In this work, Ck85 carbon steel was subjected to cyclic heat
treatment.
Process that consisted of cyclic short-duration (3.4 minutes)
holding at 800 C (above Ac3 temperature) followed by forced air
cooling. After 8 cycles (about a total 1 hour du
ration of heating and cooling cyclic), the microstructure mostly contained fine ferrite
grains and spheroidzed cementite. This microstructure possessed
an excellent combination of strength and ductility. The disintegration of lamellar pearlite through dissolution of cementite
at boundaries lamellar during short-duration holding above Ac3
temperature, and the generation of lamellar defects during nonequilibrium forced air cooling were the main reasons of
accelerated spheroidization. The strength initially increased mainly
due to the presence of finer microconstituents (ferrite and pearlite)
and then marginally decreased with the elimination of lamellar
pearlite and appearance of spheroid cementite in the microstructure.
Concrete considers as the most popular building material because of the many advantages that it has. This come up with a huge amount of concrete waste. As a way to produce a concrete which is friend to environment, four percentages 0%, 50%, 75%,
100% of coarse recycled aggregate as replacement of natural coarse aggregate in concrete mix are used in this research. The work ability and wet and dry density are presented in this study. The compressive strength at age of 7, 28, 56 days are estimated, also splitting tensile strength and modulus of elasticity are founded at 28 day. The study shows that when The percentage of recycled aggregate exceeds 50% in concrete mix the mechanical properties reduce. When 100% of recycled aggregate is used the compressive strength, splitting tensile strength and elastic modulus decrease by 14%, 22%, 25% respectively, so it is possible to use recycled aggregate concrete in production of non-structural elements.
In the present work, the rheological and mechanical properties of
polypropylene /thermoplastic starch (PP/TPS) and acrylonitril-butadienestyrene/
thermoplastic starch (ABS/TPS) blends were investigated. Starch was
plasticized using glycerol, and b
lends were prepared using a laboratory scale
with single screw extruder. Rheological properties of the prepared blends were
determined using a capillary rheometer. Mechanical properties were studied in
term of tensile tests, stress at break, strain at break and Young's modulus were
determined.
The effects of induction hardening on mechanical properties of two kinds of carbon
steel (0.59%C , 0.35%C) that are widely used in local industry, were discussed by exposed
specimens that were induction hardened with different values of power and i
nductor's
speed to hardness, tensile, and impact tests.
The results of tests showed that the mechanical properties become greater with slight
decrease in impact energy of carbon steel when induction hardening is used, and showed
the possibility to do control on product's properties by make control on treatment
parameters .
The large increase in the volume of demolition concrete waste and its impact on the
environment has led to reconsider of using concrete demolition rubble as a partial or a
whole alternative of natural aggregates to produce new concrete which has th
e required
properties to use in engineering constructions[1]. With the possibility of improving the
mechanical properties of this concrete by processing this aggregates before using it or
support this concrete with fiber to improve its structural behavior.
This research deals with the study of the replacement the natural aggregates used in
concrete with recycled concrete aggregates resulting from the demolition rubble ,
according to different replacement ratiosranging between 0 % -25 % -50 % -75 % -100%
and the impact on the concrete behavior with a natural aggregates and determine the
optimal replacementpercentage.
The results showed a relative decrease in the concrete resistance on the simple
pressure , limited decrease in the volumetric mass also, and a slight adjustment to the
behavior of concrete under the loading effect by increasing the replacement proportion of
the natural aggregateswith recycled concrete aggregates..
Thepaper studies the mechanical properties ofsteel fibers reinforced lightweight
concrete.This kind of concrete is produced by usingscoria aggregateswhich can be found
abundantly in Syria. Thelightweight concrete mixeswere designed for three differ
ent
percentage of steel fibers (0, 0.5, 0.75)%.
Different tests were performed to determine mechanical properties of product
concrete such as compressive strength, elasticity modulus, splitting tensile strengthand
flexural strengthalso; the stress–strain diagram of produced lightweight concrete was
established under compression.
The results showedanincrease of the compressive, splitting tensile and flexural
strengths reach up 16.9%, 25.6%, and 53.6% respectivelywhen the steel fibers were used.
Also the results indicated the importance of using the steel fibers to improve the
performance of concrete and change its brittle behavior to ductile behavior.
In this research a proper amount solvent has been for Neoprene
rubber to give it the required viscosity. Zinc oxide has also been
added with different ratios to improve the process of adhesion. We
made compound substances on the basis of Neoprene
and
improved them with glass fibers by means of different ways of
solidification, and with different weight ratios by means of manual
molding through designing a wooden mould containing five parts
with certain measurements, and studying the orientation of these
fibers and their effects on some mechanical characteristics of
Neoprene rubber.
the best utilization of raw material for manufacturing the optimum
quality of yarn has become inevitable for the spinning mills to face
the global competition.
mechanical properties of yarn are of the most important properties
from quality point
of view and largely depend upon the fiber length
and micronair value ; which are considered the foremost quality
parameters for the selection of raw material .
it is the purpose of this study to investigate the effect of cottons
differing fiber length and micronair value on mechanical propeties
of yarn so as to contribute in determining the optimum using of the
raw material .
Because of large industrial development which the world has seen in
all fields. scientists and researchers aim to produce new materials
that having special engineering properties with low economic cost as
fit multiple industrial application and us
es. So in This present
article We try to prepare composite materials based on aluminum
alloy (6663) and reinforcement it by different particles having size
of micron of Alumina and silicon carbide particles are added in
specific weight parentage by stir casting
technique to obtain Aluminum Which having the improving
mechanical properties
