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Abrasives and possibilities of increase in efficiency of abrasive waterjets
Martinec, Petr; Sitek, Libor
2015 - English
The contribution focuses on the research into abrasive materials and possibilities of adjustment of their properties in order to increase the efficiency of the processes of machining and cutting with abrasive waterjets. Cutting ability of commonly available garnet concentrates and nontraditional products which are starting to access to the Czech market were tested and compared. In addition, entirely new garnet products which are not commercially available yet, recycled abrasives, abrasives with various sizes of grains and heat-affected abrasives or abrasives coated with a thin plastic layer were studied.
Keywords:
abrasive waterjets; abrasives; garnet; zirconia
Available in digital repository of the ASCR
Abrasives and possibilities of increase in efficiency of abrasive waterjets
The contribution focuses on the research into abrasive materials and possibilities of adjustment of their properties in order to increase the efficiency of the processes of machining and cutting ...
Use of micro X-ray computed tomography for development and research into waterjets
Souček, Kamil; Sitek, Libor; Gurková, Lucie; Georgiovská, Lucie
2015 - English
Non-destructive methods for analysis of various types of materials have been increasingly applied recently. One of these methods is the industrial micro X-ray computed tomography (CT). This paper presents an overview of experience in using the industrial micro X-ray computed tomography during research activities at the Institute of Geonics of the CAS. It discusses possibilities of the nondestructive visualization of the inner structures of a wide range of materials and objects, including examples of its use in research and development activities related to high speed waterjets.
Keywords:
micro X-ray computed tomography; inner structure of materials; porosity; defectoscopy; waterjet
Available in digital repository of the ASCR
Use of micro X-ray computed tomography for development and research into waterjets
Non-destructive methods for analysis of various types of materials have been increasingly applied recently. One of these methods is the industrial micro X-ray computed tomography (CT). This paper ...
Visualisation and quantitative analysis of flat continuous water jet structure
Ščučka, Jiří; Zeleňák, Michal; Foldyna, Josef; Lehocká, D.; Votavová, H.
2015 - English
The results of an experiment focused on the visualisation and structural analysis of flat continuous high-speed water jet used in descaling process are presented in this paper. The aim of the work was to test the applicability of the shadowgraph technique, combined with image processing and analysis methods, to visualise the water jet structure and analyse its main quantitative parameters. Volume percentage of water and air in the water jet structure, size of droplets and water bunches and other parameters were measured on digital images taken at various distances from the nozzle outlet. Knowledge of the water jet structure below the nozzle can facilitate an optimal setting of technological conditions of the water jetting with respect to the maximum disintegration effect on treated material. The described methods can also provide important information for development of new nozzles or entire water jetting tools for disintegration of materials.
Keywords:
descaling; flat continuous water jet; visualisation; shadowgraph technique; image analysis
Available in digital repository of the ASCR
Visualisation and quantitative analysis of flat continuous water jet structure
The results of an experiment focused on the visualisation and structural analysis of flat continuous high-speed water jet used in descaling process are presented in this paper. The aim of the work ...
Concrete damaged by high temperature – possibilities of treatment with high speed water jet
Bodnárová, L.; Válek, J.; Sitek, Libor; Foldyna, Josef; Klich, Jiří
2015 - English
The paper describes analysis of behavior of cement based composite materials (concrete) exposed to high temperature. Recommendations for minimization of damage of thermally loaded structures are proposed and possibilities of renovation of fire damaged concrete using the technology of high speed water jet to remove damaged layers are given.
Keywords:
concrete; fire; high temperature; water jet
Available in digital repository of the ASCR
Concrete damaged by high temperature – possibilities of treatment with high speed water jet
The paper describes analysis of behavior of cement based composite materials (concrete) exposed to high temperature. Recommendations for minimization of damage of thermally loaded structures are ...
Hydro-abrasive machining of rotating workpieces from graphite and aluminium alloy
Cárach, J.; Hloch, Sergej; Klich, Jiří; Hlaváček, Petr; Klichová, Dagmar
2015 - English
The paper compares the quality of machined surface of graphite and aluminium alloy by abrasive water jet using the focusing tube with a diameter of df1 = 0.5 mm and df2 = 0.78 mm. The machining was carried out using the technology of rotating workpiece disintegration by abrasive water jet. Abrasive tangential water jet was used to carry out the experiment (water pressure p = 400 MPa). Workpieces were clamped in the rotating chucking appliance with rotation frequency n = 300 min-1. The change in focusing tube diameter caused the change in values of roughness parameters, and also caused the change of resulting shape of workpieces. Values of roughness parameters were measured using the MicroProf FRT optic profilometer.
Keywords:
abrasive water jet; machining; roughness parameters
Available in digital repository of the ASCR
Hydro-abrasive machining of rotating workpieces from graphite and aluminium alloy
The paper compares the quality of machined surface of graphite and aluminium alloy by abrasive water jet using the focusing tube with a diameter of df1 = 0.5 mm and df2 = 0.78 mm. The machining was ...
Effect of pulsating water jet peening on stainless steel
Hlaváček, Petr; Kruml, T.; Foldyna, Josef; Tobiáš, J.; Man, J.
2015 - English
Effects of action of pulsating water jet on polished surface of the stainless steel AISI 316L are presented. Surface slip bands appeared after this treatment. In the most severe conditions, microcracks were formed. Hardness measurement showed that the affected layer was thinner than 60 μm. Application of the pulsating water jet has beneficial effect on the fatigue life of the material.
Keywords:
pulsating water jet; surface treatment; fatigue life
Available in digital repository of the ASCR
Effect of pulsating water jet peening on stainless steel
Effects of action of pulsating water jet on polished surface of the stainless steel AISI 316L are presented. Surface slip bands appeared after this treatment. In the most severe conditions, ...
Surface strengthening of a stainless steel using pulsating water jet technology - evaluation by means of microhardness measurements
Hloch, Sergej; Ščučka, Jiří; Lehocká, D.; Simkulet, V.
2015 - English
Results of an experiment focused on surface strengthening of AISI 304 stainless steel using pulsating water jet technology is presented in the paper. The tested material was subjected to the action of pulsating water jet under changing technological conditions (water pressure, traverse speed, stand-off distance, and diameter of nozzle orifice). Microhardness measurements at various distances from the created traces were applied for assessing the material strengthening. Based on the results, it can be stated that the dynamic effects of pulsating water jet on the tested steel samples cause the material deformations leading to the formation of a zone of strengthened material along the disintegrated area.
Keywords:
pulsating water jet; stainless steel; surface strengthening; microhardness
Available in digital repository of the ASCR
Surface strengthening of a stainless steel using pulsating water jet technology - evaluation by means of microhardness measurements
Results of an experiment focused on surface strengthening of AISI 304 stainless steel using pulsating water jet technology is presented in the paper. The tested material was subjected to the action ...
Geomythology: a useful tool for geoconservation and geotourism purposes
Kirchner, Karel; Kubalíková, L.
2015 - English
The relationship between the geosciences and myths is studied by geomythology which is understood as an explanation of the geological and geomorphological features using the supernatural forces and beings. The geomythological aspect can be regarded in relation to cultural, historical and spiritual meaning or value of geodiversity and it can be included into the holistic concept of geotourism. The article briefly discuss the reasons why geomythological aspect could be used for geoconservation and geotourism purposes and it presents several examples (especially geosites and geomorphosites) from the Czech Republic where the geomythological value is (or can be) used for these purposes.
Keywords:
geosites; geomorphosites; Bohemian-Moravian Highland
Available in digital repository of the ASCR
Geomythology: a useful tool for geoconservation and geotourism purposes
The relationship between the geosciences and myths is studied by geomythology which is understood as an explanation of the geological and geomorphological features using the supernatural forces and ...
Study of quality of nine aluminium alloys surfaces created using abrasive waterjet
Klichová, Dagmar; Klich, Jiří; Gurková, Lucie
2015 - English
The article focuses on the normalized method of measurement and evaluation of a surface texture created using the abrasive waterjet. It detects selected amplitude parameters of a roughness profile providing a form of a quantified description of properties of a surface topography. It studies the change in quality of machined surfaces created by the abrasive waterjet in nine selected materials of aluminium alloys when changing the traverse speed. Studied samples were measured by an optical profilometer MicroProf FRT and further analyzed with the SPIP software.
Keywords:
surface roughness; abrasive waterjet; aluminium alloy
Available in digital repository of the ASCR
Study of quality of nine aluminium alloys surfaces created using abrasive waterjet
The article focuses on the normalized method of measurement and evaluation of a surface texture created using the abrasive waterjet. It detects selected amplitude parameters of a roughness profile ...
Measurement and analysis of abrasive particles velocities in AWJ
Zeleňák, Michal; Foldyna, Josef; Martinec, Petr; Cárach, J.; Gurková, Lucie; Nováková, Daria
2015 - English
Abrasive water jet (AWJ) is a progressive technology commonly used in many industrial applications. Potential of this technology is high and research in the field of optimal geometry design of an injection system has not been completed yet. New designs of the injection cutting head based on numerical simulation of the flow provide important information about processes occurring during the formation of AWJ. Detailed knowledge of velocities of abrasive particles during the abrasive water jet generation is vital for the verification of the numerical model. The aim of the experimental work was to test the applicability of the LIF (Laser Inducted Fluorescence) technique combined with the PTV (Particle Tracking Velocity) processing algorithms to analyze particle velocities at the output of the focusing tube. The combination of commonly used water pressures with abrasive mass flow rate was tested and the obtained results of abrasive particles velocities are presented in this paper.
Keywords:
abrasive particle velocity; LIF; PIV
Available in digital repository of the ASCR
Measurement and analysis of abrasive particles velocities in AWJ
Abrasive water jet (AWJ) is a progressive technology commonly used in many industrial applications. Potential of this technology is high and research in the field of optimal geometry design of an ...
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