Effect of Boriding on the Fatigue Resistance of C20 Carbon Steel

Boriding is a thermochemical surface treatment used to improve corrosion and wear resistance of hardened steels. In this work, we study the effect of boriding treatment in solid medium on the cyclic fatigue resistance of C20 carbon steel. Specimens of untreated and borided C20 steel in a solid medium consisting of 5% B₄C, 5% NaBF₄ and 90% SiC were subjected to rotating-bend fatigue device. The results showed that the improvement in fatigue resistance carried by the boriding treatment on C20 steel is low. This was explained by the presence of FeB boride in addition to Fe₂B boride, which leads to surface cracking.