Effect of vanadium on the high-cycle fatigue fracture properties of medium-carbon microalloyed steel for fracture splitting connecting rod: Fid-Bau Portal

Effect of vanadium on the high-cycle fatigue fracture properties of medium-carbon microalloyed steel for fracture splitting connecting rod

Hui, Weijun / Chen, Silian / Zhang, Yongjian / Shao, Chengwei / Dong, Han

Abstract

Highlights • Effect of V up to 0.45% on fatigue property of medium carbon MA steel was studied. • Fatigue strength and fatigue strength ratio increase with increasing V content. • Excellent fatigue properties can be obtained when V is higher than ∼0.28%. • Strengthening ferrite is the key to improve fatigue property of MA steel. • The fatigue crack growth behavior is similar for the MA steel with exponent m ≈3.5.

Abstract The present investigation effort was made to study the effect of V up to 0.45% on the high-cycle fatigue properties of medium-carbon microalloyed (MA) steel 37MnSiVS, for the development of new crackable MA forging steel with excellent fatigue properties. The results show that the amount of V(C,N) precipitates increases with increasing V content and most of the precipitates are less than 5nm. Owing to the significant precipitation strengthening effect of these nanosized particles, the hardness increase of ferrite with increasing V content is higher than that of pearlite and accordingly a decrease of pearlite/ferrite hardness ratio. Therefore, both fatigue strength and fatigue strength ratio increase with increasing V content and excellent fatigue properties could be obtained when V content is higher than about 0.28%. The fatigue crack growth (FCG) behavior is similar for all the three 37MnSiVS samples with an exponent m ≈3.5. It is concluded that V can improve the fatigue properties of ferrite–pearlite steel mainly through precipitation strengthening and therefore it is anticipated that MA steel’s fatigue property could be further improved as well as more fine V(C,N) particles be obtained.