Preparation of the Surface of Long-Dimensional Rods of Hydro-Cylinders for Thermal Spraying Using an Abrasive Jet

Abstract

Preliminary cleaning of the surface of hydraulic cylinder rods is of great importance for subsequent coating. The most widely used surface preparation for thermal spraying is jet-abrasive treatment. The shot blast modes provide the hardness and strength of the material being processed. The impact of the abrasive makes the surface rough, increasing the contact area. Experimental studies of jet-abrasive processing of the hydraulic cylinder rod surface, as well as its activation for the thermal spraying, were carried out. The prepared surface of the rod for thermal spraying must meet the requirements for surface roughness and the size of the hardened layer at work. The experiments made it possible to identify the optimal modes of jet-abrasive treatment, which affect surface roughness and abrasive penetration of abrasive. To obtain the desired roughness values, it is preferable to use the following: a steel shot with an abrasive particle size in the range of 0.3–1.5 mm, taking the compressed air pressure in the range of 0.4–0.7 MPa; processing time—within 3.5–5 min; counterflow angle with the surface—70–90°; consumption of abrasive particles—300–500 kg/h. A special installation for jet-abrasive processing has been designed, which makes it possible to restore the surfaces of long rods by thermal spraying directly at the site of operation of the large machines.