Pulsating water jet technology for rock erosion application has been emphasized in this study. The erosion phenomena are explored as an eroded depth, eroded width and volume eroded of the sandstone at frequency f = 20,000–40,000 Hz by using pulsed water jet. The surface was eroded at pressure 20–40 MPa; standoff distance 20 mm; nozzle diameter 1.6 mm; and feed rate of the jet 125–200 mm/s. The eroded depth, eroded width, and volume of the eroded sections were evaluated through non-contact-type optical profilometer. The result shows the relationship between feed rate of the jet, pressure, and standoff distance, which affects the erosion depth and width and volume removal. At f = 40,000 Hz, the maximum value of erosion depth, width, and volume removal was obtained. The microstructural analysis Field Emission Scanning Electron Microscopy (FESEM) examined the erosion topography, plastic deformation, and failure analysis at a frequency f = 20,000–40,000 Hz. The results reveal that the frequency change affects the erosion, and failure was observed at 40,000 Hz. This is the result of the deeper and narrow eroded surface caused by the enhanced number of impacts (200–320 impact per mm) and concentrated stream of a jet at 40,000 Hz.

Submerged jets have a variety of practical applications due to their versatility in providing efficient and environmentally friendly options for treatment in various industries. The physical background is based on the continuous water jet (CWJ) application powered via stagnation pressure. However, it is known that impact pressure is much more effective than static pressure. When the impact pressure is repeated with a high frequency per time unit, the erosive effects of water can be used even at pressures below 100 MPa, which is attractive from the point of view of the low demands of the hydraulic system. Surface modification utilising impact pressure can be achieved by employing the pulsed water jet (PWJ) method. The combination of parameters such as the traverse speed and trajectory pattern can control the number of water clusters impacting the material surface. So far, the field of application of PWJ for surface treatment has mostly been investigated water atmospheric conditions. This article focuses on the possibility of the surface modification of AISI 304L stainless steel using the PWJ method under submerged conditions. The results are compared to those obtained under atmospheric conditions. The reference samples were treated by the same technological conditions using a continuous water jet (CWJ). The affected surfaces were characterised using areal surface roughness parameters S_a, S_z, S_p, and S_v, and the surface topography and mechanism of erosion wear were evaluated by scanning electron microscopy. A significant increase in all roughness parameters was confirmed using the PWJ compared to the CWJ method (both in atmospheric and submerged conditions), which confirms the importance of using impact pressure. The surface treatment by PWJ under submerged conditions resulted in a decrease of the surface roughness parameter S_a by approximately 97% compared to atmospheric conditions at a traverse speed of 2 mm/s for perpendicular interleaved trajectory, nevertheless, the homogeneity of treatment over a larger area was improved.

The paper investigates the effect of material machinability on the quality of cutting surfaces created by abrasive waterjet in selected aluminium alloys. The texture of studied surfaces was measured by an optical profilometer and consequently assessed using the standardized amplitude parameters of the profile roughness Ra, Rz and Rq. It was found that the quality of a cutting surface is significantly influenced not only by the cutting speed and determined machinability of particular aluminium alloy but also by its strength properties.

The presented paper is focused on the evaluation of material removal during machining via an abrasive water jet with a controlled depth of cut. In the introductory parts of the work, a theoretical analysis of water jet technology and an analysis of the current state of the problem are presented. The experimental part of the work is devoted to testing the effects of technological parameters on material removal from the point of view of the maximum erosion depth and volume loss of material during machining with a low water pressure of 50 MPa. The tested material was a Ti 6Al 4V titanium alloy. The experiments were carried out by changing the traverse speed of the cutting head, the mass flow of the abrasive and the angle of inclination of the cutting head, according to the DoE 3³ experiment plan. The obtained values were evaluated using the method of variance (ANOVA) and regression analysis. Furthermore, the values of the width of the erosion track and the maximum and minimum erosion effects for both tested materials were evaluated.