Process analysis and hole type optimization of micro-groove multi-pass rolling

The micro-grooves with special structure and size have the special function of reducing surface flow resistance. Placing the micro-grooves over a larger area on the aircraft surface can achieve effective drag reduction, that is, a decrease in the resistance experienced during operation. Rolling method can be used to form micro-grooves on metal surface efficiently. However, the micro-grooves formed by this plastic forming method may have some defects, which in turn could cause serious negative impact on the drag reduction and mechanical properties of the micro-grooves. Therefore, optimization of the multi-pass rolling process to avoid the micro-groove defects is of great significance. This paper includes a series of analysis on the microstructure, strain, and material displacement of micro-grooves, which were carried out to explain the causes of micro-groove defects. Micro-grooves were formed on the surface of the sheet, and the plate also underwent both thickness reduction and extension in the Y-direction, under the pressure exerted by the roller. It was found that the extension of the plate had an adverse effect on the formation of micro-grooves; thus, the hole types of the roller were optimized accordingly. The simulation and experimental results showed that the optimized roller could produce the desired micro-grooves, which perfectly eliminated the generation of micro defects.