Gray Iron Research Articles

Numerical Optimization and Performance Study of Ni-Based Coatings on Gray Cast Iron Surface by High-Speed Laser Cladding Based on Orthogonal Test

Numerical Optimization and Performance Study of Ni-Based Coatings on Gray Cast Iron Surface by High-Speed Laser Cladding Based on Orthogonal Test

Structural and Tribological Analysis of Brake Disc–Pad Pair Material for Cars

The study of the tribological behavior of the braking system in auto vehicles requires knowing the characteristics of the material in contact and, in the work process, the friction pair brake disc pads. Material structural analysis is necessary because the wear process depends both on the friction-pair chemical composition (brake disc pads) and on the work process parameters (pressing force, rotational speed, traffic conditions, etc.). The material of the brake discs is generally the same, gray cast iron, and the brake pads can be semimetallic (particles of steel, copper, brass, and graphite, all united with a special resin), organic materials (particles of rubber, glass, and Kevlar, all joined with the help of a resin), composite materials that contain different constituents, and ceramic materials (rarely have small copper particles). Therefore, the purpose of this paper is to analyze the crystalline structure, tribological behavior (at friction and wear), and the mechanical properties of the materials of the brake disc–pad friction pair specific to the field through study and analysis.

Relationships Between Macrostructure and Microstructure in Lamellar Graphite Iron Castings

AbstractSpherical sheet steel molds filled with gray iron melts of varying chemical compositions and metallurgical conditions were air-cooled until solid, followed directly by austempering to preserve the austenite grain structure. The castings were studied using a combination of cooling curves and quantitative metallography, in order to clarify control of the austenite grain structure and its impact on the local microstructure. A novel method utilizing fast Fourier transform provided visual overview of macroscopic trends in the scale of the flake graphite structure. Castings inoculated with Sr-containing ferrosilicon featured finer eutectic cell structure but coarser equiaxed structure of austenite, emphasizing that melt treatments applied to control the graphite structure may have unintended effects on the austenite grain structure. In most non-inoculated castings, the microstructure was banded, with alternating layers of coarse and fine flake graphite with distance from the casting surface. The extent of the columnar zone of austenite grains showed no correlation with the graphite structure nor the volume fraction of dendrites. The volume-to-surface ratio of dendrites was more uniform in the columnar zone, but increased toward the center in the equiaxed zone. The casting with the highest carbon equivalent (4.34), featured zones containing finer dendrites and graphite. These zones appear to be gaps in the early solidification structure which filled later by secondary dendritic growth from surrounding austenite. This highlights that high carbon equivalent may lead to poor dendrite coherency which can make the microstructure less uniform and less predictable.

Failure Analysis of Cast Iron Housing Unit of Ucf-216 Ball Bearing Used in a Fully Automatic Concrete Building Block Machine

One of the most common problems faced by briquette machine users in the industry is the failure of the cast iron housing unit of the UCF-216 bearings, to which the main shaft of the briquette machine is attached. In this study, the failure mechanism of a cast iron housing unit of a UCF-216 bearing broken during operation in a briquette machine was analysed in order to develop a solution to the problem. Failure was occurring in the bolt hole areas of the housing unit. First of all, spectral analysis was performed and it was determined that the housing unit was grey cast iron. Then, the macrostructures of both unused and damaged housing units were examined. Some casting defects were detected in the bolt hole areas of the unused housing unit. It was also learned that during the assembly of the UCF-216 to the briquette machine, no torque meter was used while the bolts were tightened. In order to understand the effect of possible overtightening of the bolts, the system was modelled as a 3D solid. This model was exported to the finite element software and different bolt pretensions were applied considering the stresses created by the bolt tightening forces on the housing unit. As a result, it was understood that if the ratio of the stress caused by the axial bolt tightening force in the UCF-216 bearing unit to the yield stress of the UCF-216 housing unit is above 50%, fatigue failure will occur.

Experimental Investigation on Diamond Band Saw Processing of Resin Mineral Composites.

Resin mineral composite (RMC) is a new material with several times the damping properties of gray cast iron and great corrosion resistance. Due to its overall brittleness, sawing with a diamond band saw would be a suitable method. In this research, sawing experiments are carried out to study the sawing force characteristics of the material and its surface morphology during the processing. The results show that the feed force level is in the range of 3.5~5.5 N and the tangential force level is relatively low. The distribution of resin mineral components does not have a significant impact on the average sawing force but increases the fluctuation of the lateral force signal. The maximum fluctuation volume is 94.86% higher than other areas. Uneven lateral force, generated when diamond particles pass through the resin-mineral interface, is one of the causes of fluctuations. The machined surface of RMC has uniform strip scratches and a small number of pits. Maintaining a constant ratio of sawing speed to feed speed can result in approximately the same machined surface. A step structure with a height of about 10 μm appears at the interface of resin minerals. As a processing defect, it may affect the performance of RMC components in some aspects, which need a further precision machining processing.

Friction and self-repairing behaviour of magnesium silicate hydroxide-MoS2 lubricant additives on gray cast iron with Cr-coated steel ball friction pairs

To improve the tribological performance of piston ring assemblies, this work studies the friction and self-repair behavior of magnesium silicate hydroxide(MSH)/MoS2 nanoparticles as PAO6 lubricant additives, whose friction condition is simulated piston ring-cylinder liner operating condition using a friction pair composed of chrome-plated steel balls and gray cast iron. By studying the effect of different concentrations on the friction reduction and anti-wear properties, it was found that the addition of MSH/MoS2 nano-powder to PAO6 could all play a role in the friction reduction and anti-wear effect, with the best friction reduction effect at 0.5 wt% addition. The self-repairing behavior of the lubrications with 0.5 wt% MSH/MoS2 nanopowders was found on grey cast iron specimens after 8 h of friction experiment.

Friction, wear, and corrosion behavior of nitrocarburized HT250 gray cast iron

This study employed friction and wear experiments on nitrocarburized HT250 gray cast iron, utilizing GCr15 cemented carbide balls as the friction pair, to investigate the friction behavior and wear mechanism of the compound layer, diffusion layer, and matrix. The findings indicate that the diffusion layer exhibits the highest wear resistance, followed by the compound layer, while the matrix shows the lowest wear resistance. At lower loads, the wear form of the compound layer is characterized by minor flaking wear, the diffusion layer exhibits minor flaking and abrasive wear, and the matrix displays minor adhesive wear accompanied by abrasive wear. With increasing loads, the wear form of the compound layer transitions to flaking and abrasive wear, the diffusion layer shows fatigue flaking wear, and the matrix demonstrates severe adhesive wear, fatigue flaking wear, and abrasive wear. Electrochemical impedance spectroscopy and potentiodynamic polarization were employed to study the corrosion behavior of the compound layer, diffusion layer, and matrix in a 3.5 wt% NaCl solution. The results indicate a 27.7 % decrease in the corrosion current density of the compound layer compared to the matrix, with the diffusion layer exhibiting a corrosion current density two orders of magnitude lower than both the matrix and compound layer. In electrochemical impedance spectroscopy, the diffusion layer shows the highest impedance modulus, largest phase angle amplitude, and circular arc radius. It shows that the corrosion resistance of HT250 gray cast iron is improved after nitrocarburizing, especially the diffusion layer.

Study on friction and wear behavior of gray cast iron with different carbon content at different temperatures

In this paper, we study the friction and wear properties of gray cast iron with different carbon contents at various ambient temperatures. We also examine the failure forms of gray cast iron friction and wear. The research concludes that under low-temperature wear conditions, the graphite in the gray cast iron structure can enter into the interface between the friction pair, have a lubricating effect on the wear surface, and reduce the friction coefficient and wear loss of the gray cast iron material. As the graphite content in the gray cast iron structure increases, its lubrication and protection effects enhance. Consequently, the primary cause of wear failure in gray cast iron is fatigue peeling induced by plastic deformation. Under high-temperature wear conditions, an oxide layer gradually forms on the wear surface. As the experimental temperature increases, the thickness of the oxide layer on the wear surface also increases. When the oxide layer formed on the wear surface reaches a certain level of thickness, the internal expansion stress of the oxide layer increases considerably, causing the oxide layer to peel off and increase the roughness of the wear surface, friction coefficient, and wear loss. Additionally, an increase in the graphite content in the gray cast iron structure makes the surface more prone to oxidation. This leads to increased friction coefficient and wear loss, with the wear failure of gray cast iron primarily caused by the peeling of the oxidation layer.

The Effect of Nodular Graphite on Hardness and Toughness in Permanent Molds Made of Ferro Casting Ductile

The permanent mold was made of Ferro Casting Ductile as a result of sand casting. Permanent mold is mold that can be used repeatedly. This permanent mold is used to produce tensile test specimens. Tensile test specimens are made of gray cast iron. This study aims to determine and analyze the effect of spheroidal graphite on the hardness and toughness of Ferro Casting Ductile in permanent molds to make tensile test specimens. The casting process starts by making patterns using Styrofoam, making molds with green-sand sand molds, followed by pouring molten cast iron into the molds. The next process is dismantling the castings and machining to get a permanent mold according to the dimensions. Specimens for testing the chemical composition were obtained from the results of castings into spherical dies. Meanwhile, the impact, hardness, and microstructure specimens were taken from the permanent molded product. The results of the chemical composition test showed that Ferro Casting Ductile contained several main elements, namely 92.14 %Fe, 3.681 %C, 3.715 %Si, 0.182 %Mn, 0.050 %Ni, and 0.034 %Mg which affected the percentage of nodular graphite. Nodular graphite will affect the hardness of the permanent mold. Validation was carried out by testing the hardness at 3 different points 167.70 VHN, 162.77 VHN, and 155.77 VHN. Toughness was obtained from the impact test using the Charpy method, the impact values were 0.048 Joule/mm2 0.046 Joule/mm2 0.037 Joule/mm2 on 3 different specimens. From the test results, the specimen has met the FCD 400 standard.

Effect of Regular Shot Peening and Semi-Random Shot Peening Conditions on Selected Properties of the Surface Layer of Gray Cast Iron

Effect of Regular Shot Peening and Semi-Random Shot Peening Conditions on Selected Properties of the Surface Layer of Gray Cast Iron

Numerical investigation of the thermal and acoustic effect of material variations on the exhaust muffler

Exhaust mufflers are used in automobiles to prevent the noise arising from exhaust gases resulting from internal combustion engines. With the advancement of the automotive industry, exhaust mufflers have become more complex over time to reduce noise and increase driving comfort. Within the scope of this study, exhaust muffler geometries with different geometries have been designed, and harmonic acoustic analyses have been carried out. In the analysis, the airflow speed has been accepted as 30 m/s. Acoustic pressure and transmission loss data obtained because of analyses performed with 1Pa pressure input have been evaluated. As a result of the evaluations, it has been concluded that the muffler modeled in a complex structure has been better acoustically. Although the main task of exhaust muffler is to reduce the sound level at the exit of exhaust gases, it is also important to reduce the temperature of the air in the exhaust system and have good thermal conductivity so as not to jeopardize the thermal safety of the system. For this reason, CFD thermal flow analysis has been carried out with 4 different materials using a complex design with high acoustic efficiency. Gray cast iron, stainless steel, 1020 steel, and aluminum have been used as materials. In this part of the study, it has been determined that the use of aluminum material has been better in terms of thermal efficiency.

Study of the effect of overlap rate on the failure form, microstructure and wear resistance of multilayer laser cladding on grey cast iron surfaces

Laser cladding is less used in the repair of cast iron parts. In this paper, multiple layers of austenitic stainless steel powders with different overlap rates were laser clad by the process of adding a transition layer to explore the feasibility of multilayer cladding of grey cast iron. The study results show that the higher cladding layers tends to cause cracking and warping of substrate, and the increased overlap rate of the Ni transition layer can effectively inhibit these failures. The wear mass of Fe-based coatings with 33.3%∼66.7% overlap was 1.00–2.68 mg. After wear, the Fe2p and Ni2p potentials were shifted, the intensity of the O1s characteristic peaks increased, and the wear oxidation increased wear quality loss.

Control of Graphite Structure in High Phosphorus Grey Cast Iron Brake Shoes through Ferro-Silicon Inoculant

Control of Graphite Structure in High Phosphorus Grey Cast Iron Brake Shoes through Ferro-Silicon Inoculant

Исследование влияния комбинированного модификатора из отходов кремниевого производства на свойства серых чугунов

Introduction. During the metallurgical production of silicon, waste is generated that accumulates in dumps, causing harm to the environment. Disposal and recycling of solid waste from silicon production is especially important because They contain important chemical compounds (silicon dioxide, silicon carbide, carbon nanotubes) that can be used in other industries, which will bring greater economic value. Considering the possibilities for extracting these useful components from silicon production waste, it is necessary to bring processing technologies to the stage of widespread practical application. Therefore, the development of a special waste processing technology to obtain a useful product in the form of a composition of silicon dioxide and silicon carbide remains an urgent problem. Purpose of the work: to study the formation of the morphological form of graphite with the introduction of nano-modifiers from silicon production waste. The work examined samples of gray cast iron after modification with a combined modifier obtained from silicon production waste. The research methods are mechanical tests for statistical tension, analysis of the chemical composition and metallographic studies. Results and discussion. It was revealed that the mechanical properties of gray cast iron increased by 30-50% after modification with a combined modifier, compared with witness samples. The morphology of graphite is an important parameter affecting the properties of cast iron. It has been established that during the modification process the morphology of graphite changes from lamellar to vermicular. Specimens of gray cast iron with vermicular form of graphite have high strength values compared to specimens of gray cast iron with lamellar form of graphite. The presented results confirm the promise of the developed approach aimed at obtaining new classes of modifiers and products made of gray cast iron with a high range of mechanical properties.

A novel approach of composite turning for compacted graphite iron using minimum quantity lubrication and liquid nitrogen jetting by a developed setup

Compacted graphite iron (CGI) has high mechanical strength, and low thermal conductivity and content of sulfur, becoming a difficult-to-machine material. The tool life for machining grey cast iron (GCI) is 10–20 times of that of CGI, which greatly affecting the mass production in engine industry. To overcome this challenge, the influence of different spray positions on cooling and lubrication efficiency is analyzed based on the boundary layer theory, and a novel approach of composite turning with MQL lubricating flank face and liquid nitrogen (LN2) jetting cooling rake face is proposed. In virtue of boundary layer theory, negative graded pressure forms during the movement between the workpiece and cutter, resulting in that the MQL oil flows quickly to the contact area on flank face, which improves the lubrication effect. LN2 jetting is employed to cool rake face, effectively avoiding the accumulation of cutting heat on the tool and workpiece. The effects of four different cooling methods, including cutting fluid, MQL, LN2, and MQL + LN2, on the surface roughness, tool wear, and cutting force of cutting CGI and grey cast iron (GCI) were studied. According to the failure criterion of a cutting tool for the wear length of 200 μm on a flank face, the cutter life of cutting length is 2886 and 3884 m, correspondingly by cutting fluid and MQL + LN2, and the cutter life is increased by 34.6 %. In addition, the cutting force during turning CGI is 75.1 and 61.8 N by cutting fluid and MQL + LN2, respectively, and the cutting force is decreased by 17.7 %. The developed setup and findings provide a new turning method to cut a difficult-to-machine material for the use in mass production of the engine industry.

Performance and Surface Modification of Cast Iron Corrosion Products by a Green Rust Converter (Mimosa tenuiflora Extract)

One of the alternative materials used for conducting conservation treatment of iron artifacts is the rust converter, since it generates barrier properties and more stable oxides. The protective properties and surface modifications from using Mimosa tenuiflora extract as a green rust converter on a gray iron oxide layer were studied. The surface characterization was carried out using a Scanning Electron Microscope coupled to an energy-dispersive X-ray spectrometer (SEM-EDS), along with infrared spectroscopy (IR), Raman spectroscopy, X-ray Diffraction (XRD), and Water Contact Angle (WCA). Electrochemical characterization was performed with an Electrochemical Impedance Spectroscope (EIS) using 3.5 wt.% NaCl as the electrolyte. According to the results of the Raman spectroscopy and XRD, the layer of corrosion products formed after 90 days in the atmosphere was composed of goethite, lepidocrocite, maghemite, hematite, and magnetite. The surface of the corrosion products was transformed with the rust converter into an amorphous and microcracked layer. By IR, the Fe-O and C-O-Fe bonds associated with the iron chelate were found with absorption bands at 1540 and 1567 cm−1, respectively. By XRD, a modification of the magnetite crystallinity was observed. Finally, the Water Contact Angle and the protective capacity of the corrosion products were improved by the presence of the rust converter.

PENGARUH PENAMBAHAN PROSES INOKULASI TERHADAP STRUKTUR MIKRO DAN KEKERASAN PRODUK COR DENGAN MATERIAL FC 250

The inoculation process in metal casting is needed to make grey cast iron or nodular cast iron. Inoculation aims to increase the number of freezing nuclei and promotes the formation of a homogeneous microstructure. This research aims to determine the effect of the inoculation addition process on the microstructure and hardness of PP products with FC-250 material. The changes made include changes to the inoculation process and changes to the chemical composition of the induction furnace. Changes in the inoculation process include changing the inoculation process which was initially only carried out on ladles with an inoculation material weight of 0.5 kg to 2 processes, namely on ladles with an additional weight of 0.8 kg of inoculation material and an inoculation process on crucible (kowi) with an additional material weight of 0.4 kg. The results of the metallography test after the additional inoculation process showed that the pearlite and ferrite graphite spread evenly and fell into Type-A graphite. The hardness test results show that the effect of adding inoculation changes the level of hardness so that it complies with ASTM 40 specifications/standards, namely 180 – 302 HB. The hardness value after the addition of the inoculation process was 190 HB.

Examining the role of rare earth elements on grey iron’s microstructural and mechanical properties

ABSTRACT Grey cast iron, prized for its durability and thermal performance in applications like engine cylinder liners, sees widespread use in defence, engineering, and transportation. Investigating the impact of rare earth elements on its properties, a mix of lanthanum and cerium was introduced. These elements act as nucleating and graphitising agents, refining graphite microstructure and adjusting pearlite layer spacing. Results showed a notable improvement in Brinell hardness (453 HB, a 79% increase with 0.6 wt.% rare earth), compressive strength (2209 MPa), and tensile strength (501 MPa at 0.4 wt.% rare earth). However, excessive rare earth inclusion can have detrimental effects. The study underscores the potential to enhance greyggrey cast iron’s microstructure and mechanical properties through judicious rare earth additions.

Enhanced Surface Antibacterial Properties of Gray Cast Iron by Aging Precipitation of Cu Phase

Enhanced Surface Antibacterial Properties of Gray Cast Iron by Aging Precipitation of Cu Phase

The effect of solid lubricants in the brake friction composite on brake emissions: A case study with graphite, Sb2S3, and MoS2

Particulate matter produced during brake application was investigated, focusing on the effect of the solid lubricants in the brake friction composite, such as graphite, antimony trisulfide, and molybdenum disulfide. Results showed that the brake emission was significantly affected by the solid lubricant type and braking temperatures. Antimony trisulfide caused high brake emissions at moderate temperatures, whereas graphite produced high emissions at elevated temperatures. The brake emission at moderate temperatures was affected by the aggressiveness of the composites and the presence of friction films on the gray iron disc surface. In contrast, the brake emissions at elevated temperatures were determined by the thermal decomposition of the composite and the oxidation of solid lubricants.