Boride Layer Growth Kinetics on 42CrMo4 Steel

Boronizing is a type of thermal diffusion process with primary goal of increasing the surface
hardness, wear, and corrosion resistance. Wear resistance of boronized parts depends on the type
of borides that form on steel surface and their thickness. This paper focuses on evaluation of
borides layers that form on 42CrMo4 steel. Pack boronizing was carried out at temperature range
of 800-900°C in duration of 1, 3 and 5 hours. After boronizing differences in surface boride layers
were observed for different temperatures and time of boriding. Boriding compound depth and cross
section hardness was measured. From boriding compound depth values of frequency factor (d) and
activation energy were determent by means of Arrhenius equation. From frequency factor and
activation energy equation predicting growth of boride layer was determent. Results indicate
difference in boride layer thickness and volume share of boride phases depending on temperature
and time of boriding.