Wear 260 (2006) 90–98
Abrasive wear behavior of different case depth gas carburized
AISI 8620 gear steel
Gazi University, Industrial Arts Education Faculty, Technology Education Department, Ankara, Turkey
Received 29 April 2004; received in revised form 20 December 2004; accepted 23 December 2004
Available online 25 February 2005
In this study, abrasive wear behaviors of gas carburized AISI 8620 steels with different case depths were examined. AISI 8620 steels yield
excellent carburizing results and are used in manufacturing of gears. Two carburized and quenched specimens with different case depths were
produced. Specimens were prepared at HEMA Gear Factory. Wear tests were carried out using pin-on disc test machine. Specimens were
abraded under 10, 25 and 40 N loads by using 80 grid Al
and SiC abrasive papers. Mass losses were measured using an electronic balance
with accuracy of 10
g. Results of this study reveal that data on laboratory samples can be used to interpret the abrasive wear performance of
AISI 8620 gas carburized steel gears. It has been observed that gas carburizing time affects the case depth, and in turn, specimen with higher
case depth has shown better wear resistance. In addition to this, as the case depth has increased, the hardness of the material has increased as
© 2005 Elsevier B.V. All rights reserved.
Keywords: Gas carburized steels; Gear steels; Wear of AISI 8620 steels
Surface hardening is a very important process for indus-
trial application. The principal surface treatment methods
such as carburizing or carbo-nitriding, applied to various
mechanical parts before their use, are utilised to differentiate
the response of surface and core of the parts to external loads
by changing the surface properties and by introducing ap-
propriate residual stress distribution in order to improve their
fatigue and wear behavior. Carburized steels are commonly
used in production of gears undergoing cyclic loading.
Process selection and control in forming and heat treatment
operations play a crucial role in gear production and must
start at the design stage [1,2]. Material selection, choice of
forming processes, thermochemical and heat treatment oper-
ations, surface ﬁnish and condition will ultimately determine
the integrity and performance limits of the gears. From
metallurgical point of view, for the gear teeth surfaces, it is
Corresponding author. Fax: +90 312 212 77 63.
E-mail address: email@example.com (M. Izciler).
known that hardness is a crucial factor in prevention of scuff-
ing. For this reason, heavy-duty steel gear teeth are hardened
either by through hardening or surface hardening by means
of induction, heat treatment or by using a carbon-enriched
layer (case-carburizing/hardening). Surface hardened steels
are increasingly used for mechanical components since they
combine mechanical properties like high surface hardness
and high core toughness. However, treatments such as carbur-
izing or nitriding produce a proﬁle of mechanical properties,
which cannot be determined easily. Hardness or micro-
hardness measurements are generally used to estimate the
mechanical properties of the treated material . AISI 8620
cementation steels (low-carbon–low-alloy steels)areusedfor
carburizing applications. Carburizing steels are largely used
in the gear industry to improve the wear resistance of parts.
2. Experiment procedure
AISI 8620 steels are commercially produced as gear ma-
terials with the compositions shown in Table 1.
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