Gray Iron Research Articles

Development of an automated 3D metallography system and some first application examples in microstructural analysis

Abstract Traditional metallography relies on the imaging of individual section planes. However, conclusions as to spatial shapes and microstructural arrangements can only be drawn to a limited extent. The idea to reconstruct three-dimensional microstructures from metallographic serial sections is therefore obvious and not at all new. However, the manual process of preparing a great number of individual sections and assembling them into image stacks is time-consuming and laborious and therefore constitutes an obstacle to frequent use. This is why the Federal Institute for Materials Research and Testing, or BAM for short (Bundesanstalt für Materialforschung und -prüfung), is developing a robot-assisted 3D metallography system performing the tasks of preparation and image acquisition on a metallographic section fully automatically and repeatedly. Preparation includes grinding, polishing and optional etching of the section surface. Image acquisition is performed using a light optical microscope with autofocus at several magnification levels. The obtained image stack is then pre-processed, segmented and converted to a 3D model resembling a microtomographic image, but with a higher lateral resolution at large volumes. As opposed to tomographic techniques, it is possible to perform traditional chemical etching for contrasting. The integration of a scanning electron microscope is in the planning stages. Studies conducted so far have demonstrated the possibility of visualizing hot gas corrosion layers, gray cast irons and ceramic-based microelectronic structures (vias).

An Evaluation of the Tool Wear of Ceramic and Coated Carbide Inserts in Finishing Turning under the Influence of Age-Strengthening Gray Cast Iron

Gray cast iron (GCI) is a common material in the automotive industry due to its mechanical characteristics, which change primarily for materials employed for the foundry and cooling rate of material. According to the workpiece, the material of the cutting tool and cutting parameters are analyzed to improve the machining and to increment the lifetime of the tools. In this research, the foundry and machining process of an automotive component using ceramic and coated carbide tools were the study case, and the effect that they have on the age strengthening of GCI on the tool wear of the cutting tools was studied. Both inserts have the capability to machine the material with a rough surface between 1.5 to 2.0 μm. The wear mechanism of inserts and the microstructure of GCI were characterized with microscopy techniques, atomic force microscope (AFM), and energy dispersive X-ray spectroscopy (EDS). The microstructure of the workpiece shows a casting with flake graphite morphology that is linked with the induction of microcracks in the material. The experimental analysis shows that the GCI with 12 days of aging has an increased tensile strength. This improves the tool life of ceramic and coated carbide tools. There is a 50% reduction in flank wear with inserts that are machined with the GCI within five days of aging, compared with the material within twelve days. The rake face and flank wear show that abrasive and adhesive wear are the main mechanisms of ceramic inserts due to the high cutting speed. Meanwhile, adhesive and oxidative wear in the flank were the predominant type of wear for coated carbide tools.

The influence of tunnel joints on the present-day condition of a grey cast iron tunnel

The present-day condition of a grey cast iron (GCI) tunnel was investigated numerically by means of a series of plane-strain geotechnical analyses that focused on establishing the influence of the modelling approach adopted to simulate the behaviour of longitudinal tunnel joints. The GCI tunnel lining was simulated in three different ways: (i) as a continuous lining; (ii) as a jointed lining adopting a simple joint model that neglects the presence of the joint bolts and (iii) as a jointed lining adopting a more sophisticated model that considers both the nonlinear response of the joint after opening and the contribution of the bolts to the ultimate capacity. The numerical results demonstrate that accounting for the tunnel joints has a considerable impact on the tunnel response. Significant differences are also observed in the results obtained with the two joint models, hence demonstrating the practical significance of employing an advanced model able to reproduce accurately the rotational behaviour of the joint. The drainage behaviour of the joints was also investigated and the numerical results indicate that drainage even through only the knee joints causes significantly more soil consolidation than that from a watertight tunnel and consequently, larger tunnel deformations and forces.

Effect of V-Mn-Cr inoculant on microstructure and mechanical properties of grey cast iron

ABSTRACT In this study, the effects of different composition V-Mn-Cr inoculants on the microstructure and mechanical properties of GCI were investigated through Optical microscope (OM), Scanning electron microscope (SEM), Energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), etc. The results showed that the optimum quantity of inoculant was 7% V, 1% Mn and 6% Cr, and compared with the commercial inoculant samples, the tensile strength, Brinell hardness, and elastic modulus of the V-Mn-Cr inoculant samples increased by 16.7%, 14.2%, and 12.8%, respectively. V-Mn-Cr inoculants were found to refine austenite, graphite, pearlite and eutectic cells size, reduce pearlite lamellar spacing, and increase pearlite and eutectic cells number, thus improving mechanical properties. In addition, graphite nucleation substance may consist of oxides (SiO2, FeO, Cr2O3), carbides (SiC, TiC), sulfides (MnS, FeS), and XO·SiO2 silicates (X: Mn, Fe, Ca).

Influence of alloying elements and its effect on austempering of compacted graphite iron – A review

Compacted Graphite Iron (CGI) is a type of cast iron with intermediate properties between grey and ductile cast iron. The vermicular graphite structure in the CGI provides unique properties to manufacture automotive and other engineering components. However, because of its narrow range of metallurgical control, a high volume of CGI production is not attempted in many foundries. The addition of alloying elements and austempering heat treatment process has a significant effect in altering the properties and microstructure of CGI. Hence, the objective of this paper is to review the influence of various alloying elements and austempering processes in manufacturing CGI components. Eventually, the scope for the research on the development of austempered CGI is identified.

The diamagnetic component map from quantitative susceptibility mapping (QSM) source separation reveals pathological alteration in Alzheimer’s disease-driven neurodegeneration

A sensitive and accurate imaging technique capable of tracking the disease progression of Alzheimer's Disease (AD) driven amnestic dementia would be beneficial. A currently available method for pathology detection in AD with high accuracy is Positron Emission Tomography (PET) imaging, despite certain limitations such as low spatial resolution, off-targeting error, and radiation exposure. Non-invasive MRI scanning with quantitative magnetic susceptibility measurements can be used as a complementary tool. To date, quantitative susceptibility mapping (QSM) has widely been used in tracking deep gray matter iron accumulation in AD. The present work proposes that by compartmentalizing quantitative susceptibility into paramagnetic and diamagnetic components, more holistic information about AD pathogenesis can be acquired. Particularly, diamagnetic component susceptibility (DCS) can be a powerful indicator for tracking protein accumulation in the gray matter (GM), demyelination in the white matter (WM), and relevant changes in the cerebrospinal fluid (CSF). In the current work, voxel-wise group analysis of the WM and the CSF regions show significantly lower |DCS| (the absolute value of DCS) value for amnestic dementia patients compared to healthy controls. Additionally, |DCS| and τ PET standardized uptake value ratio (SUVr) were found to be associated in several GM regions typically affected by τ deposition in AD. Therefore, we propose that the separated diamagnetic susceptibility can be used to track pathological neurodegeneration in different tissue types and regions of the brain. With the initial evidence, we believe the usage of compartmentalized susceptibility demonstrates substantive potential as an MRI-based technique for tracking AD-driven neurodegeneration.

Design and Analysis of Ventilated Disc Brake by Using Different Materials: A Review

Abstract: Disc rotor is component which is used in automotive vehicle wheels to apply brakes, the concept which works during brake is frictional resistance between pad and rotor. Due to frictional resistance the heat gets generated between disc and pad so, in order to reduce the effect of heat the rotor is designed as ventilated disc. The common material which is used to manufacture the disc rotor is Grey Cast Iron. The purpose of this review paper is to study the behavior and kinds of work has been done before on Disc Brake and based on this review paper we have decided to do structural analysis on disc brake rotor using different materials like GREY CAST IRON, TITANIUM, MAGNESIUM ALLOY, ALUMINUM ALLOY, and STRUCTURAL STEEL and then compare the results of different materials with conventional material (GREY CAST IRON) that is usually used in disc brake rotor. The analysis will be done by using CATIA for modeling and ANSYS WORKBENCH 18.0 for structural analysis. Based on previous research the objective of this review paper is “Design and analysis of ventilated disc brake by using different materials”

The Production of Marine Iron Objects in Europe Following the First Industrial Revolution: The Akko Tower Shipwreck Test Case

Four ferrous objects, a winch, a heart-shaped shackle, a deadeye strap with a futtock plate, and a stud-link chain controller, that were retrieved from the Akko Tower shipwreck were studied by different methods, including conventional metallography, light microscopy, scanning electron microscopy with energy-dispersive spectroscopy, optical emission spectroscopy, microhardness measurements, and the novel field multi-focal metallography (FMM), in order to determine their composition, microstructure, and manufacturing methods. The results of FMM agree well with conventional destructive metallography. The winch drum was made of grey cast iron and its shaft was wrought iron; the heart-shaped shackle and the deadeye strap with a futtock plate were wrought iron; and the stud-link chain controller was grey cast iron similar in composition and microstructure to the winch. All the wrought iron items revealed a similar composition and microstructure. Based on the composition, microstructure, and manufacturing processes of the four items, it is suggested that they were manufactured in the mid-nineteenth century. The high quality of these items indicates that they were produced using controlled processes, probably in the same workshop.

Repair Welding of Broken Gray Cast Iron Pipes Instead of Applying Lock-Stitching Method

Repair Welding of Broken Gray Cast Iron Pipes Instead of Applying Lock-Stitching Method

Surface modification of grey cast iron by laser cladding for automotive brake disc application

In this research, Laser Cladding (LC) of three different alloys powders, two iron-based (AISI 4140 and SS420) and a Cobalt-based (Stellite 6) was performed on a Grey Cast Iron (GCI) substrate. The Stellite 6, SS420, and AISI 4140 cladding samples were tested against a semi-metallic composite brake pin for friction and wear study using a pin-on-disc friction test rig (under dry-sliding conditions). The surface wettability tests were performed on GCI, and cladding discs showed Stellite 6 and AISI 4140 were hydrophobic while SS420 and GCI were hydrophilic. Stellite 6, SS420, and AISI 4140 had surface hardness values of 542.16 HV1, 689.56 HV1, and 719.50 HV1, respectively. The friction test indicated that AISI 4140 and Stellite 6 cladding discs could produce a stable Coefficient of Friction (CoF) and friction layer coverage. SS420 could not maintain a constant CoF for the entire test duration as the plowing effect of the wear particles damaged the friction layer created on its surface. Stellite 6's average CoF value was closest to that of the GCI disc, whereas AISI 4140 and SS420 were found to have a higher average CoF. The LC on grey cast iron reduced its wear rate, with AISI 4140 being the most wear-resistant cladding, followed by SS420 and Stellite 6, respectively. All three cladding layers exhibited three-body abrasive wear, with the rolling mechanism dominating the AISI 4140 surface and sliding on the remaining two.

Comparative assessment between DFA, NSGA-II coupled with TOPSIS, GRA, and TOPSIS for multiobjective optimization of gray cast iron turning process using CBN insert

This work deals with the optimization of the machining process of EN-GJL-250 gray cast iron with a CBN/Tin-coated insert. The multiobjective optimization was performed by four methods, in order to find the optimal cutting conditions (cutting speed (Vc) , feed rate ( f), and depth of cut (ap)) that would satisfy the goals of improving surface quality, minimizing power consumption, and maximizing productivity simultaneously. The aim is to evaluate the performance of different techniques, namely desirability function approach, Grey relational analysis, technique of order preference similarity to the ideal solution (TOPSIS), and nondominated sorting genetic algorithm coupled with TOPSIS. The outcomes revealed that the methods propose different solutions, where significant divergences were mainly observed in power consumption and material removal rate objectives. This raises the issue of selecting the most appropriate optimization method for industrial needs and confirms the need for further efforts in this field, i.e. optimization of the machining process.

Microstructural Properties of Particle-Reinforced Multilayer Systems of 316L and 430L Alloys on Gray Cast Iron

Gray cast iron (GJL) is known for its excellent damping property and high thermal conductivity, thanks to its unique lamellar graphite and pearlite structure. In a recent study, laser metal deposition (LMD) was explored as a potential process to enhance the corrosion resistance and wear mechanism of this tribological system. The focus was on laser cladding of gray cast iron using two different of stainless-steel materials, namely 430L and 316L, combined with TiC and WC particles. To create the samples, a multilayer coating system was employed. A comparative analysis of the microstructures was performed to understand the interaction of the laser beam with the material (composite materials). Surface properties were then characterized using light microscopy and electron microscopy (SEM) before and after subjecting the samples to a shock corrosion test, simulating automotive conditions. Additionally, phase analyses were performed at the interfaces between the coatings and the substrate, with particular attention given to the behavior of the graphite lamellae at these interfaces. This study aims to provide valuable insights into the potential improvements that can be achieved through laser cladding on gray cast iron, specifically in terms of corrosion resistance and wear mechanisms. By analyzing the microstructures and surface properties, researchers can gain a better understanding of the performance and durability of the coated samples.

Emission and Lubrication Performance of Hazelnut Oil as A Lubricant

The aim of this study is to search the tribological and emission performances of hazelnut oil as a lubricant in one cylinder two-stroke gasoline engine and simulation-testing machine. The tribological and emission performances of mineral oil and hazelnut oil as lubricant were compared. In the experiments, simulation-testing machine and one cylinder two-stroke gasoline engine were used to determine the tribological performance of these two lubricants. The wears on the surfaces of cylinder were analyzed to examine the lubricant performances. In addition to lubrication performance, exhaust emissions of the lubricants were also measured. To observe the effects of different kinds of cylinder surface materials, TiN, CrN and gray cast iron coated cylinder surfaces were used in simulation testing machine. The wear as well as the soot formation on the cylinder surfaces increased when hazelnut oil was used as the engine lubricant. However, hazelnut oil exhibited good lubrication properties in simulation testing machine. When hazelnut oil was used, CO and HC emissions increased while CO2 emission decreased.

Improving the Properties of Gray Cast Iron by Laser Surface Modification.

Laser surface modification is a widely used technology to improve the properties of functional surfaces. In this study, the properties of gray cast iron are modified by laser surface modification, and the influence of laser quenching on the properties of cast iron in terms of frictional vibration and noise, friction and wear, internal structure, residual stress, hardness, and corrosion resistance is investigated. The experimental results show that, after high-power laser quenching, the frictional vibrations and noise of most gray cast iron specimens are decreased, but the coefficients of friction against a bearing steel counterface are increased and more stable. The surface and sub-surface hardness of all laser-quenched cast iron specimens is significantly increased. The residual stresses on the surface of the cast iron specimens are significantly increased and changed from tensile to compressive residual stresses. Experimental modal testing results show that the modal damping ratios of the laser-treated specimens are increased significantly, although their modal frequencies are not significantly changed. In addition, through the metallographic observation, XRD (X-ray diffraction) analysis, and TEM (transmission electron microscopy) observation, it is found that the microstructures of the cast iron specimen after high-power laser modification become fine-grained, and the pearlite and ferrite in the matrix become fine martensite, which leads to the improvement of the dynamical, tribological, and chemical properties of cast iron after laser modification.

Effect of Manganese on Microstructural, Mechanical, and Electrochemical Properties of Ni-Resist Gray Cast Irons

Effect of Manganese on Microstructural, Mechanical, and Electrochemical Properties of Ni-Resist Gray Cast Irons

Effect of Ultrasonic Treatment on Microstructure and Properties of Gray Cast Iron

The effect of ultrasonic treatment on the microstructure and properties of gray cast iron was studied. The samples were analyzed by metallographic microscope, scanning electron microscope, Brinell hardness tester, electronic universal testing machine, etc. The results showed that ultrasonic treatment could improve the pearlite content in the microstructure. After ultrasonic treatment, the tensile strength of gray cast iron can be improved to 266 MPa, which is 11.60% higher than that of the samples without ultrasonic treatment. Ultrasonic treatment can refine the size of graphite, which can reduce the stress concentration. In addition, the pearlite lamellar spacing can also be reduced, which is the main reason for improving the mechanical properties of gray iron.

Ductile Iron: A Low-Cost Optimal Anode Material for Electrochemical Generation of Ferrate(VI)

The effects of anode composition and temperature on anode electrochemical properties, the passivation layer’s structure, and ferrate(VI) generation in 14 M NaOH were investigated. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic polarization (GP) were used to analyze the electrochemical processes involving the electrosynthesis of ferrate using some low-cost anode materials: ductile iron, grey cast iron, and mild steel. The results proved that the presence of silicon and graphite with sphere form in the ductile iron anode significantly increased ferrate electro-generation. The optimal temperature for the electro-generation of ferrate was 30 °C–40 °C. The current efficiency using the ductile iron anode was constantly at least about 30% superior to that of the grey cast iron and mild steel electrodes. The ductile iron anode material was the most feasible option because it provides the highest ferrate concentration (1.58 g L−1) with the highest current efficiency of 74% and the lowest specific energy consumption of 1.2 kWh kg−1 ferrate.

Design analysis and fabrication of a 24 -teeth spur gear from HT250 gray cast iron

Spur gears are types of gears used for transmitting motion between two parallel shafts. This machine often encounters failure and downtime as a result of failure of the gear component. These failures include; pitting, scoring, fracture, wear, and so on. This study focused on the use of Gray Cast Iron (HT250) to develop a spur gear having 24 teeth and a protruding connecting shaft to link it to a machine using keys or other means. The fabrication process that was used to obtain gear was Casting which was done in the Foundry Workshop of the Mechanical Engineering Department in Covenant University. The failure indicated on the gear was a cyclic failure due to fracture. The stress analysis was carried out on this element using this software. A cyclic force of 10 N was subjected to the gear and the following values were obtained: the maximum Von-mises stress was 3.548 x 105N/m^2 and the minimum was 5.629 x 10-1N/m^2, The maximum displacement or deflection gotten was 6.306 x 10-5 mm and minimum is 1 X 10-30 mm, The maximum strain gotten was 2.599 x 10^-6 and the minimum was 9.825 x 10^-12. Various parameters were used to obtain the nature of failure on the material such as the force on 10 N on a single tooth and on all 24 teeth, a torque of 10 N/m, temperature of 50-degree, pressure of 20 Pa and centrifugal force of 5 rad/s. These results to variation in the von mises stress.

Particle size distribution analysis of carburized HT250 gray cast iron using ImageJ

The study focused on the particle size analyses of a carburized HT250 gray cast iron using ImageJ software to understand the pattern of carbon diffusion after the carburization process. Pulverized pal kernel shell was deployed in the carburization of several samples of the grey cast iron after which the samples were characterized using scanning electron microscope (SEM) to study the microstructure of each sample. More so, ImageJ was equally deployed in the analyses of the SEM microstructures to understand the diffusion patterns of the carbon from the pulverized palm kernel shell so as to predict their structural behavior when deployed in fabrication process. Some of the important features from the ImageJ include Surface Plot, Interactive 3D surface plot and Intensity thresholding. The result showed the various diffusion patterns of carbon into the parent material. Thus, this result will help in the field of material science on the best method of material processing for adequate mechanical and structural properties.

Deep gray matters iron deposition is positively associated with white matter hyperintensity in hypertension.

The association and underlying mechanisms between iron deposition and white matter hyperintensity (WMH) remain unclear. In this study, quantitative susceptibility mapping (QSM) was used to quantify deep gray matters iron deposition and to explore the association from both global and regional perspectives. A total of 84 patients with hypertension and 26 healthy controls underwent a strategically acquired gradient echo (STAGE) protocol, and the multi-echo data were used to reconstruct QSM images. The susceptibilities were used to describe iron content. Global region (RI) susceptibilities were measured in regions of interest, and age-related thresholds were used to determine high-iron content region (RII) susceptibilities. Compared with healthy controls, hypertension had higher total WMH scores and regional scores (all p=.001) and higher susceptibilities using the RI or RII analysis (all p<.05). In healthy controls, there was no significant association between susceptibilities and WMH scores. In hypertension, the susceptibilities of deep gray matters were positively correlated with WMH scores (RI analysis: right putamen; RII analysis: bilateral caudate nucleus head, putamen, red nucleus, substantia nigra, and dentate nucleus; age and education corrected p<.05). These findings suggest that iron deposition in deep gray matters was positively associated with WMH in hypertension, especially using the RII analysis.