- TITLE:
INVESTIGATION OF THE INFLUENCE OF THE INITIAL MICROSTRUCTURE UNDER DIFFERENT MODES OF HEAT TREATMENT ON THE MECHANICAL PROPERTIES OF 35CrMnSi STEEL
- AUTHOR(S):
V. Todorov, V. Dunchev
- ABSTRACT:
The influence of the initial microstructure on the mechanical properties of 35CrMnSi steel
samples is investigated in the article. The main goal of the research is to obtain an initial
microstructure, providing a favorable basis for subsequent processing by surface plastic
deformation. Four groups of samples are made and subjected to heat treatment in different modes.
The first group was examined in the state as-received, the other three processed by: annealing at a
temperature of 600ºC with a heating time of 90 min and furnace cooling; annealing at a temperature
of 880ºC with a heating time of 90 min and furnace cooling; normalization at a temperature of 880ºC
with a heating time of 30 min and air cooling.
By phase and microstructural analysis, it was found that phase conversion is present only after
normalization, and the resulting structure is a combination of sorbite-like perlite and residual
austenite. The samples subjected to normalization show the highest values for tensile strength,
hardness, and microhardness compared to the other groups of heat treatment modes.
- PAGES:
8-
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INVESTIGATION OF THE INFLUENCE OF THE INITIAL MICROSTRUCTURE UNDER DIFFERENT MODES OF HEAT TREATMENT ON THE MECHANICAL PROPERTIES OF 35CrMnSi STEEL
- TITLE:
INFLUENCE OF THE PROCESS PARAMETERS ON THE MICRO-HARDNESS OBTAINED OF DIAMOND BURNISHED AISI 304L STAINLESS STEEL
- AUTHOR(S):
A. P. Anchev
- ABSTRACT:
Chromium-nickel austenitic stainless steels are used in many industrial fields due to their good
strength, excellent corrosion resistance, easy deformation in the plastic field and good weldability.
Their low hardness, poor tribological properties and the possibility of localized corrosion in specific
environments may limit their use. In the temperature range 500-700оС these steels are vulnerable to
inter-granular corrosion. As a result, the conventional chemical-thermal treatments, such as
nitriding and carburizing, can increase the surface hardness, but at the expense of the corrosion
resistance due to the formation of chromium carbides. This disadvantage is overcome by low-
temperature nitriding and carburization, which are realized at temperatures below 500 ° C, but these
treatments are relatively expensive. As is well known, the austenite is easily hardened by cold plastic
deformation. With a higher degree of plastic deformation, the austenite partially turns into alpha
prime strain-induced martensite, where the hardness increases significantly. The article presents
results for the surface micro-hardness of AISI 304L cylindrical steel specimens treated with diamond
burnishing, which is a cheap green technology. The surface cold work was performed on C11
conventional lathe using a burning device with elastic fixation of the deforming polycrystalline
diamond insert. The micro-hardness obtained after a previous fine turning of 366 HV0.05 was
increased to 609 HV0.05 via diamond burnishing, i.e., the increase is 66.4%.
- PAGES:
7-
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INFLUENCE OF THE PROCESS PARAMETERS ON THE MICRO-HARDNESS OBTAINED OF DIAMOND BURNISHED AISI 304L STAINLESS STEEL
- TITLE:
AQUEOUS COMPOSITIONS BASED ON MULTICOMPONENT HYDROPHILIZED POLYMER SYSTEM
- AUTHOR(S):
R. Cherkezova, T. Hristova, K. Zafirova
- ABSTRACT:
The purpose of this work is to develop compositions based on different types of HUPER with the
addition of specific amounts of water that do not hinder the cross-linking of the unsaturated
polyester. Hydrophilized unsaturated polyester resin (HUPER) diluted with specific amounts of
water are presented. The unsaturated polyester resin (UPER) is modified with different reagents
(cement, water glass, sodium hydroxide, sulfur) after which the addition of water is completely
possible in technical terms. Water-diluted HUPER acquires new specific properties – visually it is
more homogeneous, in certain cases it is gypseous, highly embossed and with relatively good
strength indicators. The aqueous compositions of combined hydrophilizing agent of 13% SC/ 3.5%
WG and 12% SC/7% WG demonstrate increased tensile strength by 50 to 70% and tensile elongation
by 90 to 130%. Composites based on NaOH with small amounts of water (up to 15%) show
increased tensile strength by up to 47% and increased tensile elongation by up to 100%.
- PAGES:
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AQUEOUS COMPOSITIONS BASED ON MULTICOMPONENT HYDROPHILIZED POLYMER SYSTEM
- TITLE:
REVERSIBLE ENGINEERING OF DIAMOND-ABRASIVE TOOL WITH WORKING LAYER OBTAINED IN THE FORM OF CLUSTERS
- AUTHOR(S):
O. Salenko, S. Klimenko, . Shepelenko, Mohamed Budar R.F., E. Onishenko, M. Molnar, S. Mahopets
- ABSTRACT:
The paper considers the approach to increase the reliability of the tool based on the analysis of
differences in the interaction of tool surfaces individual areas in the implementation of processing.
To ensure that the properties of the surface clusters correspond to the conditions of the tool further
operation, it is proposed to perform reversible engineering, which is based on the principle of tool
wear analysis during its operation. To this end, a methodology for reengineering a diamond-abrasive
tool with a clustered working layer has been developed. The scheme of the tool quality initial
indicators formation is constructed. Efficiency evaluation of the tool surface modification on a
functional basis was performed on the basis of microcutting phenomena modeling.The basic
regularities of loadings change of a working surface parts and functional features of the tool working
surfaces clusters are established on which requirements to parameters of a diamond layer are
formulated. The efficiency of the tool surface modification on the functional basis is proved and the
basic regularities of a diamond drill, a saw of the renovator, a diamond string work during material
cutting like KIMF are defined.
- PAGES:
5-
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REVERSIBLE ENGINEERING OF DIAMOND-ABRASIVE TOOL WITH WORKING LAYER OBTAINED IN THE FORM OF CLUSTERS
- TITLE:
SEARCH OF METHODS OF CLAMPING OF THIN WALLED CYLINDRYCAL DETAILS WITH THE USE OF GENETIC-MORPHOLOGICAL APPROACH
- AUTHOR(S):
Ibrahim Farhan Salman Alrefo, Yurii Kuznetsov
- ABSTRACT:
The article introduces a generalized classification of thin-walled cylindrical details and a new
approach of genetic morphological synthesis of methods of their clamping based on the latest
advances in various areas of science and technology. The article shows that structural solutions of
thin-walled cylindrical details used in machine tools, machines, apparatuses and other technological
equipment can be classified not only by the ratio of length to outer diameter and end face and by the
presence of an end face, but by the availability of outer and inner projections as well. Such a
diversity of shapes of various thin-walled cylindrical details influences the choice of the method of
clamping them within processing quality assurance.
The article gives examples of various methods of axial, radial, tangential clamps, where they are
described as genetic codes and structural formulae using them as elementary material medium of
hereditary information in mental experiments of a material point. It is noted that the suggested
generic-morphological approach with universal genetic synthesis operators can be one of
prerequisites of employing the artificial intelligence for anticipation and synthesis of clamping
mechanisms and machine tooling in various fields of mechanical assembly manufacturing.
- PAGES:
4-
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SEARCH OF METHODS OF CLAMPING OF THIN WALLED CYLINDRYCAL DETAILS WITH THE USE OF GENETIC-MORPHOLOGICAL APPROACH
