**Chemical compositions, %:**

C: 0.90–1.10; Si: 0.15–0.35; Mn: 0.25–0.45; P: 0.025–max; S: 0.025–max; Cr: 1.30–1.60.

**101**

*Tribological Study of the Friction between the Same Two Materials (RAD Steel)*

**3. Characterization of the tribological behavior of the dry contact**

The friction coefficient is determined from the tangential force, Q\*, measured during the test by a force sensor, and the normal force applied, P, measured by a

The value of the coefficient of friction conventional said during each cycle is

While the average value of the coefficient of mechanical friction during the

µ

µ

µ

*e*

( )

δ

*g*

( )

*i*

*d*

*E*

*i*

=

<sup>=</sup> ∗ ∗

4

where Ed is the dissipated energy in Joules, δg is the amplitude of slipping in

The average value of the energy coefficient of friction during the entire test is

=

 µ <sup>=</sup> ∑1 1 *Nt e e t i*

 µ <sup>=</sup> ∑1 1 *Nt t i*

ì /P = ∗ *Q* (1)

*<sup>N</sup>* (2)

*<sup>P</sup>* (3)

*<sup>N</sup>* (4)

*DOI: http://dx.doi.org/10.5772/intechopen.93478*

**3.1 Analysis of friction, μ, and μe**

**Figure 2.** *Chrome steel balls.*

given by the following expression [4]:

sensor to gauge the constraints (**Figure 3**) [3].

entire test is expressed by the following expression [5]:

where N is the number of cycles (**Figure 4**).

expressed by the following [4]:

micrometers, and P is the normal force applied in Newtons.

*Tribological Study of the Friction between the Same Two Materials (RAD Steel) DOI: http://dx.doi.org/10.5772/intechopen.93478*

**Figure 2.** *Chrome steel balls.*
