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.
Refusion the boundaries of weld's reinforcement was done using TIG
without filler metal .The mechanical properties & micro-structure of
various zones in low carbon steel welded joints were studied.
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..
This search aims to study the effect of additive materials ( Ethyl Methyl Keton
Peroxide MEKP , Cobalt Naphthenate ) at the important values of (stress-strain) curves
( stress and elongation at break ) for the preparing specimens from reinforced an
d nonreinforced
with fiber glass unsaturated polyester resin.
The result showed that the investigated parameters are clearly affected with using
additive materials and the optimum concentration for non-reinforced specimens which was
curing in room temperature was (1% MEKP + 1% Cobalt Naphthenate) and (0.8% MEKP
+ 1% Cobalt Naphthenate), and for reinforced specimens with fiber glass was:( 1% MEKP
+ 0.8% Cobalt Naphthenate) and ((0.2-0.4) % MEKP + 1% Cobalt Naphthenate).
The results showed also that it is possible to get the better values of tensile stress at
break when the specimens was curing in oven at 100 Cº and treated at this temperature for
15 min.
درست في هذا البحث الخواص الديناميكية للبولي كربونات (P.C) في الحالتين المنصهرة و الصلبة
عند درجات الحرارة ٢٠٠ , ٢١٠ , ٢٢٠ , ٢٣٠ ºC و بزاوية تشوه للاجهاد ٢ْ ، و باستخدام جهاز
الميزان الريومتري نظام الدكتور كبيس.
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
The Loos powder Sintering for metals powder is one of
the important manufacturing methods, where contact and
solidity are insured among particles, The high porosity
Filters which is sintered from metal powders is one of the
best filters .
The re
search aim especially to study the Temperature Effect
of loos powder sintering on Mechanical properties of
bronze gas filters works at 200 bar.
