Conclusions 
The kinetics of austenitization of S.G. cast iron, can be described by an Johnson-Mehl-Avrami 
equation and for the determination of the activation energy “Q”, it was used the Arrhenius equation. 
The wear process was influenced by the structural changes of the specimen's surface. 
‘ The microhardness of the nears surface of specimens from the wear surface has a superior value and 
that values decrease with the increasing of the distance from the wear surface. 
The phase transformation of the wear surface consist in the transformation of a residual austenite 
part in “ge“martensite with the increasing of the microhardness’s surface. 
References 
(1) D. Simon: “ADI- a new material for the automotive engineer”, Foundry Trade J. 2 (1996) 66. 
(2) Y.C. Liu, JM. Schissler, JP. Chabout, H. Vetters: “Study of The Structural Evolution of 
Austempered Ductile Iron (ADI) during Tempering at 360°C”, Metallurgical Science & Tech. 13 
(1995) 12. 
(3) J.T.H. Pearce: “Abraisve wear behaviour of alloy cast irons”, The British Foundyman, 78 
(1985) 13. 
(4) 1. Milosan: “The wear surface microhardness variation of a bainitic 8.G. Cast Iron”, Metalurgia 
tee for T, = 3 (1998), 42. 
Key-word register: material science, surface engineering, heat treatment, phase transformation, 
wear, bainite, martensite, microhardness. 
tial evolution of 
iness (HV 901) 
1 wear surface) Acknowledgments 
‚rement who are The authors thank ROMAN S.A. Truck Company, Brasov (RO) for providing research and 
nstant value, financial support. 
naintained at the 
hardness and this 
he specimen are 
v gurfäce near the 
onsite 
mırface Wear. are 
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