Grey cast iron is the most widely used foundry alloy in the world due to its wide range of achievable mechanical properties, good castability, excellent wear resistance and damping properties, high thermal conductivity as well as low cost (20-40% less than steel) (Xu et al., 2005). It is used in such diverse applications as cookware and musical instruments to auto parts and heavy machineries. Microstructure of grey cast iron is characterized by dispersion of graphite flakes in a ferrous matrix. It has been evidently shown that the size, morphology and distribution of graphite flakes greatly affect the physical and mechanical properties of grey cast irons and that these characteristics depend mainly on the chemical composition of the alloy, the foundry practice adapted such as inoculation treatment used and the cooling conditions during solidification (Bartocha et al., 2005; Xu et al., 2005; …show more content…
Their results showed that average graphite nodule size, free graphite content and ferrite content of the castings decreased and pearlite and eutectic cementite contents increased as the applied pressure was raised from 0 to 75 MPa. The highest graphite nodule count was obtained at 50 MPa applied pressure. The microstructural changes were associated with the improved cooling rate and the expected changes in the corresponding phase diagram of the alloy under pressure. Applied pressure greater that 50 MPa resulted in increased cementite content and decreased graphite nodule count which resulted in lower ultimate tensile strength, fracture toughness and elongation of the castings.
This paper reports the results of a study conducted on the effects of applied pressure during solidification on the morphology of graphite flakes and casting density of a hyper-eutectic grey cast
We use metals to construct all kinds of structures, from bridges to skyscrapers to elevators. The strength as well as durability of materials that are crafted out of metal make the materials ideal not only for construction but also for many other applications.
For the other material ASTM A216 Gr WCB same pressure of 16 Mpa is applied and the stress developed is approximately as similar to the connecting rod made with material of cast iron. Figure no. 9 indicates the maximum and minimum stress developed in connecting rod at small & big end. The equivalent stress maximum and minimum values are 71.347 MPa and 4.4955e-5 MPa respectively.
Die-forming of sheet metal has been around for thousands of years. Originally the metal was manipulated by hand and hammered into the depression, by utilizing crude grooves carved into wood or stone. This technique was used to make spouts, handles, and other forms. Since then, however; they have undergone a remarkable technological evolution. Mate-female conforming dies to create hollow forms by using hydraulic pressure or drop hammer pressure, changed die-forming forever (Paisin, 2013).
For this scope of this assignment a study in the surface modification of a titanium alloy stem, used in a hip joint implant is going to be studied. A total hip joint implant consists of an articulating bearing basically the femoral head and cup and the stem. The stem is made from titanium alloy - Ti- 6Al- 4V where titanium is alloyed with aluminium and vanadium. When titanium is alloyed with these materials excellent properties are achieved such as high strength-to-weight ratio and exceptional corrosion resistance.2 However, this alloy gives poor tribological properties and tends to seize when it is subjected to sliding motion due to its low hardness of 36HRC.3 Several surface modification techniques are done on ti...
Iron is a trace element, which is a group of minerals present in small quantities in the body. Other trace elements include copper, zinc, selenium, manganese and iodine. These minerals cannot be synthesized by the body and must therefore be supplied in the diet. Iron is the most common trace element in the human body; adult males have approximately 3.5 g iron in total, or 50 mg per kg body weight while females have about 2g total iron or 35 mg per kg bodyweight. Iron can exist in oxidation states from -2 to +6, but mainly exists in the ferrous (+2) and ferric (+3) states in biological systems. As iron has the ability to accept and donate electrons readily, it can interconvert between these two forms with ease. Thus, iron can participate in
The machinability of copper and copper alloys is improved by lead, sulfur, tellurium, and zinc while it deteriorates when tin and iron are added. Lead in brass alloys with concentrations around 2 wt%, improves machinability by acting as a microscopic chip breaker, and tool lubricant, while they increase the brittleness of the alloy [17]. Lead additions are used to improve machinability. The lead is insoluble in the solid brass and segregates as small globules that help the swarf to break up in to small pieces and may also help to lubricate the cutting tool action. The addition of lead is however, affect cold ductility which may control both the way in which material is produced and the extent to which it can be post-formed after machining
-Developed and implemented strip casting overseas to eliminate a step in the steel making process
are heated to a high temperature in an oven or a kiln, so that the
The beginnings of modern processing of iron can be traced back to central Europe in the mid-14th century BC. Pure iron has limited use in today’s world. Commercial iron always contains small amounts of carbon and other impurities that change its physical properties, which are much improved by the further addition of carbon and other alloying elements. This helps to prevent oxidation, also known as rust.
The micro hardness of the prepared samples were obtained by using a Vickers Micro hardness Tester (Model : Leco LV 700, USA). 5 readings were taken for each sample to calculate the average hardness. An indentation load of 5gf was used. After calculating the average hardness for each sample, mean variance and standard deviation (S.D.) was calculated to check the consistency of the data.
This book was given to me by a good friend who knew that I had an interest in Asia. I chose to read it because it was a true story and was told that it was a good read.
In the early part of this century was a time when industry was booming with growth around the installation of major railroads. With this growth came the transatlantic cable, the telegraph, and a whole lot of steel. Steel would be needed in the construction of these new transportation systems and communications were now possible between businesses and industries. (Wren, 2005)
The basis for the understanding of the heat treatment of steels is the Fe-C phase diagram. Because it is well explained in earlier volumes of Metals Handbook and in many elementary textbooks, the stable iron-graphite diagram and the metastable Fe-Fe3 C diagram. The stable condition usually takes a very long time to develop, especially in the low-temperature and low-carbon range, and therefore the metastable diagram is of more interest. The Fe-C diagram shows which phases are to be expected at equilibrium for different combinations of carbon concentration and temperature. We distinguish at the low-carbon and ferrite, which can at most dissolve 0.028 wt% C at 727 oC and austenite which can dissolve 2.11 wt% C at 1148 oC. At the carbon-rich side we find cementite. Of less interest, except for highly alloyed steels, is the d-ferrite existing at the highest temperatures. Between the single-phase fields are found regions with mixtures of two phases, such as ferrite + cementite, austenite + cementite, and ferrite + austenite. At the highest temperatures, the liquid phase field can be found and below this are the two phase fields liquid + austenite, liquid + cementite, and liquid + d-ferrite. In heat treating of steels the liquid phase is always avoided. Some important boundaries at single-phase fields have been given special names. These include: the carbon content at which the minimum austenite temperature is attained is called the eutectoid carbon content. The ferrite-cementite phase mixture of this composition formed during cooling has a characteristic appearance and is called pearlite and can be treated as a microstructural entity or microconstituent. It is an aggregate of alternating ferrite and cementite particles dispersed with a ferrite matrix after extended holding close to A1. The Fe-C diagram is of experimental origin. The knowledge of the thermodynamic principles and modern thermodynamic data now permits very accurate calculations of this diagram.
Metals possess many unique fundamental properties that make them an ideal material for use in a diverse range of applications. Many common place things know today are made from metals; bridges, utensils, vehicles of all modes of transport, contain some form of metal or metallic compound. Properties such as high tensile strength, high fracture toughness, malleability and availability are just some of the many advantages associated with metals. Metals, accompanied by their many compounds and alloys, similar properties, high and low corrosion levels, and affects, whether negative or positive, are a grand force to be reckoned with.
In summary, the rate of cooling from the austenite phase is the main determinant of final structure and properties.