel
• microstructure
• Pinnay oil
• Karanja seed oil
• hardening
• normalising

REVIEWING EDITOR:

• Jones Ian Phillip, University of Birmingham, United Kingdom of Great Britain and Northern Ireland

SUBJECTS:

• Materials Science
• Materials Processing
• Metals & Alloys

Author’s contribution

Bhagyalaxmi – Experiment work, Drafting of paper

Jayashree P K – Designing the methodology

Ananda Hegde – Conception and design

Rajarama Hande – Revising the manuscript

Sathyashankara Sharma – Interpretation and Analysis

Disclosure statement

Authors declare that they do not have any conflict of interests whatsoever.

Data availability statement

Authors agree to share the data upon reasonable request.

Additional information

Notes on contributors

Bhagya Laxmi

Mrs. Bhagyalaxmi is working as Assistant Professor Senior Scale in the Department of Mechanical & Industrial Engineering, MIT, MAHE, Manipal. She holds B.E. (Industrial & Production Engg.) and M.Tech. (Manufacturing Engg. & Technology). She has more than 13 years of teaching experience. She has published 8 papers in journals and conferences. Her area of interest includes heat treatment of metals and manufacturing.

Jayashree P.K.

Dr. Jayashree P K is working as Associate Professor in the Department of Mechanical & Industrial Engineering, MIT, MAHE, Manipal. She holds B.E. (Industrial & Production Engg.), M.Tech. (Production Engineering) and Ph.D. (Materials Engineering) degrees. She has more than 20 years of teaching experience. Her area of interest includes materials engineering, heat treatment of metals. She has published more than 20 papers in journals and conferences.

Ananda Hegde

Dr. Ananda Hegde is working as Associate Professor in the Department of Mechanical & Industrial Engineering, MIT, MAHE, Manipal. He holds B.E. (Mechanical), M.Tech (Materials Engineering) and Ph.D. (Heat treatment) degrees. He has more than 10 years of teaching experience. His area of interest includes materials engineering, heat treatment of metals. He has published more than 25 papers in journals and conferences.

Rajarama Hande

Mr. Rajarama Hande is working as Additional Professor in the Department of Mechanical & Industrial Engineering, MIT, MAHE, Manipal. He holds B.E. (Mechanical), M.Tech. (Engineering Management). He has more than 35 years of teaching experience. His area of interest includes materials engineering. He has published 3 papers in journals.

Sathyashankara Sharma

Dr. Sathyashankara Sharma is working as Senior Professor and Head in the Department of Mechanical & Industrial Engineering, MIT, MAHE, Manipal. He holds B.E. (Mechanical), M.Tech. (Materials Engineering) and Ph.D. (Materials Engineering) degrees. He has more than 35 years of teaching experience. His area of interest includes materials engineering, heat treatment of metals and composites and deformation behavior of metals and composites. He has published more than 150 papers in journals and conferences.