Nitriding of a 42CrMo4 and a 34CrAlNi7 steel in a fluidized bed furnace

Zekeriya Cömert; Polat Topuz; Ahmet Sagin; Ahmet Topuz

doi:10.3139/120.100761

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Nitriding of a 42CrMo4 and a 34CrAlNi7 steel in a fluidized bed furnace

Zekeriya Cömert , Polat Topuz , Ahmet Sagin und Ahmet Topuz

Veröffentlicht/Copyright: 26. Mai 2013

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Aus der Zeitschrift Materials Testing Band 48 Heft 10

Abstract

This contribution presents a study about the design and the manufacturing of a fluidized bed furnace. Nitriding was carried out by using fluidized bed furnace and optimum process parameters were determined for nitriding. In these experiments DIN 7225 and DIN 8550 steels were used, and as a first step two types of steel were hardened and tempered. Nitriding was carried out by using N₂ + NH₃ at 520°C and 570°C. Nitriding times were selected as 3, 6 and 12 hours. The thickness of nitride layers varied from 6.1 to 39.73 mm. The hardness of nitride layers varied from 605 to 1114 HV. The tensile strength of the specimens were found between 618 and 1162 MPa. Their yield strength values varied from 479 to 939 MPa and their impact resistance values were found between 2.25 J/cm² and 84 J/cm². Effect of nitriding on the mechanical properties of the specimens are discussed.

Abstract

Im vorliegenden Beitrag wird die Konstruktion und die Fertigung eines Fluidbettofens vorgestellt. Das Nitrieren erfolgte mittels dieses Ofens, wofür die optimalen Prozessparameter bestimmt wurden. Für die experimentellen Untersuchungen wurden Stähle nach DIN7225 und DIN8550 verwendet. Als Erstes wurden diese Werkstoffe gehärtet und angelassen. Das Nitrieren wurde mittels N₂ + NH₃ bei 520°C und bei 570°C über 3, 6 und 12 Stunden durchgeführt. Die Dicke der Nitridschichten lag zwischen 6,1 und 39,73 mm. Die Härte der Nirtidschichten variierte zwischen 605 und 1114 HV. Es wurde eine Zugfestigkeit der Proben zwischen 618 und 1162 MPa bestimmt, während die Streckgrenze zwischen 479 und 939 MPa und die Kerbschlagzähigkeit zwischen 2,25 J/cm² und 84 J/cm² lag. Darüber hinaus wird die Wirkung des Nitrierens auf die mechanischen Eigenschaften der Proben diskutiert.

Zekeriya Cömert studied in metallurgical engineering department of Yildiz Technical University from 1995 to 1999 and achieved his master degree in 2002 in Materials Science. He is currently working for his PhD at the Yildiz Technical University.

Polat Topuz studied in the Faculty of Technical Education of Marmara University from 1995 to 1999, and at the Institute for Graduate Studies in Pure and Applied Sciences of the Marmara University from 2000 to 2003. He began his PhD studies in 2003 at the same university.

Ass. Prof. Dr. Ahmet Sagin, born 1968, studied from 1987 to 1994 at the Metallurgical Engineering Department of Yildiz Technical University, and completed in 1999 his PhD study about the investigation of fatigue behaviour of austempered ductile iron gear box and its production with the doctoral degree at the same university. Areas of interest are mechanical testing of materials, mechanical metallurgy and heat treatments of ductile iron and steels.

Prof. Dr. Ahmet Topuz received his PhD at the Yildiz Technical University in Materials Science. Since 1988 he is Professor for Materials Science at the Yildiz Technical University. From 1984 to 2004 he is heading the Materials Science Branch at Yildiz Technical University. He main scientific field is the mechanical and non destructive testing of materials.

References

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Published Online: 2013-05-26

Published in Print: 2006-10-01

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https://doi.org/10.3139/120.100761