Diffusion kinetics and characterization of borided AISI D6 steel

Abstract

In this study, the case properties and diffusion kinetics of AISI D6 steel borided in Ekabor II pow der were investigated by conducting a series of experiments at temperatures of 1123, 1223 and 1323 K for 2, 4 and 8 h. The boride layer was characterized by optical microscopy, X ray diffraction technique and micro Vickers hardness tester. X ray diffraction analysis of boride layers on the surface of the steels revealed the existence of FeB, Fe 2 B, CrB and Cr 2 B compounds. Depending on the chemical composition of substrates and boriding time, the boride layer thickness on the surface of the steel ranged from 13.54 µm and 164.42 µm. The hardness of the boride compounds formed on the surface of the steels ranged from 1672 to 2118 HV 0.05 , whereas Vickers hardness values of the untreated the steels was 584 HV 0.05 . The activation energies (Q) of the borided steel were 180.359 kJ/mol. The growth kinetics of the boride layers forming on the AISI D6 steel and the thickness of boride layers were also investigated.

Experimental investigation of process parameters for pack boronizing of SS410 using anova and machine learning approaches

“…The maximum boronizing thickness at 900 °C is 37.85 microns whereas it is more in the 950 °C process with the thickness values of 57.13 microns. The more processing temperature results more boronizing thickness and it is in agreement with the information of previous literatures [13]. The boron element (B) is reacting with the surface of the specimen (Fe) and forms iron boride.…”

“…The decrement trend has been seen in the hardness values from the surface to the core area, because the surface of the material exposed to the treatment process. After the diffusion from surface it enters to the next zones and the decrement trend of hardness is clearly shown in this experiment [13].…”

“…This analysis inferred that the duration influences more for the thickness and formation of FeB results the increase of hardness and wear resistance [12]. Ibrahim Junes et al [13] examined the boronizing layer thickness, hardness and the microstructure using the pin on disc tester, micro vickers hardness tester and SEM respectively. Villa Velazquez Mendoza et al [14] suggested an empirical equation from the regression model and ANOVA.…”

Growth Kinetics of CoB–Co2B Layers Using the Powder-Pack Boriding Process Assisted by a Direct Current Field

“…Traditional diffusion models [17][18][19] suggest that the overall growth rate of boride layer obeys the parabolic law X 2 = 2Kt, where X is the mean thickness of the total boride layer, K is the growth rate constant, and t is the exposure time of the substrate to the boriding process. To estimate the boron activation energy in the boride layer (Q), the behavior of the growth rate constant as a function of the boriding temperature must be determined.…”

Surface modification method of duplex type stainless steels by the pack boriding process

“…For low alloy steels the formation of FeB and Fe 2 B increases the thickness of the boride layer as compared to that in high alloy steels because of the affinity of boron atoms for iron [6]. The FeB layer is harder than the Fe 2 B layer, which promotes brittleness and surface defects on the material [11]. To overcome the difficulties of increasing the layer thickness in high alloy materials, the process temperature and time have to be increased [12][13][14].…”