Experimental study on the effect of abrasive water jet impact angle on the cutting performance of sandstone

Abrasive water jet is a highly efficient cutting technology. Through some sandstone cutting tests, the research on the optimal impact angle and inclined cutting mechanism of rock-like materials is carried out. Based on the macroscopic and microscopic observation of the cut’s inner wall, crystal glass cutting experiments are conducted to investigate the cutting motion process of abrasive water jet under different impact angles, revealing the variation laws of cutting depth, the characteristics of the cut’s inner wall, the trajectory of abrasive particles and the type of crystal destruction under different cutting pressures and impact angles. The test results show that the average cutting depth gradually increases with the increase of cutting pressure, while changing the impact angle can significantly change the jet’s cutting ability, and the best cutting effect is obtained at an impact angle of 75°. With the increase of the cut depth, the curved jet trajectory texture gradually appears in the cut’s inner wall , and in its bottom there are typical erosion pits and trailing phenomenon. The cut’s inner wall is mainly characterized by four types of damage features such as fracture through the crystal, fracture along the crystal, cut grooves or pits, and cement coverage, etc. It is worth noting that the four types of damage features appear at different locations in the cut at different impact angles, and this phenomenon is mainly caused by the deflection of jet, the direction of reflected flow movement, and the change in the reflection of shock wave and expansion wave. The vertical and horizontal jet components (in the same direction as the direction of propulsion), which play a dominant role in the destruction of the target, and the horizontal jet component, which is opposite to the direction of propulsion, play a secondary role in the erosion and polishing of the formed cut, but the degree of action varies under different impact angles. The macroscopic model of the abrasive water jet cutting process is established by combining the trajectory texture of cut’s inner wall and the observation results of the jet cutting process. The research results can provide a technical reference for further improving the efficiency of abrasive water jet cutting.