Author/Authors :
BARUT, Nusrettin Afyon Kocatepe Üniversitesi - Fen Bilimleri Enstitüsü, Metalurji Bölümü ve Malzeme Mühendisliği Anabilim Dalı, Turkey , YAVUZ, Demet Afyon Kocatepe Üniversitesi - Fen Bilimleri Enstitüsü, Metalurji Bölümü ve Malzeme Mühendisliği Anabilim Dalı, Turkey , KAYALI, Yusuf AfyonKocatepe Üniversitesi - Teknoloji Fakültesi - Metalurji ve Malzeme Mühendisliği Bölümü, Turkey
Title Of Article :
Investigation of the Kinetics of Borided AISI 420 and AISI 5140 Steels
Abstract :
In this study, AISI 5140 steel and AISI 420 stainless steel were pack borided at 1123, 1173 and 1223 K for retention times of 2, 4 and 6 h. The morphology of the boride layers formed on the steel surfaces as a result of the experiments was investigated by optical microscopy. The hardness values were measured by a micro-hardness device and the phases formed on the layer were determined by the XRD method. The XRD analysis revealed that FeB, Fe2B, CrB and MnB phases had formed on the boride layer. The results indicate that the boride layer thickness in all the steel samples had an incres as a function of incresing boriding time and temperature. In addition, the boride layer thickness values changed depending on the chemical composition of the steels. While the original hardness values of AISI 5140 and AISI 420 steels were 265 HV0,05 and 340 HV0,05 respectively, as a result of boriding, they increased up to 1843 HV0,05 and 1972 HV0,05. Activation energies (Q) of borided AISI 5140 steel and AISI 420 stainless steel used in the current study were determined as 194.951 and 206.161 kJ/mol, respectively. The growth kinetics of the boride layers forming on the AISI 5140 steel and AISI 420 steels and thickness of boride layers were also investigated. The adhesion properties of the boride layer were analyzed by performing the Daimler-Benz Rockwell-C adhesion method. According to the adhesion test results, the adhesion resistance of the boride layer decreased with the increase in the boriding temperature and time.
NaturalLanguageKeyword :
‘AISI 5140’ , ‘AISI 420’ , ’Boriding’ , ’Rockwell , C Indentation’ , ‘Diffusion’
JournalTitle :
Afyon Kocatepe University Journal Of Science and Engineering
