- TITLE:
EFFECT OF DIAMOND BURNISHING PROCESS VELOCITY ON 41Cr4 STEEL SURFACE INTEGRITY
- AUTHOR(S):
V. P. Dunchev
- ABSTRACT:
Diamond burnishing (DB) is a static mechanical surface treatment process based on severe
plastic deformation on the surface layer of the metal work-pieces. The main feature of the DB is that
the tangential contact type between the diamond deforming element and the surface being treated -
sliding friction contact. DB significantly reduces the roughness (up to mirror-finish surfaces),
increases the surface micro-hardness, introduces the beneficial residual stresses and modifies the
microstructure of the surface and subsurface layers in terms of grain refinement. Thus, DB
dramatically improves the surface integrity (SI) of the metal components. The basic governing
factors of the DB are the radius of the spherical-ended diamond, burnishing force, feed rate and
burnishing velocities. This article presents the outcomes from the experimental investigation of the
influence of sliding burnishing velocity on SI of 41Cr4 steel. It was established that the burnishing
velocity influences slightly on the SI. The increased burnishing velocity leads to slightly decrease of
the roughness obtained, slightly increase of the surface micro-hardness and a reduction of the
surface axial residual stresses; in contrast with the residual axial stresses, the residual surface hoop
stresses increase.
- PAGES:
1-
- DOWNLOAD:
EFFECT OF DIAMOND BURNISHING PROCESS VELOCITY ON 41Cr4 STEEL SURFACE INTEGRITY
- TITLE:
HEAT TRANSFER ENHANCEMENT BY A COMBINATION OF SPIRALLY CORRUGATED TUBES WITH A TWISTED TAPES PART 2 -THERMODYNAMIC EFFICIENCY
- AUTHOR(S):
V. Petkov
- ABSTRACT:
Extended performance evaluation criteria (PEC) equations for enhanced heat transfer surfaces
have been used to assess the multiplicative effect of combination of spirally corrugated tube with
twisted tape inserts. Thermodynamic optimum can be defined by minimizing the entropy generation
augmentation number compared with the relative increase of heat transfer rate or relative reduction
of heat transfer area.
- PAGES:
61-
- DOWNLOAD:
HEAT TRANSFER ENHANCEMENT BY A COMBINATION OF SPIRALLY CORRUGATED TUBES WITH A TWISTED TAPES PART 2 -THERMODYNAMIC EFFICIENCY
- TITLE:
HEAT TRANSFER ENHANCEMENT BY A COMBINATION OF SPIRALLY CORRUGATED TUBES WITH A TWISTED TAPES PART 1 - HYDRAULIC RESISTANCE AND HEAT TRANSFER COEFFICIENTS
- AUTHOR(S):
V. Petkov
- ABSTRACT:
Heat transfer and isothermal friction pressure drop results have been experimentally obtained
for two single-start spirally corrugated tubes combined with five twisted-tape inserts with different
relative pitches in the range of Reynolds number - . The characteristic parameters of the
tubes are height to diameter ratio, e/Di=0.0371 and 0.0261; pitch to height ratio, p/e=11.6 and 15.9;
and relative pitch, H/Di= 15.68-5.80. Significantly, higher friction factor and inside heat-transfer
coefficients than those of the smooth tube under the same operating conditions have been observed.4
10 410
- PAGES:
56-
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HEAT TRANSFER ENHANCEMENT BY A COMBINATION OF SPIRALLY CORRUGATED TUBES WITH A TWISTED TAPES PART 1 - HYDRAULIC RESISTANCE AND HEAT TRANSFER COEFFICIENTS
- TITLE:
A STUDY ON SIMULATION OF METAL CUTTING PROCESS BASED ON LS-DYNA
- AUTHOR(S):
T. T. Tung, N. Y. Nhi, N. T. Anh
- ABSTRACT:
Metal cutting is one of the most important processes in the manufacturing industries for
fabricating a particular product or a mechanical part. It was very difficult to research the
performance of a cutting process because the complex physical phenomenon of the cutting operation
makes it a challenging task in research. This paper presents numerical simulations of the metal
cutting Smoothed Particle Hydrodynamics (SPH) method. In this paper, the two cutting metal models
were built by using SPH technique. The results obtained using the model assures the exactness of the
proposed method and prove that the SPH method is a practical approach for eliminating metal
cutting problems.
- PAGES:
47-
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A STUDY ON SIMULATION OF METAL CUTTING PROCESS BASED ON LS-DYNA
- TITLE:
CLASSIFICATION OF THE DEVICES AND TOOLS FOR HOLE BURNISHING
- AUTHOR(S):
D. K. Drumeva
- ABSTRACT:
In this article a morphological classification scheme of devices/tools for hole burnishing is
proposed. The classification scheme has a hierarchical structure containing uniquely marked
elements at three levels. It is based on four main characteristics of the devices/tools for hole
burnishing. Based on the matrices of the selected main characteristics, the combinations
corresponding to different functional schemes of existing devices/tools for hole burnishing were
defined. On this basis, an analysis of the corresponding devices/tools was made in the context of
their field of application.
- PAGES:
38-
- DOWNLOAD:
CLASSIFICATION OF THE DEVICES AND TOOLS FOR HOLE BURNISHING
