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.
When we visited the United Arab Company for Spinning and Weaving In the capital, Damascus, we found
a lot of problems in the units of feeding steam, and the most prominent of these problems occur corrosion
in the pipe of steam boilers, And the coll
apse in the heat exchanger on the thread dyeing machine (the
collapse of the body and pipes), so we took a group of samples in the places that suffer problems in order
to determine the mechanical and chemical properties, we found through analysis that the boiler tubes
were made of carbon steel, while the tubes and the body of heat exchanger was made of stainless steel, has
been shown through research that pipe boilers of carbon steel suffers of problems as a result overheating,
hydrogen damage and an attack Oxide, And the body of heat exchanger was suffering from an corrosion
Cracking result of the high proportion of chromium in it (chromium ratio up to 17%), has been
developing a set of solutions represented to be the metal surfaces clean and homogeneous, and must be
feed water free of salts, suspended solids, and gases
The corrosion behaviour of plain-carbon steels in water environments has been studied. In
this study, a wide range of carbon steels are used in the most common corrosion environments
which are salt water and drinking water. The specimens were immer
sed in the water media and corrosion rates evaluated, using the weight loss method. The effect of
carbon content, corrosion environments and time of immersing on the specimens corrosion
rates of Hypo-eutectoid plain carbon steels have been studied. The aim of this work is to study
the effect of carbon content on the corrosion rate of carbon steels in different corrosion media
and various time intervals. The obtained results showed that there is a clear correlation with
the microstructure where higher Pearlite show higher corrosion rate, so the corrosion rate
increases with the carbon content. The results also show that the corrosion rate of carbon-steel
in salt water is higher than its value in drinking water. It is also found that longer exposure
time, leads to a lower corrosion rate while weight loss is still increasing.
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 .
يتناول البحث عملية ترسيب السيليسيوم من أوكسيد السيليسيوم على الفولاذ و ذلك بالطريقة
الساكنة لتحسين خواصه بحيث يصبح أكثر مقاومة للحرارة و الأكسدة و التأكل و غيرها، و السلكنة
هي اشباع السطح الفولاذي بالسيلكون، و انتاج طبقة سطحية منتظمة و متماسكة.
لق
د تمت كتابة معادلات التفاعلات الممكنة و حساب الشروط الترموديناميكية المثلى نظرياً،
و التي ستمكن من اجراء التجارب لاحقاً، و تصنيع الجهاز المطلوب.
