High-temperature tribological studies of plasma-nitrided tool steels

ABSTRACT

During hot forging/forming operations, the die surface and near surface region is subjected to severe wear. The failure of dies originates from the surface region. In this research work, plasma nitriding was done on two hot forming tool steels namely AISI H11 and AISI H13. The aim is to develop a hard and wear resistance surface required for hot forming operations. The mechanical and microstructural properties of the developed nitrided layer were critically examined. Thereafter the tribological characteristics of the untreated and plasma-nitrided specimens were studied on high-temperature pin-on-disc tribometer under the constant load of 25 N, sliding speed 0.5 m s⁻¹, sliding distance of 1500 m at different temperatures ranging from room temperature to 600°C. The results showed that the main wear mechanisms is predominantly adhesive at room temperatures and 200°C and a combination of adhesive and abrasive at elevated temperatures (400°C and 600°C).

KEYWORDS:

• Die steels
• wear
• friction
• plasma nitriding
• characterisation

Acknowledgements

The authors would like to thank the Central Tool Room Ludhiana (India) for providing heat treatment services for the die materials. The authors owe special thanks to Dr Harpreet Singh for extending the necessary facilities and support in conducting the detailed analysis at Indian Institute of Technology Ropar, Roopnagar, Punjab, and Dr S. Parkash at Indian Institute of Technology Roorkee, Roorkee.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Ghanshyam Jhala http://orcid.org/0000-0002-7014-5753

Additional information

Funding

Manpreet Kaur et al. thankfully acknowledge the research grant from Department of Science and Technology, New Delhi (India) under SERB, Science and Engineering – Engineering Scheme (File No. SR/S3/MERC/0072/2012, Dated February 28, 2013) titled ‘Development of Thermal Spray Coatings to Control Wear during High-Temperature Applications’ and (EMR/2015/000234, Dated March 11, 2016) titled ‘Development of Thermal Spray Coatings to Control Wear during High-Temperature Applications-Phase II’, to carry out this research and development work.