Gray Iron Research Articles

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.

The Influence of Filling System Design on Quality Performance in Gray Iron

Significant evidence now supports the quality improvement seen in castings that employ naturally pressurized filling systems in their production. However, despite the documented evidence for improvement, these systems have not become ubiquitous. Gray iron, the industry’s most prominent alloy, has been particularly slow to accept the shift in system design. The suggested tolerability of gray iron to turbulence, the market’s price sensitivity, and the perceived economics of naturally pressurized systems are potential factors that have hindered adoption. However, if, through improved quality, the economic justification for these systems can be made in this adverse setting, there is a merit in their application to all alloys and processes. A sample gray iron part, currently being produced in a foundry environment with known porosity issues, was selected, to which a new system and several basin designs were applied. A mixed method analysis of casting simulations, production trials, and economic and environmental modeling was used to evaluate system performance. The results show a strong association between filling system design and sub-surface porosity. However, no association was found between basin design and porosity occurrence at lower porosity levels. Nevertheless, the economic and environmental modeling highlights that quality-orientated systems yield significant financial and environmental savings for the organization due to reduced scrap levels. These findings imply that quality-orientated system designs should be employed even when cost is the most critical measure.

Effects of Heat Treatment on Microstructures and Mechanical Properties of a Low-Alloy Cylinder Liner.

Cylinder liners, considered a crucial component of internal combustion (IC) engines, often require excellent mechanical properties to ensure optimal engine performance under elevated temperatures, pressures, and varying loads. In this work, a new low-alloy cylinder liner, incorporating a low content of molybdenum, copper, and chromium into gray cast iron, was fabricated using a centrifugal casting process. Subsequently, the heat treatment processes were designed to achieve bainite microstructures in the cylinder liner through rapid air cooling, isothermal transformation, and tempering. The effects of different air-cooling rates and tempering temperatures on the microstructure evolution and mechanical properties of cylinder liner were investigated. The results revealed that during the supercooled austenite transformation process, rapid air cooling at a rate of 14.5-23.3 °C/s can effectively bypass the formation of pearlitic structures and directly induce the formation of bainite structures. Once the temperature exceeded 480-520 °C, hardness and tensile strength increased with the temperature increase owing to the enhancement of the lower bainite content, the reduction of residual austenite, and the precipitation of the fine hard carbides in the matrix. With temperatures above 520-550 °C, the carbide and lower bainite organization coarsened, thereby reducing the hardness and tensile strength of the material. Therefore, the optimal heat treatment parameters were rapid cooling at 14.5-23.3 °C/s rate to obtain bainite, and tempering of 480-520 °C for finer and more uniform bainite. In addition, the results of the characterization of the mechanical properties of the cylinder liner after heat treatment showed that the hardness, tensile strength, and wear resistance were improved with the refinement of the bainite.

Analysing Bevel Gears for Efficient Power Transmission: A Study on Design, Simulation and Performance Assessment

Bevel gears find application in transmitting motion between unequally aligned shafts, typically forming a 90° angle relative to each other. Some of the several types that are available commercially are the straight bevel, the Zerol bevel, the spiral bevel, and the hypoid. Stainless steel, gray cast iron, titanium alloy and structural steel were used for the behavioural assessment. The design and modelling of the straight bevel gears were carried out using SolidWorks 2015, while ANSYS 18.2 was employed simulating to simulate the gears' stress and deformation. The 3D solid model generated using SolidWorks was imported into ANSYS, where the analysis was conducted using the finite element software, ANSYS Workbench. Stress distribution plot, deformation plot, and equivalent strain plot were generated. The highest stress, measuring 73.536 MPa, became evident as the load concentrated near the base of the gear teeth. The finite element analysis revealed a minimal likelihood of gear failure, and the least deformation was observed in the structural steel configuration, resulting in a deformation of 8.2354 x 10^-3 mm. Consequently, the gear pair can successfully transmit 6 kW of power without experiencing any failures with a good safety factor

ПРОГНОЗИРОВАНИЕ ОТКАЗОВ ДЕТАЛЕЙ МЕТАЛЛУРГИЧЕСКОГО ОБОРУДОВАНИЯ ПО КРИТЕРИЯМ ПРОЧНОСТИ, ИЗГОТОВЛЕННЫХ ИЗ СЕРОГО ЧУГУНА, НА ОСНОВЕ МИКРОСТРУКТУРНОГО МОДЕЛИРОВАНИЯ НАПРЯЖЕННОГО СОСТОЯНИЯ

The article proposes a methodology for estimating the gamma-percent life of metallurgical equipment parts made of grey cast iron on the basis of micro structural modelling of its stress state, which is formulated using known relationships for estimating the average life of mechanical equipment parts by the criterion of kinetic strength, the linearisation method of random arguments allowing to estimate the variance of the function under study and tools of micro structural modelling of the stress state of the material. It allows at the stages of design and operation to take into account the all-round influence of loading conditions of the investigated technical object, its operating temperature, physical and mechanical characteristics of structural components of grey cast iron on gamma-percent resource. Its main distinctive features are mathematical dependences allowing estimating the value of dispersion of parameters necessary for calculation of resource characteristics, as well as the possibility of taking into account the anisotropy of the real structure of grey cast iron. In addition, the procedure of verification of the proposed methodology by comparing theoretically obtained values of gamma-percent resource with the value established in the normative and technical documentation is carried out. The spacer plate of SMD-110 jaw crusher, made of grey cast iron of GI-20 grade, is considered as an object of research physical and mechanical characteristics of its structural components, such as modulus of elasticity and Vickers micro hardness were experimentally evaluated using the method of instrumental indentation. The prediction error does not exceed 18%, which in turn confirms a sufficient level of reliability of the theoretical solutions proposed in this article, which can be used in the design of metallurgical equipment parts made of grey cast iron, as well as in the formation of the periodicity structure of its repairs.

ПРОГНОЗИРОВАНИЕ ОТКАЗОВ ДЕТАЛЕЙ МЕТАЛЛУРГИЧЕСКОГО ОБОРУДОВАНИЯ ПО КРИТЕРИЯМ ПРОЧНОСТИ, ИЗГОТОВЛЕННЫХ ИЗ СЕРОГО ЧУГУНА, НА ОСНОВЕ МИКРОСТРУКТУРНОГО МОДЕЛИРОВАНИЯ НАПРЯЖЕННОГО СОСТОЯНИЯ

The article proposes a methodology for estimating the gamma-percent life of metallurgical equipment parts made of grey cast iron on the basis of micro structural modelling of its stress state, which is formulated using known relationships for estimating the average life of mechanical equipment parts by the criterion of kinetic strength, the linearisation method of random arguments allowing to estimate the variance of the function under study and tools of micro structural modelling of the stress state of the material. It allows at the stages of design and operation to take into account the all-round influence of loading conditions of the investigated technical object, its operating temperature, physical and mechanical characteristics of structural components of grey cast iron on gamma-percent resource. Its main distinctive features are mathematical dependences allowing estimating the value of dispersion of parameters necessary for calculation of resource characteristics, as well as the possibility of taking into account the anisotropy of the real structure of grey cast iron. In addition, the procedure of verification of the proposed methodology by comparing theoretically obtained values of gamma-percent resource with the value established in the normative and technical documentation is carried out. The spacer plate of SMD-110 jaw crusher, made of grey cast iron of GI-20 grade, is considered as an object of research physical and mechanical characteristics of its structural components, such as modulus of elasticity and Vickers micro hardness were experimentally evaluated using the method of instrumental indentation. The prediction error does not exceed 18%, which in turn confirms a sufficient level of reliability of the theoretical solutions proposed in this article, which can be used in the design of metallurgical equipment parts made of grey cast iron, as well as in the formation of the periodicity structure of its repairs.

ANALYSIS OF CUTTING FLUID ON MASS LOSS OF CARBIDE INSERT IN THE MILLING PROCESS

The Machining process is manufacturing in the world industry that is widely used. The coolant in the machining process functions to lower the temperature and lubricate and clean the gram in the cutting process. The application of coolant in the cutting process is to maintain the quality of the workpiece during the cutting process and also serves to improve tool life so that the tool does not wear out easily. This study aims to determine the effect of a chemical-based coolant based on dromus oil and vegetable CPO on tool wear in the face milling process and to determine whether or not the liquid is effective in reducing and slowing down tool wear. In this research, the face milling process used a grey cast iron specimen as the workpiece specimen used and also used a carbide insert chisel cutting tool with the TPKN 22 VC2 type. The research was carried out by varying the engine speed and also the coolant variation, the engine speed variations used were 80, 360 and 720 Rpm. In the process of administering coolant using the method, it is sprayed directly onto the workpiece area which is cut continuously, in the milling process with a response variable that can be in the form of data or tool wear values that have been observed and tested using a microscope test tool, using the weight (mass) method to see the wear value. This research aims to see how effective the use of vegetable- based coolant (CPO) during experiments as a coolant in the machining process aims to ensure that the final value of tool insert wear must be smaller with (CPO) compared to chemical coolant (dromus).