Improving the Performance of Electroless Nickel Coatings Using TiN Nanoparticles on Gray Cast Iron

Cam shafts used in automobiles are produced by cast iron (grey cast iron, nodular cast iron) or steel. In this study, effect of chill formation on the surface of grey and nodular cast irons is investigated on the wear behavior, hardness, impact toughness and microstructure of grey and nodular cast irons. For this purpose, four types cam shaft made of grey cast iron with and without chill on the surfaces and nodular cast iron with and without chill on the surfaces, were casted. Mechanical tests were conducted after the camshafts have been produced by casting method. Surface hardness and wear resistance of grey and nodular cast irons have been improved by chill formation on the surfaces and it is concluded that the amount of wear on the surfaces of grey cast iron with chill and nodular cast iron with chill is almost the same. Maximum hardness value was obtained on the surface of grey cast iron with chill. The impact toughness has been found to decrease by chill formation. Maximum impact toughness value was obtained on nodular cast iron. Microstructures of grey cast iron with and without chill and nodular cast iron with and without chill were examined under optical microscope and worn surfaces of cast irons were examined by scanning electron microscopy (SEM). Wear mechanisms of the four types of cast iron were evaluated by SEM examination. Keywords: Cam shafts, Cast irons, Chill formation, Mechanical properties, Microstructure

Wear resistance of cast irons used in brake disc rotors

In this paper, sliding friction and wear behaviors of gray cast iron A35 and white cast iron manufactured by quenching from the same cast iron in water were studied and compared by employing pin-on-disk wear tests. Microstructure of the worn surfaces before and after the wear tests were investigated by optical microscope observations. These images show that flakes separated from the surface in gray cast iron due to delamination process, while in white cast iron, the separation of materials from its surface is in the form of powder. In addition, the gray cast iron had higher graphite volume fraction with Type-A graphite flake morphology. The results show that white cast iron has less rate of wear than gray cast iron due to the higher hardness. However, gray cast iron because of presenting graphite flakes in its surface (lubricant property) has lower average coefficient of friction.

Engine castings are made in grey iron which has UTS (ultimate tensile strength)around 250 MPa. Requirement is to make grey cast iron with higher strength without loosing grey cast iron properties namely thermal conductivity and damping capacity. Objective is to develop high grade cast iron by adding alloying elements. Base iron was made in medium frequency induction furnace. Furnace was charged with medium carbon steel and foundry returns as charge materials. Carbon and silicon percentage in base iron was raised by adding petroleum coke and ferro silicon alloys during melting stage. Hot liquid metal was taken into ladle and alloy tin (Sn) addition had been done into the same metal Alloyed liquid metal was poured into a drys and mould in the bar form. Inoculation (ferrosilicon) had been done before pouring into sample mould. Base grey iron was alloyed with tin in the range 0.010–0.100 wt %.Four numbers (nos.) of test bar samples had been made in the different tin percentage range keeping copper constant in the range 0.45–0.5 wt %. Tin(Sn) was added in grey iron to study mechanical and microstructural properties. Tensile, hardness and impact test had been performed for mechanical properties study. Microstructural properties had been studied on optical microscope for the same tin varied samples. UTS was found upto 253–376.11 MPa, hardness upto 173–222.33 BHN and impact strength upto 3.33–4 J.

Effect of microstructure and surface features on wetting angle of a Fe-3.2 wt%C.E. cast iron with water

This study developed a ceramic composite material (CMC) for use as a refractory material from “Kankara” clay (kaolin) as a matrix material mixed with gray cast iron (GCI) as reinforcement. The CMCs were prepared by varying the percentage by weight of the gray cast iron using 5, 10, 15, 20, 25, 30, 35, 40 and 45 wt%. Tests were conducted on the developed CMC, using standard test techniques, to determine physical and the mechanical properties of the produced composites. The results for mechanical properties showed improvement in the hardness value from 47% at 5% GCI content to 94% at 45% GCI content; the compressive strength improved from 3.11% at 5% GCI to a peak of 7.15% at 25% GCI and then descended down to 3.74% at 45% GCI content while the ultimate tensile strength improved from 0.75% at 5% GCI to a peak of 1.87% at 25% GCI down to 1.34% at 45% GCI content. Equally, there is an increase in bulk density from 1.74% for 5% GCI content to 2.09% for 45% GCI contentment. The linear shrinkage reduced from 11.57% to 1.15%; water absorption also reduced from 33.68% to 15.20%; apparent porosity too reduced from 42.2% to 16.02%. However, cold crushing strength initially increased with increase in GCI content from 3.89 to a peak of 13.32 V for 25% GCI content and progressively dropped to a value of 5.25 V at 45% GCI content. All the values obtained from the blends are within the recommended values for kiln shelves. However, the CMC developed on 25% GCI content showed the best combination of both mechanical and physical properties required of a good material for the production of kiln shelves.

Effect of misch metal inoculation on microstructure, mechanical and wear properties of hypoeutectic gray cast irons

Two types of cast iron were employed in this work. Grey cast iron was the first type, and ductile was the second one. Two specimens of the grey cast iron sample were used; one was kept without heat treatment, and the second was completely heat-treated by ferritisation regime. The two specimens of ductile cast iron were used similarly; one was kept without heat treatment grey and the second was ferritised by heat treatment. Potentiodynamic technique was applied for collecting corrosion data of the above four metal specimens in HCl solutions in the absence and presence of thiourea as an inhibitor. The measurements were performed in different concentrations of HCl (0.05, 0.2, 0.5, and 1 M) at 20?C and in the absence of an inhibitor, on the other hand, corrosion parameters were collected in 0.2 M HCl at different temperature levels (20?C, 30?C, 40?C, and 50?C). Thiourea was added in different concentrations to 0.2 M HCl at 25?C, then corrosion data was deduced. An optical microscope was used to investigate the microstructure of grey and ductile cast iron before and after heat treatment. Corrosion resistance and corrosion rates were collected directly from potentiostat, where Tafel lines were applied to the software. The above raw data was used to deduce activation thermodynamic parameters (Ea*, &#916H?, and ΔS?) of dissolution processes in the absence of thiourea by applying Arhenius equation. Adsorption parameters, in the presence of thiourea, were deduced using the kinetic model and the Flory-Huggins isotherms were used as inhibition mechanisms for the investigation before and after treatment.

Cast a different iron: Grey and mottled cast iron production in early China

ASTM specification A 48 classifies gray irons in terms of tensile strength. The usual microstructure of gray iron is a matrix of pearlite with graphite flakes dispersed throughout. Section sensitivity effects are used in the form of a wedge test in production control to judge the suitability of an iron for pouring a particular casting. Mechanical property values obtained from test bars are sometimes the only available guides to the mechanical properties of the metal in production castings. Gray iron castings are used widely in pressure applications such as cylinder blocks, manifolds, pipe and pipe fittings, compressors, and pumps. Where high impact resistance is needed, gray iron is not recommended. The machinability of most gray cast iron is superior to that of most other cast irons of equivalent hardness, as well as to that of virtually all steel. Gray iron is used widely for machine components that must resist wear.

The wear resistance and damping capacity of hypoeutectic grey cast iron (carbon equivalent =3·59%) were investigated as a function of the relative amount of primary fraction of solid. In the present study the authors have used a cooling plate to produce semisolid iron slurry. Sand mould castings with 14 mm strip thickness were used in the present study. For comparison, damping capacity was also carried out on ordinary ductile iron specimen made from Y block with 15 mm thickness. The wear resistance of grey cast iron was improved using the semisolid processing. The wear rate of grey iron decreases as the fraction of solid increases until 0·12. Further increase of fraction of solid increases the wear rate due to formation of interconnected fine graphite type D. Frictional wear mechanism of iron casting is strongly affected by shape, size and arrangement of graphite precipitates. For semisolid casting at high loading, increasing the sliding speed increases the rate of oxidation and consequently changes the wear mechanism. The damping capacity of semisolid grey cast iron is lower than ordinary grey iron but higher than ductile iron for all strain amplitude ranges. The damping capacity of both ordinary and semisolid grey cast iron increases with strain amplitude.

Cast iron, especially ductile iron, is being used more and more in most countries of the world due to its excellent mechanical properties, castability, and good price. Cast iron alloys can be given a wide range of properties by changing the alloy composition, inoculation, and treatment, heat treatment, or cooling conditions. On a weight basis, most castings are made in gray cast iron. Some examples of gray and ductile iron products are shown in Fig. 1 [1]. The main factors for the high usage are good casting properties, low price, good cutability, and unique properties like damping and good tribology. Lamellar gray cast iron has very good damping capacity. This property is used in many components where damping of sound and vibration is important. Gray iron, also called lamellar graphite iron, is an iron–carbon–silicon alloy with different alloying elements. To understand the microstructure formations and to model them and other important phenomena, both the solidification and the solid-state transformations must be considered. These phase transformations are, to a large extent, affected by nucleation and growth kinetics which are dependent on, for example, handling of the melt, charge material, melting method, metal treatment, inoculation, pouring method, casting process and mold material, cooling power of the mold, and other factors. Many of these important material and process factors and combinations of them are still not fully understood today. Consequently, it is necessary that a foundry producing cast iron components has very strict process control in order to avoid unpredictable problems in production. When this is the case, it will also be possible to use simulation tools for predicting solidification sequence, microstructures, mechanical properties, as well as formation of defects.

DLC deposited onto nitrided grey and nodular cast iron substrates: An unexpected tribological behaviour

Ductile iron is currently one of the most popular construction materials. Its mechanical properties are close to those of steel. The basic material in the production of ductile iron is gray iron, which can be produced in a cupola or in an electric induction or electric arc furnace. After tapping the gray cast iron from the furnace, the gray cast iron is processing into ductile iron. This process is called modification. Magnesium and its alloys and cerium are most often used as modifiers. In addition to the modification, the cast iron must then be inoculated. This paper deals with the impact of gray cast iron modification on the working environment. The experiments were performed in two foundries, where three modification technologies were used: the pouring method, the Tundisch cover and the Flottret method. The aim of the experiments was to determine how the individual modification methods affect the development of magnesium vapor, the content of carbon monoxide in the working environment and the temperature in the working environment. During the experiments, the CO content and temperature were measured before the modification itself, immediately after the modification and one hour after the modification. The greatest development of CO occurred after the modification. This was most significant in the pouring method. A similar situation occurred in the case of a change in temperature. Within one hour of the start of the modification, both the CO content and the ambient temperature returned to the original level before the modification.

Tribological study of gray cast iron with automotive brake linings: The effect of rotor microstructure