Boruration thermochimique d'un acier C38 dans un bain de sels borax–SiC

Effect of Boriding on the Fatigue Resistance of C20 Carbon Steel

“…This comparison has pointed out that fatigue strength of borided specimens is slightly better than of untreated ones. Contrary to the results obtained by Bouaziz et al [10] where they found that the boriding of an XC38 steel in a molten salt consisting of borax and SiC reduces its fatigue strength by 20 to 25%, we have found that the boriding treatment performed on C20 steel improves the fatigue strength of this steel by about 20%.…”

“…The microhardness values corresponding to the different zones are summarized in Table II. The hardness values obtained from the surface towards the core of the substrate represent a hardness gradient which can be very advantageous during rotational bending tests [10].…”

Effect of Boride Incubation Time During the Formation of Fe2B Phase

“…To estimate the boron activation energy, we must have a minimum of three treatment temperatures and thicknesses' values of the layer for each temperature. From the experimental data 15 , we can estimate the activation energy of the diffusion of boron in the XC38 steel substrate using the equation (1): (1) The variable u represents the layer thickness (µm), D 0 is the diffusion coefficient of boron (µm 2 /s), t is the time (s) of boronizing, Q is the value of the activation energy measured in Joule/mole, R is the gas constant (R=8.314 Joule/mole.K) and T is the temperature in Kelvin. Figure 1 depicts the evolution of the thickness of the boronized layer (Fe 2 B) of the steel according to the reciprocal temperature.…”

“…To calculate the incubation time, the mathematical model 16 and experimental data 15 have been used; the difference between data obtained experimentally and by simulation allowed us to determine the incubation time, it is expressed by the following equation: (9) and (10) Where k is the growth rate constant, the variable λ I represents the thickness corresponds to the incubation time (µm), λ sim is the simulated thickness with τ=0 and the λ exp thickness is experimentally obtained.…”

“…In this paper, we numerically study the thermochemical boronizing of the XC38 steel dipped into a salt bath (70% borax 30% of silicon carbide) at temperatures between 850° C to 1050° C for 2, 4 and 6 hours 15 . We proceed to calculate the diffusion coefficient from experimental data; this coefficient is used in the mathematical model to estimate the kinetics of boronizing the XC38 steel.…”