Improving the technological process of increas-ing the durability of the working tool of hydrau-lic hammers by detonation spraying

The development of modern technology places increasing demands on the performance of the hydraulic hammer parts. In a complex of problems of increasing their reliability and durability the question of wear resistance occupies a special place. Insufficient wear resistance limits the productivity of hydraulic hammers and their service life, increases the cost of repair and purchase of spare parts. Goal. The purpose of this work is to scientifically substantiate and experimentally confirm the effectiveness of strengthening the critical parts of the hydraulic hammer by detonation spraying. Methodology. Detonation spraying with hard alloy powder VK 25 (80 %) and the binder material PT-NA-01 (Ni 91 %, Al 9%) was performed on a cleaned surface without pre-treatment. VK 25 powder is a tungsten-cobalt carbide (WC-Co) containing up to 25% cobalt, and is used for work in conditions of fretting corrosion, abrasive wear at normal and elevated (up to 650 ° C) temperatures. A granular powder of 20 – 100 μm was used, which was melted in an oxygen-acetylene flame and gas flow and was transferred to the surface of the part. The thickness of the sprayed layer was 0.1 mm. The surface roughness of the parts before spraying was Ra 0.35–2.5. As a result of spraying, the roughness of the working surfaces of the parts increased to the values of Ra 4.8–5.4. Results. The composition of the coating based on tungsten carbide was chosen to strengthen the surface of the investigated parts by detonation spraying. Detonation spraying modes were selected. The conditions for hardening treatment were determined. The nature of damage to parts after detonation spraying was established. Originality To solve the problem of improving the performance of the working tool of hydraulic hammers, the use of the detonation method of coating was proposed. Practical value. The test results of the details strengthened by detonation spraying showed that the increase of wear resistance by 1,8 times in comparison with an initial variant was reached.

NON-DESTRUCTIVE CONTROL OF A HYDRAULIC HAMMER PISTON, DESIGNED FOR GEOLOGICAL EXPLORATION ACTIVITIES

The piston part provided to us by the Bulgarian company to clarify the reason for its breakage.

USE OF DETONATION SPUTTERING TO INCREASE THE DURABILITY OF HYDRAULIC HAMMER CRITICAL PARTS

Currently, the use of new methods of surface strengthening has become relevant to improve the working tool. These methods include detonation sputtering. The purpose of this work was to scientifically substantiate and experimentally confirm the effectiveness of strengthening critical parts of a hydraulic hammer by detonation sputtering. As a result of the study, the effect of detonation sputtering on the wear resistance and mechanical properties of the hydraulic hammer working tool was established, and structural changes in the material during its operation were analyzed. The results of testing parts strengthened with detonation sputtering show that an increase in wear resistance by 1.8 times is achieved compared to the initial state.

ABOUT THE POSSIBILITY OF APPLICATION OF ENERGY STORAGE IN IMPACT MACHINES

The article discusses the possibility of using energy storage devices in the form of pneumatic and mechanical springs for hydraulic percussion machines as part of robotic drilling systems. New design schemes are proposed that allow changing the energy parameters of the machine in accordance with the external operating conditions for the implementation of adaptive technological processes. Simulation modeling of the proposed schemes in the ITI SimulationX software package made it possible to determine the dynamic parameters and study the working cycle of the hydraulic hammer. The analysis of the results obtained showed the possibility of creating these types of machines, taking into account their advantages and disadvantages.

Research Results on Influence of Hydraulic Hammer Design Parameters

The article presents the results of the theoretical research on the influence of the design parameters on the output characterictics of a hydraulic hammer. The hydraulic hammer under the study has a hydraulic percussive mechanism of a permanent pressure-type structure with a spool free control unit. A design model of a hydraulic percussive mechanism with a spool free control unit has been developed. The mathematical model of the hydraulic percussive mechanism of a permanent pressure-type structure with a spool free control unit is presented. The oscillogram resulting from the theoretical studies, which defines the operation of the hydraulic percussive mechanism, is presented. A range of the rational zones for selecting the main design parameters of the hydraulic percussive mechnism is obtained.