Mechanical and fatigue properties of micro-groove structure formed by multi-pass rolling

The micro-groove structure can reduce the resistance of the object in the fluid, thereby reducing fuel consumption and environmental pollution. Roll forming is an efficient method to obtain micro-grooves. While preparing the groove structure in a large area, the work hardening and residual compressive stress introduced by rolling can improve the fatigue resistance of the micro-groove surface. In this paper, the fatigue properties of specimens with micro-grooves were studied. The fatigue performance of the outer semicircle-inner trapezoidal combined groove is basically the same as that of the semicircle, which is 24.8% higher than that of the simple trapezoidal groove. The combination grooves can achieve a drag reduction of 11.8% when the incoming flow velocity is 2.5 m/s. It is concluded that the outer semicircle-inner trapezoidal groove structure has both the fatigue resistance of the semicircle groove and the drag reduction performance of the trapezoidal groove. It is feasible to prepare the composite micro-groove by multi-pass rolling.