- TITLE:
POROSITY DISTRIBUTION AND MICROHARDNESS OF A COLD ARC PULSE™ WIRE ARC ADDITIVELY MANUFACTURED AlSi x MECHANICAL PLATE
- AUTHOR(S):
Nikolay Petrov, Maria Ormanova , Iliya Zhelezarov
- ABSTRACT:
Porosity is known as the main problem of aluminum alloys regardless of the method for formation of aluminum components due to the unique thermophysical properties of this metal. The larger the heat input is, the higher the likelihood is of formation of pores within the structure of the components, whether be they caused by the gas adsorption or due to the expansion and then shrinkage of the material during the heating/cooling cycle. Since the pore formation mechanisms of additively manufactured specimens is still unclear, during the present work a wire arc additively manufactured specimen was used in order to study the concentration of pores within the structure of the last along its volume. Additionally, the less studied cold arc pulse (CAP) mode was employed during the specimens manufacturing. Since the structure directly influences the mechanical properties of the components, a microhardness map was prepared as well as investigation of the microhardness as a function of the specimen�s height. The results were summarized and indicated an increasing trend of the porosity of the specimen towards its top section. The larger defects were observed closer towards the bottom of the specimen due to the lower interpass temperature, this the worse fusion of the aluminum. Despite this the microhardness along the face-wall of the specimen and its cross section remained the same within the margin of error. The possibility of decreasing the porosity and increasing the quality of the deposited components was discussed.
- DOI:
https://doi.org/10.62853/HAEA7843
- PAGES:
2-07
- HOW TO CITE THIS ARTICLE:
Petrov N., Ormanova M., Zhelezarov I. Porosity distribution and microhardness of a cold arc pulse wire arc additively manufactured AlSix mechanical plate. Journal of the Technical University of Gabrovo. 68 (2024) 2-7
- TITLE:
PERSPECTIVES AND DEVELOPMENT TRENDS FOR APPLICATION OF ADDITIVE TECHNOLOGIES IN MODERN DENTISTRY IN THE LIGHT OF INDUSTRY 4.0
- AUTHOR(S):
Tsanka Dikova
- ABSTRACT:
Additive manufacturing technologies (AMTs) offer a new approach for cost-effective production of goods and services and are therefore quite rightly included as part of the Fourth Industrial Revolution, Industry 4.0. Last years great attention is paid to the AMTs as technologies of the future development in many countries all over the world including the European Union. Depending on the availability of a good base of installed 3D printers and intellectual potential, the countries are divided into two groups: 1) leaders in the field of 3D printing technology and 2) countries with large bases of equipment, but lack of trained and qualified labor force. The aim of the present paper is to analyze the perspectives and development trends for application of additive technologies in modern dental medicine in the light of Industry 4.0. The constant development of AMTs will accelerate their implementation in various fields and in particular in medicine/dentistry. The 3D printing technologies are first applied in dentistry, due to the possibility for fabrication of individual dental constructions. Currently, almost all worldrenowned companies for production of dental materials and machines develop additive technologies and manufacture the corresponding equipment. According to the forecasts, the 3D printing is expected to be widely used in dental clinics and laboratories in the next 5-10 years. The additive technologies most often applied in dentistry include stereolithography, fused deposition modeling, selective electron beam melting, selective laser melting/sintering and ink-jet printing. The great variety of materials used in these processes allow constructions with different purposes to be made for all areas of dental medicine - surgery, oral implantology, conservative dentistry, orthodontics and prosthetic dentistry.
- DOI:
https://doi.org/10.62853/ELSJ6320
- PAGES:
1-11
- HOW TO CITE THIS ARTICLE:
Dikova T. Perspectivies and development trends for application of additive technologies in modern dentistry in the light of industry 4.0. Journal of the Technical University of Gabrovo. 68 (2024) 1-11.
- TITLE:
FOUR KORDINATNYY FLOORING LAYOUT OF PORTAL COMPOSITION
- AUTHOR(S):
Y. Kuznetsov, I.R. Kobets
- ABSTRACT:
The article highlights the relevance and formulates the problem of creating small-sized workbenches with computer hardware, inspecting the data generators and the design of such workbenches, and proposing options for a table-top workbench with a portal layout. The example of the preparation of a folding part shows the procedure for breaking up the ceramic program.
- DOI:
https://doi.org/10.62853/OXBF6930
- PAGES:
6-10
- HOW TO CITE THIS ARTICLE:
Kuznetsov Y., I.R. Kobets. FOUR KORDINATNYY FLOORING LAYOUT OF PORTAL COMPOSITION. Journal of Technical University Gabrovo. 69 (2024)
- TITLE:
SURFACE MODIFICATION OF TITANIUM ALLOYS Ti-6Al-4V AND Ti-6Al-7Nb: METHODS FOR ENHANCING WEAR RESISTANCE AND BIOCOMPATIBILITY. A BRIEF REVIEW
- AUTHOR(S):
V. Koeva, D. Veselinov, R. Yankova, H. Skulev, I. Rusev
- ABSTRACT:
Titanium and its alloys, primarily Ti-6Al-4V and Ti-6Al-7Nb, are widely used in various high-tech sectors due to their excellent mechanical properties, high corrosion resistance, and low density. However, these materials exhibit low wear resistance and a tendency to gall during friction, limiting their applicability in aggressive environments or under heavy loads. This review discusses the main challenges associated with the tribological properties of titanium alloys and various modern surface modification techniques, including chemical and electrochemical methods, laser coatings, ion implantation, and nanocoatings. The advantages of these techniques in improving wear resistance are analyzed, with a focus on applications in aerospace and medicine. Special attention is given to the impact of friction in different environments and the anti-friction properties of titanium alloys. The review highlights the need for further development of surface modification technologies to enable broader use of titanium and its alloys in extreme conditions and to extend their service life.
- DOI:
https://doi.org/10.62853/UZCI2687
- PAGES:
52-55
- HOW TO CITE THIS ARTICLE:
Koeva V. , D. Veselinov, R. Yankova, H. Skulev, I. Rusev. Surface modification of titanium alloys Ti-6Al-4V and Ti-6Al-7Nb: Methods for enhansing wear resistance and biocompatibility. A brief review. JTUG. 69 (2024) 52-55.
- TITLE:
OPTIMIZATION OF DEFECT PREVENTION IN HOT FORGING OF CuZn40Pb2 BRASS ALLOY WATER VALVE COVERS: A FINITE ELEMENT AND EXPERIMENTAL APPROACH
- AUTHOR(S):
I. Cetintav, F. Karacam
- ABSTRACT:
This study explores the hot forging process of CuZn40Pb2 brass alloy water valve covers through a combination of finite element modeling and experimental trials. Key factors influencing defect formation, such as the cylindrical workpiece geometry and die temperature, are examined in detail. Simulations using Deform 3D software focused on the impact of temperature on material flow behavior, incorporating inputs such as geometry, filling sequence, and applied force. Experimental findings underscored the crucial role of the friction coefficient, which diminishes with the use of lubricants, in controlling material flow. The reduction in friction, caused by heat generated from die friction during forging, was found to elevate the risk of defects. Stress and strain analysis from the simulations revealed a complex interaction between temperature and friction, significantly affecting defect formation. The strong correlation between simulation and experimental results confirmed the value of computational modeling in predicting and preventing defects. This research provides valuable insights into optimizing hot forging parameters for CuZn40Pb2 brass alloy components, enabling improvements in product quality and process efficiency.
- DOI:
https://doi.org/10.62853/MMQR6587
- PAGES:
48-51
- HOW TO CITE THIS ARTICLE:
Cetintav I., F. Karacam. optimization of defest prevention in hot forging of CuZn40Pb2 brass alloy water valve covers: a finite element and experimental approach. JTUG 69 (2024) 48-51
