Original Article

Investigation of the formation of non-metallic inclusions in 16MnCr5 steel

¹ Izmir Katip Çelebi University, Department of Materials Science and Engineering Çiğli, İzmir, Turkey
² Özkan Demir Çelik Sanayi A.Ş., Aliağa, İzmir, Turkey

^* e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 11 March 2026
Accepted: 15 June 2026

Abstract

Steel materials used in a wide variety of areas from skyscrapers to household appliances maintain their solid place with their exceptional properties. However, despite the use of very advanced technologies in the sector, it cannot be said that flawless steel production can still be achieved. For example, inclusions are one of the most common defects in steel. These formations, which can be defined as non-metallic inclusions consisting of oxide, sulfide and nitride compounds during steel production, can cause cracks, tears and surface defects in the final product. In this study, it was aimed to convert inclusions such as Al₂O₃ and MnS into more harmless forms by applying Ca wire feeding during the liquid steel production phase. In this context, 16MnCr5 grade steel was selected as a member of the BS EN 10084 standard case hardening steel group for the examination. Then it was first deoxidized with aluminium. Then calcium metal was added to the molten steel by wire feeding to modify and control non-metallic inclusions. Elemental composition was determined using the Thermo Arl 4460 optical emission spectrometer. Following this, the samples were analysed under an optical microscope with the aid of specialized Clemex image analysis software. Morphological characteristics were captured using a Carl Zeiss Sigma 300 VP Scanning Electron Microscope (SEM). The micrograph obtained from the analysis confirmed that the calcium treatment had been effectively implemented.